imageBy George Ochoa

A delay of more than six hours from the time of admission to the time of appendectomy was associated with an increased risk for surgical site infection (SSI) among patients with nonperforated appendicitis, according to a study in Annals of Surgery (2012;256:538-543).

The paper’s lead author, Pedro G. Teixeira, MD, surgical critical care fellow, Department of Surgery, University of Southern California (USC), Los Angeles County (LAC) + USC Medical Center, in Los Angeles, told General Surgery News, “As a surgical community, we’ve attempted to decrease the rate of complications. SSIs have been used as a marker of quality care delivery. Identifying something that we do that increases the rate of SSIs is very relevant.”

In the retrospective study, the records of patients admitted with appendicitis to LAC+USC Medical Center from July 2003 to June 2011 were reviewed. Over the eight-year period, 4,529 patients were admitted with appendicitis and 4,108 (91%) underwent appendectomy. Perforation occurred in 23% (942) of the patients who received appendectomy. A delay to appendectomy was not associated with a higher perforation rate.

After adjusting for age, leukocytosis, sex, surgical technique (open vs. laparoscopic) and perforation, the time from admission to appendectomy (time to appendectomy) greater than six hours was independently associated with an increase in SSI (odds ratio [OR], 1.54; 95% confidence interval [CI], 1.01-2.34; P=0.04). Time to appendectomy did not significantly increase SSI risk in patients with perforated appendicitis, but it did so in patients without perforation. A delay of greater than six hours resulted in a significant increase in SSI from 1.9% to 3.3% in patients with nonperforated appendicitis (OR, 2.16; 95% CI, 1.03-4.52; P=0.03], such that the incidence of SSI in nonperforated appendicitis reached a level similar to that with perforation (3.3% vs. 3.9%; P=0.47).

The average time from admission to appendectomy was 11 hours and 50 minutes. Dr. Teixeira noted that this was “a little long,” although 36% of patients were operated on within six hours.

“There are several reasons for a delay,” he said. “Because some data show that a delay is acceptable, some surgeons are reassured that it wouldn’t negatively affect the outcomes. Also, we have a very busy hospital, and even though it is open 24/7, in some cases multiple trauma patients might affect the timing and cause a delay.”

John E. Mazuski, MD, PhD, professor of surgery, Washington University School of Medicine, in St. Louis, who was not associated with the study, wrote by email: “This is an important paper from several standpoints. A key point is that it is a very large, albeit retrospective study.” The important conclusions, he stated, are “that appendiceal perforation is not directly related to timing of appendectomy” and “that there was an important consequence to a delay in appendectomy, which is an increase in infectious risk.”

Dr. Mazuski noted several limitations of the study, including the use of a composite end point for SSI that “does intermix complications which may be of different importance” as well as the restriction to the experience of a single public hospital.

“Another limitation with the paper is the way in which delay of appendectomy was measured,” he said. “The time recorded is that between hospital admission and appendectomy, but neither of these is precisely characterized. … [Another] major potential limitation is the lack of data on antibiotic usage relative to the delay. … Were the patients experiencing a significant delay (>6 hours) being treated with antibiotics?”

Regarding how the study should affect clinical practice, Dr. Teixeira said, “Our paper suggests that expediting surgical intervention is appropriate. It may not be appropriate to wait more than six hours.”

“I think it would be premature to suggest that practice patterns should be altered based on the findings of this study,” Dr. Mazuski countered. “To bring the performance of appendectomy down to the suggested six-hour time point … would probably require a significant increase in resources just for this one disease process.” The “role of antibiotics in permitting a safe delay in appendectomy” needs to be addressed with further research, he said.

Dr. Teixeira reported no relevant financial conflicts of interest. Dr. Mazuski reported receiving research funding and serving as a consultant and speaker for several pharmaceutical companies making antibiotics that can be used in the treatment of intra-abdominal infections, including AstraZeneca, Forest Laboratories, Merck and Pfizer.