How V-CHEK Works

Non-invasive, cuffless BP monitor measuring BP, heart rate, and oxygen saturation

Optical sensors embedded in integrated hardware capture physiological signals at the fingertip
Waveforms analyzed by V-CHEK algorithms determine SBP and DBP relative to calibration point
Measured data displayed on device and smartphone app via Bluetooth
Requires no patient interaction — comfortable for daily home BP measurements
Calibration using sphygmomanometer reference before first use

Calibration Protocol

Step 1: Rest

Patient rested 5 min seated, hand open and relaxed, legs uncrossed.

Step 2: Reference BP

Three reference measurements (Ref1, Ref2, Ref3) using mercury sphygmomanometer. Average SBP and DBP entered in app.

Step 3: V-CHEK Measurement

Within 60s of reference, place finger on sensor. All four vital signs displayed in 40–60 seconds.

Conclusions & Key Messages

V-CHEK provides daytime BP measurements comparable to traditional sphygmomanometer
Negligible bias for BP (−0.377 mmHg), heart rate (−0.078 bpm), and SpO₂ (0.173%)
No statistically significant differences in resting SBP and DBP
Easy to learn and use across all age groups without assistance
Promising tool for cuffless BP monitoring in clinical and home settings

Published in: Journal of Indian College of Cardiology, Volume 14, Issue 3, July–September 2024

Authors: Rahul S. Patil, C. N. Manjunath, K. R. Nishanth

Institution: Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru

DOI: 10.4103/jicc.jicc_46_23

Photoplethysmography

(PPG) Technology

The science of measuring blood pressure through light — how V-CHEK uses PPG sensors for painless, accurate vital sign monitoring.

What is PPG?

Photoplethysmography uses light to detect blood volume changes in tissue

PPG is a non-invasive optical technique that uses red and green LED light sources to illuminate blood vessels beneath the skin. An optical sensor detects the amount of light absorbed or reflected by blood, creating a waveform that represents pulse and blood flow characteristics.

V-CHEK’s proprietary algorithms analyze these waveforms to determine systolic and diastolic blood pressure changes relative to a calibration reference point — all without physical compression.

Traditional Cuff vs. V-CHEK Optical Sensor

Traditional Sphygmomanometer

Painful physical occlusion of brachial artery
Mercury column / gauge measurement at upper arm
Requires cuff inflation and deflation cycle
Arm compression causes discomfort
Single snapshot measurement

V-CHEK Optical Blood Pressure Sensor

Fingertip tissue measurement — zero compression
Capillary network illuminated by red & green LEDs
Optical sensor tracks vascular flow continuously
Data tracking without painful pressure
Non-compressed measurement zone

PPG Sensor Components

Red & Green LEDs

Dual-wavelength light sources illuminate fingertip tissue to capture vascular blood flow patterns.

Optical Sensor

High-sensitivity photodetector captures reflected light intensity changes corresponding to pulse waves.

Signal Processing

Advanced algorithms convert PPG waveforms into accurate BP, heart rate, and SpO₂ readings.