Normobaric hyperoxia as an adjuvant to endovascular treatment in acute ischemic stroke: a systematic review and meta-analysis

Normobaric hyperoxia (NBO) has emerged as a potential adjuvant therapy for enhancing cerebral oxygenation and neuroprotection in patients with acute ischemic stroke (AIS). The combination of endovascular treatment (EVT) with NBO may offer synergistic benefits by mitigating ischemic injury and improving tissue reperfusion outcomes. This meta-analysis of randomized controlled trials (RCTs) aimed to evaluate the therapeutic efficacy and safety profile of NBO therapy in AIS patients undergoing EVT. We searched five databases (PubMed, Embase, Cochrane Library, Web of Science, and Scopus) from their inception to 15 March 2025, for RCTs comparing NBO vs. control in EVT-treated AIS. The primary outcomes were 90-day functional independence and all-cause mortality. The safety outcomes comprised symptomatic intracranial hemorrhage (sICH), any intracranial hemorrhage, and early neurological deterioration. Data synthesis was performed using random-effects models. Risk of bias and evidence certainty were assessed with the Cochrane tool and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach, respectively. This meta-analysis incorporated five RCTs comprising 730 patients. The NBO group demonstrated a significant enhancement in 90-day functional independence (RR = 1.27, 95% CI: 1.10–1.47, p = 0.001) and a reduction in mortality (RR = 0.61, 95% CI: 0.40–0.93, p = 0.02). Subgroup analyses revealed that initiating NBO therapy pre-EVT improved functional outcomes (RR = 1.38, 95% CI: 1.13–1.68, p = 0.001), whereas post-EVT NBO administration lowered mortality rates (RR = 0.44, 95% CI: 0.21–0.93, p = 0.03). The safety outcomes, including sICH, any ICH, and early neurological deterioration, did not exhibit significant differences between groups. NBO as an adjuvant therapy to EVT improves functional independence and reduces mortality in AIS patients, without an increase in safety risks. These results support the potential integration of NBO into EVT protocols to enhance patient recovery. However, further high-quality, multicenter RCTs are warranted to validate these findings and optimize NBO application.