Cerebrovascular response to valsalva maneuver: Methodology, normal values, and retest reliability

PURPOSE: To provide reference values of cerebrovascular reactivity measured with transcranial Doppler ultrasonography in response to rapid changes in blood pressure during the late straining phase (IIb) of a Valsalva maneuver (VM). METHODS: Middle cerebral artery blood flow velocity, arterial blood pressure changes, and end-tidal partial carbon dioxide pressure (pCO(2) ) concentrations were simultaneously and noninvasively measured in 60 healthy subjects. Centro-peripheral Valsalva ratio was calculated by the quotient of cerebrovascular reactivity and peripheral arterial blood pressure response to VM during phase IIb. Age dependency and short- and long-term reliability of indices were evaluated. Correlation between the autonomic response and changes of pCO(2) was calculated. RESULTS: Centro-peripheral Valsalva ratio was higher in younger healthy subjects, whereas peripheral autonomic reactivity appeared age-independent. There was no correlation between dynamic autoregulatory response and pCO(2) . Short- and long-term measurements of autoregulatory indices showed excellent reliability. CONCLUSIONS: VM is a suitable maneuver to evaluate dynamic autonomic response using transcranial Doppler ultrasonography and noninvasive arterial blood pressure monitoring. Autonomic response during VM does not depend on pCO(2) . Normal human subjects show age-dependent centro-peripheral autoregulatory response.