Transcript Document

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
# Positive Blood Culturess
14
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.
‫‏‬
‫‏‬
‫‏‬
‫‏‬
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A prior retrospective chart review conducted at York Hospital (unpublished data)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.
8
6
4
2
PSI I
n=66
PSI II
n=86
PSI III
n=142
PSI IV
n=287
PSI V
n=190
Pneumonia Severity Index Score
Figure 3. Breakdown of Positive Blood
Cultures, grouped by PSI Score
http://www.biomerieux.com/upload/bactalert_culture_media_press_thumb1.jpg
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.
10
0
Introduction:
‫‏‬
12
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
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%
Table 1. Pneumonia Risk Factors That Might
Predict Positive Blood Cultures
Pneumonia Risk Factors
p= *
OR
95% CI
COPD
0.242
0.601
(0.242-2.738)
Immunocompromised
0.739
0.814
(0.242-2.738)
Nursing Home Resident
0.139
0.456
(0.157-1.323)
Previous Hospitalization
0.936
1.143
(0.458-2.851)
Pneumonia Severity Index
p= *
OR
95% CI
PSI I
0.774
1.196
(0.353-4.052)
PSI II
0.426
0.559
(0.131-2.387)
PSI III
0.801
0.882
(0.332-2.345)
PSI IV
0.222
0.602
(0.264-1.371)
PSI V
0.046
2.109
(0.996-4.462)
*Pearson Chi Square Test
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 = 0.046 by Pearson Chi Square Test and
Odds Ratio = 2.109 (95% CI = 0.996 – 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. 1995.
Clinical Utility of Blood Cultures in Adult Patients with Community-Acquired
Pneumonia Without Defined Underlying Risks. Chest 108:932-936.
‫ ‏‬Theerthakarai R., El-Halees W., Ismail M., Solis R.A., Khan M.A. 2001. Nonvalue
of the Initial Microbiological Studies in the Management of Nonsevere CommunityAcquired Pneumonia. Chest 119:181-184.
‫ ‏‬Campbell S.G., Marrie T.J., Anstey R., Dickinson G., Ackroyd-Stolarz S. 2003. The
Contribution of Blood Cultures to the Clinical Management of Adult Patients
Admitted to the Hospital With Community-Acquired Pneumonia. Chest 123:11421150.
‫ ‏‬Bryan C.S. 1999. Blood Cultures for Community-Acquired Pneumonia. Chest
116:1153-1155.
‫ ‏‬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. 1997. A Prediction Rule to Identify Low-Risk
Patients with Community-Acquired Pneumonia. New England Journal of Medicine
336:243-250.
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
# Positive Blood Culturess
14
12
10
8
6
4
2
0
PSI 1
n=66
PSI 2
n=86
PSI 3
n=142
PSI 4
n=287
Pnuemonia Severity Index Score
PSI 5
n=190