Abstract 280: Association Between Duration of Hyperoxia, Organ Failure and Survival After Cardiac Arrest
Background: Prior administrative database studies correlate hyperoxia (based on initial paO2) after cardiac arrest (CA) with increased mortality. These studies did not quantify duration of hyperoxia or incorporate important variables in predicting post-CA survival. We hypothesized hyperoxia duration would not be associated with organ failure or mortality after adjustment for important CA prognostic variables.
Methods: 185 CA survivors receiving >24h mechanical ventilation had oxygen exposure classified hourly based primarily on ABG paO2 or if missing within 2h based on SpO2 as: hypoxic (paO2≤50 or SpO2≤88%), normoxic (paO2 51-150 or SpO2 89-99% or 100% on FiO2≤0.40), moderately hyperoxic (paO2 151-300), severely hyperoxic (paO2>300) and probably hyperoxic (SpO2=100 when Fio2>0.40, no ABG). Univariate regression correlated durations of oxygen exposure to 24h SOFA score and survival to hospital discharge with multivariate regressions incorporating CA type, sex and use of hypothermia (p<0.10 in univariate correlations to outcomes).
Results: Classification based on initial paO2 revealed no significant differences in survival or SOFA (Table 1). Moderate hyperoxia and to a lesser degree combined moderate and severe hyperoxia exposure were associated with SOFA reduction whereas normoxia and hypoxia exposure were associated with higher SOFA, even after multivariate adjustment (Table 2). Severe hyperoxia exposure was associated with reduced survival in univariate but not multivariate analyses.
Conclusions: Exposure to moderate hyperoxia was associated with reduced organ failure whereas severe hyperoxia exposure was not and may correlate with worse survival.
- © 2012 by American Heart Association, Inc.