Analyzing prophylactic antibiotic administration in procedures lasting more than four hours: Are published guidelines being followed?

Published guidelines for surgical antibiotic prophylaxis recommend that an appropriately selected and administered antibiotic should be repeated in a timely manner in lengthy procedures. To assess concordance with published guidelines we reviewed the prophylactic antibiotic usage in procedures lasting more than 4 hours at a 500-bed university hospital. The records of 300 procedures longer than 4 hours in duration from the gastrointestinal, neurosurgery, and vascular surgery services were retrospectively reviewed. Analysis was confined to the usage of antibiotics in a prophylactic setting. Using a liberal interpretation of the American College of Surgeons, Centers for Disease Control and Prevention, Surgical Infection Society, and Medical Letter Guidelines each case was evaluated for the appropriateness of the antibiotic selection, the interval between the first dose and the skin incision, and the timeliness of repeat dosing. Twenty-five patients (8.3%) did not receive any antibiotic coverage at all. One hundred ninety cases (63.3%) received the correct antibiotic, but only 96 (32%) received it in a timely manner before surgery. Nine patients (3%) in 300 cases received repeat doses at the correct time for the entire duration of the surgery in complete compliance with the published guidelines. We conclude that antibiotic prophylaxis of lengthy procedures is rarely in accordance with published guidelines.