Are blood cultures effective in the evaluation of fever in perioperative patients?

Blood cultures are routinely performed as part of the evaluation of fever in the perioperative period. Results of 364 blood culture vials representing 108 consecutive febrile events (temperature greater than or equal to 101.5 degrees F) in 72 patients on adult surgical services without evidence of sepsis in a metropolitan hospital were prospectively studied. Eighty-nine percent of patients had undergone an operation prior to the febrile episode. Microorganisms were isolated in blood culture vials from 9 of 108 patient febrile events. Of these blood cultures, five were positive (contained pathogens), and four represented contaminants. Two of five positive blood cultures occurred in patients with an identifiable source of bacteremia. The cost of processing all blood culture vials was $13,992, which amounted to $2,798 spent to identify each of the five patients with positive blood cultures. Blood culture vials were more likely to be positive if blood was drawn during postoperative days 4 through 10, as opposed to days 1 through 3, or if it was drawn from patients with factors depressing immune function or who had indwelling devices. Neither the magnitude of the absolute leukocyte count nor the maximum temperature at the time of phlebotomy predicted a positive blood culture. The use of resin vials produced sterile cultures in the 10 vials submitted. In no case did a positive blood culture have a measurable effect on reducing patient morbidity or mortality.