Impact of hyperoxemia on mortality in critically ill patients with ventilator-associated pneumonia

Background: The objective of this study was to assess the impact of hyperoxemia on mortality in critically ill patients with ventilator-associated pneumonia (VAP). Methods: This observational study was performed in a 50-bed mixed intensive care unit (ICU) during a 1-year period. Quantitative microbiological confirmation was required for VAP diagnosis. Hyperoxemia was defined as peripheral capillary oxygen saturation (SpO(2)) >= 98%. SpO(2) was hourly collected in all study patients during the whole period of mechanical ventilation. The primary objective was to assess the influence of hyperoxemia on ICU mortality. Results: Ninety-three patients with VAP were all included in this study. ICU-mortality rate was 32% (30 of 93 patients). The mean percentage of time spent with hyperoxemia in survivors and nonsurvivors at ICU admission, before, after or at the time of VAP diagnosis was not significantly different. Multivariate analysis identified age, and sequential organ dysfunction assessment at the day of VAP occurrence as independent risk factors for ICU mortality [odds ratio (OR) =1.04 (95% CI, 1.01-1.08) per year, P=0.019; 1.19 (95% CI, 1.06-1.34) per point, P=0.003; respectively]. The time spent with hyperoxemia before VAP occurrence was not significantly associated with mechanical ventilation free days, or ICU length of stay. Conclusions: Hyperoxemia at ICU admission, or during ICU stay, had no significant impact on ICU mortality in critically ill patients with VAP.