Appendectomy timing: waiting until the next morning increases the risk of surgical site infections

To investigate the association between time from admission to appendectomy (TTA) and the incidence of perforation and infectious complications.

Immediate appendectomy to prevent perforation has been challenged by recent studies supporting a semielective approach to acute appendicitis.

Patients admitted with appendicitis from July 2003 to June 2011 were reviewed. Age, sex, admission white blood cell count, surgical approach (open vs laparoscopic), TTA, and pathology report were abstracted. Primary outcomes included perforation and surgical site infection (SSI). Logistic regression was performed both to identify independent predictors of perforation and to investigate the association between TTA and SSI.

Over 8 years, 4529 patients were admitted with appendicitis and 4108 (91%) patients underwent appendectomy. Perforation occurred in 23% (n = 942) of these patients. Logistic regression identified 3 independent predictors of perforation: age 55 years or older [odds ratio (95% confidence interval) OR (95% CI), 1.66 (1.21-2.29); P = 0.002], white blood cell count more than 16,000 [OR (95% CI), 1.38 (1.15-1.64); P < 0.001], and female sex [OR (95% CI), 1.20 (1.02-1.41); P = 0.02]. Delay to appendectomy was not associated with higher perforation rate. However, after controlling for age, leukocytosis, sex, laparoscopic approach, and perforation, TTA of more than 6 hours was independently associated with an increase in SSI [OR (95% CI), 1.54 (1.01-2.34); P = 0.04]. Delay of more than 6 hours resulted in a significant increase in SSI from 1.9% to 3.3% among patients with nonperforated appendicitis [OR (95% CI), 2.16 (1.03-4.52); P = 0.03], raising the incidence of SSI in nonperforated appendicitis to levels similar to those with perforation (3.3% vs 3.9%, P = 0.47).

In this series, appendectomy delay did not increase the risk of perforation but was associated with a significantly increased risk of SSI in patients with nonperforated appendicitis. Prompt surgical intervention is warranted to avoid additional morbidity in this population.