Normobaric Hyperoxia Enhances Stroke Recovery: The Results of The OPENS-2 Trials Published on THE LANCET

Recently, the results of a multicenter, randomized, single-blind, placebo-controlled trial named “Normobaric Hyperoxia Combined with Endovascular Treatment for Acute Ischemic Stroke (OPENS-2 trial)” are published on THE LANCET. The study results indicate that normobaric hyperoxia combined with endovascular treatment can significantly improve the functional outcomes of patients with acute ischemic stroke, without increasing safety concerns.

Acute ischemic stroke is a common cerebrovascular disease. Although endovascular treatment can improve the recanalization rate for patients, about half of the patients still do not achieve favorable functional outcomes 90 days later. Normobaric hyperoxia treatment, due to its low cost, wide availability, and ease of use, is considered to potentially reach the ischemic penumbra before reperfusion and provide effective concentrations, thereby improving patient outcomes.

Under the leadership of Prof. Xunming JI together with the OPENS-2 trial investors from key cerebrovascular research centers in China, e.g., Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China and Department of Neurosurgery, Xuanwu Hospital, Capital Medical University etc., this trial was conducted from April 22, 2021, to February 5, 2023. In total, 473 patients were screened, and 282 were randomly assigned to either the normobaric hyperoxia group (n=140) or the placebo group (n=142). At 90 days, the median mRS score in the normobaric hyperoxia group was 2 (IQR 1-4), compared to 3 (1-4) in the placebo group, with an adjusted common odds ratio of 1.65 (95% CI 1.09-2.50; p=0.018). The mortality rates at 90 days were 10% in the normobaric hyperoxia group and 12% in the placebo group, and the rates of serious adverse events were 20% and 23%, respectively, with no significant differences between the groups.

The study results indicate that for patients with acute ischemic stroke due to large-vessel occlusion in the anterior circulation, normobaric hyperoxia combined with endovascular treatment results in significantly better functional outcomes at 90 days compared to placebo normobaric hyperoxia, without raising safety concerns. Future research should further validate these findings and explore the application of normobaric hyperoxia in different populations and time windows.

Researchers plan to conduct larger-scale, multicenter, randomized controlled trials to further assess the efficacy and safety of normobaric hyperoxia combined with endovascular treatment, particularly in different ethnic and age groups. Additionally, studies will explore the potential of normobaric hyperoxia in pre-hospital settings or later time windows after stroke onset.

This study provides new insights into the treatment of acute ischemic stroke patients and has significant clinical implications and application prospects.

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