title: Determination of cerebral blood flow dynamics during retrograde cerebral perfusion using power M-mode transcranial Doppler.
abstract: BACKGROUND
  Retrograde cerebral perfusion (RCP) during profound hypothermic circulatory arrest has been used as an adjunct for cerebral protection for repairs of the ascending and transverse aortic arch. Transcranial Doppler ultrasound has been used to monitor cerebral blood flow during RCP with varying success. The purpose of this study was to characterize cerebral blood flow dynamics during RCP using a new mode of monitoring known as transcranial power motion-mode (M-mode) Doppler ultrasound.
  
  
  METHODS
  Data on pump-flow characteristics and patient outcomes were collected prospectively for patients undergoing ascending and transverse aortic arch repair. Retrograde cerebral perfusion during profound hypothermic circulatory arrest was used for all operations. Intraoperative cerebral blood flow dynamics were monitored and recorded using transcranial power M-mode Doppler ultrasound.
  
  
  RESULTS
  Between August 2001 and March 2002, we used transcranial power M-mode Doppler ultrasound monitoring for 40 ascending and transverse aortic arch repairs during RCP. Mean RCP time was 32.2 +/- 13.8 minutes. Mean RCP pump flow and RCP peak pressure for identification of cerebral blood flow were 0.66 +/- 0.11 L/min and 31.8 +/- 9.7 mm Hg, respectively. Retrograde cerebral blood flow during RCP was detected in 97.5% of cases (39 of 40 patients) with a mean transcranial power M-mode Doppler ultrasound flow velocity of 15.5 +/- 12.3 cm/s. In the study group, 30-day mortality was 10.0% (4 of 40 patients). The incidence of stroke was 7.6% (3 of 40 patients); the incidence of temporary neurologic deficit was 35.0% (14 of 40 patients).
  
  
  CONCLUSIONS
  Transcranial power M-mode Doppler ultrasound consistently demonstrated retrograde middle cerebral artery blood flow during RCP. Transcranial power M-mode Doppler ultrasound can provide optimal RCP with individualized settings of pump flow.
authors.affiliation: DEPARTMENT OF Cardiothoracic and Vascular Surgery, Houston, Texas 77030, USA. anthony.l.estrera@uth.tmc.edu
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Estrera
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Garami
authors.forename: Charles C
authors.initials: CC
authors.lastname: Miller
authors.forename: Roy
authors.initials: R
authors.lastname: Sheinbaum
authors.forename: Tam T T
authors.initials: TT
authors.lastname: Huynh
authors.forename: Eyal E
authors.initials: EE
authors.lastname: Porat
authors.forename: Anders
authors.initials: A
authors.lastname: Winnerkvist
authors.forename: Hazim J
authors.initials: HJ
authors.lastname: Safi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001018:Aortic Diseases / Q000503:physiopathology / Q000601:surgery*; D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D010477:Perfusion / Q000379:methods*; D011446:Prospective Studies; D012039:Regional Blood Flow; D017585:Ultrasonography, Doppler, Transcranial