title: Transcranial Doppler sonography as a potential screening tool for preanaesthetic evaluation:  a prospective observational study.
abstract: BACKGROUND
  Intraoperative cervical spine rotation may compromise cerebral blood flow in susceptible individuals by distortion of cervical arteries.
  
  
  OBJECTIVE
  To investigate the effect of five cervical spine positions on cerebral blood flow in the middle cerebral artery.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Fifty-six male and 24 female patients scheduled for general anaesthesia for routine surgery. Exclusion criteria were cranial spine pathology and cerebral vascular disease.
  
  
  METHODS
  Maximum rotation of the head to the left and right side with and without hyperextension, and hyperextension in the neutral position.
  
  
  METHODS
  Change of mean blood flow velocity in the middle cerebral artery measured by transcranial Doppler sonography.
  
  
  RESULTS
  Age had a significant effect on mean blood flow velocity in the left middle cerebral artery in the neutral position (P = 0.047). There was a significant difference in mean blood flow velocity in the left middle cerebral artery between patients younger than 40 years and patients older than 59 years [61.2 (16.6) ml min(-1) vs. 47.7 (16.2) ml min(-1); P = 0.015]. There was a significant effect of head position on mean blood flow velocity in both the left and in the right middle cerebral arteries (P = 0.039 left, P = 0.025 right). Twenty patients had a decrease of more than 20% from their baseline mean blood flow velocity.
  
  
  CONCLUSIONS
  Neck rotation and/or extension resulted in a significant change of blood flow in the middle cerebral artery.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Schwanenweg, Germany. axel.fudickar@uksh.de
authors.forename: Axel
authors.initials: A
authors.lastname: Fudickar
authors.forename: Joern
authors.initials: J
authors.lastname: Leiendecker
authors.forename: Anna
authors.initials: A
authors.lastname: Köhling
authors.forename: Juergen
authors.initials: J
authors.lastname: Hedderich
authors.forename: Markus
authors.initials: M
authors.lastname: Steinfath
authors.forename: Berthold
authors.initials: B
authors.lastname: Bein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000776:Anesthesiology / Q000379:methods*; D002560:Cerebrovascular Circulation; D002574:Cervical Vertebrae / Q000601:surgery; D005260:Female; D006257:Head / Q000098:blood supply; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000473:pathology; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D012399:Rotation; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*