Pulse transit time technique for cuffless unobtrusive blood pressure measurement: from theory to algorithm

Abstract

Cuffless technique holds great promise to measure blood pressure (BP) in an unobtrusive way, improving diagnostics and monitoring of hypertension and its related cardiovascular diseases, and maximizing the independence and participation of individual. Pulse transit time (PTT) has been the most commonly employed techniques for cuffless BP estimation. Many studies have been conducted to explore its feasibility and validate its performance in the clinical settings. However, there is still issues and challenges ahead before its wide application. This review will investigate the understanding and development of the PTT technique in depth, with a focus on the physiological regulation of arterial BP, the relationship between PTT and BP, and the summaries of the PTT-based models for BP estimation.

Estimation and Validation of Arterial Blood Pressure Using Photoplethysmogram Morphology Features in Conjunction With Pulse Arrival Time in Large Open Databases

“…Since the arterial diameter change affects total peripheral resistance, a direct influencer of BP [15], PIRP can theoretically be used for BP estimation. In this paper, PIRMD and PIRIT are additionally defined using PPG intensity of the maximum derivative or intersecting-tangent points of PPG (PIMD or PIIT) instead of PIP in (3), respectively.…”

“…One of the reasons for this may be that PAT alone cannot fully reflect the complex BP dynamics and that conventionally measured PAT in ubiquitous BP monitoring involves PAT measured at peripheral arteries rather than central arteries. PAT is associated with BP through the physiological characteristics of arterial vessels such as arterial elastance, but BP is affected by physiological factors other than arterial elastance [15]. In order to address this issue, many studies have attempted to find new predictors for BP estimation through extracting physiologically meaningful features from the morphology of PPG waveforms [25][26][27][28][29][30][31][33][34][35][36][37][38].…”

“…As one of the promising techniques for realizing NCBPM, pulse wave velocity (PWV) based approaches have gained the most interest over the recent decades [7][8][9][10][11][12][13][14]. This technique based on the concept that the velocity of the arterial pulse traveling in an artery is affected by physiological variations of the arterial vessels, which is closely related to BP [15]. PWV can be approximated using its surrogate, pulse transit time (PTT), which is the time delay for the arterial pulse to propagate between two arterial sites.…”

Rapid Declines in Systolic Blood Pressure Are Associated With an Increase in Pulse Transit Time

“…Several researchers have investigated PTT for BP-estimation, typically measuring PTT from the ECG R-peak to the PPG signal at the finger. A review of these efforts was recently published by Ding and Zhang [8]. Researchers have also employed machine learning methods, such as deep neural networks, to find additional PPG-features that may complement or replace PTT for BPestimation [9].…”

Feasibility of a new free mobility procedure to evaluate the function of the autonomic nervous system in patients with syncope

“…Transcranial Doppler (TCD) allows studying changes of cerebral blood flow of the Middle Cerebral Artery (MCA) with passive position changes 17,18 , and active orthostatism 19 . The technique of the measurement of the Pulse of Transit Time using the electrocardiogram and photo-plethysmography by infrared light allows recording the arterial blood pressure in each heartbeat 20,21 . TCD and other different ways of recording beat-to-beat pressure have added to the TT protocol 12,22 .…”