Cerebral Oxygenation Dynamics During Initial Mobilization in Aneurysmal Subarachnoid Hemorrhage：An Exploratory Near-Infrared Spectroscopy Study

Introduction: Aneurysmal subarachnoid hemorrhage (aSAH) carries high early mortality and long-term functional impairment. Although early mobilization (EM) may enhance recovery, concerns regarding cerebral perfusion instability and delayed cerebral ischemia often limit its implementation. Objective physiological indicators to guide safe EM in aSAH remain limited. Methods: In this prospective, single-center exploratory study, 27 patients with aSAH during the cerebral vasospasm period underwent standardized EM delivered by a multidisciplinary team. Regional cerebral oxygen saturation (rSO₂) was continuously monitored using near-infrared spectroscopy (NIRS), along with mean arterial pressure (MAP), heart rate (HR), and peripheral oxygen saturation (SpO₂). Patients were categorized into low (< 63%, n = 10) and high (≥ 63%, n = 17) baseline rSO₂ groups. Changes in rSO₂ and systemic hemodynamics during postural transition from supine to sitting were analyzed. Results: Baseline rSO₂ was significantly lower in the low rSO₂ group in both the supine (61.2 ± 1.1 vs. 67.2 ± 3.3, p < 0.001) and sitting positions (59.9 ± 2.7 vs. 65.7 ± 4.0, p < 0.001), with no significant group-by-posture interaction. MAP demonstrated a significant group-by-position interaction (p = 0.033), whereas HR and SpO₂ showed no significant interactions. Conclusion: EM was associated with modest, posture-related reductions in cerebral oxygenation that were not accompanied by major systemic instability. NIRS monitoring may provide useful physiological information during EM and support the development of individualized mobilization strategies in patients with aSAH.