Utility of Blood Cultures in Pneumonia Patients Admitted Through The Emergency Department Donald N. Pyle, II, *Ronald S. Benenson MD, *Andrew M. Kepner MD York College of Pennsylvania and *York Hospital, York, PA Abstract: ‏Blood cultures have become a standard of care for proper diagnosis of pneumonia patients. The objective of this study was to identify risk factors that would enable Emergency Department (ED) clinicians to reduce or eliminate blood cultures in pneumonia patients. 882 records of patients admitted to York Hospital through the ED were reviewed. Out of the 771 eligible charts, 4% were found to have positive blood cultures. Of these, all were found to be sensitive to standard pathway antibiotics that are part of a pathway set already utilized in the ED. The only correlation between risk factors evaluated and positive blood cultures were in PSI V patients, and this relation was marginal, at best. Introduction: The American Thoracic Society and the American Society for Infectious Diseases recommend two sets of blood cultures as part of the evaluation of hospitalized pneumonia patients. A number of studies in the literature suggest that there is limited utility to these blood cultures: ‏In 1995, Chalisani et al. found a 6.6% positive blood culture rate among hospitalized patients with pneumonia. The most common pathogen was Streptococcus pneumoniae with a few positive cultures for Haemophilus influenzae, Streptococcus pyogenes and Escherichia coli. Of the 34 patients with positive blood cultures, only seven had a change in therapy based on the blood cultures. ‏Theerthakarai et al. (2001) performed a prospective evaluation of 74 hospitalized patients with non-severe community-acquired pneumonia and found that none of the 74 had positive blood cultures. This also would agree with limited usefulness of using blood cultures. ‏Campbell et al. (2003) had a similar positive blood culture rate of 5.7% among hospitalized patients with pneumonia. Their conclusion was that blood cultures have limited usefulness in the routine management of patients admitted to the hospital with uncomplicated community-acquired pneumonia. ‏A prior retrospective chart review conducted at York Hospital (unpublished data) consisted of 531 patients with pneumonia admitted to the hospital through the ED. Results showed only 34 of 1,079 (3.2%) blood cultures were positive. Out of these positive blood cultures, five of them contained organisms which were resistant to pneumonia pathway antibiotics (Pseudomonas, Streptococcus viridans, and MRSA). All positive blood cultures were from patients who had either come from an extended care facility or who had been hospitalized in the past two months. ‏Bryan (1999) published a contradictory argument to the limited usefulness of blood cultures. According to his research, situations which would warrant blood cultures include altering therapy based on a positive blood culture or treating unanticipated resistant organisms. Bryan commented that pneumococcal pneumonia was “an inappropriate place to begin cost cutting”. He pointed out two anecdotal cases where positive blood cultures did alter therapy. Bryan suggested that positive blood cultures “remain the gold standard” for the diagnosis of pneumococcal pneumonia. Objectives: By carefully reviewing a large database of pneumonia patients, we expect 1.) to identify criteria that predict positive blood culture results, and 2.) to develop an approach to use these criteria in the Emergency Department. Results: ‏882 charts reviewed ‏111 excluded due to a non-pneumonia discharge diagnosis, such as a non-positive x-ray finding (Figure 1) ‏771 eligible charts identified ‏30 (4%) patients had positive blood cultures (Figure 3) ‏PSI Risk Class V was found to have p = by Pearson Chi Square Test and Odds Ratio = (95% CI = – 4.462) for positive blood cultures (Table 1) ‏All positives were sensitive to standard pneumonia pathway antibiotics Conclusions: ‏There is no statistically significant correlation between risk factors studied and positive blood cultures except PSI Risk Class V (Table 1) ‏All positive blood cultures were sensitive to pneumonia pathway antibiotics ‏In our community hospital population the addition of blood cultures did not affect clinical management and suggests that they may be eliminated for many pneumonia patients Literature Cited: ‏Chalasasni N.P., Valdecanas M.A., Gopal A.K., McGowan J.E., Jurado R.L Clinical Utility of Blood Cultures in Adult Patients with Community-Acquired Pneumonia Without Defined Underlying Risks. Chest 108: ‏Theerthakarai R., El-Halees W., Ismail M., Solis R.A., Khan M.A Nonvalue of the Initial Microbiological Studies in the Management of Nonsevere Community- Acquired Pneumonia. Chest 119: ‏Campbell S.G., Marrie T.J., Anstey R., Dickinson G., Ackroyd-Stolarz S The Contribution of Blood Cultures to the Clinical Management of Adult Patients Admitted to the Hospital With Community-Acquired Pneumonia. Chest 123: ‏Bryan C.S Blood Cultures for Community-Acquired Pneumonia. Chest 116: ‏Fine M.J., Auble T.E., Yealy D.M., Hanusa B.H., Weissfeld L.A., Singer D.E., Coley C.M., Marrie T.J., Kapoor W.N A Prediction Rule to Identify Low-Risk Patients with Community-Acquired Pneumonia. New England Journal of Medicine 336: Acknowledgments: Special thanks for time spent in advising and assistance with this project: ‏ - Melissa Schlenker - Emergency Dept. Research Associate, York Hospital ‏ - Daniel Dowd, DO - Emergency Dept. Attending, York Hospital ‏ - Deborah Ricker, Ph.D. – Biology Dept. Chair, York College of PA ‏ - Bradley Rehnberg, Ph.D – Biology Dept. Professor, York College of PA Pneumonia Risk Factorsp= *OR95% CI COPD ( ) Immunocompromised ( ) Nursing Home Resident ( ) Previous Hospitalization ( ) Pneumonia Severity Indexp= *OR95% CI PSI I ( ) PSI II ( ) PSI III ( ) PSI IV ( ) PSI V ( ) Table 1. Pneumonia Risk Factors That Might Predict Positive Blood Cultures Figure 3. Breakdown of Positive Blood Cultures, grouped by PSI Score *Pearson Chi Square Test Methods: ‏A retrospective chart review of pneumonia patients admitted through the ED for 2001 & 2002 ‏IRB/HIPAA approvals obtained ‏Patients were identified by the Pneumonia admission DRG (96, 97) ‏Patients were >18 years old ‏Antibiotics were started in the ED. These were based on a Pneumonia Pathway that has been used at York Hospital for the past 10 years ‏Following risk factors were evaluated: ‏- pneumonia severity index (PSI), used for the evaluation of comorbidity ‏ factors, devised by Fine et al. (1997) ‏- recent hospitalization ‏- immunocompromised state ‏- nursing home residency ‏- Chronic Obstructive Pulmonary Disease ‏Bacterial sensitivity to standard pneumonia pathway antibiotics was analyzed ‏Data analyzed: Pearson Chi-Square Test, Odds Ratios, CI 95% Figure 1. Pneumonia-infected Lungs of an Adult, as Observed by X-ray. Spatial Opaqueness in the Lower- Right Lobe (Lower-left cloudiness in Photo) are Indicative of Pneumonia. Figure 2. Plastic-Bottled Blood Cultures have Become more Popular for Safety-Precaution Measures in many Hospitals