Penicillin skin testing in cardiac surgery

BackgroundPenicillin is the most commonly reported allergy in cardiac surgical patients and a history of penicillin allergy frequently results in the use of vancomycin for antibiotic prophylaxis. However, clinical history is unreliable and true allergy is rare. Penicillin allergy testing has the potential to reduce vancomycin use and indirectly the potential for selection of vancomycin-resistant organisms, a national priority.MethodsAfter the publication of the 2007 Society of Thoracic Surgeons practice guideline report, we initiated a penicillin allergy testing service for cardiac surgical patients in 2009. We sought to determine the true incidence of penicillin allergy in the tested population, whether testing availability reduced vancomycin use in those tested, and if vancomycin use was reduced in the entire cardiac surgical population as a whole.ResultsA total of 276 patients were skin tested for allergy to penicillin or cephalosporin. Testing recommended no penicillin use in 13.8% of those tested giving a true penicillin allergy incidence of 0.9%. Only 24 of the 276 patients tested (9%) received vancomycin. However, given the small percentage of the total population that underwent allergy testing, the overall use of vancomycin in the cardiac surgery practice was not reduced in the posttesting period.ConclusionsThe true rate of contraindication to penicillin in a cardiac surgical population is very low. Penicillin allergy testing can reduce vancomycin use in the tested population, but better means of conducting the testing and making the results available are necessary to reduce unnecessary vancomycin use in a broader cardiac surgical population.