Key result
Repeated rapid hypotension maintains a stable ~8-second nadir time for MAP and prefrontal oxygenation.
Why the study?
It was unknown whether the time to nadir of mean arterial pressure and cerebral oxygenated hemoglobin changes across repeated episodes of rapid hypotension.
Does the time to nadir of mean arterial pressure and cerebral oxygenation change during repeated episodes of rapid hypotension in healthy males?
Does the time to nadir of mean arterial pressure and cerebral oxygenation change during repeated episodes of rapid hypotension in healthy males?
The time to nadir for mean arterial pressure and cerebral oxygenation remains stable at approximately 7 to 8 seconds during repeated episodes of rapid hypotension.
Answers are grounded in this paper and cite their sources.
May guide monitoring timing in serial hypotension; leaves open validation in patients with impaired autoregulation.
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.
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Tokuda et al. (2026) studied Healthy volunteers (n=16). Rapid hypotension induced via bilateral thigh occlusion and rapid deflation was evaluated on Time to nadir of mean arterial pressure (MAP) and oxygenated hemoglobin (O₂Hb) in the right and left prefrontal cortices. Repeated rapid hypotension induced via bilateral thigh occlusion resulted in stable times to nadir for mean arterial pressure and cerebral oxygenation at approximately 7 to 8 seconds post-deflation.
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