Effect of early hyperoxemia on mortality in mechanically ventilated septic shock patients according to Sepsis-3 criteria: analysis of the MIMIC-III database.

Abstract

Hyperoxemia may be associated with increased mortality in emergency room or ICU patients. However, its effect during septic shock is still debated. To evaluate the effect of hyperoxemia on ICU mortality, during the first 24 h of ICU stay, in mechanically ventilated patients with septic shock according to SEPSIS-3 criteria. A retrospective cohort study of ICU admissions recorded in the Medical Information Mart for Intensive Care-III, a retrospective ICU database, was performed. Two oxygen exposures during the first 24 h were compared: average PaO2 (TWA-PaO2) between 70 and 120 mmHg in the normoxemia group and above 120 mmHg in the hyperoxemia group. The primary outcome was mortality during ICU stay. Four hundred eighty-eight ICU admissions met the inclusion criteria: 214 in the normoxemia group and 274 in the hyperoxemia group. The median TWA-PaO2 was 99.1 (88.9-107.6) mmHg in the normoxemia group and 151.5 (133.6-180.2) mmHg in the hyperoxemia group. ICU mortality was lower in the hyperoxemia group than in the normoxemia group in univariate analysis [29.6 vs. 39.7%, respectively; OR 0.64 (0.44-0.93); P = 0.024], but not in multivariate analysis [OR 0.98 (0.62-1.56); P = 0.93]. There was no difference between the two groups in ICU length of stay [8.0 (4.3-15.0) vs. 8.4 (4.7-15.0) days; P = 0.82]. We did not find any impact of early hyperoxemia on mortality in this population of mechanically ventilated patients with SEPSIS-3 septic shock criteria.