DESIGNING A CLINICAL TRIAL PROTOCOL INCLUDING PHYSICAL AND MENTAL ACTIVITIES TO EXPLORE BLOOD PRESSURE DYNAMICS FOR MEDICAL DEVICE DEVELOPMENT

Abstract

Objective: Cuff blood pressure monitoring is uncomfortable, limited for daily-routine and it provides sparse measurements in time. To enable continuous non-invasive monitoring, a new cuffless blood pressure (BP) meter based on photoplethysmography (PPG) is assessed in a first clinical trial. It aims at exploring the relationship between BP variations and optical features, including a wide range of intra-individual BP variations. Design and method: The initial cohort of the clinical trial (NCT05393401, approved by Human Research Review Board (CPP SM I) and Health French Ministry) includes five healthy subjects (1F/4M, age [37-60] years). Each subject is monitored with a medical-grade continuous BP meter, and a multi-sensing homemade platform integrating gold standard cuff measurements. The latter gathers PPG sensors, an ECG, a nasal cannula. The subject undertakes the following exercises: rest, static and dynamic strength exercises with a Pilates fitness ring, mental calculation, guided relaxation, and wall sit exercise. Each phase lasts 3 minutes, except the relaxation (10 minutes) and is followed by a 3-minute recovery. Results: The impact of each activity is quantified by the range of mean arterial pressure (MAP), i.e. the difference between the initial value and the extremum during the interval. As the table shows, the highest median impact is achieved with the dynamic ring (+39 mmHg) and the wall sit (+33mmHg). The static ring and the stress occurred by the calculation exercise have a lower impact with an increase of 21mmHg and 19mmHg. Finally, the effect of the relaxation is verified with a median decrease of 13 mmHg. Conclusions: These preliminary results (trial still running) show that building an accurate BP meter requires exploring the full range of BP in response to various physiological mechanisms. Therefore, it is necessary to combine relaxing and physical activities. Their impact vary among subjects and activities and illustrate that special care should be taken using real-time monitoring.