Transcranial Doppler sonography as a potential screening tool for preanaesthetic evaluation: a prospective observational study

Abstract

Context: 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.

Design: Prospective observational study.

Setting: University hospital.

Patients: Fifty-six male and 24 female patients scheduled for general anaesthesia for routine surgery. Exclusion criteria were cranial spine pathology and cerebral vascular disease.

Interventions: Maximum rotation of the head to the left and right side with and without hyperextension, and hyperextension in the neutral position.

Main outcome measures: 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.

Conclusion: Neck rotation and/or extension resulted in a significant change of blood flow in the middle cerebral artery.