Drive training assistant system for ambulances to reduce blood pressure variation during deceleration

This paper proposes the drive training assistant system for ambulance drivers to avoid the excessive blood pressure variation of patients caused by brake operation. The system has two functions. The first is to estimate the blood pressure variation in real time based the acceleration of a car and to inform a driver with an electric sound when the estimated blood pressure variation exceeds the pre-specified level. The second function is to inform a driver of the start timing to apply a brake with a synthetic sound when the distance to a next intersection is less than the brake distance necessary to keep the blood pressure variation below the pre-specified bound. The brake distance is calculated in real time based on the present speed of the car, the passing speed at the next intersection, the slope angle of a road and the pre-given tolerable blood pressure variation. This paper mainly focuses on the second function and its availability. The prototype system was constructed using a commercial smartphone with a GPS sensor, a triaxial accelerometer and a speaker. The availability of the system was examined through the car experiment. It was confirmed that, by starting a brake operation after the brake timing announcement of the system, the blood pressure variation was controlled below the pre-specified tolerable bound.