Analysis of Acceleration-Induced Blood Pressure Variation Assumed in Ambulance Services, Estimation of Difference between Body Portions

Abstract

The accelerated motion of an ambulance changes the blood pressure （BP） of an ill or injured person. The purpose of this study was to estimate the difference in such acceleration-induced BP variation between body portions. First, using a computer-controlled tilt bed, we simulated the BP variation in an artery inside the brain, the subclavian artery and the peripheral artery of the upper limb by changing the position of the left arm of a volunteer. We repeated this simulation for 15 healthy volunteers under 15 combinations of three positions and five acceleration patterns. Next, using the left hand finger BP measured at the different positions, we calculated the arithmetic averages of increments of the mean BP and the instantaneous pulse rate every 0.01 seconds. By comparing them to each other, we could explain the BP variation as a superposition of variations due to reflexes such as the vestibular-cardiovascular reflex caused by sudden change of acceleration, the baroreceptor reflex and the mechanical effect on the blood. The peak-to-peak value of the BP variation indicated that the acceleration had a larger effect on the BP in the subclavian artery, the peripheral artery of the upper limb and the artery inside the brain in this order.