Cephalothin prophylaxis in cardiac valve surgery. A prospective, double-blind comparison of two-day and six-day regimens.

A prospective, double-blind study comparing a 6 day with a 2 day regimen of cephalothin prophylaxis was conducted among 200 patients undergoing prosthetic valve replacement. No cases of endocarditis occurred during the 2 month follow-up. Sternal wound infection developed in 2.8 per cent of the 6 day group and 2.1 per cent of the 2 day group. Pneumonia developed in 8.5 per cent of the 6 day and 5.3 per cent of the 2 day group; most of the bacteria isolated were susceptible to cephalothin. Urinary tract infection developed more frequently in the 2 day group (17.0 versus 8.5 per cent), particularly during the first 6 postoperative days. Three of 11 patients with no detectable cephalothin in their sera at the close of operation developed staphylococcal wound infections, compared with 2 of 175 patients whose sera contained cephalothin at the close of surgery (p = 0.002, Fisher's exact test). A short course of prophylactic antibiotics is prudent, but there is no justification for prolonging their administration.