EVALUATION OF BLOOD PRESSURE ESTIMATION USING PULSE TRANSIT TIME DURING CHANGES IN PHYSIOLOGICAL STATUS

Open Access
Author:
Sklarsky, Amanda Nicole
Area of Honors:
Kinesiology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Dr. James Pawelczyk, Thesis Supervisor
  • Dr. Mary Jane DeSouza, Honors Advisor
Keywords:
  • PULSE TRANSIT TIME
  • BLOOD PRESSURE
  • COLD PRESSOR TEST
  • STATIC HANDGRIP
  • SHG
  • CPT
  • PTT
  • CARDIOVASCULAR DISEASE
  • CVD
  • PECA
  • PHYSIOLOGICAL STATUS
  • PTT BP ESTIMATION
  • MEDICAL DEVICE
  • CONTINUOUS
  • NONINVASIVE
  • CUFF-LESS
  • CUFF-FREE
  • PRE-EJECTION PERIOD
  • PEP
  • CARDIAC OUTPUT
  • CARDIAC RESISTANCE
Abstract:
The nation’s leading cause of death since 1921 – Cardiovascular Disease (CVD) – is a pressing issue in society. Blood Pressure (BP) is a significant indicator of cardiovascular health and is thus central to much research. The issue lies in the fact that BP is generally not measured on a day-to-day basis, as the available forms of measurement are unconducive to daily measurement (i.e. cuff-based, non-continuous, and/or invasive). Pulse Transit Time (PTT) – the time delay between blood ejection to the heart to arrival at a peripheral point - is a promising metric in overcoming this issue and has been incorporated in a few wearable medical devices to date. This retrospective study aimed to determine whether PTT could withstand alterations in physiological status, specifically alterations in cardiac output and resistance. These changes were elicited via Cold Pressor Test (CPT) and Static Handgrip (SHG) protocols and were intended to reveal whether PTT is truly a reliable measurement that can be used in daily life by consumers of wearable medical devices. The results showed that there was in fact a significant difference between conditions (CPT vs. SHG) in BP measurement. Thus, PTT may not be transferable across physiological conditions. In the form utilized in this investigation, PTT does not appear to be sufficiently accurate for use in wearable medical devices. However, the inverse relationship between PTT and BP was consistent with that of other research studies, so PTT may be useful in considering relative changes in BP. Further research might consider individualized calibration to overcome variability between subjects. Nevertheless, the significant difference between the physiological states calls into question the broad utility of estimations of BP from PTT. Estimates derived with this methodology should be interpreted conservatively.