Cerebral Oxygenation Changes During Sequential Postural Transitions From Supine to Walking in Healthy Adults: An Exploratory Near-Infrared Spectroscopy Study.

Objective Early mobilization (EM) in the intensive care unit (ICU) reduces complications from prolonged bed rest and improves functional outcomes. However, there are still no objective criteria for cerebral hemodynamics during postural changes, especially walking. Methods This exploratory observational study used near-infrared spectroscopy (NIRS) to measure prefrontal cerebral oxygenation changes in 14 healthy adults during sequential postural transitions from supine rest to sitting, standing, and walking. The following parameters were assessed: oxygenated hemoglobin (O₂Hb), deoxygenated hemoglobin (HHb), total hemoglobin (tHb), regional cerebral oxygen saturation (rSO₂), mean arterial pressure (MAP), and heart rate (HR). Results ΔO₂Hb decreased, and ΔHHb increased relative to the supine baseline, with significant differences in the magnitude of change across sitting, standing, and walking (ΔO₂Hb, p = 0.012; ΔHHb, p < 0.001). rSO₂ differed significantly across the four postural conditions, with lower values observed in upright postures than in the supine position (p < 0.001). The magnitude of ΔtHb did not differ significantly among sitting, standing, and walking (p = 0.257). MAP (p = 0.015) and HR (p < 0.001) differed significantly across the four postural conditions. Conclusions Sequential postural transitions from supine rest to sitting, standing, and walking were associated with changes in NIRS-derived cerebral oxygenation in healthy adults, characterized by decreases in O₂Hb and increases in HHb during progression to upright postures. These findings characterize cerebral oxygenation changes across a stepwise mobilization sequence and may provide preliminary reference data for evaluating cerebral oxygenation during mobilization.