Exposure to high concentrations of inspired oxygen does not worsen lung injury after cardiac arrest

Abstract

IntroductionPost-cardiac arrest patients are often exposed to 100% oxygen during cardiopulmonary resuscitation and the early post-arrest period. It is unclear whether this contributes to development of pulmonary dysfunction or other patient outcomes.MethodsWe performed a retrospective cohort study including post-arrest patients who survived and were mechanically ventilated at least 24 hours after return of spontaneous circulation. Our primary exposure of interest was inspired oxygen, which we operationalized by calculating the area under the curve of the fraction of inspired oxygen (FiO2AUC) for each patient over 24 hours. We collected baseline demographic, cardiovascular, pulmonary and cardiac arrest-specific covariates. Our main outcomes were change in the respiratory subscale of the Sequential Organ Failure Assessment score (SOFA-R) and change in dynamic pulmonary compliance from baseline to 48 hours. Secondary outcomes were survival to hospital discharge and Cerebral Performance Category at discharge.ResultsWe included 170 patients. The first partial pressure of arterial oxygen (PaO2):FiO2 ratio was 241 ± 137, and 85% of patients had pulmonary failure and 55% had cardiovascular failure at presentation. Higher FiO2AUC was not associated with change in SOFA-R score or dynamic pulmonary compliance from baseline to 48 hours. However, higher FiO2AUC was associated with decreased survival to hospital discharge and worse neurological outcomes. This was driven by a 50% decrease in survival in the highest quartile of FiO2AUC compared to other quartiles (odds ratio for survival in the highest quartile compared to the lowest three quartiles 0.32 (95% confidence interval 0.13 to 0.79), P = 0.003).ConclusionsHigher exposure to inhaled oxygen in the first 24 hours after cardiac arrest was not associated with deterioration in gas exchange or pulmonary compliance after cardiac arrest, but was associated with decreased survival and worse neurological outcomes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0824-x) contains supplementary material, which is available to authorized users.

Impact of Lung Compliance on Neurological Outcome in Patients with Acute Respiratory Distress Syndrome Following Out-of-Hospital Cardiac Arrest

“…Our neurologic intact survival rate of acute respiratory distress syndrome (ARDS) patients was lower than previous studies, which reported rates ranging from 29.8-53.2% [13][14][15]. The incidence of ARDS following cardiac arrest (CA) has not been well reported; it varies from 5-65% depending on how ARDS is defined [8,16]. However, it may be common due to the overlap between the pathophysiology of ARDS and PCAS.…”

Effect of supplemental oxygen exposure on myocardial injury in ST-elevation myocardial infarction

“…Our measure of oxygen exposure accounts for both the dose and duration of oxygen treatment, and has been used in previous studies to evaluate the effect of oxygen exposure on lung injury 14 15. In our study, the area under the 12 h oxygen dose×time curve was strongly correlated with measures of myocardial injury, which performed better than peri-interventional measures of oxygen exposure, which only account for oxygen supplementation in the early stages of reperfusion.…”

Impact of lung compliance on neurological outcome in patients with acute respiratory distress syndrome following out-of-hospital cardiac arrest

“…Even though the clinical impact of ARDS on PCAS patients is not fully known, the occurrence of ARDS after CA may have a negative impact on both survival and recovery of neurologic impairments [15][16][17]. In addition, the incidence of ARDS following CA has not been well reported; it varies from 5-65% depending on how ARDS is defined [8,18]. However, it may be common due to the overlap between the pathophysiology of ARDS and PCAS.…”