Antibiotic timing and errors in diagnosing pneumonia.

Background: The percentage of patients with community-acquired pneumonia (CAP) whose time to first antibiotic dose (TFAD) is less than 4 hours of presentation to the emergency department (ED) has been made acorequalitymeasure,andpublicreportinghasbeeninstituted. We asked whether these time pressures might also have negative effects on the accuracy of diagnosis of pneumonia. Methods:We performed a retrospective review of adult admissionsforCAPfor2periods:group1,whenthecore quality measure was a TFAD of less than 8 hours; and group2,whentheTFADwasloweredtolessthan4hours. We examined the accuracy of diagnosis of CAP by ED physicians. Results:Atotalof548patientsdiagnosedashavingCAP were studied (255 in group 1 and 293 in group 2). At admission,group2patientswere39.0%lesslikelytomeet predefined diagnostic criteria for CAP than were group 1 patients (odds ratio, 0.61; 95% confidence interval, 0.42-0.86) (P=.004). At discharge, there was agreement between the ED physician’s diagnosis and the predefined criteria for CAP in 62.0% of group 1 and 53.9% of group 2 patients (P=.06) and between the ED physician’s admitting diagnosis and that of the discharging physician in 74.5% of group 1 and 66.9% of group 2 patients (P=.05). The mean (SD) TFAD was similar in group 1 (167.0 [118.6] minutes) and group 2 (157.8 [96.3] minutes). Conclusion:Reduction in the required TFAD from 8 to 4 hours seems to reduce the accuracy by which ED physicians diagnose pneumonia, while failing to reduce the actual TFAD achieved for patients.