A novel instrument for continuous blood pressure monitoring

Project Summary/Abstract Problem High blood pressure (BP) is a substantial public health problem that affects 45% of adults (75% of individuals over age 65) and is a leading cause of excess cardiovascular morbidity and mortality. BP monitoring has high diagnostic and prognostic value as an important marker of cardiovascular disease. Static BP snapshots, which are typically obtained via sphygmomanometry during doctor’s office visits, have documented reliability issues, including “white-coat” hypertension and poor technique. Auscultatory or oscillometric cuff-based ambu- latory BP monitors (ABPMs) that can be worn in home settings and provide regular automated measurements over 24-hour periods have seen widespread adoption. However, these devices also suffer from poor reliability because measurements are seldom performed according to the specified guidelines even with training (e.g., seated, feet not crossed, arm cuff maintained at heart level, etc.). They also yield only intermittent measure- ments (potentially missing important BP events), worsen sleep quality due to their intrusiveness, confound BP measurements due to autonomic response to cuff inflations, and are obtrusive and uncomfortable. Solution The proposed Blood Pressure Sage (BP-SAGE ) system will be a novel, reliable, easy-to-use, and comfortable (non-cuff-based) continuous ABPM (cABPM) that can operate 24/7, even during activities of daily living (ADL) and sleep without disturbing or requiring any action from the wearer, and without imposing stringent measurement guidelines.This new class of BP monitor will be an important addition to clinical practice, accurately and unobtrusively assessing individuals with established or suspected hypertension, even during movement and without uncom- fortable cuff inflations. BP-SAGE will provide accurate BP estimates without restricting users’ mobility, body postures, or arm elevations. The beat-to-beat BP estimates may be used directly or averaged over arbitrary intervals (e.g., to reproduce conventional ABPM results).The Phase I effort will demonstrate proof-of-concept and feasibility for the BP-SAGE methodology via rigorous evaluation in both healthy and hypertensive subjects. In particular, BP-SAGE systolic, diastolic, and mean arterial BP estimates will be obtained during rest and at different BP levels and compared to criterion BP measurements obtained using a laboratory-grade continuous noninvasive BP (cNIBP) monitor. As a true pulse transit time (PTT)-based technique, and based on the proposed novel modeling approach that also accounts for variations in vasomotor tone, BP-SAGE will obviate the need for repeated calibrations associated with traditional pulse arrival time (PAT)-based methods. BP-SAGE software will automatically generate clear, interpretive reports that meet international standards and include summary data to simplify interpretation by clinicians. BP-SAGE will fulfill the need for an ergonomic, accurate, reliable, and low-cost continuous BP monitoring for use in healthcare and clinical research.