Evaluation of blood pressure changes using vascular transit time

Area of Science:

• Physiology
• Biomedical Engineering
• Cardiovascular System

Background:

• Hemodynamic system imbalances can indicate conditions like syncope, dizziness, or hypertension.
• Monitoring blood pressure (BP) responses to postural changes is crucial for assessing these conditions.
• Conventional BP monitoring methods can be uncomfortable, limiting prolonged patient observation.

Purpose of the Study:

• To investigate the correlation between blood pressure (BP) variations and vascular transit time (VTT).
• To assess the feasibility of using photoplethysmography and phonocardiography for non-invasive BP estimation.
• To develop a regression equation for estimating BP based on VTT changes.

Main Methods:

• Utilized photoplethysmography and phonocardiography to measure vascular transit time (VTT) at the upper limb.
• Recruited 31 healthy adults who performed postural changes (arm at heart level, raised, lowered).
• Computed associations between BP indices (systolic, diastolic, mean arterial pressure), heart rate, and VTT changes.

Main Results:

• Observed significant correlations between VTT changes and systolic BP (R² = 0.820), diastolic BP (R² = 0.517), and mean arterial pressure (R² = 0.673).
• Systolic BP exhibited the strongest correlation with VTT changes.
• A regression equation was formulated to link systolic BP and VTT.

Conclusions:

• Vascular transit time (VTT) serves as a reliable, non-invasive indicator of blood pressure variations.
• This method offers a more comfortable alternative for prolonged hemodynamic monitoring compared to conventional techniques.
• VTT measurement excludes the pre-ejection period, providing a distinct physiological parameter.