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Croatian Medical Journal, Vol. 53 No. 1, 2012.

Original scientific paper

Predictors of positive blood cultures in critically ill patients: a retrospective evaluation

Marco Previsdomini orcid id orcid.org/0000-0001-6361-3187 ; Intensive Care Unit, Ospedale Regionale Bellinzona e Valli Bellinzona, Switzerland
Massimiliano Gini ; Department of Internal Medicine Ospedale Regionale Bellinzona e Valli, Bellinzona, Switzerland
Bernard Cerutti ; Unit of Development and Research in Medical Education Faculty of Medicine, University of Geneva, Geneva, Switzerland
Marisa Dolina ; Cantonal Institute of Microbiology Bellinzona, Switzerland
Andreas Perren orcid id orcid.org/0000-0001-8834-5385 ; Intensive Care Unit, Ospedale Regionale Bellinzona e Valli Bellinzona, Switzerland

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Abstract

Aim To identify predictors of bacteremia in critically ill patients,
to evaluate the impact of blood cultures on the outcome,
and to define conditions for breakthrough bacteremia
despite concurrent antibiotic treatment.
Methods A descriptive retrospective study was performed
over a two-year period (2007-2008) in the medico-surgical
Intensive Care Unit (ICU) of the San Giovanni Hospital in
Bellinzona, Switzerland.
Results Forty-five out of 231 patients (19.5%) had positive
blood cultures. Predictors of positive blood cultures
were elevated procalcitonin levels (>2 μg/L, P < 0.001),
higher severity scores (Simplified Acute Physiology Score
II>43, P = 0.014; Sequential Organ Failure Assessment >4.0,
P < 0.001), and liver failure (P = 0.028). Patients with bacteremia
had longer hospital stays (31 vs 21 days, P = 0.058),
but their mortality was not different from patients without
bacteremia. Fever (t > 38.5°C) only showed a trend toward
a higher rate of blood culture positivity (P = 0.053). The rate
of positive blood cultures was not affected by concurrent
antibiotic therapy.
Conclusions The prediction of positive blood culture results
still remains a very difficult task. In our analysis, blood
cultures were positive in 20% of ICU patients whose blood
was cultured, and positive findings increased with elevated
procalcitonin levels, liver failure, and higher severity scores.
Blood cultures drawn >4 days after the start of antibiotic
therapy and >5 days after surgery could detect pathogens
responsible for a new infection complication.

Keywords

Hrčak ID:

82891

URI

https://hrcak.srce.hr/82891

Publication date:

15.2.2012.

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