Early Operation Is Associated With a Survival Benefit for Patients With Adhesive Bowel Obstruction

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1 PAPERSOFTHE133RD ASA ANNUAL MEETING Early Operation Is Associated With a Survival Benefit for Patients With Adhesive Bowel Obstruction Pedro G. Teixeira, MD, Efstathios Karamanos, MD, Peep Talving, MD, PhD, Kenji Inaba, MD, MSc, Lydia Lam, MD, and Demetrios Demetriades, MD, PhD Objective: To evaluate the effect of surgical delay on the outcomes of patients with adhesive small bowel obstruction (ASBO). Background: It is generally accepted that patients with uncomplicated ASBO failing nonoperative management should be operated on within 5 days. However, the optimal time of operation within this 5-day period is unknown. Methods: Patients requiring surgery for ASBO were identified from the National Surgical Quality Improvement Program database. Linear regression was performed to evaluate the impact of incremental surgical delay in mortality and complications. The study population was stratified by time to intervention (24-hour intervals), and logistic regression was performed to adjust for premorbid conditions and presentation physiology. The outcomes included 30-day mortality and infectious complications. Results: A total of 4163 patients underwent laparotomy for ASBO. Mortality and complications increased significantly with operative delay. Delay of 24 hours or more was associated with significantly higher mortality: 6.5% vs 3.0%; adjusted odds ratio (AOR) [95% confidence interval (CI), 1.58 ( )]; P = The delayed operation group ( 24 hours) also had significantly higher rates of surgical site infections [12.9% vs 10.0%; AOR (95% CI), 1.33 ( ); P = 0.007], pneumonia (7.9% vs 5.2%; AOR (95% CI), 1.36 ( ); P = 0.025], sepsis [7.6% vs 5.1%; AOR (95% CI), 1.45 ( ); P = 0.007], and septic shock [6.2% vs 3.5%; AOR (95% CI), 1.47 ( ); P = 0.018]. Early operation was associated with significantly shorter hospital stay [8.4 ± 8.3 vs 14.4±13.5 days; adjusted mean difference (95% CI), 5.2 ( 5.9 to 4.4); P<0.001]. Conclusions: Early operative intervention for patients with ASBO is associated with a significant survival benefit, lower incidence of local and systemic complications, and shorter hospitalization. Keywords: adhesions, adhesive, bowel obstruction, delay, outcomes (Ann Surg 2013;258: ) Adhesive small bowel obstruction (ASBO) is a significant problem after abdominal surgery, resulting in an overall 5% readmission rate 1 and major cost implications. 2 The management of this condition is challenging, as the benefits of an operative intervention, which may induce formation of additional adhesions, are weighed against a nonoperative strategy, which, although effective in 65% to 80% of the cases, 3 7 may delay surgery. According to evidence-based guidelines, for patients without evidence of strangulation or peritonitis, a period of expectant management up to 3 to 5 days is acceptable It is unclear, however, whether this approach results in unnecessary delays for those patients From the Los Angeles County + University of Southern California Medical Center, Los Angeles. Disclosure: The authors declare no conflicts of interest. Reprints: Demetrios Demetriades, MD, PhD, Division of Acute Care Surgery and Surgical Critical Care, University of Southern California, Los Angeles County + University of Southern California Medical Center, 2051 Marengo St, IPT, C5L100, Los Angeles, CA demetria@usc.edu. Copyright C 2013 by Lippincott Williams & Wilkins ISSN: /13/ DOI: /SLA.0b013e3182a1b100 who ultimately require surgery and whether the time spent waiting for spontaneous resolution of ABO results in additional morbidity. The objective of this study was to evaluate the impact of surgery delay in mortality and complication rates for patients with acute ASBO. METHODS All patients requiring emergent surgical intervention for ASBO were identified from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database. The NSQIP is a validated quality improvement program sponsored by the ACS that uses risk-adjusted outcomes to measure and improve surgical care. Using the NSQIP database version containing data from 2005 to 2010, all patients undergoing emergent abdominal operations were selected and the resulting subset of data was filtered using the postoperative diagnosis of intestinal or peritoneal adhesions with obstruction, International Classification of Diseases, Ninth Revision, code Patient characteristics abstracted included demographic information, comorbidities, ASA classification, history of tobacco and ethanol use, sepsis status on admission, wound classification, and time span from admission to operation. The primary outcome was 30-day mortality. Secondary outcomes included need for bowel resection, development of local and systemic complications, need for reintubation, need for reoperation, and hospital length of stay (LOS). To evaluate the impact of surgical delay in mortality, linear regression analysis was performed using time to surgery, with 24-hour increments as the independent variable. Factors associated with mortality were then explored using univariate analysis. Proportions were compared using the χ 2 or Fisher exact test, and means were compared using the unpaired Student t test or Mann-Whitney rank sum test as appropriate. All factors that were significant at P < 0.2 were entered into a stepwise logistic regression, with mortality as the dependent variable. The probability of mortality derived from this equation was saved as a continuous variable and plotted against the actual mortality, building a receiver operating characteristic curve to assess the strength of the regression model. For the stepwise logistic regression, time to operation was entered both as a continuous variable and as a dichotomous variable (<24 hours vs 24 hours). The study population was then stratified according to the time to operation into 2 groups: less than 24 hours versus 24 hours or more. Univariate analysis was performed to compare the 2 study groups for differences in baseline characteristics. Crude outcomes were derived. To assess the differences in outcomes between the 2 study groups adjusting for premorbid conditions and presentation physiology, a logistic regression model was built for each of the outcomes of interest including all factors that on univariate analysis were found to be different at P < Adjusted outcomes with 95% confidence intervals were derived. For hospital LOS, which is a continuous outcome, a generalized linear regression model was used, applying the same criteria of cofactors selection previously described for the categorical outcomes. Adjusted mean difference and 95% confidence interval was derived. Because surgical delay by Annals of Surgery Volume 258, Number 3, September

2 Teixeira et al Annals of Surgery Volume 258, Number 3, September 2013 definition adds additional days to the total hospital LOS, the time from operation to discharge was also compared between the 2 study groups and adjusted mean difference was estimated using generalized linear regression to control for confounders. All data analysis was performed using SPSS 16.0 for Windows (SPSS, Inc). Summary data are presented as a raw percentage or mean ± standard deviation. Statistical significance was considered for P < RESULTS During the 6-year study period, 4163 patients underwent an emergent laparotomy for ASBO. Overall characteristics of this population are outlined in Table 1. The majority of surgical interventions (61%; n = 2522) were performed after 24 hours from admission. Overall mortality was 5.1%. When mortality and development of complications were stratified by the time from admission to operation in 24-hour increments, a statistically significant increasing trend was observed both for mortality and for complication rates (Fig. 1). Patients who underwent a laparotomy more than 72 hours from admission had a 3-fold increase in mortality and 2- fold increase in the incidence of systemic infectious complications compared with those for whom the operation was performed within 24 hours. After stepwise logistic regression analysis, 12 independent predictors of mortality were identified and are summarized in Table 2. The area under the receiver operating characteristic curve for this regression model was 0.86 (95% CI, ; P < 0.001). According to this model, surgical delay represented by daily increments from admission to operation had an odds ratio for mortality of 1.16 (95% CI, ; P < 0.001). An additional logistic regression model was built, now with the time-to-operation variable entered as a dichotomous variable (<24 hours vs 24 hours). According to this analysis, surgery delay of 24 hours or more was independently associated with mortality [OR (95% CI), 1.64 ( ); P = 0.005]. The area under the receiver operating characteristic curve for this second regression was 0.86 (95% CI, ; P < 0.001). The study population was then stratified into 2 groups according to the time from admission to operation (<24 hours vs 24 hours). Comparison of these groups is summarized in Table 3. Crude and adjusted outcomes are outlined in Table 4. Patients who underwent laparotomy 24 hours or more from admission had a significantly higher mortality (6.5% vs 3.0%; P < 0.001). After adjustment for confounding factors using multivariable analysis, the difference in mortality remained statistically significant [adjusted odds ratio (AOR) (95% CI), 1.58 ( ); P = 0.009]. Complications were also significantly more frequent in patients undergoing delayed operation. Surgical site infections were significantly higher in patients in the 24 hours or more group at 12.9% compared to 10.0% in the less than 24-hour group (P = 0.005). This difference remained statistically significant after multivariable analysis [AOR (95% CI), 1.33 ( ); P = 0.007]. Systemic infectious complications were also significantly more frequent in the delayed group (20.5% vs 12.2%; P < 0.001), and this difference prevailed after adjustment for confounders [AOR (95% CI), 1.62 ( ); P < 0.001]. The rate of unplanned intubation was higher in the delayed group (5.6% vs 3.8%; P = 0.007); however, this difference faded after adjustment [AOR (95% CI), 1.15 ( ); P = 0.396]. The need for bowel resection was not affected by the surgery timing [26.6% vs 24.3%; AOR (95% CI), 1.03 ( ); P = 0.675]. Patients who underwent an early operation had a significantly shorter hospital LOS (8.4 ± 8.3 days vs 14.4 ± 13.5 days), with a mean difference (95% CI), 6.03 ( 6.76 to 5.30); P < After multivariable analysis, this difference in hospital LOS remained TABLE 1. Overall Patient Characteristics and Outcomes Overall (n = 4163) Age, mean ± SD, yr 62.8 ± 17.1 Age >60 yr 55.6 (2314) Female sex 60.6 (2522) Tobacco 20.2 (843) Alcohol 3.2 (132) Obese 20.4 (850) Overweight 28.4 (1181) ASA (2626) Preoperative WBC count >16, (526) Comorbidities Diabetes on oral medication 8.1 (339) Diabetes on insulin 5.1 (212) Dyspnea 10.2 (423) COPD 8.9 (370) Pneumonia 2.3 (97) Ascites 9.4 (392) CHF 1.5 (64) MI 1.0 (43) PCI 6.1 (252) Previous cardiac surgery 6.3 (261) Angina 1.2 (49) Acute renal failure 1.8 (77) Requiring dialysis 1.8 (76) Peripheral vascular disease 2.5 (104) TIA 3.0 (125) Stroke without neurological deficit 3.0 (125) Stroke with neurological deficit 2.6 (110) Hemiplegia 1.1 (44) Paraplegia 0.6 (23) Quadriplegia 0.4 (15) Wound classification Clean 36.6 (1525) Clean/contaminated 44.0 (1832) Contaminated 12.4 (516) Infected 7.0 (290) Admission septic status SIRS 26.9 (1119) Sepsis 4.4 (184) Septic shock 2.1 (87) Outcomes Mortality 5.1 (213) SSIs 11.7 (489) Superficial SSI 6.9 (288) Deep SSI 1.8 (75) Abscess 2.9 (121) Wound dehiscence 1.8 (75) Systemic infectious complications 17.3 (719) Pneumonia 6.9 (286) UTI 4.5 (189) Sepsis 6.6 (274) Septic shock 5.1 (214) Unplanned intubation 4.9 (204) Return to the OR 8.1 (339) Values given are % (n), unless otherwise specified. CHF indicates congestive heart failure; COPD, chronic pulmonary obstructive disease; MI, myocardial infarction; OR, operating room; PCI, percutaneous coronary intervention; SIRS, systemic inflammatory response syndrome; SSI, surgical site infection; TIA, transient ischemic attack; UTI, urinary tract infection; WBC, white blood cell. statistically significant, favoring the patients in the early operation group [adjusted mean difference (95% CI), 5.20 ( 5.90 to 4.49); P < 0.001]. The time from operation to discharge was also significantly shorter for the patients who underwent surgery within 24 hours (8.4 ± 8.3 days vs 11.2 ± 12.2 days), with a mean difference (95% CI), 2.75 ( 3.43 to 2.08); P < This difference C 2013 Lippincott Williams & Wilkins

3 Annals of Surgery Volume 258, Number 3, September 2013 Surgical Delay Increases Mortality in Patients With SBO TABLE 3. Comparison of Patient Characteristics According to the Surgery Timing Groups FIGURE 1. Time to operation and associated outcomes. SSI indicates surgical site infection. TABLE 2. Stepwise Logistic Regression for Mortality Odds Ratio Step Factor (95% CI) P R 2 1 Septic shock 6.82 ( ) < ASA ( ) Age >60 yr 3.04 ( ) < Sepsis 3.24 ( ) < Time to OR (daily 1.16 ( ) < increments) 6 COPD 2.07 ( ) < PAD 2.55 ( ) SIRS 1.95 ( ) < Obesity (BMI >30) 1.98 ( ) < CHF 2.31 ( ) ARF 2.20 ( ) Wound classification clean 0.65 ( ) Area under the receiver operating characteristic curve: 0.86 (95% CI: ; P < 0.001). ARF indicates acute renal failure; BMI, body mass index; CHF, congestive heart failure; CI, confidence interval; COPD, chronic pulmonary obstructive disease; OR, operating room; PAD, peripheral arterial disease; SIRS, systemic inflammatory response syndrome. remained significant after adjusting for confounders [adjusted mean difference (95% CI), 2.09 ( 2.75 to 1.42); P < 0.001]. DISCUSSION In this review of the ACS NSQIP database, a delay in surgical intervention for patients with ASBO was found to be an independent predictor of mortality, with an odds ratio of 1.16 [(95% CI, ); P < 0.001]. Patients who had their operation delayed by 24 hours or more had significantly higher risk-adjusted mortality than those patients undergoing early surgical intervention [6.5% vs 3.0%; AOR (95% CI), 1.58 ( ); P = 0.009]. This represents a 53% relative reduction in mortality associated with early operation. According to recently published evidence-based guidelines from the World Society of Emergency Surgery, if no evidence of strangulation or peritonitis exist, nonoperative management of ASBO can be attempted for up to 72 hours. 9 The EAST Practice Management Guidelines for Small Bowel Obstruction also suggest that nonoper- <24 h (n = 1641) 24 h (n = 2522) P Age, mean ± SD 60.8 ± ± 17.2 <0.001 Age >60 yr 49.8 (818) 59.3 (1496) <0.001 Female sex 61.0 (1001) 60.3 (1521) Tobacco 20.2 (332) 20.3 (511) Alcohol 2.5 (41) 3.6 (91) Obese 22.6 (371) 19.0 (479) Overweight 29.4 (483) 27.7 (698) ASA (903) 68.3 (1723) <0.001 Preoperative WBC count 16.5 (266) 10.4 (260) <0.001 >16,000 Comorbidities Diabetes on oral 8.2 (135) 8.1 (204) medication Diabetes on insulin 4.3 (71) 5.6 (141) Dyspnea 7.9 (129) 11.7 (294) <0.001 COPD 8.0 (132) 9.4 (238) Pneumonia 0.7 (12) 3.4 (85) <0.001 Ascites 7.6 (125) 10.6 (267) CHF 0.5 (8) 2.2 (56) <0.001 MI 0.4 (7) 1.4 (36) PCI 4.9 (80) 6.8 (172) Previous cardiac 4.0 (66) 7.7 (195) <0.001 surgery Angina 0.5 (8) 1.6 (41) Acute renal failure 1.3 (22) 2.2 (55) Requiring dialysis 1.0 (17) 2.3 (59) Peripheral vascular 1.8 (29) 3.0 (75) disease TIA 2.3 (37) 3.5 (88) Stroke without 2.2 (36) 3.5 (88) neurological deficit Stroke with 1.8 (29) 3.2 (81) neurological deficit Hemiplegia 0.9 (14) 1.2 (30) Paraplegia 0.3 (5) 0.7 (18) Quadriplegia 0.5 (8) 0.3 (7) Wound classification Clean 37.2 (610) 36.3 (915) Clean/contaminated 43.5 (714) 44.3 (1118) Contaminated 12.5 (205) 12.3 (311) Infected 6.8 (112) 7.1 (178) Admission septic status SIRS 28.2 (463) 26.0 (656) Sepsis 2.9 (48) 5.4 (136) <0.001 Septic shock 1.5 (24) 2.5 (63) Values given are % (n), unless otherwise specified. CHF indicates congestive heart failure; COPD, chronic pulmonary obstructive disease; MI, myocardial infarction; PCI, percutaneous coronary intervention; SIRS, systemic inflammatory response syndrome; TIA, transient ischemic attack; WBC, white blood cell. ative management can be attempted for up to 3 to 5 days. 8,10 These recommendations are in contrast with the findings of the present study, as a delay in surgery of more than 72 hours was associated with a 3-fold increase in mortality and a 2-fold increase in the incidence of systemic infectious complications compared with surgical procedures performed within 24 hours. Schraufnagel et al 11 also found an association between operative delay and mortality, using the Nationwide Inpatient Sample. In their review of 4826 patients undergoing surgery for ASBO, a delay of more than 3 days was independently associated with mortality [odds ratio (95% CI), 1.64 ( ); P < 0.01]. 11 Cox et al 6 demonstrated that 88% of patients managed with a nonoperative trial resolved within 48 hours, and C 2013 Lippincott Williams & Wilkins 461

4 Teixeira et al Annals of Surgery Volume 258, Number 3, September 2013 TABLE 4. Outcomes Comparison According to the Surgery Timing Groups <24 h (n = 1641), %(n) 24 h (n = 2522), %(n) P AOR (95% CI) Adjusted P Mortality 3.0 (50) 6.5 (163) < ( ) SSIs 10.0 (164) 12.9 (325) ( ) Superficial SSI 6.0 (98) 7.5 (190) ( ) Deep SSI 1.5 (25) 2.0 (50) ( ) Abscess 2.3 (37) 3.3 (84) ( ) Wound dehiscence 1.5 (24) 2.0 (51) ( ) Systemic infectious complications 12.2 (201) 20.5 (518) < ( ) <0.001 Pneumonia 5.2 (86) 7.9 (200) ( ) UTI 3.0 (50) 5.5 (139) < ( ) Sepsis 5.1 (83) 7.6 (191) ( ) Septic shock 3.5 (58) 6.2 (156) < ( ) Unplanned Intubation 3.8 (62) 5.6 (142) ( ) Return to the OR 7.6 (124) 8.5 (215) ( ) OR indicates operating room; SSI, surgical site infection, UTI, urinary tract infection. they recommended caution should the expectant management extend for longer than 2 days. Chu et al 12 also used the Nationwide Inpatient Sample to investigate the impact of surgery timing on the outcomes of patients with ASBO, but contrarily to the previous findings, they did not demonstrate an association between delay and mortality. The major difference between these studies is the fact that Chu et al did not include patients who required bowel resection, which is a major contributor to worse outcomes, including mortality and the need for intensive care. The present study found that a delay in surgery also had a significant negative impact on postoperative complications. A 40% relative reduction in systemic infectious complications was demonstrated for patients undergoing laparotomy within 24 hours compared with the delayed operation group [20.5% vs 12.2%; AOR (95% CI), 1.62 ( ); P < 0.001]. Surgical site infections were also significantly more frequent among the patients with a delayed operation [12.9% vs 10.0%; AOR (95% CI), 1.33 ( ); P = 0.007]. These are consistent with the findings from a retrospective analysis of 91 patients undergoing laparotomy for ASBO in which a delay of more than 48 hours was associated with a 2-fold increase in the rate of postoperative complications. 13 Fevang et al. 14 also demonstrated a significant trend of increasing postoperative complications associated with surgery delay in a review of 496 patients with ASBO treated operatively. Although the mortality also increased with incremental surgery delay in their series, that finding did not reach statistical significance. 14 In a study of 141 patients with complete ASBO, Bickell et al 15 demonstrated that the risk of bowel resection significantly rises when surgery is delayed for more than 24 hours. This finding was not confirmed by the present study, as delayed operation was not associated with significantly higher incidence of enterectomies [26.6% vs 24.3%; AOR (95% CI), 1.03 ( ); P = 0.675]. The concept of bacterial translocation offers a reasonable explanation for the association between surgical delay and the development of systemic infectious complications found in the current study. Bacterial translocation has been defined as the passage of viable bacteria from the intestinal intraluminal compartment into mesenteric lymph nodes and distant organs. 16,17 This concept has been extensively explored as the cause of systemic infections and multiple organ dysfunction syndrome in critically ill patients. 18 During obstructive processes, intestinal peristalsis is disrupted and leads to bacterial overgrowth, 19 which contributes to translocation. In an elegant study, Deitch 20 was able to confirm the occurrence of bacterial translocation in humans by isolating viable bacteria from mesenteric lymph nodes and demonstrate that the incidence of this phenomenon was significantly higher in patients undergoing laparotomy for bowel obstruction than in controls (59% vs 4%; P < 0.001). The occurrence of bacterial translocation was independent of bowel ischemia, as none of the patients in the series had necrotic intestinal segments or required enterectomy. The most common organism isolated was Escherichia coli in 72% of the cases. 20 Similarly, Sagar et al 21 found evidence of bacterial translocation in 40% of patients requiring surgery for bowel obstruction compared with 7% in the control group (P < 0.001). Bacterial translocation has been associated with systemic postoperative infections in both experimental and clinical studies. Using a mouse model of bowel obstruction, Deitch et al 22 demonstrated that within 6 hours of bowel ligation, 60% of the mesenteric lymph nodes were positive for translocated bacteria, and between 24 to 48 hours, the translocation had reached systemic level, with bacteria isolated from liver, spleen, and blood. The number of colony-forming units per gram of tissue had a stepwise increase with time, with a 7-fold increase at 48 hours compared with the levels at 24 hours. 22 In the clinical setting, Shiomi et al 23 demonstrated that patients with mesenteric lymph nodes positive for bacteria were more likely to develop a systemic postoperative infection than controls (71% vs 21%). Sagar et al 21 demonstrated that not only patients with documented translocation had a significantly higher incidence of postoperative systemic infections (36% vs 11%, P < 0.05) but also that the organism responsible for the systemic infection matched the mesenteric node isolate in 43% of the cases. The higher incidence of complications observed among the patients in the delayed surgery group might have contributed to the significantly longer hospital LOS demonstrated for those patients. After adjusting for confounders, delayed operation was associated with estimated additional 5.2 hospital days. This prolongation of hospitalization could not be explained solely by the longer preoperative time that this group, by definition, had. Comparison of the time span between surgery and discharge revealed that after adjustment for confounders, patients who were operated on within the initial 24 hours were discharged on average 2.1 days earlier than the patients in the delayed operation group. One of the challenges during the management of patients with ASBO is the concern that the decision to perform an operation will result in additional adhesion formation and a potentially worse situation in the future. Although a likely explanation for delaying the surgical intervention, this concern is not supported by the available C 2013 Lippincott Williams & Wilkins

5 Annals of Surgery Volume 258, Number 3, September 2013 Surgical Delay Increases Mortality in Patients With SBO literature, as patients treated surgically were found to have both a lower recurrence rate and a longer time to recurrence than those managed conservatively. 24,25 The ability to rule out bowel strangulation secondary to ASBO remains the cornerstone of nonoperative management, but it may be difficult on clinical grounds. 26 What ensues is the risk of selecting patients with silent bowel ischemia or at risk of strangulation to nonoperative management and not recognizing failure of the nonoperative strategy. 27 Although the present study was not designed to address the issue of which patients should be selected for operative treatment, it provides evidence that time is a critical factor in the outcomes of those patients who require surgical intervention. Multiple studies investigating predictors of the need for surgical exploration in patients with ASBO, with emphasis on radiological findings, have been published There is no consensus, however, and the role of these predictors in clinical practice remains unclear. An important adjunct in the decision to proceed with laparotomy is the use of high-osmolarity water-soluble contrast imaging. Water-soluble contrast imaging is useful both to identify those patients who are candidates for nonoperative management and to increase the success rate of this treatment strategy. Two meta-analyses have demonstrated that the presence of contrast in the colon within 24 hours of the admission predicts the resolution of the obstruction with 96% to 97% sensitivity and 96% to 98% specificity. 34,35 According to Branco et al, 34 the use of water-soluble contrast is associated with a significant reduction in the need for surgical intervention and a shorter hospital stay. When these findings are examined in light of the increased complications and mortality associated with surgical delay demonstrated by the present study, they suggest that all patients selected for a trial of nonoperative management of ASBO should undergo a water-soluble contrast study early after the admission and surgical exploration seriously considered if no progression of contrast is identified within 24 hours. The retrospective nature of this study is one of its major limitations. It is possible that surgical delay is a surrogate for an overall worse preoperative status and reflects the reluctance to intervene surgically in such patients. The comprehensive list of variables available in the NSQIP database, however, allowed for a robust comparison of the study groups and assessment of risk-adjusted outcomes, therefore minimizing the selection bias effect. CONCLUSIONS Early operative intervention for patients with ASBO is associated with a significant survival benefit, lower incidence of local and systemic complications, and shorter hospitalization. REFERENCES 1. Barmparas G, Branco BC, Schnüriger B, et al. The incidence and risk factors of post-laparotomy adhesive small bowel obstruction. J Gastrointest Surg. 2010;14: Ray NF, Denton WG, Thamer M, et al. Abdominal adhesiolysis: inpatient care and expenditures in the United States in J Am Coll Surg. 1998;186: Seror D, Feigin E, Szold A, et al. How conservatively can postoperative small bowel obstruction be treated? Am J Surg. 1993;165: ; discussion Tanaka S, Yamamoto T, Kubota D, et al. Predictive factors for surgical indication in adhesive small bowel obstruction. Am J Surg. 2008;196: Jeong WK, Lim S-B, Choi HS, et al. Conservative management of adhesive small bowel obstructions in patients previously operated on for primary colorectal cancer. J Gastrointest Surg. 2007;12: Cox MR, Gunn IF, Eastman MC, et al. The safety and duration of non-operative treatment for adhesive small bowel obstruction. Aust N Z J Surg. 1993;63: Miller G, Boman J, Shrier I, et al. Natural history of patients with adhesive small bowel obstruction. Br J Surg. 2000;87: Diaz JJJ, Bokhari FF, Mowery NTN, et al. Guidelines for management of small bowel obstruction. J Trauma. 2008;64: Catena F, Di Saverio S, Kelly MD, et al. Bologna Guidelines for Diagnosis and Management of Adhesive Small Bowel Obstruction (ASBO): 2010 evidencebased guidelines of the World Society of Emergency Surgery. World J Emerg Surg. 2011;6: Maung AA, Johnson DC, Piper GL, et al. Evaluation and management of small-bowel obstruction: an Eastern Association for the Surgery of Trauma practice management guideline. J Trauma Acute Care Surg. 2012;73 (suppl 4):S362 S Schraufnagel D, Rajaee S, Millham FH. How many sunsets? Timing of surgery in adhesive small bowel obstruction. J Trauma Acute Care Surg. 2013;74: Chu DI, Gainsbury ML, Howard LA, et al. Early versus late adhesiolysis for adhesive-related intestinal obstruction: a nationwide analysis of inpatient outcomes. J Gastrointest Surg. 2012;17: Joseph SP, Simonson M, Edwards C. Lets just wait one more day: impact of timing on surgical outcome in the treatment of adhesion-related small bowel obstruction. Am Surg. 2013;79: Fevang BT, Fevang JM, Søreide O, et al. Delay in operative treatment among patients with small bowel obstruction. Scand J Surg. 2003;92: Bickell NA, Federman AD, Aufses AH. Influence of time on risk of bowel resection in complete small bowel obstruction. J Am Coll Surg. 2005;201: Berg RDR, Garlington AWA. Translocation of certain indigenous bacteria from the gastrointestinal tract to the mesenteric lymph nodes and other organs in a gnotobiotic mouse model. Infect Immun. 1979;23: Deitch EA, Winterton JJ, Li MM, et al. The gut as a portal of entry for bacteremia. Role of protein malnutrition. Ann Surg. 1987;205: Deitch EA. Gut-origin sepsis: evolution of a concept. Surgeon. 2012;10: Roscher R, Oettinger W, Beger HG. Bacterial microflora, endogenous endotoxin, and prostaglandins in small bowel obstruction. Am J Surg. 1988;155: Deitch EAE. Simple intestinal obstruction causes bacterial translocation in man. Arch Surg. 1989;124: Sagar PM, MacFie J, Sedman P, et al. Intestinal obstruction promotes gut translocation of bacteria. Dis Colon Rectum. 1995;38: Deitch EA, Bridges WM, Ma JW, et al. Obstructed intestine as a reservoir for systemic infection. Am J Surg. 1990;159: Shiomi H, Shimizu T, Endo Y, et al. Relations among circulating monocytes, dendritic cells, and bacterial translocation in patients with intestinal obstruction. World J Surg. 2007;31: Barkan HH, Webster SS, Ozeran SS. Factors predicting the recurrence of adhesive small-bowel obstruction. Am J Surg. 1995;170: Williams SB, Greenspon J, Young HA, et al. Small bowel obstruction: conservative vs. surgical management. Dis Colon Rectum. 2005;48: Sarr MG, Bulkley GB, Zuidema GD. Preoperative recognition of intestinal strangulation obstruction. Prospective evaluation of diagnostic capability. Am J Surg. 1983;145: Zielinski MD, Bannon MP. Current management of small bowel obstruction. Adv Surg. 2011;45: Zielinski MD, Eiken PW, Bannon MP, et al. Small bowel obstruction who needs an operation? A multivariate prediction model. World J Surg. 2010;34: Sheedy SP, Earnest F, Fletcher JG, et al. CT of small-bowel ischemia associated with obstruction in emergency department patients: diagnostic performance evaluation. Radiology. 2006;241: Maglinte DDT, Howard TJ, Lillemoe KD, et al. Small-bowel obstruction: stateof-the-art imaging and its role in clinical management. Clin Gastroenterol Hepatol. 2008;6: O Daly BJ, Ridgway PF, Keenan N, et al. Detected peritoneal fluid in small bowel obstruction is associated with the need for surgical intervention. 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6 Teixeira et al Annals of Surgery Volume 258, Number 3, September Branco BC, Barmparas G, Schnüriger B, et al. Systematic review and meta-analysis of the diagnostic and therapeutic role of water-soluble contrast agent in adhesive small bowel obstruction. Br J Surg. 2010;97: Abbas S, Bissett IP, Parry BR. Oral water soluble contrast for the management of adhesive small bowel obstruction. Cochrane Database Syst Rev. 2005:CD DISCUSSANTS G.J. Jurkovich (Denver, CO): Dr Teixeira and colleagues from the University of Southern California have once again managed to challenge current surgical dogma, or perhaps it is that they have recycled this 100-year-old adage, never let the sun set on a bowel obstruction. That, of course, is variably attributed to Charles Scudder, surgeon-in-chief at the Massachusetts General Hospital in 1908 and one of the founders of the ACS. While that adage has guided generations of surgeons, Dr Teixeira has noted in his discussion that the current best national and international evidence-based guidelines regarding the management of bowel obstructions are to decompress the bowel and wait 3 to 5 days for resolution, with care of course being taken during observation period to exclude strangulation or ischemia. What these authors have shown using the NSQIP database is that for a very specific subset of patients, any delay more than 24 hours increases morbidity, mortality, infections, LOS, and, of course, cost. Their data analysis is limited by the administrative database but makes a compelling argument that, for this subset of patients, the longer you wait, the greater the complications. They have managed to add caution to the current guidelines of waiting and watching bowel obstruction and hence have perhaps recycled a century-old adage. This is a very specific subset of patients, namely, only those who eventually underwent operation, and as such, is likely much more specific and maybe even a unique subset of the entire population of patients who present with bowel obstruction. Added to this, are the limitations of the database, which preclude a careful analysis of clinical laboratory findings and the surgical history. Nonetheless, a very similar study presented last year at the American Association for the Surgery of Trauma by Schraufnagel and Milham supports these conclusions in general. They used the National Inpatient Sample Database for 2009, about 8 million people, and identified 27,000 patients with bowel obstruction. Of note, only 5000, or 18%, eventually underwent operation. Like the present study, they observed an increased mortality and complication rate with a delay in surgery, but unlike the present study, they recommend 3 to 5 days of observation as being acceptable, noting that 60% of patients are successfully managed nonoperatively within 3 days, 80% within 5 days, and 90% within 7 days. So what is the magic number of days we should be observing patients with bowel obstruction and no signs of intestinal ischemia? One sunset; 3 sunsets; 5 sunsets? I have the following additional questions for the authors: First, what percentage of patients in the NSQIP database with small bowel obstruction (SBO) is in fact successfully managed nonoperatively? Would not operating at 24 hours for every patient with SBO subject a massive number of patients to an unnecessary operation? Second, are there patients in the NSQIP database with bowel obstruction who underwent an operation that is not categorized as emergent, as this subset was picked out? Are there specific criteria that defined an emergent population? Third, I suspect these data are not available, but how many patients received a water-soluble contrast computed tomography (CT) during their evaluation? Many have suggested, and perhaps most of us now rely upon, this diagnostic and occasionally therapeutic test to separate those with complete versus partial bowel obstruction. I will close, then, with a not uncommon clinical scenario. A patient presents 5 years after trauma laparotomy with signs and symptoms of a nonischemic bowel obstruction. How would you manage this patient? Would you perform an abdominal CT scan with water-soluble contrast, and if the obstruction was incomplete, would you observe that patient, or would you operate within 24 hours? Response From P.G. Teixeira: The Schraufnagel and Milham study added a significant and important contribution to this subject. As you pointed out, both currently available best evidence guidelines in the literature recommend 3 to 5 days of expectant management for patients who present with SBO and no evidence of bowel ischemia. This recommendation, however, is based on the likelihood of spontaneous resolution of the obstruction during this time period and does not take into account the effect of the delay resulting from the observation period in the outcomes of those patients who ultimately require an operation. Schraufnagel and colleagues were able to demonstrate that observation beyond 3 days not only is less likely to be successful but is also associated with increased mortality. They did not, however, investigate whether shorter delays were also detrimental. Our findings are in agreement with theirs and provide additional data suggesting that for patients who require surgical intervention for adhesive bowel obstruction, surgical delay of more than 24 hours is associated with worse outcomes. Furthermore, as suggested by Dr Scudder more than 100 years ago, those patients probably would not see the sunset without an operation. Regarding the nature and the limitation of the NSQIP database, you have made extremely important comments. The NSQIP database includes only those patients who were treated operatively. Our study was not designed and cannot answer the question of which patients need an operation. This is a very important point, and making that distinction is fundamental to an adequate application of our findings. You correctly pointed out that operating at 24 hours for patients presenting with SBO could subject a large number of patients to unnecessary operations. We agree that the majority of ASBO cases will resolve spontaneously. Our goal as surgeons caring for those patients is to determine which patients are likely to fail a trial of nonoperative management, because, based on our findings for that group of patients, the clock is ticking from the moment they come through the door. That is why we used very strict inclusion criteria and selected a well-defined study population. You mentioned that only those patients undergoing emergent operations were included in the study. Indeed, there are patients in the NSQIP database who had nonemergent procedures for a bowel obstruction. We chose not to include those patients because they most likely represent a population with chronic symptoms undergoing elective lysis of adhesions, which puts them in a different category. The challenge is how to expedite the identification of those patients who will fail the period of nonoperative management. You highlight a very important point regarding the use of water-soluble contrast. That data are unfortunately not available in the NSQIP database, but we know from recent systematic reviews that watersoluble contrast imaging is 97% accurate to identify the patients who will need an operation. The use of this imaging modality can, C 2013 Lippincott Williams & Wilkins

7 Annals of Surgery Volume 258, Number 3, September 2013 Surgical Delay Increases Mortality in Patients With SBO therefore, quickly identify patients who are not candidates for nonoperative management and expedite a surgical intervention. Regarding the practical question of a patient with a previous trauma laparotomy now presenting with evidence of nonischemic bowel obstruction, at our institution, this patient would undergo a CT scan of the abdomen and pelvis with water-soluble oral contrast. The patient would be admitted to the surgical observation unit, which is a designated area where the patient can be closely monitored. The follow-up would include serial examinations and serial abdominal x-rays every 4 to 6 hours to monitor the progression of the oral contrast. Failure to demonstrate contrast progression through the colon within 24 hours would be a very strong indication for surgical exploration. DISCUSSANTS M.T. Dayton (Buffalo, NY): I wonder if there might not be a little bias in one of the groups that you looked at, namely, the surgeons. A lot of judgment is involved in making the decision to operate on a patient with bowel obstruction, and I can think of a couple of reasons why we may wait more than 24 hours. One is because we think the bowel obstruction is going to get better. However, the other might be because the patient is sicker, has a bad heart, bad lungs, and we are going to wait a little bit longer, to give the patient a little more of a chance, because we know that the operation carries substantial risk. My question is, in your more than 24-hour group, is it not possible that it disproportionately represented sicker patients; patients with bad lungs, bad hearts, and that may account, at least in part, for the higher incidence of complications that you saw. In fact, I think you showed that the more than 24-hour group had more diabetes, they had more vascular disease, and so forth. So is it not possible that you have biased the sampling by placing more of those sicker patients in that second group, the greater than 24-hour group? Response From P.G. Teixeira: Dr Dayton raises a very important point. The possibility of bias does exist in this type of retrospective study. We used appropriate statistical tools to minimize this bias. As we performed the adjustment using logistic regression analysis, the goal was to control for all the confounding factors identified between the study populations. The database is comprehensive and provides an extensive list of variables that can be included in the logistic regression, therefore minimizing the selection bias. DISCUSSANTS C.E. Lucas (Detroit, MI): My question is a follow-up of Dr Drayton s question. When we go to see the patient with bowel obstruction, we rapidly do a risk-benefit ratio. We know that the 37-year-old patient who had an appendectomy for ruptured appendix 10 years ago can be really helped with a 45-minute operation, whereas the 43-year-old patient who has had prior ovarian cancer and has had radiation creates a more challenging problem. Are you comparing apples and oranges? The comorbidities that you identified do not really address what went on in the belly at a previous operation. Response From P.G. Teixeira: Dr Lucas makes an excellent point, and that is the challenge we face every time we see a patient with SBO; weighting the risk of performing that operation against the risk of observing the patient for 1, 2, or 3 days and, at the end of that period of observation, be forced to perform an operation. Even among those challenging patients that Dr Lucas is referring to, there is a group that will need to be surgically explored irrespective of our initial reluctance to do so. This is the most important message of the study. According to the data, for those patients who cannot get away without an operation, delaying surgery is detrimental, with a significant increase in morbidity and mortality. C 2013 Lippincott Williams & Wilkins 465