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

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.