Survi Kyal

Toward Ubiquitous Blood Pressure Monitoring via Pulse Transit Time: Theory and Practice

Ubiquitous blood pressure (BP) monitoring is needed to improve hypertension detection and control and is becoming feasible due to recent technological advances such as in wearable sensing. Pulse transit time (PTT) represents a well-known potential approach for ubiquitous BP monitoring. The goal of this review is to facilitate the achievement of reliable ubiquitous BP monitoring via PTT. We explain the conventional BP measurement methods and their limitations; present models to summarize the theory of the PTT-BP relationship; outline the approach while pinpointing the key challenges; overview the previous work toward putting the theory to practice; make suggestions for best practice and future research; and discuss realistic expectations for the approach.

Towards continuous monitoring of pulse rate in neonatal intensive care unit with a webcam.

We describe a novel method to monitor pulse rate (PR) on a continuous basis of patients in a neonatal intensive care unit (NICU) using videos taken from a high definition (HD) webcam. We describe algorithms that determine PR from videoplethysmographic (VPG) signals extracted from multiple regions of interest (ROI) simultaneously available within the field of view of the camera where cardiac signal is registered. We detect motion from video images and compensate for motion artifacts from each ROI. Preliminary clinical results are presented on 8 neonates each with 30 minutes of uninterrupted video. Comparisons to hospital equipment indicate that the proposed technology can meet medical industry standards and give improved patient comfort and ease of use for practitioners when instrumented with proper hardware.

A method to detect cardiac arrhythmias with a webcam

We describe a novel method to detect the presence of atrial fibrillation (A-Fib) by video recording of the face of a patient. The signal processing algorithm extracts A-Fib episodes by processing time-series signals generated by video images in a remote sensing environment. The process removes the non-stationary components of the green component of the RGB signal. Beat-to-beat pulse points are detected using an adaptive threshold technique; the successive thresholds are based on variations detected in previous magnitudes of the pulse peaks. The existence of cardiac arrhythmia is determined by quantifying the variability of the peak-to-peak intervals. We report preliminary results of our on-going study on six subjects undergoing electro-cardioversion for persistent A-Fib.