Thoracic trauma, both in isolation and as part of the. Does size matter? A prospective analysis of versus French chest tube size in trauma

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1 ORIGINAL ARTICLE Does size matter? A prospective analysis of versus French chest tube size in trauma Kenji Inaba, MD, Thomas Lustenberger, MD, Gustavo Recinos, MD, Crysanthos Georgiou, MD, George C. Velmahos, MD, Carlos Brown, VR, Ali Salim, MD, Demetrios Demetriades, MD, and Peter Rhee, MD, Los Angeles, California BACKGROUND: METHODS: RESULTS: CONCLUSIONS: LEVEL OF EVIDENCE: KEY WORDS: The optimal chest tube size for the drainage of traumatic hemothoraces and pneumothoraces is unknown. The purpose of this study was to compare the efficacy of small versus large chest tubes for use in thoracic trauma. Our hypothesis was that (1) there would be no difference in clinically relevant outcomes including retained hemothoraces, the need for additional tube insertion, and invasive procedures and (2) there would be an increase in pain with the insertion of large versus small tubes. This is a prospective, institutional review board-approved observational study. All patients requiring open chest tube drainage within 12 hours of admission (January 2007 January 2010) were identified at a Level I trauma center. Clinical demographic data and outcomes including efficacy of drainage, complications, retained hemothoraces, residual pneumothoraces, need for additional tube insertion, video-assisted thoracoscopy, and thoracotomy were collected and analyzed by tube size. Small chest tubes (28 32 Fr) were compared with large (36 40 Fr). During the study period, a total of 353 chest tubes (small: 186; large: 167) were placed in 293 patients. Of the 275 chest tubes inserted for a hemothorax, 144 were small (52.3%) and 131 were large (47.7%). Both groups were similar in age, gender, and mechanism; however, large tubes were placed more frequently in patients with a Glasgow Coma Scale 8, severe head injury, a systolic blood pressure 90 mm Hg, and Injury Severity Score 25. The volume of blood drained initially and the total duration of tube placement were similar for both groups (small: days vs. large: days; adjusted (adj.) p 0.427). After adjustment, no statistically significant difference in tube-related complications, including pneumonia (4.9% vs. 4.6%; adj. p 0.282), empyema (4.2% vs. 4.6%; adj. p 0.766), or retained hemothorax (11.8% vs. 10.7%; adj. p 0.981), was found when comparing small versus large chest tubes. The need for tube reinsertion, image-guided drainage, video-assisted thoracoscopy, and thoracotomy was likewise the same (10.4% vs. 10.7%; adj. p 0.719). For patients with a pneumothorax requiring chest tube drainage (n 238), there was no difference in the number of patients with an unresolved pneumothorax (14.0% vs. 13.0%; adj. p 0.620) or those needing reinsertion of a second chest tube. The mean visual analog pain score was similar for small and large tubes ( and ; p 0.237). For injured patients with chest trauma, chest tube size did not impact the clinically relevant outcomes tested. There was no difference in the efficacy of drainage, rate of complications including retained hemothorax, need for additional tube drainage, or invasive procedures. Furthermore, tube size did not affect the pain felt by patients at the site of insertion. (J Trauma. 2012;72: Copyright 2012 by Lippincott Williams & Wilkins) II. Chest tube; thoracostomy tube; size; trauma; complications; retained hemothorax; residual pneumothorax; pain. Thoracic trauma, both in isolation and as part of the multisystem injury spectrum, is extremely common. The majority of these patients, however, require no treatment. If Submitted: August 2, 2011, Revised: October 8, 2011, Accepted: December 5, From the Division of Trauma and Surgical Critical Care (K.I., T.L., G.R., C.G., D.D.), Los Angeles County and the University of Southern California Medical Center, University of Southern California-Keck School of Medicine, Los Angeles, California; Division of Trauma, Emergency Surgery, and Surgical Critical Care (G.C.V.), Massachusetts General Hospital, Boston, Massachusetts; Department of Surgery (C.B.), University Medical Center Brackenridge, University of Texas Southwestern-Austin, Austin, Texas; Department of Surgery (A.S.), Cedars-Sinai Medical Center, UCLA, Los Angeles, California; and Division of Trauma, Critical Care and Emergency Surgery (P.R.), University of Arizona, Tucson, Arizona. Address for reprints: Kenji Inaba, MD, FRCSC, FACS, Division of Trauma and Surgical Critical Care, Los Angeles County University of Southern California Medical Center, University of Southern California-Keck School of Medicine, 1200 North State Street, IPT, C5L100, Los Angeles, CA ; kinaba@surgery.usc.edu. DOI: /TA.0b013e an invasive procedure is required, it is most often for a pneumothorax or a hemothorax, and in the majority of cases, simple tube thoracostomy alone is the definitive treatment. 1 3 Traditionally, for the treatment of these traumatic pneumothoraces and hemothoraces, large bore chest tubes have been recommended. 4 In the 8th edition of the ATLS program, a 36-Fr tube is recommended for a hemothorax and a 38-Fr tube for a massive hemothorax. In the student DVD, a 36-Fr tube is recommended in the surgical skills section. 5 Theoretically, for the drainage of blood, a larger opening may facilitate the speed and completeness of drainage while mitigating the propensity of the blood within the tube to clot. For traumatic pneumothoraces, larger tubes may again be selected as there is often blood in addition to air within the thoracic cavity. No data, however, are available to support these practices and as such, there are no evidence-based consensus recommendations for the optimal tube size to be used in trauma. 422 J Trauma

2 J Trauma Inaba et al. Therefore, the purpose of this study was to analyze the impact of chest tube size on clinically relevant outcomes including the incidence of retained hemothoraces, need for intervention, and pain. Our hypothesis was that (1) there would be no difference in clinically relevant outcomes and (2) there would be an increase in pain in those who have placement of a large versus small chest tube. METHODS The Los Angeles County and University of Southern California Medical Center is an American College of Surgeons-verified academic Level I trauma center. After institutional review board approval, all patients who had a chest tube placed within the first 12 hours of admission for chest injury admitted from January 2007 to January 2010 were identified and followed prospectively. Patients who died within 24 hours of chest tube insertion were excluded. Chest tubes (Atrium Medical, Hudson, NH; 20 28, 32, 36, 40 Fr) were placed with an open technique by surgical or emergency medicine residents supervised by an attending physician. The size of the chest tube inserted was at the discretion of the patient s attending physician or surgeon. Prophylactic antibiotics were administered before chest tube insertion (Cefazolin 2 g intravenously). Patient variables collected included demographics, mechanism of injury (blunt vs. penetrating), physiologic parameters on admission, specific chest injuries, associated injuries, and injury severity scoring. Continuous variables were converted into dichotomous variables using clinically relevant cut-points (age 55 years, systolic blood pressure 90 mm Hg, Glasgow Coma Scale 8, Injury Severity Score 25, and Abbreviated Injury Score 3). Chest tube-related variables collected included the tube size (French), initial output, and chest tube-related complications. Those complications included pneumonia, empyema, retained hemothorax, and unresolved pneumothorax (persistent air leak or residual pneumothorax) and were counted only if they occurred in the hemithorax ipsilateral to the chest tube. In evaluable patients, pain intensity at the site of chest tube insertion was evaluated within an hour of placement using the Visual Analog Scale (VAS) pain score. Aretainedhemothoraxwasdefinedasapersistentheterogeneous fluid collection detected by computed tomography evaluation (Hounsfield unit readings on computed tomography of 35 70) within 14 days of initial chest tube placement and requiring intervention. Patients with a retained hemothorax were managed according to the attending surgeon s discretion with additional chest tube placement, intrapleural thrombolysis with tissue plasminogen activator, urokinase or streptokinase, videoassisted thoracoscopy, and/or thoracotomy. A chest tube size of 28 Fr and 32 Fr was considered as small and a tube size of 36 Fr or 40 Fr was considered as large. The primary outcome measure for this study was the development of chest tube-related complications associated with small and large chest tubes. Statistical Analysis The demographic and clinical patient characteristics associated with small and large chest tubes were compared Figure 1. Study outline of patients with chest trauma requiring thoracostomy tube insertion. PTX, pneumothorax; HTX, hemothorax. using bivariate analysis. The p values for categorical variables were derived from the chi-square or two-sided Fisher s exact test and for continuous variables from Student s t test or Mann-Whitney U test. Multivariate analysis was performed to control for confounders diverging significantly (p 0.05) between the compared groups. For continuous outcomes, analysis of covariance was used to adjust for confounders that were significant at p Values are reported as mean standard deviation for continuous variables and as percentages for categorical variables. All analyses were performed using the Statistical Package for Social Sciences (SPSS Windows), version 16.0 (SPSS, Chicago, IL). RESULTS During the 3-year study period, a total of 353 chest tubes were placed in 293 patients (Fig. 1). Overall, 186 (52.7%) were small (28 32 Fr) and 167 (47.3%) were large (36 40 Fr) chest tubes. The majority of the tubes were placed in the emergency department (67.1%; n 237), followed by placement in the operating room (20.2%; n 71) and in the intensive care unit or on the floor (12.7%; n 45). Management of Hemothoraces A hemothorax requiring chest tube placement was present in 233 patients (79.5%) with 42 patients having bilateral hemothoraces (Fig. 1). Of the 275 chest tubes inserted, 144 were small (52.3%) and 131 were large (47.7%). A comparison of demographic and clinical characteristics according to small and large chest tubes in patients with a hemothorax is presented in Table 1. Large chest tubes were placed in patients who had a lower Glasgow Coma Scale, had a higher percentage of severe head injuries, were more frequently hypotensive, and had more often an Injury Severity Score 25. No differences with regards to associated chest injuries 2012 Lippincott Williams & Wilkins 423

3 Inaba et al. J Trauma TABLE 1. Comparison of Clinical and Demographic Characteristics According to Small or Large Chest Tubes in Patients With a Hemothorax Total (n 275) Small Chest Tube (n 144) Large Chest Tube (n 131) Age (yr), mean SD Age 55 yr 17.8% (49/275) 20.8% (30/144) 14.5% (19/131) Male 87.3% (240/275) 86.1% (124/144) 88.5% (116/131) Penetrating 52.7% (145/275) 50.7% (73/144) 55.0% (72/131) RR 30/min 11.3% (31/275) 9.7% (14/144) 13.0% (17/131) GCS % (34/275) 8.3% (12/144) 16.8% (22/131) SBP 90 mm Hg 9.8% (27/275) 5.6% (8/144) 14.5% (19/131) Head AIS % (45/275) 8.3% (12/144) 25.2% (33/131) Abdomen AIS % (73/275) 28.5% (41/144) 24.4% (32/131) Extremity AIS % (52/275) 18.1% (26/144) 19.8% (26/131) ISS, mean SD ISS % (79/275) 22.9% (33/144) 35.1% (46/131) Operative interventions on admission Craniotomy/craniectomy 1.8% (5/275) 1.4% (2/144) 2.3% (3/131) Thoracotomy 10.5% (29/275) 10.4% (15/144) 10.7% (14/131) Laparotomy 33.1% (91/275) 34.7% (50/144) 31.3% (41/131) SD, standard deviation; RR, respiratory rate; SBP, systolic blood pressure; AIS, Abbreviated Injury Scale; ISS, Injury Severity Score. p TABLE 2. Specific Chest Injuries According to Small or Large Chest Tubes in Patients With a Hemothorax Total (n 275) Small Chest Tube (n 144) Large Chest Tube (n 131) p Pneumothorax 73.8% (203/275) 75.0% (108/144) 72.5% (95/131) Pulmonary contusion 41.5% (114/275) 40.3% (58/144) 42.7% (56/131) Rib fractures 51.3% (141/275) 55.6% (80/144) 46.6% (61/131) Sternal fracture 7.3% (20/275) 5.6% (8/144) 9.2% (12/131) Subcutaneus emphysema 38.9% (107/275) 40.3% (58/144) 37.4% (49/131) Pneumomediastinum 11.3% (31/275) 11.8% (17/144) 10.7% (14/131) Flail chest 4.7% (13/275) 5.6% (8/144) 3.8% (5/131) TABLE 3. Chest Tube-Related Complications in Patients With a Hemothorax Total (n 275) Small Chest Tube (n 144) Large Chest Tube (n 131) p Adjusted OR (95% CI)* Adjusted p* Complication overall 15.6% (43/275) 16.7% (24/144) 14.5% (19/131) ( ) Pneumonia 4.7% (13/275) 4.9% (7/144) 4.6% (6/131) ( ) Empyema 4.4% (12/275) 4.2% (6/144) 4.6% (6/131) ( ) Retained hemothorax 11.3% (31/275) 11.8% (17/144) 10.7% (14/131) ( ) OR, odds ratio; CI, confidence interval, SBP, systolic blood pressure; AIS, Abbreviated Injury Scale; ISS, Injury Severity Score. *Adjusted for GCS 8, SBP 90 mm Hg, Head AIS 3, ISS 25. were found on bivariate analysis between the two study groups (Table 2). There was no difference in the initial chest tube output found between those who received a large chest tube compared with small ( ml vs ml; p 0.067). The duration of tube placement was similar for both groups (small: days vs. large: days; adjusted (adj.) p 0.427). Overall, in 15.6% (n 43) of the chest tubes, a complication related to the tube occurred (Table 3). There were no differences in the overall or specific complication rates when comparing small and large chest 424 tubes. In particular, no statistically significant difference was found with regards to the incidence of retained hemothoraces when comparing small and large chest tubes (11.8% vs. 10.7%; adj. p 0.981, adj. odds ratio [95% confidence interval] 1.01 [ ]). Adescriptionofallinterventionsfollowinginitial chest tube placement is depicted in Table 4. Overall, in 5.1% of the cases (n 14), an additional chest tube was inserted, 6.2% (n 17) underwent intrapleural thrombolysis, in 4.0% (n 11) an image-guided drainage was performed, 2.9% (n 8) received a video-assisted thora Lippincott Williams & Wilkins

4 J Trauma Inaba et al. TABLE 4. Interventions Required After Initial Chest Tube Placement in Patients With a Hemothorax Total (n 275) Small Chest Tube (n 144) Large Chest Tube (n 131) p Adjusted OR (95% CI)* Adjusted p* Additional chest tube insertion 5.1% (14/275) 5.6% (8/144) 4.6% (6/131) ( ) Intrapleural thrombolysis 6.2% (17/275) 6.2% (9/144) 6.1% (8/131) ( ) Image-guided drainage 4.0% (11/275) 3.5% (5/144) 4.6% (6/131) ( ) VATS 2.9% (8/275) 2.8% (4/144) 3.1% (4/131) ( ) Thoracotomy 1.1% (3/275) 1.4% (2/144) 0.8% (1/131) ( ) VATS, video-assisted thoracoscopy; OR, odds ratio; CI, confidence interval; SBP, systolic blood pressure; AIS, Abbreviated Injury Scale; ISS, Injury Severity Score. *Adjusted for GCS 8, SBP 90 mm Hg, Head AIS 3, ISS 25. Figure 2. Detailed description of the management of the hemothoraces. All patients undergoing thoracotomy had an unsuccessful attempt at video-assisted thoracoscopy (VATS). coscopy, and 1.1% (n 3) of the patients ultimately required a thoracotomy. Sixteen patients (5.8%) underwent two procedures and six patients (2.2%) required three procedures for the treatment of their retained hemothorax. There were no statistically significant differences with respect to the treatment modalities or the number of treatments required when comparing the cohorts of small and large chest tubes. The specific treatment for the 31 retained hemothoraces is illustrated in Figure 2. Management of Pneumothoraces When patients with a pneumothorax were analyzed separately, a total of 238 patients presented with a pneumothorax with or without associated hemothorax (Fig. 1). In 78 patients, the sole indication for the chest tube placement was a pneumothorax. Of the 281 chest tubes placed, 150 (53.4%) were small and the remaining 131 (46.6%) tubes were large. Following chest tube placement, an unresolved pneumothorax was observed in 38 cases (13.5%). However, there were no statistically significant differences in incidence when comparing small versus large chest tubes (14.0% vs. 13.0%; adj. p 0.620, adj. odds ratio [95% confidence interval] 1.21 [ ]). Furthermore, there was no statistically significant difference between small and large chest tubes that required reinsertion of a chest tube for the treatment of an unresolved pneumothorax (3 for small and 5 for large chest tubes; p 0.426). VAS Pain Score Overall, 158 patients (44.8%) could be evaluated for pain intensity at the site of chest tube insertion using the VAS score within an hour of placement. The mean VAS score was and for small and large chest tubes, respectively (p 0.237). DISCUSSION One of the most common invasive procedures performed in the injured trauma patient is chest tube insertion. Traditionally, a large bore chest tube has been recommended, 4 with the ATLS program making specific reference to tubes in the 36 Fr to 38 Fr range. 5 The theory underlying this preference for large bore tubes has been the prevention of blood clotting within the lumen of the tube. The reality is that there is very little evidence underlying this choice to utilize larger bore tubes, and the decision regarding size is often based on opinion. In a survey of cardiothoracic surgeons and specialty cardiac surgery nurses by Shalli, 6 for example, 87% of surgeons responded that their concern for blood clotting 2012 Lippincott Williams & Wilkins 425

5 Inaba et al. J Trauma within a chest tube is what affected their choice to use a large (36 Fr) tube. Chest tube size is commonly measured in terms of the French scale, describing the outer diameter of the tube. As 1 Fr is 0.33 mm (diameter in mm French size/3), increasing French size corresponds to an increase in the outer diameter of the tube. The physical principle by which flow is determined is Poisseuille s law for fluids and the Fanning equation for gases. For fluids, Poisseuille s law characterizes internal radius (to the fourth power), the pressure difference between the ends of the tube, liquid viscosity, and the length of the tube as being the primary determinants of flow. For gases, radius (to the fifth power) and again the pressure differential, length, and a friction factor determine flow. Although a small change in the inner radius of the tube should therefore theoretically increase flow significantly, there are numerous other considerations that likely impact the true clinical application of these equations to how well air and blood are drained. First, although the external diameter is being described by the chest tube size, the inner diameter will vary depending on the wall thickness. Perhaps more importantly, the actual obstruction to flow or rate-limiting step is the narrowest point along the length of the tube. For some commercially available tubes, the end that connects to the drainage system is cut to size and this narrowing will become the bottleneck. Other tubes will be attached to the drainage system through a standard connector, which will become the narrowest point, often much smaller than the inner diameter of the chest tube. Because the same connector is used irrespective of the actual size of the chest tube selected, the obstruction to flow will be constant. Drainage efficacy also relies on the number and size of the side holes, which will vary with the size and manufacturer of the tube. Any kinking of the tube and the effect of wall suction may also impact flow. Finally, any solid or semisolid material such as clots within the pleural cavity, blood, or muscle may also partially obstruct the tube and impact flow to an extent not captured by either Poiseuille s law or the Fanning equation. Thus, in practice, the theoretical advantage of larger bore chest tubes may not in fact hold true. In a preclinical and in vitro study by Niinami et al., 7 19 Fr tubes were compared with 28 Fr tubes. When the ability to drain water at a set pressure of 10 mm Hg was measured, the larger tube had a drainage capacity ninefold higher than the smaller. However, when placed in vivo into a swine model with an induced hemothorax, both tubes had similar drainage capacities. In another study by Park, 8 the flow of five fluids with differing viscosities (water, pseudocyst fluid, blood, purulent fluid, and purulent fluid with urokinase) was tested through seven 30-cm catheters ranging from 6 Fr to 18 Fr. They found that although increasing catheter size improved flow, for the majority of fluids, increasing the size past 8 Fr inner diameter and for purulent material 12 Fr inner diameter did not make a significant difference in the efficacy of drainage. 426 In this prospective analysis of injured patients undergoing chest tube placement, there was no difference in the initial output or duration of tube placement when large tubes were compared with small. As a marker of clinically relevant efficacy in draining blood or air, there was no difference in the complication rate and, specifically, no difference in the incidence of pneumonias, empyemas or retained hemothoraces, or the need for subsequent interventions. When pneumothoraces were analyzed separately, there was no difference in the unresolved pneumothorax rate or the need for reinsertion of a chest tube to treat this complication. Interestingly, despite the fact that it is often perceived by clinicians that larger tubes are more painful, 6 in approximately half of the patients, a visual analog pain score could be performed and no difference was noted in their perception of pain attributed to the chest tube size. This study specifically targeted the size of tubes used for open drainage of the pleural cavity. There is increasing experience being gained in the use of percutaneous tube drainage with catheters that are in the sub-20 Fr range. Studies in the nontrauma population have compared their efficacy with larger tubes placed by the open technique with favorable results. 9,10 These tubes are currently not being used in the care of our patients and thus were not included in our analysis. In the future, however, the role of these tubes, their efficacy, pain, and complication rate warrant investigation as they may prove to be equally efficacious as larger bore tubes placed utilizing the open technique. CONCLUSIONS In conclusion, in this prospective analysis of the impact of chest tube size, whether a small or a large bore tube was used, for both hemothoraces and pneumothoraces, there was no difference in the rate of complications including retained hemothorax. There was also no difference in the need for reinsertion of a tube or the number of invasive procedures required to manage these complications. Likewise, there was no demonstrable difference in the pain attributed to the chest tube size. The choice of tube size for open insertion therefore did not impact outcomes. Further evaluation of percutaneously placed drainage systems is warranted. AUTHORSHIP This study was conceived of and designed by K.I., G.C.V., C.B., A.S., D.D., and P.R. K.I., T.L., G.R., and C.G. collected the data, which were analyzed by K.I., T.L., G.R., C.G., D.D., and P.R. All authors contributed to data interpretation, manuscript preparation, and critical review. DISCLOSURE The authors declare no conflicts of interest. REFERENCES 1. Khandhar SJ, Johnson SB, Calhoon JH. Overview of thoracic trauma in the United States. Thorac Surg Clin. 2007;17: Kulshrestha P, Munshi I, Wait R. Profile of chest trauma in a level I trauma center. J Trauma. 2004;57: Lippincott Williams & Wilkins

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