Adjuvant high-flow normobaric oxygen after mechanical thrombectomy for posterior circulation stroke: A randomized clinical trial

Background: Recent studies suggest only a third of posterior circulation stroke patients have a good functional outcome with a high mortality after mechanical thrombectomy. To mitigate mortality rates and increase functional outcomes, we investigated the safety and efficacy of high-flow, normobaric oxygen (NBO) after endovascular recanalization in posterior circulation stroke.Methods: This is a prospective randomized controlled study. Eligible patients were randomized to receive highflow NBO by a Venturi mask (FiO2 50%, flow 15 L/min) or routine low-flow oxygen supplementation by nasal cannula (flow 3 L/min) after vessel recanalization for 6 h. Patient demographics, procedural metrics, complications, functional outcomes, symptomatic intracranial hemorrhage (sICH), and infarct volume were assessed.Results: While we assessed 122 patients for eligibility, 87 patients were randomly assigned (44 patients to the NBO group). Post operatively there was no significant difference in distribution of global disability scores on the mRS at 90 days or functional independence between the two groups. We did observe a trend suggesting reduced mortality at 90 days with reduced infarct volume in the NBO group, however this was not statistically significant. No significant differences were seen in the rate of sICH, pneumonia or urinary infection between the two groups. When comparing our results with the BASICS and BEST study, our study did reveal a significantly better prognosis after endovascular therapy.Conclusion: Our results indicate that high-flow adjuvant NBO therapy was safe. However, the current study does not provide evidence for a significant neuroprotection effect in posterior circulation stroke patients after endovascular recanalization.