A Novel Minimally Occlusive Cuff Method Utilizing Ultrasound Vascular Imaging for Stress-Free Blood Pressure Measurement: A-Proof-of-Concept Study.

Abstract

Occlusive cuff inflation in ambulatory blood pressure (BP) monitoring disturbs the daily life of the user and affects efficacy of monitoring. To overcome this limitation, we have developed a novel minimally occlusive cuff method for stress-free measurement of BP. This study aimed to experimentally evaluate the reliability of this method. In this method, a thin plate-type ultrasound probe placed between the cuff and the skin is used to measure the ultrasonic dimension of the artery. Analyzing the arterial dimension and the cuff pressure measured during mild cuff inflation (cuff pressure <50mmHg) allows estimation of systolic BP (SBPe) and diastolic BP (DBPe). We evaluated this method in six anesthetized dogs by attaching the cuff with the probe to the right thigh to get SBPe and DBPe. We measured reference SBP and DBP using an intra-arterial catheter and determined the pulse arrival time (PAT), commonly employed in cuffless BP monitoring. BP was perturbed by infusing noradrenaline or nitroprusside. DBPe correlated tightly with DBP with a coefficient of determination (R2) of 0.85 ± 0.08, and predicted DBP with a mean ± standard deviation of error of 3.9 ± 7.9mmHg after one-time calibration. Reciprocal of PAT correlated poorly with DBP (R2 = 0.49 ± 0.17), and predicted DBP less accurately than this method. SBPe correlated well with SBP (R2 = 0.78 ± 0.08). This method reliably tracks BP changes without occlusive cuff inflation. Once calibrated, this method measures DBP accurately. This method has the potential for stress-free BP measurement in ambulatory BP monitoring.