Identifying Risk Factors for Postoperative Sepsis in Laparoscopic Gastric Bypass

L J Blair, MD, T C Cox, MD, C R Huntington, MD, T Prasad, MA, A E Lincourt, PhD, MBA, K S Gersin, MD, FACS, FASMBS, B T Heniford, MD, FACS, V A Augenstein, MD, FACS. Carolinas Medical Center

Introduction: Surgeons should consider optimizing a patient’s modifiable risk factors before elective surgery to reduce morbidity and mortality. Postoperative sepsis is a rare but serious complication following elective surgery. The purpose of this study was to identify the rate of postoperative sepsis following elective laparoscopic gastric bypass and to identify pertinent pre-operative risk factors.

Methods: The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was queried from 2005 – 2012 for the top CPT codes associated with the development of postoperative sepsis following laparoscopic gastric bypass. Patients who developed sepsis following this procedure were compared to those who did not. Results were analyzed using the chi square test for categorical variables and Wilcoxon two sample test for continuous variables. A multiple logistic regression model was used to estimate the odds ratio of developing sepsis associated with current smoking, while controlling for age, race, gender, BMI, CCI score, and operative time.

Results: During the study period, 56,060 patients underwent laparoscopic gastric bypass. Of those, 470 patients developed postoperative sepsis (0.84%). Patient demographics and comorbidities were compared as seen in Table 1. Specifically, the development of sepsis was associated with increased operative time (p<0.001), greater number of preoperative comorbidities including diabetes (p<0.001), hypertension (p<0.001), current tobacco use (p<0.003), and increased pack year smoking history (p<0.001). Length of stay was significantly greater in the sepsis group (10.5±14.2 days vs 2.4±5.1 days, (p<0.001). There was over a 40 times greater chance of 30- day mortality for patients who developed sepsis (4.5% vs 0.11%, p<0.001). Multiple logistic regression analysis showed that current smokers had a 61 % greater chance of developing sepsis compared to non-smokers, controlling for age, race, gender, BMI, CCI score, and operative time (OR: 1.61, 95% CI:1.22 – 2.13; p-value = 0.0009).

Conclusions: Laparoscopic gastric bypass is uncommonly associated with postoperative sepsis. When it occurs, it portends a considerably greater chance of death. Current smoking status and pack-years are independently associated with the chance of post-operative sepsis and are modifiable risk factors. Therefore, cessation of smoking should be strongly advocated before surgery.

Table 1 – NSQIP Characteristics of the Postoperative Sepsis and No Sepsis Groups Following Laparoscopic Gastric Bypass

Sepsis

(n=470)

No sepsis

(n= 55,590)

P value
Age (years) 47.6±11.3 44.9±11.4 0.001
BMI (kg/m2) 47.3±8.9 46.7±8.2 0.199
Operative time (minutes) 160±75 135±55 0.001
Diabetes (% patients) 40% 30% 0.001
Hypertension (% patients) 66% 54% 0.001
Smokers (pack years) 80(8.7±18.5) 6,472(5.6±14.2) 0.001
Length of stay (days) 10.6±14.2 2.4±5.1 0.001
30 day mortality 4.5% 0.11% 0.001

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