title: Cerebrovascular response to valsalva maneuver: methodology, normal values, and retest reliability.
abstract: OBJECTIVE
  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.
authors.affiliation: MEDAS Ostschweiz, Interdisciplinary Medicine, St. Gallen, Switzerland.
authors.forename: Thomas-Martin
authors.initials: TM
authors.lastname: Wallasch
authors.forename: Peter
authors.initials: P
authors.lastname: Kropp
mesh_terms: D000328:Adult; D000367:Age Factors; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000502:physiology*; D008991:Monitoring, Physiologic / Q000379:methods; D012016:Reference Values; D015203:Reproducibility of Results; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods; D014636:Valsalva Maneuver / Q000502:physiology*; D055815:Young Adult