The Impact of Intraoperative Adverse Events on the Risk of Surgical Site Infection in Abdominal Surgery

Author(s):
Brandon Wojcik; Kelsey Han; Thomas Peponis; April Mendoza; Martin Rosenthal; Noelle Saillant; Peter Fagenholz; David King; George Velmahos; Haytham Kaafarani

Background:

Intraoperative adverse events (iAEs) were recently shown to independently correlate with an increased risk of postoperative mortality, morbidity, readmissions and length of hospital stay. We sought to further understand the impact of iAEs on surgical site infections (SSIs) in abdominal surgery and delineate which patient populations are most affected.

Hypothesis:

All patients with iAEs have an increased risk for SSI, especially those with pre-existing risk factors for SSI.

Methods:

To identify iAEs, a well-described 3-step methodology was used: (1) the 2007-2012 ACS-NSQIP database was merged with our tertiary academic center’s administrative database, (2) the merged database was screened for iAEs in abdominal surgery using the ICD-9-CM-based Patient Safety Indicator “accidental puncture/laceration”, and (3) each flagged record was systematically reviewed to confirm iAE occurrence. Univariate and backwards stepwise multivariable analyses (adjusting for demographics, comorbidities, type and complexity of surgery) were performed to study the independent correlation between iAEs and SSIs (superficial, deep incisional, and organ-space). The correlation between iAEs and SSIs was especially investigated in patients deemed a priori at high risk for SSIs, specifically those older than 60 and those with diabetes, obesity, cigarette smoking, steroid use or ASA class ≥3.

Results:

A total of 9288 operations were included and iAEs were detected in 183 (1.9%). Most iAEs consisted of bowel (44%) or vessel (29%) injuries and were addressed intraoperatively (92%). SSI occurred in 686 (7.4%) cases and included 331 (3.5%) superficial, 32 (0.34%) deep and 333 (3.6%) organ-space infections. As in our prior studies, iAEs were independently correlated with deep/organ-space SSI [OR=1.94, 95% CI 1.2-3.4, p=0.007]. Most interestingly, the occurrence of an iAE was correlated with increased SSI rate in the low-risk but not the high-risk patient populations. Specifically, iAEs increased SSI in patients younger than 60 [OR=2.69, 95% CI 1.55-4.68, p<0.001], non-diabetics [OR=1.69, 95% CI 1.08-2.67, p=0.02], non-obese [OR=3.03, 95% CI 1.89-4.85, p<0.001], non-smokers [OR=1.7, 95% CI 1.1-2.64, p=0.018], with no steroid use [OR=1.77, 95% CI 1.18-2.65, p<0.005], and with ASA class <3 [OR=2.26, 95% CI 1.31-3.87, p=0.003].

Conclusions:

iAEs are independently associated with increased SSIs, particularly in patients with less pre-existing risk factors for SSI. Preventing iAEs or mitigating their impact, once they occur, may help decrease the rate of SSIs.