An evaluation of a PTT-based method for noninvasive and cuffless estimation of arterial blood pressure

The aim of this study is to determine if a noninvasive and cuffless blood pressure (BP) estimation method using pulse transit time (PTT) can accurately track the changes in BP after a treadmill exercise. Experiments were conducted on 12 healthy subjects, who were directed to run on a treadmill at 10 kph for 4 minutes. For each subject, 13 trials were recorded in total, including 11 trials obtained immediately after exercise and during the 60-minute recovery period. BP was measured at the finger by the Finometer and at the brachial arteries by a sphygmomanometer respectively. PTT was determined as the time interval between the peak of the electrocardiogram R wave and the foot of the photoplethysmogram. Both PTT-based device and Finometer were calibrated initially and Finometer calibration was also performed after exercise to the sphygmomanometer. Experimental results showed that there was only occasional discrepancy between BPs measured by Finometer and PTT-based device during the recovery period, i.e., at 5 minutes after exercise (p=0.008 for systolic BP and p=0.03 for diastolic BP). At all other post exercise time spots there were no significant differences between BPs measured by Finometer and PTT-based device.