title: Relationships between cerebral blood flow velocities and arterial pressures during intra-aortic counterpulsation.
abstract: OBJECTIVE
  To determine the effects of intra-aortic counterpulsation (IABP) on cerebral blood flow velocity.
  
  
  METHODS
  Prospective self-controlled study.
  
  
  METHODS
  University hospital surgical intensive care unit.
  
  
  METHODS
  Nineteen cardiac surgical patients requiring perioperative IABP assistance.
  
  
  METHODS
  Simultaneous recording of transcranial Doppler middle cerebral artery blood flow velocity and arterial pressure in response to changes in the magnitude of augmentation and trigger ratio.
  
  
  RESULTS
  Instantaneous cerebral blood flow velocities correlated with arterial pressures during IABP (r = 0.650) at different magnitudes of augmentation and trigger ratios. The increase in arterial pressure during balloon inflation was associated with an increase in cerebral blood flow velocity, and the decrease in arterial pressure in response to balloon deflation was associated with a decrease in cerebral blood flow velocity that was dependent on the magnitude of augmentation. Different magnitudes of augmentation or trigger ratios had no effect on peak systolic cerebral blood flow velocity, mean cerebral blood flow velocity, mean arterial pressure, or the mean velocity-to-pressure ratio. Instantaneous cerebral blood flow velocity to arterial pressure ratios were lowest in response to balloon deflation at the time of pre-ejection.
  
  
  CONCLUSIONS
  IABP modified the phasic profile of cerebral blood flow to reflect the arterial pressure waveform without affecting mean cerebral blood flow velocity. Peak systolic cerebral blood flow velocity was maintained in augmented beats despite the decreased systolic arterial pressure associated with afterload reduction. The acute decrease in cerebral blood flow velocity at pre-ejection was balanced by increased cerebral blood flow velocity during balloon inflation in diastole.
authors.affiliation: Department of Anesthesia, University of Pennsylvania, Philadelphia 19104-4283, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Cheung
authors.forename: W J
authors.initials: WJ
authors.lastname: Levy
authors.forename: S J
authors.initials: SJ
authors.lastname: Weiss
authors.forename: D K
authors.initials: DK
authors.lastname: Barclay
authors.forename: M M
authors.initials: MM
authors.lastname: Stecker
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007423:Intra-Aortic Balloon Pumping; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies