Normal values of volume flow in the internal carotid artery measured by a new angle-independant Doppler technique for evaluating cerebral perfusion

Abstract

Background. Cerebral blood flow is an important parameter when monitoring critically ill patients. Blood flow volume within the internal carotid artery (ICA) was shown to be correlated with the cerebral blood flow. The aim of our study was to provide normal values of the internal carotid artery volume flow using this new technology (QuantixND, Cardiosonix Ltd., Israel). Method. The QuantixND System is an angle-independant Doppler system that employs two digital high resolution ultrasound heads within one probe in an defined angle to each other. Thus several flow velocities within the vessel and the vessel diameter can be measured. 77 healthy patients (41 women, 36 men) were included and divided into age groups of ten-year intervals (mean age 48.9 years). Internal carotid artery flow was evaluated as well as physiological and hematological parameters (hematocrit, arterial blood pressure etc). Findings. We found that the blood flow volume in the ICA decreased significantly with age. No side-to-side effects as well as no gender-related differences could be observed. There was no influence of hemoglobin, hematocrit and blood pressure in this healthy population. Conclusions. There is an age-related decrease in blood flow volume with age that can be easily and exactly determined by the use of the new angle-independant doppler technique.