Dynamic Changes in Cerebral Oxygenation and Arterial Pressure During Repeated Rapid Hypotension

This study aimed to determine the changes in the time to nadir of mean arterial pressure (MAP) and oxygenated hemoglobin (O₂Hb) in the right and left prefrontal cortices (R-PFC and L-PFC, respectively) during repeated episodes of rapid hypotension. Four cycles of blood pressure reduction were induced via bilateral thigh occlusion at 250 mmHg followed by rapid deflation. Sixteen healthy male university students participated. MAP was recorded beat by beat, and O₂Hb was continuously monitored using near-infrared spectroscopy. The time from deflation to nadir was measured and compared across each deflation cycle. MAP and O₂Hb in the R-PFC and L-PFC reached their nadir values approximately 7 to 8 s post-deflation, with no significant changes observed across repetitions. These findings indicate that the time to nadir of MAP and O₂Hb in the R-PFC and L-PFC remains stable during repeated rapid hypotension.