Background: Cardiac arrest survivors may have disabilities due to hypoxic brain injury. Patients with obstructive sleep apnea are exposed to intermittent hypoxemia that may lead to ischemic preconditioning. We have hypothesized that patients with obstructive sleep apnea have better neurological outcomes following a cardiac arrest due to preconditioning of the brain.
Methods: We retrospectively analyzed all the survivors of in-hospital cardiac arrest from January 2006 to September 2016. Patients with confirmed or suspected obstructive sleep apnea were selected for further analysis and those without were used as comparison. Primary outcome was neurological functionality on hospital discharge by the Cerebral Performance Category.
Results: A total of 739 patients had cardiac arrest within the study period. The immediate mortality rate was 59% (N=43) in patients with obstructive sleep apnea and 94% (N=623) in those without (p<0.001). Approximately 10% (N=73) were discharged alive and these were selected for further analysis. Patients without obstructive sleep apnea had more frequently "Poor" outcomes compared to those with obstructive sleep apnea (OR 2.91; 95% CI, 1.11-7.66; p=0.03). After adjusting in a multivariate analysis, obstructive sleep apnea was "protective" of "Poor" neurological outcomes: adjusted OR 0.21; 95% CI, 0.06-0.64; p=0.01.
Conclusion: Patients with obstructive sleep apnea had better unadjusted survival rates, and favorable adjusted neurological outcomes at discharge compared to those without obstructive sleep apnea. These results suggest that obstructive sleep apnea patients may tolerate better acute brain ischemia due to preconditioning.
Keywords: Cardiac arrest; Intermittent hypoxia; Ischemic preconditioning; Neurological outcomes; Obstructive sleep apnea.
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