Assessment of the value of routine blood cultures in the evaluation and treatment of patients with chorioamnionitis.

ABSTRACT

OBJECTIVE: The objective of this investigation was to determine the usefulness of blood cultures in evaluating patients with chorioamnionitis who were treated in accordance with a specific antibiotic protocol. METHODS: We reviewed the records of 539 patients with chorioamnionitis who delivered at our facility over a 3 year period (July 1, 1989-June 30, 1992). Patients had one set of aerobic and anaerobic blood cultures at the time of their initial assessment. They were treated initially with ampicillin or vancomycin plus gentamicin. Those who required cesarean delivery also received clindamycin postoperatively. Patients who had a poor initial response to therapy were treated empirically with selected antibiotics targeted against likely resistant organisms until the results of bacteriologic cultures were available. Bacteremic patients had repeat blood cultures while on therapy. We analyzed the medical records to determine the frequency with which blood culture results led to meaningful changes in patient management. We also compared the duration of febrile morbidity in bacteremic vs. nonbacteremic patients. RESULTS: Thirty-nine of 538 patients (7.2%, 95% confidence interval [CI] 5.2-9.2%) had positive blood cultures. In only one patient did the result of the blood culture definitively alter therapy. This patient had a fever of unknown origin, and the finding of a positive blood culture ultimately led to the diagnosis of chorioamnionitis. The mean duration of febrile morbidity was not significantly different in bacteremic vs. nonbacteremic patients (2.03 vs. 1.74 days). None of the repeat blood cultures was positive. The cost of blood cultures in the study population was $72,759.00. CONCLUSIONS: The routine use of blood Cultures in the assessment of patients with chorioamnionitis rarely provides information that justifies a change in clinical management when patients are treated in accordance with the specific antibiotic protocol outlined in this investigation.