Early hyperoxia in the intensive care unit is significantly associated with unfavorable neurological outcomes in patients with mild-to-moderate aneurysmal subarachnoid hemorrhage

Abstract

Introduction: Although oxygen administration is fundamental in the management of aneurysmal subarachnoid hemorrhage (SAH) patients in the acute stage, hyperoxia has harmful effects. The effects of hyperoxia on neurological outcomes in SAH patients are unclear. We aimed to examine the association of hyperoxia during the first 24 h in the intensive care unit (ICU) with unfavorable neurological outcomes in SAH patients. Methods: We retrospectively selected consecutive adult patients admitted to ICU for SAH between January 2009 and April 2018. We defined normoxia during the first 24 h in ICU as PaO2 of 60 mm Hg to 120 mm Hg, mild hyperoxia as PaO2 of 121 mm Hg to 200 mm Hg, moderate hyperoxia as PaO2 of 201 mm Hg to 300 mm Hg, and severe hyperoxia as PaO2 of >300 mm Hg. Univariate and multivariate analyses were performed to examine the association between hyperoxia during the first 24 h in ICU and unfavorable neurological outcomes (i.e., modified Rankin scale score of 3-6 at hospital discharge). Results: Among 196 SAH patients, 90 had unfavorable neurological outcomes. Hyperoxia was observed in 93.4% of patients. No significant association was observed between unfavorable neurological outcomes and hyperoxia in overall patients. However, we found that early hyperoxia in ICU was significantly associated with unfavorable neurological outcomes in SAH patients with Hunt and Kosnik (H&K) grades I to III (Relative risk, 1.84; 95% confidence interval, 1.10-2.94; P ¼ 0.02). Conclusions: Early hyperoxia was not associated with unfavorable neurological outcomes in overall SAH patients, but it was associated with unfavorable neurological outcomes in those with H&K grades I to III.