Selective versus routine antibiotic use in acute appendicitis.

Whether prophylactic antibiotics should be employed routinely in all patients with presumed appendicitis rather than be administered selectively to those with suspected perforation remains a controversial issue. The outcome of 312 adult patients undergoing appendectomy during periods of selective (I, n = 153) and routine (II, n = 159) antibiotic use were compared. Although the rates of misdiagnosis were comparable (9% vs 13%), significantly more patients with appendicitis in Period II had perforated appendicitis (29 of 139 vs 44 of 139, P less than 0.05). Prophylactic antibiotics were given to 43 (28%) patients in Period I compared to 132 (83%) in Period II (P less than 0.001). This, increased frequency was true for both simple (21% vs 81%, P less than 0.001) and perforated (66% vs 86%, P less than 0.05) appendicitis. A single antibiotic, most frequently a cephalosporin, was used significantly more often in Period II (44% vs 82%, P less than 0.001). There was no significant difference in the methods of wound closure between the two periods. The incidence of infectious complications was similar in patients with simple appendicitis in both periods (8% vs 11%), but it was significantly greater during Period I in patients with perforated appendicitis (45% vs 20%, P less than 0.05). The overall infection rate was similar in both periods (16% vs 22%). Thus, high-risk patients with perforated appendicitis were more likely to receive antibiotics and had a lower infection rate with routine antibiotic use. Furthermore, there was no overall change in the infection rate during this period, despite the use of less toxic, single drug regimens and a greater percentage of perforated appendicitis.