Hyperoxia is associated with increased mortality in patients treated with mild therapeutic hypothermia after sudden cardiac arrest*

Abstract

OBJECTIVE: To determine whether higher levels of PaO2 are associated with in-hospital mortality and poor neurological status at hospital discharge in patients treated with mild therapeutic hypothermia after sudden cardiac arrest. DESIGN: Retrospective analysis of a prospective cohort. PATIENTS: A total of 170 consecutive patients treated with therapeutic hypothermia in the cardiovascular care unit of an academic tertiary care hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 170 patients, 77 (45.2%) survived to hospital discharge. Survivors had a significantly lower maximum PaO2 (198 mm Hg; interquartile range, 152.5-282) measured in the first 24 hrs following cardiac arrest compared to nonsurvivors (254 mm Hg; interquartile range, 172-363; p = .022). A multivariable analysis including age, time to return of spontaneous circulation, the presence of shock, bystander cardiopulmonary resuscitation, and initial rhythm revealed that higher levels of PaO2 were significantly associated with increased in-hospital mortality (odds ratio 1.439; 95% confidence interval 1.028-2.015; p = .034) and poor neurological status at hospital discharge (odds ratio 1.485; 95% confidence interval 1.032-2.136; p = .033). CONCLUSIONS: Higher levels of the maximum measured PaO2 are associated with increased in-hospital mortality and poor neurological status on hospital discharge in patients treated with mild therapeutic hypothermia after sudden cardiac arrest.