Surgical site infection and timing of prophylactic antibiotics for appendectomy

Pre-operative prophylactic antibiotics may decrease the frequency of surgical site infection after appendectomy. However, the optimal timing for administration of pre-operative prophylactic antibiotics is unknown. The purpose of this study was to evaluate the effect of timing of prophylactic antibiotics on the frequency of surgical site infection after appendectomy.

Medical records were reviewed retrospectively for 577 consecutive patients who had appendectomy for acute appendicitis from 2006 to 2009. Quality assurance guidelines for timing of prophylactic antibiotics before the skin incision were changed from 0 to 30 min before the skin incision (before June 2008) to 30 to 60 min before the skin incision (after June 2008).

Surgical site infection occurred in 28 patients (4.9%). There was no difference in frequency of surgical site infection with different timing of pre-operative prophylactic antibiotic (pre-operative time 0 to 30 min: 9 infections [3.6%]; 31 to 60 min: 13 infections [5.4%]; 61 to 120 min: 5 infections [7.0%]; >120 min: 1 infection [6.6%]). Multivariable analysis showed that surgical site infection was associated significantly with medical comorbidity but not perforated appendicitis.

The frequency of surgical site infection was independent of timing of preoperative prophylactic antibiotics but was associated with the presence of medical comorbidity.