Blood cultures not helpful for community-acquired pneumonia

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Blood cultures not helpful for community-acquired pneumonia

J Fam Pract. 2003 August;52(8):587-604

By

David L. Priebe, MD

Lee Chambliss, M. , MD MSPH

BACKGROUND: Many clinical guidelines recommend routine blood cultures in the initial evaluation of community-acquired pneumonia. Previous research cast doubt on this approach.¹
POPULATION STUDIED: The researchers recruited adults presenting with community-acquired pneumonia to 19 Canadian hospital emergency departments between January and July 1998. Patients were eligible if they had 2 or more signs or symptoms—including temperature <38°C, productive cough, chest pain, dyspnea, and crackles on auscultation—and a chest radiograph showing an opacity compatible with acute pneumonia.
STUDY DESIGN AND VALIDITY: This was a prospective observational study that used data gathered from a prior multicenter clinical trial, conducted to determine the effects of a clinical pathway for community-acquired pneumonia.² Patients were assigned, using cluster randomization, to a conventional or study arm.
OUTCOMES MEASURED: Investigators reported the percentage of positive blood cultures, how the results led to a change in antibiotic therapy, and whether the changes were appropriate. They also determined if blood cultures correlated with severity of illness, using the Pneumonia Severity Index Scores (PSIS).
RESULTS A total of 1743 patients met inclusion criteria and 1022 were admitted. Of these, 716 were randomized to the intervention arm and 1027 to the conventional arm. Blood cultures were drawn on 760 (74.4%) patients. Forty-three (5.66%) had positive blood cultures with significant organisms. The pathogens cultured were the usual pneumonia organisms—Streptococcus pneumoniae (68.%), Staphlococcus aureus (11%), and Hemophilus influenzae (11%), with small percentages of Escherichia coli, Enterobacteraceae, and Klebisella pneumoniae. The cost of 2 blood cultures was $41.70, yielding a total cost of roughly $31,000, or $2000 (Canadian) per positive blood culture that lead to a change in therapy.

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Blood cultures not helpful for community-acquired pneumonia

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