Management of Enteroatmospheric Fistula with Negative Pressure Wound Therapy

Transcription

1 University of New Mexico UNM Digital Repository Doctor of Physical Therapy Capstones Health Sciences Center Student Scholarship Management of Enteroatmospheric Fistula with Negative Pressure Wound Therapy Wanli Lei University of New Mexico Follow this and additional works at: Recommended Citation Lei, Wanli. "Management of Enteroatmospheric Fistula with Negative Pressure Wound Therapy." (2015). This Capstone is brought to you for free and open access by the Health Sciences Center Student Scholarship at UNM Digital Repository. It has been accepted for inclusion in Doctor of Physical Therapy Capstones by an authorized administrator of UNM Digital Repository. For more information, please contact

2 Management of Enteroatmospheric Fistula with Negative Pressure Wound Therapy By: Wanli Lei Doctoral Candidate University of New Mexico School of Medicine Division of Physical Therapy Class of 2015 Advisor: Marybeth Barkocy, P.T., DPT, Assistant Professor Printed Name of Advisor: Signature: Date: Approved by the Division of Physical Therapy, School of Medicine, University of New Mexico in partial fulfillment of the requirements for the degree of Doctor of Physical Therapy. 1

3 ABSTRACT Background and Purpose: Enteroatmospheric fistula (EAF) is one severe complication of laparotomy. Negative pressure wound therapy (NPWT) has been successfully employed to manage numerous wounds, but probably contraindicated in an open abdomen (OA) wound due to its risks of increasing EAF incidence. This case report aims to explore the possibility of using NPWT to manage EAF in a patient with OA. Case Description: Mrs. A. was a 42 year old patient admitted to Lovelace Women s Hospital, Albuquerque, New Mexico, on 12/19/2014 for robot-assisted laparoscopic vaginal hysterectomy. On 12/22/2014, the patient underwent midline laparotomy for bowel resection, drainage of fecal peritonitis, cleanse of contaminated abdominal cavity and removal of abdominal wall mesh due to bowel perforation secondary to prior surgery. On 1/6/2015, the patient underwent the 3 rd surgery for bowel resection and drainage of abscess due to EAF formed through dehiscence of the prior anastomosis. Commercial NPWT kit V.A.C. (KCI, San Antonio, TX) was used by the physical therapist to manage the OA after the 2 nd and 3 rd surgery. The patient was discharged for home health on 1/16/2015 with a portable V.A.C system. Outcomes: The patient met the short term goals including development of healthy granulation tissues, shrinkage of the wound, and no occurrence of future complications. Discussion: Available evidences partially disapproved the caution of increasing EAF incidence by NPWT and supported advantages of NPWT in OA management, including decrease of mortality, increase of fascial closure, and healing of EAFs and enterocutaneous fistula (ECF) or transformation of EAFs to ECFs. With commercial NPWT system specifically designed for OA management, improvement of existing NPWT systems, and interdisciplinary cooperation, EAF, one of the severe complications of OA, could be controlled successfully. Keywords: enteroatmospheric fistula; negative pressure wound therapy; physical therapy. 2

4 Section 1: Background and Purpose Although minimally invasive surgical techniques such as laparoscopy have advantages of creating small trauma in treatment of abdominal or pelvic pathologies, laparotomy has to be employed as a salvage surgery under many emergent situations, including peritonitis (sepsis), trauma, and abdominal compartment syndrome 1,2. The mortality after laparotomy varies with different pathological backgrounds. Ineffective wound management contributes to the mortality as high as 60% 1. After laparotomy, compared with delayed fascial closure, early fascial closure significantly reduced mortality (12.3% versus 24.8%) 3. However, to avoid increase of intra-abdominal pressure (IAP) caused by visceral edema, delayed primary intention of fascia is the only choice and formed an OA requiring intensive multidisciplinary management 2,4. Many temporary abdominal closure (TAC) techniques have been developed to manage OA wounds, such as negative pressure wound therapy (NPWT, or vacuum assisted closure VAC), vacuum pack, dynamic retention sutures, Wittmann patch ( artificial burr ), plastic silo (Bogota bag), Mesh/sheet, skin approximation, zipper and loose packing 4,5. Of all the TACs, NPWT is the most widely used OA management technique due to its high fascial closure rates and low mortality. Commercial NPWT kits or home-made VAC systems developed by surgeons have been used clinically to manage OA wounds 5 ; however, there are few evidences to support usage of such system in OA management 1 ; on the other hand, such system has potential risks to increase incidence of OA complications such as EAF 6. Fistula is the abnormal connection between two epithelial surfaces. ECF is the connection between the mucosal surface of intestine and the abdominal skin. EAF is the opening of intestine wall that can discharge intestinal contents into the open abdominal cavity. As one of the severest complications of OA, about 75%~85% of EAFs were caused by abdominal surgery 7. Although ECF can be managed through ostomy or surgical repair, EAF can t be repaired directly by surgery but must be managed intensively to control bowel effluent. High bacterial load and digestive enzymes in the bowel effluent from EAFs can 3

5 cause septic infections spreading in neighboring viscera. Small EAFs can be sealed by biological dressings such as human acellular dermal matrix and fibrin glue; large EAFs can be managed by NPWT 2 or other TACs to divert the bowel effluent and transform to ECFs for future surgical repair. However, potential risks of facilitating fistula formation by negative pressure cautions clinicians about its use in OA management 8. About 2% to 18% of surgical patients in intensive care units have had emergent laparotomy 1. Several patients admitted to Lovelace Women s Hospital underwent laparotomy due to different abdominal or pelvic pathologies. We have used commercial NPWT system V.A.C. (KCI, San Antonio, Texas) to manage the OA wound. One of the patients, a middle aged super morbidly obese female, developed EAF and had to undergo 2 successive bowel resections in 2 weeks. Although the EAF was formed by dehiscence of bowel anastomosis in the 2 nd surgery, if V.A.C system facilitated formation of the EAF could not be excluded. Therefore, my PICO question is Can negative pressure wound therapy be used to manage enteroatmospheric fistula in middle-aged morbidly obese female patients? Section II: Case Description Introduction Mrs. A is a 42 year patient lives with 2 kids in 1 story house without steps. She was hospitalized to Lovelace Women s Hospital, Albuquerque NM for robot-assisted laparoscopic vaginal hysterectomy on 12/19/2014. She had history of midline laparotomy to repair umbilical hernia about one year ago. Extensive adhesiolysis and enterolysis were carried out with the hysterectomy because of severe abdominal adhesions formed after the previous surgery. On 12/22/2014, the patient underwent 1 st bowel resection due to small bowel perforation and peritonitis through midline laparotomy along the old incisions. V.A.C system from KCI, San Antonio, Texas was ordered to manage the OA wound by physical therapist. On 1/6/2015, the patient underwent 2 nd bowel resection due to EAF formed around the dehiscence of previous bowel 4

6 anastomosis. The physical therapist kept on managing the OA wound with V.A.C system until the patient was discharged for home health with a portable V.A.C. system on 1/16/2015, after being cleared by surgeons, physicians, physical therapist, and occupational therapist when the patient recovered to suitable functional levels without other complications identified. Her parents would take care of her. Examination Patient History: 42 year old Mrs. A was admitted to Lovelace Women s Hospital with medical diagnoses of uterine fibroid (ICD10 code: D25), menorrhagia (ICD10 code: N92.4), dysmenorrhea (ICD10 code: N94.6) and super morbid obesity (ICD10 code: E66.2) on 12/19/2014. She was scheduled for robot-assisted laparoscopic-assisted vaginal hysterectomy to remove the uterine fibroid on the same day. Laparotomy was considered twice during the surgery due to severe adhesion formed after previous repairment of umbilical hernia through midline laparotomy and super morbid obesity of the patient, but the surgeons decided to go ahead with the vaginal hysterectomy after extensive adhesiolysis and enterolysis. On 12/21/2014, the patient complained of abdominal pain and underwent detailed medical examinations, including CT scan, for potential bowel injury secondary to the surgery, but evidences were not enough to exclude or verify peritonitis. On 12/22/2014, the patient underwent emergent laparotomy due to significant abdominal pain, hypoxia and tachycardia. Small bowel resection was employed to repair perforation caused by the previous gynecological surgery. Since then, physical therapist had been using V.A.C system to manage the OA wound. During dressing change thereafter, green bowel effluent gushed out. On 1/6/2015, the patient underwent 2 nd bowel resection due to multiple intra-abdominal abscesses and EAF formed around the dehiscence of the previous bowel anastomosis. Social History The patient does not smoke, drink or use recreational drugs. Past Medical History Uterine fibroids, menorrhagia, dysmenorrhea and morbid obesity. 5

7 Past Surgical History Incisional ventral hernia repair done one year ago. Allergies No. Patient Goals Return home as soon as possible. Systems Review General: The patient is awake, alert, shakes her head yes or no appropriately to questions. Vital Signs: T-Max 39.5 and T current 38.4; pulse 101; BP 126/81; SaO2 95% on 2L of oxygen. HEENT: Pupils are equal and react to light. Sclera is clear. Oral mucosa is moist. ET is in place. Cardiovascular: Regular, although tachycardia. Lungs: Clear to auscultation bilaterally. Neurologic: Appropriate. Abdomen: Rounded secondary to adipose. Tender without peritoneal signs. Tests and Measures on re-ordered evaluation for physical therapy: Physical Assessment: 42 year old morbidly obese female patient previously independent with good family support and home accessibility. Pain caused by open abdomen wound decreased patient s mobility. She stated that she would like to be discharged to home as soon as possible. Patient History: as aforementioned. Orientation: orientedx4 (person, place, time, and situation) Vision: normal. ROM: normal. Strength: general weakness due to the surgery. Bed Mobility: min to mod left rolling; min to mod supine to sit; min to mod supine scoot. 6

8 Gait/Stair: not available. Sit to/from stand: max assistancex2 both. Activities Post Treatment: patient dangled and up in chair, call light within reach; and back to bed. Patient/Family Education: sterile wound care; body mechanics; safety precautions. Evaluation: Diagnosis: Open wound of abdominal wall with penetration into peritoneal cavity (ICD code 10: S31.6). Wound Management: Wound size: L 26cm; W 5cm; D 4cm. Wound appearance: clear, slough, moist. Wound margins: defined. Surrounding area: intact. Exudate amount: light. Exudate description: serous. Negative pressure wound therapy: 125 mmhg, continuous. Negative pressure wound therapy dressings: dry, intact. Black foam size: large. Black foam sponge count in: 1. Drainage in canister: serous. Wound intervention response: tolerated, improvement. Physical Therapy Practice Patterns: Integumentary Pattern E Impaired integumentary integrity associated with skin involvement extending into fascia, muscle, or bone and scar formation. Narrative Assessment: 42 year old morbidly obese female patient was hospitalized for robot-assisted vaginal hysterectomy. She underwent 1 st bowel resection through salvage laparotomy due to bowel peroration secondary to prior surgery, and 2 nd bowel resection due to EAF formed around the dehiscence 7

9 of the anastomosis. With NPWT, the open abdomen wound size decreased and functional mobilities of the patient improved. The patient had good family support, previous independent functions, and accessible home. She was motivated and participated in physical exercise. The patient will be discharged for home health with a portable V.A.C system. Problem List: Open abdomen wound Pain Decreased ambulation ability Decreased transfer ability Decreased bed mobility Short Term Goals (2 weeks): STG1: The open abdomen wound will decrease 3 cm in any one of the three dimensions in 2 weeks with V.A.C. system. STG2: The patient will walk 20 feet with a forward wheel walker under minimal assistance on level ground to ambulate between bed and bathroom. STG3: The patient will get out of bed twice a day with minimal assistance of 1 in 2 weeks. Plan of Care: The physical therapist will check the wound daily to prevent infection and other complications. Patient will be trained on bed mobility twice per day, functional sit and stand transfer 5 times per day, and ambulation once per day. Assistance will be started at maximal of two and decreased according to patient s progress. The NPWT dressings will be changed every 3 days. Patient s parents who will take care of her were trained on wound care and sterile techniques. Interventions: Wound check 8

10 Dressing changes Bed mobility exercise Supine to sit, sit to supine exercise Sit to/from stand exercise Gait training Patient/family education: fall prevention, body mechanics, gait. Outcomes: Patient was discharged on 1/16/2015 after cleared by physician, PT and OT with a portable V.A.C. system (KCI, San Antonio, Texas). STGs were achieved as following: Wound length decreased 5cm and depth decreased 0.5cm in 2 weeks. Patient got out of bed with minimal assistance of 1 twice a day. Patient walked 25 feet after 2 weeks of training with a FWW with minimal assistance on level ground. Section III: Evidence Based Analysis Methodologies of Search: Multiple databases including PubMed, CINAHL, Cochrane, Google Scholar and PEDro were searched with key words negative pressure wound therapy or vacuum assisted closure and enteroatmospheric fistula or enterocutaneous fistula (detailed process see Fig1). Available articles were filtered out through inclusion and exclusion criteria, and qualified studies were further critically reviewed (detailed process see Fig1) 9

11 Fig.1. Flow chart of critical review of evidences for the PICO. Articles Analyzed: Except PEDro, all the other databases retrieved one or more studies matching the key words. Studies were further selected with inclusion and exclusion criteria (Fig. 1.). PubMed was the best to filter out studies not satisfying the inclusion criteria. Google Scholar was the worst for the search because there were no filters available. Only 82 out of 521 studies satisfied the inclusion criteria, and most of them were covered by the 31 papers from PubMed. However, 2 papers, including one systematic review, were retrieved from Google Scholar and were not covered by other databases, indicating it is still a good source for data mining. After repeated papers were excluded, full PDFs of 16 papers were retrieved and further reviewed. At last, nine studies which answered my PICO question, including 3 systematic reviews, 1 clinical trial, 3 case control studies and 2 case reports, were selected according to their evidence levels (Fig.1). Other 7 papers were cited for background about management of EAFs or ECFs. Full PDF files of the 9 studies answered my PICO questions were retrieved and critically reviewed. Evidence levels (Oxford Centre for Evidence-based Medicine Levels of Evidence, March 2009), purpose, 10

12 outcome measures and results of the 9 articles were listed in Table. 1. Full summaries and detailed intervention or systematic analyses were attached in Appendix A and B. Table 1. Critical review of 9 studies. No Study Evidence Level Purpose Outcome Measures Results 1 Gui D., et. al (2014) Vacuum- Assisted Wound Care (VAC ) for Enteric Fistula Closure: How We Do It. 4 Managing fistula effluent effectively through VAC system to help heal of enterocutaneous fistula (ECF) and enteroatmospheric fistula (EAF), or transform EAF to ECF through diversion Closure of ECF/EAF; Transformation of EAF to ECF; Duration of VAC usage; Time of ECF/EAF closure. 5 ECFs of 4 patients were closed; 1 EAF in one patient was closed; 3 EAFs in 3 patients were transformed to ECFs for future closure. 2 B. TK., et. al, (2008) Temporary Abdominal Closure Techniques: A Prospective Randomized Trial Comparing Polyglactin 910 Mesh and Vacuum- Assisted Closure 3 Atemma JJ., et. al., (2014) Systematic Review and Meta-analysis of the Open Abdomen and Temporary Abdominal Closure Techniques in Non-trauma Patients. 4 Bruhin A., et. al., (2014) Systematic review and evidence based recommendation s for the use of Negative Pressure Wound Therapy in the open abdomen. 1b 2a - 2a - of enteral effluent. Comparing 2 temporary abdominal closure (TAC) systems (Polyglactin 910 Mesh: MESH; and Vacuum assisted closure: VAC) in the management of open abdomen (OA) Systematic review about temporary abdominal closure treatment in the OA management of peritonitis patients. Develop evidence-based recommendations relevant to manage different grades of open abdomen (OA) according to the treatment goals, likelihood of complications, and treatment protocols. Delayed primary fascial closure rate; Fistula rate; Cost of the 2 treatment. Fascial closure rate; Fistula rate; Mortality. Fascial closure rate; Mortality; Similar fascial closure rate ((VAC 31% vs. MESH 26%); VAC has higher fistula rate (VAC 21% vs. MESH 5%); KCI VAC most expensive; MESH less expensive; tranditional VAC cheapest. NPWT was the most widely used TAC; Increase of fascial closure rate and decrease of fistula rate by NPWT system were required to be combined with other surgical treatments; Mortality changes with different TAC; NPWT has high but not the hightest mortality. commercial NPWT kits showed better fascial closure rate in nonseptic and septic patients than other variants without increasing fistula rates; mortality is related with specific abdominal pathologies; 11 clinical recommendations were defined. 5 Olona C., et. al., 3b Compare efficacy of Fascial closure rate; Compared with V.A.C. 11

13 (2014) Comparative study of open abdomen treatment: ABThera TM vs. abdominal dressing TM. 6 Ozer MT., et. al., (2014) A simple novel technique for enteroatmospher ic fistulae: silicone fistula plug. 7 Tavusbay C., et. al., (2014) Use of a vacuum-assisted closure system for the management of enteroatmospher ic fistulae. 8 Hutan JM., et. al., (2013) Use of intraabdominal VAC (Vacuum Assisted Closure) lowers mortality and morbidity in patients with open abdomen. 9 Stevens P. (2009) Vacuum-assisted closure of laparostomy wounds: a critical review of the literature. ABThera TM and V.A.C abdominal dressing TM in abdominal wall closure time, types of closure, and controlling complications such as fistula. 4 Treating an enteroatmospheric fistula (EAF) in a 73 year old patient after multiple surgeries during a short time frame with a suspended silicone fistula plug 4 Analyze the management of enteroatmospheric fistulae (EAF) in open abdomen (OA) patients with vacuum-assisted closure (VAC) therapy. 3b 2a - Compare management of open abdomen (OA) patients with Kern laparostomy and vacuum-assisted closure (VAC) in terms of mortality, abdominal wound closure types, and fistula healing. Systematically review available evidences for management of grade II or III abdominal wounds using the commercial vacuum assisted closure (VAC) Abdominal Dressing System. Fistula rate; Mean abdomen closure time Healing of the EAF. Type of EAFs according to bowel effluent volume; Fascial closure. Mortality; Fistula rate; Fascial closure rate. Retrospective study; Prospective study; Randomized clinical trial. abdominal dressing TM group, ABThera TM group showed a higher percentage of primary closures (41% vs. 11 %) in shorter time frame (17 vs. 26 days), and a lower fistula rate (4 % vs 20%). The patient recovered from the treatment without further bowel resection. Nonsurgical closure of the EAFs with VAC system was achieved in four patients; Enteral effluent in 6 patients was controlled and EAFs were transformed to enterocutaneous fistula (ECF) followed by surgical closure; No VAC-related complications were observed in this study Compared with KERN group, VAC group showed significant decrease in mortality, significantly higher closure rate of abdominal wall, and significantly higher possibility of successfully transforming EAFs to ECFs for future surgical closure. Prospective studies showed VAC abdominal dressing system could be employed to delay the fascial closure without increase the fistula rate; retrospective studies showed this system could decrease the re-open surgeries and shorten the 12

14 hospital stay; randomized trial showed this system improved the fascial closure rate. Discussion: Laparotomy has been employed widely as a salvage surgery in peritonitis (sepsis), trauma, and abdominal compartment syndrome. After laparotomy, the abdominal wall can only be closed by delayed primary intension under many situations and the OA wound needs to be managed through multidisciplinary cooperation. Many TAC strategies, including NPWT, have been developed to temporarily close the OA 4,5,9. NPWT has been successfully used to manage various kinds of wounds such as trauma, pressure ulcer and diabetic ulcer, but probably contraindicated for OA management due to its risk of increasing EAFs 6. Complications of OA managed by different TACs vary with different pathological backgrounds. Few high quality randomized clinical trials have been designed to compare outcome measures including mortality, fascial closure rates and fistula rates of different TACs in delayed abdominal wall closure, which resulted to contradictory conclusions. Bruhin et al recommended NPWT for both septic (peritonitis) and non-septic OA patients 9, while Atema et al didn t find enough evidences to recommend NPWT for peritonitis OA patients 5. Both systematic reviews failed to elucidate if NPWT increased EAF rates in OA patients or not. In the narrative systematic review, Stevens categorized available evidences into retrospective, prospective and randomized clinical trial (only one study available) groups and claimed that NPWT didn t increase incidence of EAFs 10 ; however, low level evidences and no meta-analysis compromised the reliability of the study. Benefits and risks of each TAC in OA management, especially related with the severe complication of EAFs, need further clarification. Bee et. al. designed a randomized clinical trial to compare management of OA with NPWT and MESH. Results showed that the NPWT group had much higher EAF rate (21% vs. 13

15 5%), although not statistically significant 11. Hutan et. al. found that compared with traditional KERN, the NPWT group patients showed much lower mortality (37.04% vs %) and increased fascial closure rate (88.89% vs %) in OA management, but the fistula rate was higher in the NPWT group (33.3% vs. 23.5%) 12. These studies indicated the NPWT did facilitate, and possibly cause, formation of EAFs. However, NPWT system successfully closed EAFs (11.1% vs. 0%) or diverted bowel effluent to avoid damage of viscera (66.7% vs. 0%) 12. This was the only study indicating no relationship of the outcome measures with BMI, gender and age. Obviously, benefits of NPWT outweigh its risks, so could be used in OA management. When combined with other wound care techniques, EAFs could be managed with NPWT more efficiently 13 : small size EAFs could be directly blocked with dressings; moderate size EAFs could be controlled by diverting bowel effluent; whereas the large size EAFs could be isolated to form an ostomy for effluent control. Through intensive interdisciplinary cooperation, including medical, surgical, nutritional and wound care, EAFs were successfully controlled in all 10 patients who survived from the OA with NPWT 13. In addition, clinicians could creatively custom-design strategies to manage the bowel effluent. Ozer et. al. tagged a silicone plug to an elastic band with sutures and pushed the plug across the fistula into the intestine. Small tension was created through hanging the elastic band under a foam bridge over the external abdominal wall. NPWT system was started 10 days after the EAF was entirely blocked by the silicone plug. After the EAF healed, the suture was cut and the silicone plug was excluded during defecation 14. In addition, with creative modifications, the traditional V.A.C. system could even be used to close EAFs and ECFs successfully or transform EAFs to ECFs for future surgical closure 15. The rough granulofoam was covered by a layer of smooth polyurethane drape which would contact the viscera, with superficial cut on the draping side and a deep cruciform cut on the other side of the foam, small draining tubes were pushed cross the foam and directly divert the bowel effluent by the NPWT system. Of course, considering the volume of the V.A.C canister, this strategy probably would only work for management of 14

16 low output (<200ml), but not suitable for moderate (between 200 and 500ml) and high output (>500ml daily bowel effluent) EAFs or ECFs. EAF can be further prevented with improved commercial V.A.C system. KCI developed specific ABThera system for OA management. In ABThera system, the granulofoam equally radiating to 6 directions is sandwiched by smooth polyurethane membrane with the viscera contacting surface fenestrated, which can distribute negative pressure equally in different directions. Compared with prior versions of V.A.C. abdominal dressing system, ABThera further decreased the EAF rate from 20% to 4%, which was statistically significant 16. Conclusion/Bottom Line: In OA management, traditional NPWT system, including commercial VAC kits, did show higher fistula rates, although not statistically significant. However, NPWT can reduce mortality, increase fascial closure, and manage bowel effluent from EAFs/ECFs or transform EAF to ECF. Its benefits outweigh its risks. In addition, the NPWT system should be further improved to reduce its risk of increasing EAF incidence clinically. The outcome measures of NPWT were not varied with BMI, gender and age. Therefore, NPWT can be used to manage EAF in middle aged morbidly obese female patients. Based on the evidences, the physical therapist, as one essential component in the multidisciplinary cooperation, can provide skilled and creative wound care with NPWT to manage EAFs. Acknowledgement: I would like to thank Marybeth Barkocy, PT, DPT, for her supervision and critical review of this manuscript. Thanks also given to my clinical instructor Kathy Brandt, PT, who managed the patient with V.A.C. system, and other colleagues in Lovelace Women s Hospital who provided help to finish this project. References: 1. Boele van Hensbroek P, Atema JJ, Herrle F, Dijkgraaf MG, Goslings JC. Negative pressure wound therapy for managing the open abdomen after midline laparotomy. In: The Cochrane Collaboration, ed. 15

17 Cochrane Database of Systematic Reviews. Chichester, UK: John Wiley & Sons, Ltd; Accessed February 14, Becker HP, Willms A, Schwab R. Small bowel fistulas and the open abdomen. Scand J Surg. 2007;96(4): Accessed February 14, Chen Y, Ye J, Song W, Chen J, Yuan Y, Ren J. Comparison of Outcomes between Early Fascial Closure and Delayed Abdominal Closure in Patients with Open Abdomen: A Systematic Review and Meta-Analysis. Gastroenterol Res Pract. 2014;2014:1-8. doi: /2014/ Boele van Hensbroek P, Wind J, Dijkgraaf MGW, Busch ORC, Carel Goslings J. Temporary Closure of the Open Abdomen: A Systematic Review on Delayed Primary Fascial Closure in Patients with an Open Abdomen. World J Surg. 2009;33(2): doi: /s Atema JJ, Gans SL, Boermeester MA. Systematic Review and Meta-analysis of the Open Abdomen and Temporary Abdominal Closure Techniques in Non-trauma Patients. World J Surg. 2014:1-14. doi: /s Rao M, Burke D, Finan PJ, Sagar PM. The use of vacuum-assisted closure of abdominal wounds: a word of caution. Colorectal Dis. 2007;9(3): doi: /j x. 7. Haack CI, Galloway JR, Srinivasan J. Enterocutaneous Fistulas: A Look at Causes and Management. Curr Surg Rep. 2014;2(10). doi: /s Davis KG, Johnson EK. Controversies in the Care of the Enterocutaneous Fistula. Surg Clin North Am. 2013;93(1): doi: /j.suc

18 9. Bruhin A, Ferreira F, Chariker M, Smith J, Runkel N. Systematic review and evidence based recommendations for the use of Negative Pressure Wound Therapy in the open abdomen. Int J Surg. 2014;12(10): doi: /j.ijsu Stevens P. Vacuum-assisted closure of laparostomy wounds: a critical review of the literature. Int Wound J. 2009;6(4): Accessed January 15, Bee TK, Croce MA, Magnotti LJ, et al. Temporary Abdominal Closure Techniques: A Prospective Randomized Trial Comparing Polyglactin 910 Mesh and Vacuum-Assisted Closure: J Trauma Inj Infect Crit Care. 2008;65(2): doi: /ta.0b013e31817fa Hutan JM, Hutan MS, Skultety J, et al. Use of intraabdominal VAC (Vacuum Assisted Closure) lowers mortality and morbidity in patients with open abdomen. Bratisl Med J. 2013;114(08): doi: /bll_2013_ Tavusbay C, Genc H, Cin N, et al. Use of a vacuum-assisted closure system for the management of enteroatmospheric fistulae. Surg Today doi: /s Ozer MT, Sinan H, Zeybek N, Peker Y. A simple novel technique for enteroatmospheric fistulae: silicone fistula plug. Int Wound J. 2014;11(s1): Accessed January 15, Gui D, Pepe G, Callari C, Persiani R, Di Giorgio A, Magalini S. Vacuum-Assisted Wound Care (VAC ) for Enteric Fistula Closure: How We Do It. World J Surg. 2014;38(12): Accessed January 15,

19 16. Olona C, Caro A, Duque E, et al. Comparative study of open abdomen treatment: ABThera TM vs. abdominal dressing TM. Hernia doi: /s

20 Appendix A Summaries of Studies 1. Gui D, Pepe G, Callari C, Persiani R, Di Giorgio A, Magalini S. Vacuum-Assisted Wound Care (VAC ) for Enteric Fistula Closure: How We Do It. World J Surg. 2014;38(12): Level of Evidence: 4 Purpose: managing fistula effluent effectively to help heal of enterocutaneous fistula (ECF) and enteroatmospheric fistula (EAF), or transform EAF to ECF through diversion of enteral effluent. Methods: 8 patients with ECFs or EAFs were treated with modified vacuum assisted closure (VAC) system: polyurethane draping was cut into small pieces, and central part of granufoam was cut in cruciform, small draining tubes contact with fistula and cross the draping and granufoam to divert enteral effluent to the VAC system directly. The negative pressure was between 50 and 75 mmhg. Results: of all the 8 patients, 5 ECFs of 4 patients were closed; 1 EAF in one patient was closed; 3 EAFs in 3 patients were transformed to ECFs for future closure. Critique/bottom line: EAFs and ECFs can t spontaneously heal and need intensive multi-disciplinary techniques for the management. In this case series, the authors provided modifications of the existing VAC system to manage EAFs and ECFs without requirement of extra surgical repair. Weakness of the study: case series with small sample size, all the EAFs and ECFs were under control probably by chance. Poor external validity. 19

21 2. Stevens P. Vacuum-assisted closure of laparostomy wounds: a critical review of the literature. Int Wound J. 2009; 6(4): Level of Evidence: 2a - Purpose: systematically review available evidences for management of grade II or III abdominal wounds using the commercial vacuum assisted closure (VAC) Abdominal Dressing System. Methods: articles in different databases were searched and selected with strict inclusion and exclusion criteria followed by critical review. Available evidences were stratified into prospective, retrospective and randomized trial categories. Results: prospective studies showed VAC abdominal dressing system could be employed to delay the fascial closure without increase the fistula rate; retrospective studies showed this system could decrease the re-open surgeries and shorten the hospital stay; randomized trial showed this system improved the fascial closure rate. Critique/bottom line: the commercial VAC abdominal dressing system can be used safely to manage open abdomen wound without causing fistula. Weakness of the study: narrative systematic review without meta-analysis. It s difficult to judge if the system significantly improves the management of OA and associated complications, such as fistula. 20

22 3. Hutan JM, Hutan MS, Skultety J, et al. Use of intraabdominal VAC (Vacuum Assisted Closure) lowers mortality and morbidity in patients with open abdomen. Bratisl Med J. 2013;114(08): doi: /bll_2013_094. Level of Evidence: 3b Purpose: comparing management of open abdomen (OA) patients with Kern laparostomy and vacuumassisted closure (VAC) in terms of mortality, abdominal wound closure types, and fistula healing. Methods: data of 17 OA patients underwent Kern laparostomy management from 2000 to 2006 were collected retrospectively (KERN group); data of 27 patients underwent vacuum assisted closure from 2007 to 2011 were collected prospectively (VAC group). Mortality, abdominal closure, enteroatmospheric fistula (EAF) rate, primary EAF closure rate and transformation of EAF to enterocutaneous fistula (ECF) were compared. Results: compared with KERN group, VAC group showed significant decrease in mortality, significantly higher closure rate of abdominal wall, and significantly higher possibility of successfully transforming EAFs to ECFs for future surgical closure. Critique/bottom line: the benefits of VAC system to decrease mortality and shorten abdominal closure time overdue its potential risk of causing fistula, not mentioning actually we can use VAC to manage EAFs successfully. Weakness of the study: half retrospective data, half prospective data, small sample size with high attritions. All resulted to low external validity of this study. 21

23 4. Tavusbay C, Genc H, Cin N, et al. Use of a vacuum-assisted closure system for the management of enteroatmospheric fistulae. Surg Today doi: /s Level of Evidence: 4 Purpose: analyzing the management of enteroatmospheric fistulae (EAF) in open abdomen (OA) patients with vacuum-assisted closure (VAC) therapy. Methods: 18 of 33 patients (ten male/eight female) undergoing OA management due to abdominal sepsis developed EAFs. VAC system was used to control and manage the complex abdominal wound and fistula effluent in all but one of these patients. Results: nonsurgical closure of the EAFs with VAC system was achieved in four patients. Enteral effluent in 6 patients was controlled and EAFs were transformed to enterocutaneous fistula (ECF) followed by surgical closure. No VAC-related complications were observed in this study. Critique/bottom line: EAF is a severe complication resulted from OA surgeries with high incidence. Management of EAF with negative pressure wound therapy (AKA: VAC) has been under debate due to its risks of increasing EAF rate. This study showed management of EAFs with NPWT system can heal the EAFs or transform EAFs to ECFs through diverting enteral effluent, which can be surgically closed afterwards. Weakness of the study: case series with small samples, 8 of 18 patients died during the treatment and were not analyzed. All limited external validity of this study. 22

24 5. Bee TK, Croce MA, Magnotti LJ, et al. Temporary Abdominal Closure Techniques: A Prospective Randomized Trial Comparing Polyglactin 910 Mesh and Vacuum-Assisted Closure. J Trauma Inj Infect Crit Care. 2008;65(2): doi: /ta.0b013e31817fa451. Level of Evidence: 1b Purpose: compare 2 temporary abdominal closure (TAC) systems (Polyglactin 910 Mesh: MESH; and Vacuum assisted closure: VAC) in the management of open abdomen (OA). Methods: Patients satisfied the inclusion criteria were prospectively randomized into MESH or VAC groups for OA management. In VAC group, dressing were changed every 3 days; in MESH group, mesh cinching and closure were assessed twice a day. Both groups underwent skin grafting when granulation tissue was evident, if delayed primary closure was not possible. Results: 31 and 20 patients were randomized into VAC and MESH group with equal distribution in different indications. Outcome measures were not statistically different between the 2 groups, including delayed primary fascial closure (VAC 31% vs. MESH 26%) and fistula rates (VAC 21% vs. MESH 5%). Critique/bottom line: Although many TAC systems are available for delayed fascial closure in OA management, insufficient evidences and potential risks of causing severe complications such as fistula cautioned usage of them. This study showed both VAC and MESH systems could be employed safely in OA management without increasing complications. Weakness of the study: small sample size and big attritions limited external validity of this study. 23

25 6. Atema JJ, Gans SL, Boermeester MA. Systematic Review and Meta-analysis of the Open Abdomen and Temporary Abdominal Closure Techniques in Non-trauma Patients. World J Surg. 2014:1-14. doi: /s Level of Evidence: 2a - Purpose: systematically review studies about management of open abdomen (OA) with temporary abdominal closure (TAC) in peritonitis patients. Methods: studies related with OA patients due to peritonitis were retrieved and systematically reviewed. Results: Overall quality of the studies was low. Negative pressure wound therapy (NPWT) was the most widely used TAC. Increase of fascial closure rate and decrease of fistula rate by NPWT system were required to be combined with other surgical treatments. Critique/bottom line: NPWT has been employed widely in wound care; however, open abdomen (OA) is one type of complicated wounds need multidisciplinary cooperation. Weakness of the study: low quality studies didn t provide enough data for the meta-analysis and only OA resulted from peritonitis was studied, which decreased both internal and external validity. 24

26 7. Bruhin A, Ferreira F, Chariker M, Smith J, Runkel N. Systematic review and evidence based recommendations for the use of Negative Pressure Wound Therapy in the open abdomen. Int J Surg. 2014;12(10): doi: /j.ijsu Level of Evidence: 2a - Purpose: develop evidence-based recommendations relevant to manage different grades of open abdomen (OA) according to the treatment goals, likelihood of complications, and treatment protocols. Methods: systematically review studies about efficacy of temporary abdominal closure (TAC) treatments including variants of negative pressure wound therapy (NPWT); then evidence-based recommendations were developed for management of different grades of OA. Results: in OA management, commercial NPWT kits showed better fascial closure rate in non-septic and septic patients than other variants without increasing fistula rates. Eleven evidence-based recommendations suitable for different stages and grades of OA management were developed. Critique/bottom line: although NPWT probably can t decrease the mortality which is more related with the medical conditions, it improves the fascial closure rate and will not cause fistula in management of OA. Weakness of the study: no RCT studies in management of OA available temporarily; low quality articles increase the bias of this systematic review and decreased its external validity. 25

27 8. Olona C, Caro A, Duque E, et al. Comparative study of open abdomen treatment: ABThera TM vs. abdominal dressing TM. Hernia doi: /s Level of Evidence: 3b Purpose: comparing efficacy of ABThera TM and V.A.C abdominal dressing TM in abdominal wall closure time, types of closure, and controlling complications such as fistula. Methods: Retrospective case control study was carried out to compare abdominal dressing TM group (46 patients) and ABThera TM group (27 patients) on the outcome measures including time required for abdominal closure and types of the closure, and fistula rates. Results: compared with V.A.C. abdominal dressing TM group, ABThera TM group showed a higher percentage of primary closures (41% vs. 11 %) in shorter time frame (17 vs. 26 days), and a lower fistula rate (4 % vs 20%). Critique/bottom line: risk of causing fistula in open abdomen (OA) patients with negative pressure wound therapy systems (NPWT) have been under cautions. This study shows that we can further decrease the risks and employ the benefits of commercial NPWT kits specifically designed to manage OA wound. Weakness of the study: retrospective case control study. Data of the 2 groups were collected in different time frames. These will affect the internal validity of this study. In addition, authors used wrong fistula rate (17% in abdominal dressing TM group) for the statistical analysis and failed to identify the statistically significant difference about fistula rates between the 2 groups. 26

28 9. Ozer MT, Sinan H, Zeybek N, Peker Y. A simple novel technique for enteroatmospheric fistulae: silicone fistula plug. Int Wound J. 2014;11(s1): Level of evidence: 4 Purpose: treating an enteroatmospheric fistula (EAF) in a 73 year old patient after multiple surgeries during a short time frame with a suspended silicone fistula plug. Methods: A silicone plug tagged with a piece of suture was place into the jejunum through the EAF opening. The small intestine was suspended through an elastic band tied to the suture under a foam bridge outside of the abdomen. After enteral effluent was controlled 10 days later, negative pressure wound therapy (NPWT) was used to manage the open abdomen with initial pressure at 50 mmhg and then gradually increased. Results: the EAF successfully closed 2 months after NPWT and the silicone plug was discharged with defecation. Critique/bottom line: Management of EAFs through bowel resection is not available for some patients due to shortened digestive tract after multiple abdominal surgeries. Silicone plug can seal the fistula and block the enteral effluent under suspension pressure; then NPWT can heal the wound in short time. This is a successful example of multi-disciplinary management of EAFs. Weakness of the study: a case report, this patient probably was lucky enough to recover. External validity is limited. 27

29 Appendix B Critical Analyses of Studies Name: Wanli Lei Systematic Review Evidence Appraisal Worksheet Citation (use AMA or APA format): Stevens P. Vacuum-assisted closure of laparostomy wounds: a critical review of the literature. Int Wound J. 2009;6(4): Level of Evidence (Oxford scale): 2a - Does the design follow the Cochrane method? Step 1 formulating the question Do the authors identify the focus of the review A clearly defined question should specify the types of: people (participants), interventions or exposures, outcomes that are of interest studies that are relevant to answering the question The author focused on the effectiveness of vacuum assisted closure system (mainly the V.A.C system of KCI company) in open abdomen wound management. Step 2 locating studies Should identify ALL relevant literature Did they include multiple databases? Was the search strategy defined and include: o Bibliographic databases used as well as hand searching o Terms (key words and index terms) o Citation searching: reference lists o Contact with experts to identify grey literature (body of materials that cannot be found easily through conventional channels such as publishers) o Sources for grey literature The author searched multiple databases, including EMBASE, OvidMEDLINE, AMED, GlobalHealth, British Nursing Index, PsycINFO, Health Management Information Consortium (HMIC), Meta- Press, the Cochrane Library, Google Scholar, PubMed, Scopus, Web of Science, Bandolier, Zetoc and the Centre for Reviews and Dissemination. Ongoing trials and non-indexed citations were retrieved through Medline Inprocess. Open abdomen OR laparostomy OR abdominal compartment syndrome AND VAC dressing OR VAC OR TNP were used as medical subject headings (MeSH) and as keywords. The author didn t retrieve relevant studies according to 28

30 Part 3:Critical Appraisal/Criteria for Inclusion Were criteria for selection specified? Did more than one author assess the relevance of each report Were decisions concerning relevance described; completed by non-experts, or both? Did the people assessing the relevance of studies know the names of the authors, institutions, journal of publication and results when they apply the inclusion criteria? Or is it blind? Part 3 Critically appraise for bias: Selection Were the groups in the study selected differently? Random? Concealed? Performance- Did the groups in the study receive different treatment? Was there blinding? Attrition Were the groups similar at the end of the study? Account for drop outs? Detection Did the study selectively report the results? Is there missing data? Part 4 Collection of the data Was a collection data form used and is it included? Are the studies coded and is the data coding easy to follow? Were studies identified that were excluded & did they give reasons why (i.e., which criteria they failed). bibliographies and didn t consult experts to identify grey literature. Inclusion criteria provided in the review: publications related with VAC dressings used in type II or III abdominal wounds. Only one author assessed the papers and decided relevance of papers. The author knew all the information related with retrieved papers, including author names, institutions, journals and results. Selection: The groups in the study were selected randomly through keywords search in different databases, but the author didn t conceal the information of each paper retrieved. Performance: groups in this study received different treatment. Only one of the groups was blinded. Attrition: the groups were different at the end of the study. The author didn t account the dropouts but over-reviewed the result from different types of studies. Detection: the study selectively reported the results of different groups, including retrospective, prospective, RCT and case series. All selected papers were covered in the study and no data missed. The author provided a narrative SR and didn t code RCT, prospective and retrospective studies; but he coded case series. One study contains both retrospective and prospective cohorts and resulted to the total number of studies retrieved to 12; however, the author only mentioned 6 in the abstract. The author didn t explain this and it was very confusing. The author provided exclusion criteria, including articles focusing on vacuum pack 29

31 and non-vacuum dressings; articles focusing on enterocutaneous fistulae (type IV wounds); editorials, letters, duplicated references and review articles (except systematic reviews and meta-analyses); individual case reports. Are the results of this SR valid? 1. Is this a SR of randomized trials? Did they limit this to high quality studies at the top of the hierarchies a. If not, what types of studies were included? b. What are the potential consequences of including these studies for this review s results? 2. Did this study follow the Cochrane methods selection process and did it identify all relevant trials? a. If not, what are the consequences for this review s results? 3. Do the methods describe the processes and tools used to assess the quality of individual studies? a. If not, what are the consequences for this review s results? 4. What was the quality of the individual studies included? Were the results consistent from study to study? Did the investigators provide details about the research validity or quality of the studies included in review? 5. Did the investigators address publication bias Are the valid results of this SR important? 6. Were the results homogenous from study to study? a. If not, what are the consequences for this review s results? 7. If the paper is a meta-analysis did they report the statistical results? Did they include a forest plat? What other This is not a SR of RCT. It summarized results from 1 RCT, 3 prospective cohorts, 2 retrospective cohorts, and 6 case series. Including the heterogeneous studies in this SR decreased the validity and generalizability of the review s results. No; but the author followed Crombie s model to critically review the papers. He identified available studies according to his inclusion and exclusion criteria. Yes. The author provided evidence levels and assigned levels to each study selected. But he used ESPEN guidelines, not a well-accepted evidence system. Even so, all the studies retrieved were not on the top of the hierarchies. The quality of the individual studies was very low. Results varied among the studies. The author included validity and quality of these studies in the review. Yes. He detailed bias of each study. No. This decreased validity and generalizability of this SR s results. This is a narrative SR, not a meta-analysis. Therefore, no statistical results, not forest pot, and not CIs. 30

32 statistics do they include? Are there CIs? 8. From the findings, is it apparent what the cumulative weight of the evidence is? From the findings, cumulative weight of the evidences is not apparent but confusing. Can you apply this valid, important evidence from this SR in caring for your patient/client? What is the external validity? 9. Is your patient different from those in this SR? 10. Is the treatment feasible in your setting? Do you have the facilities, skill set, time, 3 rd party coverage to provide this treatment? 11. Does the intervention fit within your patient/client s stated values or expectations? a. If not, what will you do now? Yes, my patient is different from those in this SR. Yes, the treatment is still feasible in my settings. We are using the V.A.C system from KCI to manage the OA and EAF of our patient. Yes. Our patient expected to return home as soon as possible. She agreed to use the VAC system to manage her OA and EAF. What is the bottom line? Summarize your findings and relate this back to clinical significance This is a low-evidence level SR. However, it s important to our treatment plan, because it showed the VAC system didn t increase the incidence of fistula significantly. We can use it to further help our patient. 31

33 Name: Wanli Lei Systematic Review Evidence Appraisal Worksheet Citation (use AMA or APA format): Atema JJ, Gans SL, Boermeester MA. Systematic Review and Meta-analysis of the Open Abdomen and Temporary Abdominal Closure Techniques in Non-trauma Patients. World J Surg. 2014:1-14. doi: /s Level of Evidence (Oxford scale): 2a - Does the design follow the Cochrane method? Step 1 formulating the question Do the authors identify the focus of the review A clearly defined question should specify the types of: people (participants), interventions or exposures, outcomes that are of interest studies that are relevant to answering the question The authors reviewed literature on the open abdomen (OA) and TAC (temporary abdominal closure) in peritonitis patients. They focused on analysis of indications and assessment of delayed fascial closure, enteroatmospheric fistula (EAF) and mortality, overall and per TAC technique. Totally, 74 studies describing 78 patient series, comprising 4,358 patients of which 3,461 (79 %) had peritonitis were further meta-analyzed. Step 2 locating studies Should identify ALL relevant literature Did they include multiple databases? Was the search strategy defined and include: o Bibliographic databases used as well as hand searching o Terms (key words and index terms) o Citation searching: reference lists o Contact with experts to identify grey literature (body of materials that cannot be found easily through conventional channels such as publishers) o Sources for grey literature The authors searched different databases, such as PubMed, EMBASE (Ovid), and Cochrane Central Register of Controlled Trials with key words open abdomen management and TAC. Abstracts retrieved and reviewed by 2 authors independently. Disagreement was discussed and agreed by both authors before retrieving all the papers published in different languages including English, German, Spanish and Dutch. The authors didn t contact experts to identify grey literatures. They did searched bibliographies of all included articles and relevant review papers manually for additional relevant articles. 32

34 Part 3:Critical Appraisal/Criteria for Inclusion Were criteria for selection specified? Did more than one author assess the relevance of each report Were decisions concerning relevance described; completed by non-experts, or both? Did the people assessing the relevance of studies know the names of the authors, institutions, journal of publication and results when they apply the inclusion criteria? Or is it blind? Part 3 Critically appraise for bias: Selection Were the groups in the study selected differently? Random? Concealed? Performance- Did the groups in the study receive different treatment? Was there blinding? Attrition Were the groups similar at the end of the study? Account for drop outs? Detection Did the study selectively report the results? Is there missing data? Part 4 Collection of the data Was a collection data form used and is it included? Are the studies coded and is the data coding easy to follow? Were studies identified that were excluded & did they give reasons why (i.e., which criteria they failed). The authors specified their inclusion criteria: studies with non-traumatic peritonitis patients with OA and TAC; studies with over half of the OA patients diagnosed with peritonitis, or the data concerning peritonitis patients could be retrieved separately; studies providing information about the applied TAC techniques and reported at least two of the three outcomes: delayed fascial closure rate, EAF rate, and mortality; at last, papers published in English, German, Spanish, or Dutch. All the papers reviewed by the 2 authors independently but they didn t blind the information of the selected papers, including author names, institutions, journals, and results. Selection: groups in the study were randomly selected according to the inclusion and exclusion criteria; but the groups were not concealed. Both authors know which groups they selected. Performance: groups in the study received different treatment; only one group was a randomized clinical trials. Even so, it s not blinded due to the obviously different treatment. Attrition: all the patients in the groups were hospitalized and must under one or other treatments; however, there did have attritions due to death of the patients during the treatment. Detection: the study didn t selectively report the results. Authors over-reviewed and analyzed all the data available. The authors provide data retrieval forms and coded each data. It s very easy to follow in the forms. In addition, the authors provided detailed exclusion criteria including duplicate; irrelevant; article types; case series less than 5 patients; nonperitonitis patients; less than 50% peritonitis patients and no separate data; no data on outcomes of interest; language; no full text available; pediatric series. 33

35 Are the results of this SR valid? 12. Is this a SR of randomized trials? Did they limit this to high quality studies at the top of the hierarchies a. If not, what types of studies were included? b. What are the potential consequences of including these studies for this review s results? 13. Did this study follow the Cochrane methods selection process and did it identify all relevant trials? a. If not, what are the consequences for this review s results? 14. Do the methods describe the processes and tools used to assess the quality of individual studies? a. If not, what are the consequences for this review s results? 15. What was the quality of the individual studies included? Were the results consistent from study to study? Did the investigators provide details about the research validity or quality of the studies included in review? 16. Did the investigators address publication bias Are the valid results of this SR important? 17. Were the results homogenous from study to study? a. If not, what are the consequences for this review s results? 18. If the paper is a meta-analysis did they report the statistical results? Did they include a forest plat? What other statistics do they include? Are there CIs? This is not a SR of randomized trials. Of the 74 studies, one is RCT, 19 prospective studies, 53 retrospective studies, and 1 non-specified study. The potential consequences of including so many non-rcts will decrease the validity and generalizability of the conclusion. This study didn t follow Cochrane methods selection process but followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline, which is accepted by Cochrane too. Therefore, the critical review process will not decrease the validity of the results. Yes, the authors used Jadad for randomized comparative studies, Newcastle Ottawa Scale (NOS) for non-randomized observational studies, to assess the quality of individual studies. Yes, the quality of individual studies was included. Due to only 1 RCT, which is Jadad score, all the others were NOS. Yes, the authors mentioned the bias probably had a profound effect on delayed fascial closure rates. The results are heterogeneous from study to study. This will affect both the internal and external validity of the review s results. It is a meta-analysis and the authors reported the statistical results, but they didn t include a forest plot. They assessed heterogeneity with the χ 2 and I 2 statistics. When p value less than 0.1 and I 2 above 75 %, it s significant. Review Manager 5.2 (The Cochrane Collaboration; Copenhagen, 34

36 19. From the findings, is it apparent what the cumulative weight of the evidence is? Denmark) was used for analysis. And the authors reported CIs. The findings didn t support an obvious conclusion. Can you apply this valid, important evidence from this SR in caring for your patient/client? What is the external validity? 20. Is your patient different from those in this SR? 21. Is the treatment feasible in your setting? Do you have the facilities, skill set, time, 3 rd party coverage to provide this treatment? 22. Does the intervention fit within your patient/client s stated values or expectations? b. If not, what will you do now? My patient belongs to one of the groups analyzed in this SR. She is an acute peritonitis patient secondary to traumatic (iatrogenic) injury (gynecological surgery). Yes, we have been using VAC to manage our patient s EAF. Yes, our patient expected to return home as soon as possible. She agreed to use the VAC system to manage her OA. What is the bottom line? Summarize your findings and relate this back to clinical significance Although the results of this SR are not highly reliable due to garbage in and garbage out problem. I did see the usually used VAC (aka. negative pressure wound therapy, NPWT) treatment increase incidence of EAFs in OA patients, although it s not statistically significant. To help my patient better, I need to consider using other wound management strategies or further improve the efficacy of available VAC system. 35

37 Name: Wanli Lei Systematic Review Evidence Appraisal Worksheet Citation (use AMA or APA format): Bruhin A, Ferreira F, Chariker M, Smith J, Runkel N. Systematic review and evidence based recommendations for the use of Negative Pressure Wound Therapy in the open abdomen. Int J Surg. 2014;12(10): doi: /j.ijsu Level of Evidence (Oxford scale): 2a - Does the design follow the Cochrane method? Step 1 formulating the question Do the authors identify the focus of the review A clearly defined question should specify the types of: people (participants), interventions or exposures, outcomes that are of interest studies that are relevant to answering the question Step 2 locating studies Should identify ALL relevant literature Did they include multiple databases? Was the search strategy defined and include: o Bibliographic databases used as well as hand searching o Terms (key words and index terms) o Citation searching: reference lists o Contact with experts to identify grey literature (body of materials that cannot be found easily through conventional The authors formed an expert panel and focus on the effectiveness of different temporary abdominal closure (TAC) treatments on open abdomen (OA) patients. They classified OA into different grades. Outcome measures include fascial closure rate, fistula rate, and mortality. Based on the critical review results, the expert panel provides clinical recommendations for open abdomen (OA) wound management. Among all the evidence supported treatments, negative pressure wound therapy is the top choice for OA management. The authors only searched PubMed, probably missed some relevant publications. They used key words for the search. Relevant papers missed in the search but identified in bibliographies of reference lists were retrieved. They contacted authors if they found missed data in the retrieved articles. The authors didn t contact experts to identify grey literature but consulted other experts for their opinions about their recommendations. 36

38 o channels such as publishers) Sources for grey literature Part 3:Critical Appraisal/Criteria for Inclusion Were criteria for selection specified? Did more than one author assess the relevance of each report Were decisions concerning relevance described; completed by non-experts, or both? Did the people assessing the relevance of studies know the names of the authors, institutions, journal of publication and results when they apply the inclusion criteria? Or is it blind? Part 3 Critically appraise for bias: Selection Were the groups in the study selected differently? Random? Concealed? Performance- Did the groups in the study receive different treatment? Was there blinding? Attrition Were the groups similar at the end of the study? Account for drop outs? Detection Did the study selectively report the results? Is there missing data? Part 4 Collection of the data Was a collection data form used and is it included? Are the studies coded and is the data coding easy to follow? Were studies identified that were excluded & did they give reasons why (i.e., which criteria they failed). The 5 authors critically reviewed all available relevant studies independently and discussed before reaching a consensus. The authors didn t conceal the information of the studies under review, including author names, institutions, journals and results. Selection: the groups in the study selected randomly. Performance: the groups in the study received different treatment. Most of them are cohort study or case series, not blinded. Attrition: the groups are different at the end of the study. No drop outs but still existed attritions due to death of the patients. Detection: The study didn t selectively report the results. The authors retrieved and analyzed all the data available. Therefore, no missing data. The authors used PRISMA 2009 checklist for their critical review, which was included in the supplemental data without listing details of each analysis. They did code each study according to their evidence level but didn t include in the study or supplemental data. The exclusion criteria include: duplicates; in vivo studies; pediatric; major technical modification; irrelevant clinical area; reviews/comments/letters; case studies with subjects less than 6; no relevant outcomes/not available; paper couldn t be retrieved. 37

39 Are the results of this SR valid? 23. Is this a SR of randomized trials? Did they limit this to high quality studies at the top of the hierarchies a. If not, what types of studies were included? b. What are the potential consequences of including these studies for this review s results? 24. Did this study follow the Cochrane methods selection process and did it identify all relevant trials? a. If not, what are the consequences for this review s results? 25. Do the methods describe the processes and tools used to assess the quality of individual studies? a. If not, what are the consequences for this review s results? 26. What was the quality of the individual studies included? Were the results consistent from study to study? Did the investigators provide details about the research validity or quality of the studies included in review? 27. Did the investigators address publication bias Are the valid results of this SR important? 28. Were the results homogenous from study to study? a. If not, what are the consequences for this review s results? 29. If the paper is a meta-analysis did they report the statistical results? Did they include a forest plat? What other statistics do they include? Are there CIs? 30. From the findings, is it apparent what the cumulative weight of the evidence is? This is not a SR of RCTs. It combines evidences from few RCTs but not related with OA management. Most of the evidences were from case reports and cohort studies. Even so, the evidences were still from available high quality studies. The potential consequences will decrease the validity of the results. This study didn t follow Cochrane but PRISMA methods. Because the authors only searched PubMed, they probably missed some relevant studies. Both will contribute to decrease of validity of this study. Yes. The authors used SIGN system to assign evidence level for each study. The quality of each study was comparatively low. The authors didn t provide details about validity or quality of the studies but discussed the reasons, which include the heterogeneity among the available studies. Yes. But they didn t provide details of which bias they were worrying about. The results were heterogeneous from study to study. But the authors classified the studies into different categories according to the OA grades and TAC treatments. In each subgroup, the results are comparatively homogenous. There were little meta-analyses and the authors reported the mortality, fistula rates and fascial closure rates. No forest plot, no other statistics and no CIs. Because the authors stratified the studies into 38

40 different subgroups, the cumulative weight of the evidences is apparent. Can you apply this valid, important evidence from this SR in caring for your patient/client? What is the external validity? 31. Is your patient different from those in this SR? 32. Is the treatment feasible in your setting? Do you have the facilities, skill set, time, 3 rd party coverage to provide this treatment? 33. Does the intervention fit within your patient/client s stated values or expectations? c. If not, what will you do now? No. My patient belongs to one of the subgroups. Yes. We have been using the NPWT on this patient. Yes. The patient agreed and liked the NPWT system from KCI. She was discharged to home with a portable NPWT system. What is the bottom line? Summarize your findings and relate this back to clinical significance OA has been employed widely for different abdominal pathologies. Its high mortality needs multidisciplinary cooperation. OA wound management is critical to decrease the mortality and related severe complications, including fascial retraction and fistula. There are many types of TAC to manage OA wound. This SR provided evidence that NPWT system is one of the top choices. It would not cause but successfully manage fistula in OA patients. 39

41 Name: Wanli Lei Intervention Evidence Appraisal Worksheet Citation (use AMA or APA format): Gui D, Pepe G, Callari C, Persiani R, Di Giorgio A, Magalini S. Vacuum-Assisted Wound Care (VAC ) for Enteric Fistula Closure: How We Do It. World J Surg. 2014;38(12): Level of Evidence (Oxford scale): 4 Is the purpose and background information sufficient? Study Purpose Stated clearly? Usually stated briefly in abstract and in greater detail in introduction. May be phrased as a question or hypothesis. A clear statement helps you determine if topic is important, relevant and of interest to you. Consider how the study can be applied to PT and/or your own situation. What is the purpose of this study? Literature Relevant background presented? A review of the literature should provide background for the study by synthesizing relevant information such as previous research and gaps in current knowledge, along with the clinical importance of the topic. Describe the justification of the need for this study This is a case series study. The authors didn t provide an abstract and didn t state the study purpose clearly. From the whole paper, the purpose of this study is to manage fistula drainage effectively to help heal of enterocutaneous fistula (ECF) and enteroatmospheric fistula (EAF), or transform EAF to ECF. The authors provided a little relevant background. ECF and EAF have the chances to heal only if the drainage gets managed successfully. The commercial V.A.C system has been used for fistula control, but need some modifications to improve its efficiency. Does the research design have strong internal validity? Discuss possible threats to internal validity in the research design. Include: Assignment Attrition This study is a case series, not a RCT. Assignment: 8 patients got the same treatment; no control; their EAFs or ECFs probably healed by chance. Threat to internal validity. 40

42 History Instrumentation Maturation Testing Compensatory Equalization of treatments Compensatory rivalry Statistical Regression Attrition: no patient dropout or death; no threat. History: EAFs or ECFs can t heal automatically without intensive care. No threat. Instrumentation: heal or transform of EAF to ECF measured objectively; no threat. Maturation: no automatic heal or transformation of the fistula; no threat. Testing: objective measurement, heal or transformation; no threat. Compensatory equalization of treatments: no control group; no threat. Compensatory rivalry: no control group; no threat. Statistical regression: no threat, heal or transformation, no outliers. Are the results of this therapeutic trial valid? 34. Did the investigators randomly assign subjects to treatment groups? a. If no, describe what was done b. What are the potential consequences of this assignment process for the study s results? 35. Did the investigators know who was being assigned to which group prior to the allocation? a. If they were not blind, what are the potential consequences of this knowledge for the study s results? 36. Were the groups similar at the start of the trial? Did they report the demographics of the study groups? a. If they were not similar what All patients got same treatment without control. They probably got better results by chance. This decreased generalizability of the studies. All patients in the same treatment, the investigators knew all of them, but this will not affect the objective measurement of the outcomes. Only one group. The authors reported demographics of the patients. This will not affect the validity of the study. 41

43 differences existed? b. Do you consider these differences a threat to the research validity? How might the differences between groups affect the results of the study? 37. Did the subjects know to which treatment group they were assign? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 38. Did the investigators know to which treatment group subjects were assigned? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 39. Were the groups managed equally, apart from the actual experimental treatment? a. If not, what are the potential consequences of this knowledge for the study s results? 40. Was the subject follow-up time sufficiently long to answer the question(s) posed by the research? a. If not, what are the potential consequences of this knowledge for the study s results? 41. Did all the subjects originally enrolled complete the study? a. If not how many subjects were lost? b. What, if anything, did the authors do about this attrition? c. What are the implications of the attrition and the way it was handled with respect to the study s findings? 42. Were all patients analyzed in the groups to which they were randomized (i.e. was there an intention to treat analysis)? a. If not, what did the authors do with the data from these subjects? b. If the data were excluded, what are the potential consequences for this study s results? Are the valid results of this RCT important? Only one group, but it will not affect the study s results. ECFs/EAFs will not heal spontaneously but need intensive inter-disciplinary cooperation. Yes. This will not affect the study s results, because healing of ECF and EAF or transformation of the EAF to ECF can be measured objectively. Only one group. As aforementioned, this will not affect the study s results. Yes. All the patients were followed to heal of ECF and EAF or transformation of EAF to ECF. Yes. All the 8 patients completed the study. No drop outs or death. Only one group. All the 8 patients were measured but don t need further analysis. 42

44 43. What were the statistical findings of this study? a. When appropriate use the calculation forms below to determine these values b. Include: tests of differences With p-values and CI c. Include effect size with p-values and CI d. Include ARR/ABI and RRR/RBI with p-values and CI e. Include NNT and CI f. Other stats should be included here This is a not a RCT but a case series study. No statistical analysis need to be carried out. 44. What is the meaning of these statistical findings for your patient/client s case? What does this mean to your practice? 45. Do these findings exceed a minimally important difference? Was this brought up or discussed? a. If the MCID was not met, will you still use this evidence? No statistical analysis needed. This study doesn t need minimally important differences or MCID, because the results are healing or not healing. Can you apply this valid, important evidence about an intervention in caring for your patient/client? What is the external validity? 46. Does this intervention sound appropriate for use (available, affordable) in your clinical setting? Do you have the facilities, skill set, time, 3 rd party coverage to provide this treatment? 47. Are the study subjects similar to your patient/ client? a. If not, how different? Can you use this intervention in spite of the differences? 48. Do the potential benefits outweigh the potential risks using this intervention with your patient/client? 49. Does the intervention fit within your patient/client s stated values or Yes. We have been using the V.A.C. system to manage our patient s fistula but failed. Once when we change the dressings, the green drainage erupted like a volcano. If we can identify the fistula in the early time and drain the bowel contents successfully at the beginning, the patient probably doesn t need the 2nd small bowel resection. Yes, one of the patient in the study share similar situation to our patient. Yes. The drainage of the small bowel caused abscess in abdominal cavity of our patient, and she had to get an acute open abdomen (OA) surgery. Yes. Our patient tried to return home as soon as possible. She agreed to accept the VAC system to 43

45 expectations? a. If not, what will you do now? manage her OA. 50. Are there any threats to external validity in this study? Yes. The sample size is too small and no controls. The 100% success rate probably resulted by chances. We can t predict if we can use this technique to manage our patient s EAF. What is the bottom line? PEDRO score (see scoring at end of form) Summarize your findings and relate this back to clinical significance Not a RCT; not suitable for PEDro scale. ECF and EAF are severe complications of OA patients. They will not heal without intensive care and treatment. NPWT has been proved an effective technique in the wound management of OA; however, many clinicians have cautioned that NWPT probably causes EAF in OA patients. This study provides a modification of the NPWT system. Through managing the fistula drainage, ECF and EAF can be healed or EAF can be transformed to ECF for surgical closure. Therefore, we can decrease the mortality related with the EAF or ECF. Our patient had to get 2nd bowel resections due to the failure of EAF management. This study provided evidence that we can help similar cases in the future. 44

46 Name: Wanli Lei Intervention Evidence Appraisal Worksheet Citation (use AMA or APA format): Hutan JM, Hutan MS, Skultety J, et al. Use of intraabdominal VAC (Vacuum Assisted Closure) lowers mortality and morbidity in patients with open abdomen. Bratisl Med J. 2013;114(08): doi: /bll_2013_094. Level of Evidence (Oxford scale): 3b Is the purpose and background information sufficient? Study Purpose Stated clearly? Usually stated briefly in abstract and in greater detail in introduction. May be phrased as a question or hypothesis. A clear statement helps you determine if topic is important, relevant and of interest to you. Consider how the study can be applied to PT and/or your own situation. What is the purpose of this study? Literature Relevant background presented? A review of the literature should provide background for the study by synthesizing relevant information such as previous research and gaps in current knowledge, along with the clinical importance of the topic. Describe the justification of the need for this study Yes. The authors stated the purpose of this study clearly. They were trying to compare Kern laparostomy and vacuum-assisted closure (VAC) in terms of mortality, closure of abdominal wound, and fistula management in open abdomen (OA) patients. Yes. The authors provided relevant background to justify the need of this study. OA surgery has been employed widely to manage complicated intraabdominal pathologies. However, OA has very high mortality rate and needs interdisciplinary cooperation of healthcare providers. There are different strategies to manage OA, including Kern and VAC. No studies have been carried out to compare the effectiveness of these different modalities yet. Therefore, the authors tried to compare the effectiveness of these 2 modalities in OA management. Does the research design have strong internal validity? Discuss possible threats to internal Assignment: case control study. Demographics of subjects in KERN and VAC groups varied greatly. 45

47 validity in the research design. Include: Assignment Attrition History Instrumentation Maturation Testing Compensatory Equalization of treatments Compensatory rivalry Statistical Regression Threat to internal validity. Attrition: 11/17 of patients in KERN group and 10/27 of patients in VAC died. The authors tried to compare outcome measures including mortality, OA closure rate and fistula rate. Attrition due to death will affect the analysis of OA closure and fistula rate. Threat to internal validity. History: accumulated date of KERN group patients were from 2000 to 2006; VAC group from 2007 to Patients in different time schedule probably could get better or skilled care in addition to the treatment. Threat to internal validity. Instrumentation: objective outcome measurements, no threat. Maturation: OA and complications such as EAFs need multidisciplinary cooperation and will not heal automatically with time passing by. No threat. Testing: no testing needed. No threat. Compensatory equalization of treatments: KERN group data were collected retrospectively; VAC group data were collected prospectively. Can t exclude the possibility that the authors worked more carefully with the VAC group and tried to get better results in VAC group. Threat to internal validity. Compensatory rivalry: patients in both groups didn t know other treatments. No threat. Statistical regression: no outliers in the outcome measures. No threat. Are the results of this therapeutic trial valid? 46

48 1. Did the investigators randomly assign subjects to treatment groups? a. If no, describe what was done b. What are the potential consequences of this assignment process for the study s results? 2. Did the investigators know who was being assigned to which group prior to the allocation? a. If they were not blind, what are the potential consequences of this knowledge for the study s results? 3. Were the groups similar at the start of the trial? Did they report the demographics of the study groups? a. If they were not similar what differences existed? b. Do you consider these differences a threat to the research validity? How might the differences between groups affect the results of the study? 4. Did the subjects know to which treatment group they were assign? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 5. Did the investigators know to which treatment group subjects were assigned? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 6. Were the groups managed equally, apart from the actual experimental treatment? a. If not, what are the potential consequences of this knowledge for the study s results? 7. Was the subject follow-up time sufficiently long to answer the question(s) posed by the research? a. If not, what are the potential consequences of this knowledge for the study s results? 8. Did all the subjects originally enrolled complete the study? No. This is a case control study. KERN group data were collected retrospectively from 2000 to VAC group data were collected prospectively from 2007 to This will decrease the validity of the study. Yes. The investigators knew all the patients in the 2 different groups. This will increase their treatment in VAC group and skew the study s results to support VAC system. No. Patients in KERN and VAC group have different indications, such as damage control surgery and dehiscence of laparotomy for OA. Probably they would respond to the treatment differently and affect the measurement of outcomes. No. Patients in both groups didn t know they were assigned to different groups. Yes. For the retrospective group KERN, they only analyzed the data collected objectively. But for the prospective group VAC, they probably will work with bias to help the patients more and get better results. This will artificially increase the benefits of VAC treatment. Unclear. The authors didn t provide details of management of Patients in the 2 groups. No. All the patients were only followed until discharge. Probably the 2 group patients would show similar outcome measures after discharge. No. There are many patients died during the 47

49 a. If not how many subjects were lost? b. What, if anything, did the authors do about this attrition? c. What are the implications of the attrition and the way it was handled with respect to the study s findings? 9. Were all patients analyzed in the groups to which they were randomized (i.e. was there an intention to treat analysis)? a. If not, what did the authors do with the data from these subjects? b. If the data were excluded, what are the potential consequences for this study s results? Are the valid results of this RCT important? 10. What were the statistical findings of this study? a. When appropriate use the calculation forms below to determine these values b. Include: tests of differences With p-values and CI c. Include effect size with p-values and CI d. Include ARR/ABI and RRR/RBI with p-values and CI e. Include NNT and CI f. Other stats should be included here hospitalization, which is only good for the mortality comparison, but will skew the results of OA closure rate and fistula rate. The authors didn t consider the effects of attrition. No. There is no intention to treat analysis. The authors didn t analyze and discuss the effects of death on outcome measures such as OA closure rate and fistula rate. Statistical analysis showed VAC system decrease the mortality and improved the OA closure rate significantly. Although the fistula rates of the 2 groups were not statistically different, 11.1% EAF closed and 66.7% EAF managed through diverting enteral contents, compared with 0% of EAF closure or diversion of enteral contents in KERN group, the difference is statistically significant ( p=0.0325). 11. What is the meaning of these statistical findings for your patient/client s case? What does this mean to your practice? 12. Do these findings exceed a minimally important difference? Was this brought up or discussed? a. If the MCID was not met, will you still use this evidence? The p value is less than 0.05, which means the difference between KERN and VAC group in EAF management is not occurred by chance. In the future, I can use VAC system to manage EAFs in OA patients. The authors didn t discuss minimal clinically important difference in the study, but 0% vs. 11.1% healing and 66.7% diversion of enteral content between KERN and VAC group is so dramatically different. It should be clinically important. 48

50 Can you apply this valid, important evidence about an intervention in caring for your patient/client? What is the external validity? 13. Does this intervention sound appropriate for use (available, affordable) in your clinical setting? Do you have the facilities, skill set, time, 3 rd party coverage to provide this treatment? 14. Are the study subjects similar to your patient/ client? a. If not, how different? Can you use this intervention in spite of the differences? 15. Do the potential benefits outweigh the potential risks using this intervention with your patient/client? 16. Does the intervention fit within your patient/client s stated values or expectations? a. If not, what will you do now? Yes. We tried to use the VAC system to manage OA and EAF of our patient but failed. If we followed the study s VAC protocol, we should have successfully diverted the enteral effluent and avoided the sepsis of our patient and she should not have undergone the 2 nd resection surgery, which increased frozen abdomen risks. Not clear. There is no detailed demographic information about the patients. Our patient is a 42 year old morbidly obese female (BMI over 40), probably not similar to the patients in the study, which has an average BMI less than 30. However, we can still try to use VAC techniques to manage our patient s EAF. Yes. Compared with KERN modality, the VAC system decreased mortality and improved OA closure rate. Although VAC group did show higher ratio of EAFs, the difference is not statistically significant. In addition, VAC system successfully healed or diverted enteral contents and avoided sepsis. Therefore, the benefits of this system outweigh its risk. Yes. Our patient expected to return home as soon as possible. She agreed to try the VAC system. 17. Are there any threats to external validity in this study? Yes. The sample size is small and there are many patients died in both group and not analyzed, which decreased its generalizability. What is the bottom line? PEDRO score (see scoring at end of form) Summarize your findings and relate this back to clinical significance Case control study, not a RCT; not suitable for PEDro scale. Compared with Kern modality, VAC system decreased mortality and improved OA closure 49

51 rate. VAC group did show higher ratio of EAFs; however, compared with 0% successful management of EAFs in KERN group, 77.8% of the successful management of EAFs in VAC system proved its advantages in OA care. Although VAC had not been well accepted in OA management, the results of this study showed promising advantages and benefits for the OA patients. 50

52 Name: Wanli Lei Intervention Evidence Appraisal Worksheet Citation (use AMA or APA format): Tavusbay C, Genc H, Cin N, et al. Use of a vacuum-assisted closure system for the management of enteroatmospheric fistulae. Surg Today doi: /s Level of Evidence (Oxford scale): 4 Is the purpose and background information sufficient? Study Purpose Stated clearly? Usually stated briefly in abstract and in greater detail in introduction. May be phrased as a question or hypothesis. A clear statement helps you determine if topic is important, relevant and of interest to you. Consider how the study can be applied to PT and/or your own situation. What is the purpose of this study? Literature Relevant background presented? A review of the literature should provide background for the study by synthesizing relevant information such as previous research and gaps in current knowledge, along with the clinical importance of the topic. Describe the justification of the need for this study The authors stated purpose of this study clearly: to analyze the management of enteroatmospheric fistulae (EAF) in open abdomen (OA) patients using vacuum-assisted closure (VAC ) therapy Yes. The authors provided enough background for the study. EAF directly discharges enteral contents into the OA and causes severe complications such as sepsis. However, control leaked enteral contents can avoid the complications and let the EAF closure or transform to enterocutaneous fistula (ECF), which can be closed surgically in the future. Does the research design have strong internal validity? Discuss possible threats to internal validity in the research design. Include: Assignment Attrition Assignment: case series, no assignment. Threat to internal validity. Attrition: 8 of the patients died due to sepsis. Threat to negate the effectiveness of the VAC 51

53 History Instrumentation Maturation Testing Compensatory Equalization of treatments Compensatory rivalry Statistical Regression system in management of EAF. History: patients not entered in the management in the same time, but admitted to the hospital between 2008 and Later admitted patients probably got better results due to improvement of the skills of the healthcare providers. Instrumentation: objective measurement of the EAF. No threat. Maturation: EAF can t heal automatically, but must need intensive care and treatment. No threat. Testing: not testing needed. No threat. Compensatory equalization of treatments: case series. No comparison groups. No threat. Compensatory rivalry: cases series. No competitive groups. No threat. Statistical regression: no statistical calculation required. No threat. Are the results of this therapeutic trial valid? 1. Did the investigators randomly assign subjects to treatment groups? a. If no, describe what was done b. What are the potential consequences of this assignment process for the study s results? 2. Did the investigators know who was being assigned to which group prior to the allocation? a. If they were not blind, what are the potential consequences of this knowledge for the study s results? 3. Were the groups similar at the start of the trial? Did they report the Cases series, not RCT. No randomly assignment of subjects. This will decrease the validity of the study. Case series. The investigators knew all the OA patients, but it will not affect the study s results because the authors only analyzed the accumulated data. Only one group. Demographic data showed the 52

54 demographics of the study groups? a. If they were not similar what differences existed? b. Do you consider these differences a threat to the research validity? How might the differences between groups affect the results of the study? 4. Did the subjects know to which treatment group they were assign? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 5. Did the investigators know to which treatment group subjects were assigned? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 6. Were the groups managed equally, apart from the actual experimental treatment? a. If not, what are the potential consequences of this knowledge for the study s results? 7. Was the subject follow-up time sufficiently long to answer the question(s) posed by the research? a. If not, what are the potential consequences of this knowledge for the study s results? 8. Did all the subjects originally enrolled complete the study? a. If not how many subjects were lost? b. What, if anything, did the authors do about this attrition? c. What are the implications of the attrition and the way it was handled with respect to the study s findings? 9. Were all patients analyzed in the groups to which they were randomized (i.e. was there an intention to treat analysis)? a. If not, what did the authors do with the data from these subjects? b. If the data were excluded, what are the potential consequences distribution of the subjects varied greatly. Therefore, it s difficult to exclude the possibilities that patients with different age will respond to the treatment differently. All the subjects are OA patients, and they got VAC treatment to manage their EAFs. However, it didn t affect the study s results because the patients couldn t control heal/closure or transformation of the EAFs. Yes. But this will not affect the study s results. The investigators only analyzed the accumulated data. All the patients got the same management with VAC system. No control group. This decreases the validity of the study s results. Yes. All the patients were followed until the EAF heal or transformed into ECF and later closed through surgery. No. Eight of the patients died of uncontrollable sepsis. This is a case series, no statistical analysis was carried out. Therefore, effects of the attrition can t be judged but it should decrease the validity of the study s results. Yes. All the patients were followed up and outcomes of the vacuum assisted closure treatment, including closure or transformation of EAF, or death, were measured. 53

55 for this study s results? Are the valid results of this RCT important? 10. What were the statistical findings of this study? a. When appropriate use the calculation forms below to determine these values b. Include: tests of differences With p-values and CI c. Include effect size with p-values and CI d. Include ARR/ABI and RRR/RBI with p-values and CI e. Include NNT and CI f. Other stats should be included here 11. What is the meaning of these statistical findings for your patient/client s case? What does this mean to your practice? 12. Do these findings exceed a minimally important difference? Was this brought up or discussed? a. If the MCID was not met, will you still use this evidence? No statistical analysis. Not available. Not available. Can you apply this valid, important evidence about an intervention in caring for your patient/client? What is the external validity? 13. Does this intervention sound appropriate for use (available, affordable) in your clinical setting? Do you have the facilities, skill set, time, 3 rd party coverage to provide this treatment? 14. Are the study subjects similar to your patient/ client? a. If not, how different? Can you use this intervention in spite of the differences? Yes. Our patient has high drainage EAF, which resulted to sepsis and the patient had to undergo 2 small bowel resections. This not only shortened her digestive tract, but also increased the risk of frozen abdomen. If we can manage the drainage of EAF with the VAC system, the patient probably didn t need the small bowel resections. This study provided us another strategy to manage the EAF. Yes. Demographics of the patients showed successful management of EAF in middle aged females with morbid obesity, which was similar to our patient. 15. Do the potential benefits outweigh the Yes. VAC system has been under debate about its 54

56 potential risks using this intervention with your patient/client? 16. Does the intervention fit within your patient/client s stated values or expectations? a. If not, what will you do now? 17. Are there any threats to external validity in this study? potential to cause EAFs. However, this study showed we can employ VAC system to control the leaked contents of the EAFs and facilitate heal or transformation of EAFs to ECFs. Without management, the EAFs will not heal or transform to ECFs and cause severe complications, including death. Yes. Our patient expected to go home as soon as possible and she agreed to use the VAC for her OA. However, failure to manage the EAF resulted to 2 bowel resections. This not only delayed the whole healing process of OA, but also increased the frozen abdomen risks in this patient. Yes. The sample size is small and 44.4% of patients died. In addition, this is not a RCT. We don t know how reliable and valid the results are. What is the bottom line? PEDRO score (see scoring at end of form) Case series, not RCT; not suitable for PEDro scale. Summarize your findings and relate this back to clinical significance EAFs are severe complications in OA patients. They will not heal automatically but must be managed in a multidisciplinary technique. Negative pressure wound therapy (AKA vacuum assisted closure) has been proved to improve healing of wounds, but its use in OA has been under debate because of risk to cause EAFs. This study showed VAC system actually can be used to manage the EAFs successfully. 55

57 Name: Wanli Lei Intervention Evidence Appraisal Worksheet Citation (use AMA or APA format): Bee TK, Croce MA, Magnotti LJ, et al. Temporary Abdominal Closure Techniques: A Prospective Randomized Trial Comparing Polyglactin 910 Mesh and Vacuum- Assisted Closure: J Trauma Inj Infect Crit Care. 2008;65(2): doi: /ta.0b013e31817fa451. Level of Evidence (Oxford scale): 1b Is the purpose and background information sufficient? Study Purpose Stated clearly? Usually stated briefly in abstract and in greater detail in introduction. May be phrased as a question or hypothesis. A clear statement helps you determine if topic is important, relevant and of interest to you. Consider how the study can be applied to PT and/or your own situation. What is the purpose of this study? Literature Relevant background presented? A review of the literature should provide background for the study by synthesizing relevant information such as previous research and gaps in current knowledge, along with the clinical importance of the topic. Describe the justification of the need for this study Yes. The authors stated the purpose clearly. They compared morbidity and mortality differences between two abdominal coverage methods with polyglactin mesh (MESH) or vacuum assisted closure (VAC) after damage control laparotomy or abdominal compartment syndrome. Yes. The authors provided enough relevant background. Under many situations, delayed fascial closure in open abdomen (OA) required temporary abdominal closure (TAC). There were many TAC strategies but none of them were supported by evidences. The authors aimed to compare two TAC systems (MESH and VAC) with a randomized clinical trial. Does the research design have strong internal validity? Discuss possible threats to internal validity in the research design. Include: Assignment Assignment: randomized. No threat. Attrition: 26% of VAC and 25% of MESH patients died in hospital. Threat to internal validity. 56

58 Attrition History Instrumentation Maturation Testing Compensatory Equalization of treatments Compensatory rivalry Statistical Regression History: all the patients randomly accepted the treatment. No threat. Instrumentation: all are objective measurement. No threat. Maturation: OA can t heal spontaneously, but need one or other treatment. No threat. Testing: no specific test needed. No threat. Compensatory equalization of treatments: authors didn t know which one will be better. No threat. Compensatory rivalry: patients couldn t heal their OA through hard work. No threat. Statistical regression: age, gender and other objective measurements were matched and didn t show outliers. No threat. Are the results of this therapeutic trial valid? 1. Did the investigators randomly assign subjects to treatment groups? a. If no, describe what was done b. What are the potential consequences of this assignment process for the study s results? 2. Did the investigators know who was being assigned to which group prior to the allocation? a. If they were not blind, what are the potential consequences of this knowledge for the study s results? 3. Were the groups similar at the start of the trial? Did they report the demographics of the study groups? a. If they were not similar what differences existed? Yes. VAC or MESH protocols were sealed in envelopes and randomly pulled out by nurse before the start of the surgery. Yes. MESH and VAC were totally different surgeries the authors did and they know exactly which patient was in which group. But no big problem for the validity of the trials, because the authors didn t know which treatment would be better. Yes. There were no statistically differences between the 2 groups. 57

59 b. Do you consider these differences a threat to the research validity? How might the differences between groups affect the results of the study? 4. Did the subjects know to which treatment group they were assign? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 5. Did the investigators know to which treatment group subjects were assigned? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 6. Were the groups managed equally, apart from the actual experimental treatment? a. If not, what are the potential consequences of this knowledge for the study s results? 7. Was the subject follow-up time sufficiently long to answer the question(s) posed by the research? a. If not, what are the potential consequences of this knowledge for the study s results? 8. Did all the subjects originally enrolled complete the study? a. If not how many subjects were lost? b. What, if anything, did the authors do about this attrition? c. What are the implications of the attrition and the way it was handled with respect to the study s findings? 9. Were all patients analyzed in the groups to which they were randomized (i.e. was there an intention to treat analysis)? a. If not, what did the authors do with the data from these subjects? b. If the data were excluded, what are the potential consequences for this study s results? Are the valid results of this RCT important? No. Even they knew which treatment group they were assigned, they couldn t change anything about the outcomes of the surgeries. Yes, because they did the surgeries. As mentioned above, this will not affect the study s results. Yes. All the patients were managed equally except the MESH or VAC treatment. Authors didn t state the follow-up clearly, but from the results, it appeared the follow-up should be sufficient until the OA wound was closed by skingraft after granulation tissue formed. No. Many of the patients died, and the authors excluded 3 patients died in 7 days after hospitalization. All the other died patients were included for calculation. It still decreased the validity of this study. No. The authors excluded 3 patients died in 7 days after hospitalization. Because 1 in MESH, 2 in VAC, probably VAC system has higher mortality. If exclude the patients, the difference would be leveled out. 58

60 10. What were the statistical findings of this study? a. When appropriate use the calculation forms below to determine these values b. Include: tests of differences With p-values and CI c. Include effect size with p-values and CI d. Include ARR/ABI and RRR/RBI with p-values and CI e. Include NNT and CI f. Other stats should be included here Authors used statistical suite JMP 7.0 (SAS Institute, Cary, NC) for the analysis: χ 2 for discrete variables, unpaired Student s t test for continuous variables (p< 0.05 set as statistical significance). No effect size, ARR, and NNT etc; no p value and CI were calculated for these items either. 11. What is the meaning of these statistical findings for your patient/client s case? What does this mean to your practice? 12. Do these findings exceed a minimally important difference? Was this brought up or discussed? a. If the MCID was not met, will you still use this evidence? The results showed the fistula rates between MESH and VAC were not statistically significant, which means the VAC system we used should probably not the culprit in the formation of fistula in our patient. There was no MCID available, thus the authors didn t discuss it in their study. Even if the MCID was not met, I would like to still use this evidence, which showed VAC didn t increase the incidence of the fistula in OA patients. Can you apply this valid, important evidence about an intervention in caring for your patient/client? What is the external validity? 13. Does this intervention sound appropriate for use (available, affordable) in your clinical setting? Do you have the facilities, skill set, time, 3 rd party coverage to provide this treatment? 14. Are the study subjects similar to your patient/ client? a. If not, how different? Can you use this intervention in spite of the differences? 15. Do the potential benefits outweigh the potential risks using this intervention Yes. We were using the VAC system to manage the OA in our patient. The authors didn t provide details of the patients. Probably our patient was different. Because in the study, most of the patients were males, while our patient is a morbidly obese female patient. Even so, I would like to use the intervention. I don t think the gender difference would be a big issue in the OA patients. Yes. Both MESH and VAC system decreased the mortality and increased fascial closure. 59

61 with your patient/client? 16. Does the intervention fit within your patient/client s stated values or expectations? a. If not, what will you do now? Yes. Our patient expected to return home as soon as possible. VAC has been proved effective to help heal of the OA wound. 17. Are there any threats to external validity in this study? Yes. The sample size is small, and attrition rate is too high. Although the fistula rates are not statistically different, 21% in VAC vs. 5% in MESH defined the p value closing to 0.05, indicating the VAC system probably would increase the incidence of fistula. What is the bottom line? PEDRO score (see scoring at end of form) 5/10 1Y2N3Y4N5N6N7Y8N9Y10Y Summarize your findings and relate this back to clinical significance OA has been used widely in abdominal pathologies. Under many situations, the fascial closure needs to be delayed and managed with TAC. Although there are many TACs available, no enough evidences support the treatment. In addition, TACs probably increase the incidence of fistula. This study used a randomized clinical trial to compare 2 of the TACs. Results showed both decreased the mortality and successfully managed the OA until delayed primary closure available. More importantly, both TACs didn t increase the incidence of the fistula, indicating that we can manage the OA in patients. 60

62 PEDro scale 1. eligibility criteria were specified no yes _X_ 2. subjects were randomly allocated to groups (in a crossover study, subjects were randomly allocated an order in which treatments were received) no _X_ yes 3. allocation was concealed no yes _X_ 4. the groups were similar at baseline regarding the most important prognostic indicators no _X_ yes 5. there was blinding of all subjects no _X_ yes 6. there was blinding of all therapists who administered the therapy no _X_ yes 7. there was blinding of all assessors who measured at least one key outcome no yes _X_ 8. measures of at least one key outcome were obtained from more than 85% of the subjects initially allocated to groups no _X_ yes 9. all subjects for whom outcome measures were available received the treatment or control condition as allocated or, where this was not the case, data for at least one key outcome was analyzed by intention to treat no yes _X_ 10. the results of between-group statistical comparisons are reported for at least one key outcome 11. the study provides both point measures and measures of variability for at least one key outcome no yes _X_ no yes 61

63 Name: Wanli Lei Intervention Evidence Appraisal Worksheet Citation (use AMA or APA format): Olona C, Caro A, Duque E, et al. Comparative study of open abdomen treatment: ABThera TM vs. abdominal dressing TM. Hernia doi: /s Level of Evidence (Oxford scale): 3b Is the purpose and background information sufficient? Study Purpose Stated clearly? Usually stated briefly in abstract and in greater detail in introduction. May be phrased as a question or hypothesis. A clear statement helps you determine if topic is important, relevant and of interest to you. Consider how the study can be applied to PT and/or your own situation. What is the purpose of this study? Literature Relevant background presented? A review of the literature should provide background for the study by synthesizing relevant information such as previous research and gaps in current knowledge, along with the clinical importance of the topic. Describe the justification of the need for this study Yes, the authors stated the study purpose clearly. There are 2 purposes: first, analyzing closure time required for V.A.C abdominal dressing and ABThera TM systems in open abdomen (OA) management; second, examining closure types and complications such as fistulae. Yes. The authors provided relevant background. OA has been widely employed for abdominal pathologies. Management of OA becomes a challenge. Negative pressure wound therapy (NPWT) has been used successfully in OA management. The authors collected cumulative data of OA patients used commercial NPWT kits V.A.C abdominal dressing and ABThera TM. Therefore, they set up a case control study to compare the 2 systems in OA closure and associated complications such as fistula. Does the research design have strong internal validity? Discuss possible threats to internal Assignment: case control study. One group 46 subjects, the other one 27. Demographics of the 62

64 validity in the research design. Include: Assignment Attrition History Instrumentation Maturation Testing Compensatory Equalization of treatments Compensatory rivalry Statistical Regression subjects in 2 groups matched. No threat to the internal validity. Attrition: Abdominal dressing group lost 15 subjects, ABThera TM group lost 4 subjects. Threat to the internal validity. History: case control study. Abdominal group subjects were before 2010; ABThera group after There probably exist other improvements in OA management. Threat to the internal validity. Instrumentation: measure of days for closure of OA, or other complications are objective. No threat. Maturation: patients were matched well. None of them could heal automatically without intensive wound care. No threat. Testing: no testing in the study. No threat. Compensatory equalization of treatments: case control retrospective study. No threat. Compensatory rivalry: no threat as above. Statistical regression: although the authors didn t discuss it, we can see the ranges of days required for the closure of OA is huge. There probably had some outliers. Threat to internal validity. Are the results of this therapeutic trial valid? 1. Did the investigators randomly assign subjects to treatment groups? a. If no, describe what was done b. What are the potential consequences of this assignment process for the study s results? No. Patients underwent 2 different OA NPWT systems. One group between 2006 and 2010; the other between 2011 and Investigators can t randomly assign subjects into different groups. However, this is a case control study. The authors only analyzed the data accumulated during the 63

65 2. Did the investigators know who was being assigned to which group prior to the allocation? a. If they were not blind, what are the potential consequences of this knowledge for the study s results? 3. Were the groups similar at the start of the trial? Did they report the demographics of the study groups? a. If they were not similar what differences existed? b. Do you consider these differences a threat to the research validity? How might the differences between groups affect the results of the study? 4. Did the subjects know to which treatment group they were assign? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 5. Did the investigators know to which treatment group subjects were assigned? a. If yes, what are the potential consequences of the subjects knowledge for this study s results 6. Were the groups managed equally, apart from the actual experimental treatment? a. If not, what are the potential consequences of this knowledge for the study s results? 7. Was the subject follow-up time sufficiently long to answer the question(s) posed by the research? a. If not, what are the potential consequences of this knowledge for the study s results? 8. Did all the subjects originally enrolled complete the study? a. If not how many subjects were lost? b. What, if anything, did the authors past. There didn t have bias to treatment, and it will not decrease the external validity of the study s results. Yes. They didn t randomly assign the patients into different groups, but it will not affect the validity of this study. Reasons as listed above. Yes. The demographics of the 2 groups matched well, no statistically significant differences were identified between the 2 groups. No. This is a retrospective case control study. The patients received available wound care during the hospitalization and didn t know that they would be assigned into different groups. Yes. As explained above, this will not affect the validity of the study because the authors only analyzed the accumulated data. They didn t change anything, including measure the outcomes. Unclear. The authors didn t mention if the 2 group patients were managed differently. However, there did have the threat that ABThera TM group got better care, because these patients were hospitalized after Yes. The authors followed most of the patients until their OA closed. No. 15 lost follow up in abdominal dressing group; 4 lost in the ABThera group. The authors only excluded 6 patients in the abdominal dressing group and counted all the patients in the ABThera 64

66 do about this attrition? c. What are the implications of the attrition and the way it was handled with respect to the study s findings? 9. Were all patients analyzed in the groups to which they were randomized (i.e. was there an intention to treat analysis)? a. If not, what did the authors do with the data from these subjects? b. If the data were excluded, what are the potential consequences for this study s results? Are the valid results of this RCT important? 10. What were the statistical findings of this study? a. When appropriate use the calculation forms below to determine these values b. Include: tests of differences With p-values and CI c. Include effect size with p-values and CI d. Include ARR/ABI and RRR/RBI with p-values and CI e. Include NNT and CI f. Other stats should be included here group into the analysis. The attrition was mainly caused by comorbidities, such as sepsis or myocardial infarction. They are not related with the NPWT systems. Yes, there were intention to treat analyses; however, the authors excluded 6 in abdominal dressing group. Three of them were pancreatitis; the other three were myocardial infarction during the follow up. This will decrease the validity of the study because these 6 patients probably responded to the treatment differently. This study compared 2 treatments and measured 2 outcomes: days required for the closure of OA and fistula rates in the 2 groups. The authors analyzed the 1 st outcome and provided statistical data. They mentioned the difference of fistula rate between the 2 groups was not statistically significant but didn t provide data. I will analyze the fistula rates. In the results part, the authors mentioned that V.A.C abdominal dressing group had 20% fistula rate; the ABThera TM system had 4% fistula rate. But in their abstract, they mentioned 17% vs. 4% fistula rates in the 2 groups. I will analyze the data according to the results. All the calculations are listed out as following: V.A.C abdominal dressing group as control; ABThera TM as experimental group. CER=20% EER=4% RRR=80% ARR=16% NNT=6.25 SE=0.074 Z=2.16 P= % CI of ARR = (2%, 30%) 65

67 11. What is the meaning of these statistical findings for your patient/client s case? What does this mean to your practice? 95% CI of NNT = (3.3, 50) CER and EER are the fistula rates in V.A.C abdominal dressing and ABThera TM groups separately. RRR is the relative risk reduction rate, which means that patients treated with ABThera TM system will decrease the fistula rate by 80% compared with patients treated with V.A.C abdominal dressings. ARR is the absolute risk reduction rate, which means the patients treated with ABThera TM system has 16% decrease of fistula rate compared with patients treated with V.A.C. abdominal dressings. NNT is number needed to treat, which means every7 patients treated with ABThera TM system, one fistula complication can be prevented in one patient. CI (95%) is the confidence interval when 100 similar experiments repeated, 95 of the time the effect size will be located in the range. In this study, 95% of the time, the absolute risk reduction will be between 2% and 30%; 95% of the time, the treatment of 4 to 50 OA patients with ABThera TM system will prevent one case of fistula. 12. Do these findings exceed a minimally important difference? Was this brought up or discussed? a. If the MCID was not met, will you still use this evidence? At last, the most important statistic number is P value, which is , less than pre-selected 0.05, which means the difference of fistula rates between the 2 groups are not happened by chance. This result is contradictory to the authors conclusion; but again, probably they used the 17% vs. 4% fistula rates in their abstract wrongly. The authors didn t discuss minimal important difference in this study. They mentioned the difference of the 2 groups in fistula rates was not significant; however, my analysis showed probably the authors used wrong data in their analysis. 66

68 Because they didn t provide enough background, I don t know if the findings exceed the minimal clinically important difference. Can you apply this valid, important evidence about an intervention in caring for your patient/client? What is the external validity? 13. Does this intervention sound appropriate for use (available, affordable) in your clinical setting? Do you have the facilities, skill set, time, 3 rd party coverage to provide this treatment? 14. Are the study subjects similar to your patient/ client? a. If not, how different? Can you use this intervention in spite of the differences? 15. Do the potential benefits outweigh the potential risks using this intervention with your patient/client? 16. Does the intervention fit within your patient/client s stated values or expectations? a. If not, what will you do now? Yes. We have been using the usual KCI V.A.C system to manage our patient s OA and fistula but failed. If we use the ABThera system at the beginning, the patient would probably not need the 2 nd resection of small bowels. No. My patient was much younger than all the patients in this study, and she underwent OA after an iatrogenic cause of bowel rupture due to gynecological surgery. Even so, I would like to use the intervention, because the systems only used for wound care, not related with their causes. Yes. If I use the ABThera TM system, the possibility of forming fistula would further decrease. Compared with V.A.C abdominal dressing system, no extra risks of this system were identified according to this study. Yes. The patient expected to return home as soon as possible. ABThera TM system shortened the closure time of OA surgery. 17. Are there any threats to external validity in this study? Yes. This is a case control study, and most of the subjects are older than 50. Probably the younger patients will respond to the treatment differently. For example, if bowel movement is faster in younger population, that would probably cause more fistula. What is the bottom line? PEDRO score (see scoring at end of form) Summarize your findings and relate this back to clinical significance Case control study, not RCT; not suitable for PEDro scale. NPWT has been under debate about its usage in OA management, because it has the risks to cause 67

69 enteroatmospheric fistula. This case control study did show V.A.C abdominal dressing system had higher fistula rate compared with ABThera TM system. In the future, we can use the ABThera TM NPWT system to prevent EAFs in OA patients. Relative risk reduction (RRR) CER EER CER EER Absolute risk reduction (ARR) CER-EER Number needed to treat (NNT) 1/ARR CER 20% 4% 80% 16% 6.25 NNT=1/ARR=1/0.16=6.25 According following formula, SE= CI (95%) of ARR =ARR+/_1.96*SE=(2%, 30%) CI (95%) of NNT=1/CI (95%) of ARR= (3.3, 50) Z=ARR/SE=2.16, P value can be calculated through the Z score online. 68