Comparison of two mechanical carotid baroreceptor stimulation techniques

We compared two mechanical carotid baroreceptor stimulation techniques, the phase related external suction (PRES) method and the conventional neck suction techniques concerning their effects on blood pressure and heart rate responses in a group of 10 normotensive men. The cuff pressure using the PRES method was phase-locked in time to the R-wave of the ECG. During the conventional neck suction technique the cuff pressure changes were not related to the cardiac cycle, it was either negative or positive. Blood pressure was measured in four of the patients both invasively and noninvasively to compare the two baroreceptor stimulating methods. The results have indicated that (1) both mechanical carotid baroreceptor stimulation technique showed a significant heart rate deceleration to baroreceptor stimulation. (2) The heart rate changes were more pronounced during the continuous neck cuff technique, and the heart rate recovered sooner to the baseline. The variation of baroreceptor activity as induced by the PRES method seems to prevent habituation much more than the continuous neck suction method. (3) The systolic blood pressure decrease was significant both during PRES and continuous neck suction stimulation. A higher decrease in systolic blood pressure was shown during continuous neck suction stimulation compare to the PRES stimulation. (4) The diastolic blood pressure changes showed the same alteration for baroreceptor stimulation as compared to the control condition but there was no difference between the two stimulation methods. (5) The noninvasive Finapres blood pressure device measures blood pressure reliably.