Clinical aspects and predictors of mortality of Pseudomonas aeruginosa pneumonia in a cohort of critically ill patients

Introduction

Pseudomonas aeruginosa (PA) pneumonia (PN) represents a serious complication of long-term hospitalization [1]. The aim of our study is to analyze the clinical characteristics and predictors of mortality of PAPN in critically ill patients.

Methods

All patients admitted to the 18-bed ICU of our university hospital between 1 January 2009 and 30 June 2010, affected by PAPN, were retrospectively enrolled in a cohort study.

Results

Over the study period 1,109 patients were admitted and 322 bacterial PN were diagnosed. Sixty-five PAPN occurred: 52 ICU-acquired (ICUa) and 13 non-ICU-acquired (nICUa). Patients were mainly admitted because of a medical condition (71%), with a median length of ICU stay of 29.2 ± 27.6 days. The median SAPS II and SOFA scores were 40 ± 13.5 and 6.2 ± 3. A total of 35.4% of PA isolated were multidrug-resistant (MDR), 49.2% of patients with PAPN received a >24 hour delayed adequate antimicrobial treatment (DAAT >24 hours) and 57% received an anti-pseudomonas combination therapy; 25 patients (38.5%) died in the ICU. Comparing patients with ICUaPN with those with nICUaPN, the former group were younger (P < 0.01), with a longer length of ICU stay (P < 0.01), more frequently admitted for a traumatic reason (P = 0.02) and presented less severe SAPS II (P < 0.05). The independent risk factors associated with ICU mortality are listed in Table 1.

Table 1 Chronic renal failure (CRF)

Conclusions

PA has appeared as a relevant respiratory pathogen in our cohort of critically ill patients, either in ICU or pre/ICU settings. Patients' (baseline clinical condition), PA (MDR) and physicians' (DAAT >24 hours) related factors can influence the outcome of PN. The knowledge of local bacterial epidemiology and the prompt use of an anti-pseudomonas empiric treatment in patients with recognized PA risk factors could improve the outcome of severe MDR PAPN.