A Novel Modular Tonometry-Based Device to Measure Pulse Pressure Waveforms in Radial Artery

Abstract

The paper presents the development of a new device for measuring continuous pulse pressure waveforms (PPW) from the radial artery via applanation tonometry. The development focuses on improved accuracy, open and affordable design using off-the-shelf components, and greater user control in setting operational and calibration parameters to address user variability. The device design parameters are optimized through a tissue device interaction study based on a computational model. The design incorporates modular components and includes a sensor module for arterial flattening and pressure pick-up, a differential screw mechanism and a related algorithm for controlled stepwise motion and data collection during flattening, and a brace for wrist-flexion adjustment. Maximum pulse amplitude (PA) was used as an indicator of the optimum level of arterial flattening for recording the PPW. The PPW was observed to distort due to changes in parameters like gel-head placement, hold-down pressure (HDP), and wrist extension. The pressure waveforms collected using the device were validated using limited data against established products and showed good correlation within ±1.96 standard deviation of the mean difference in a Bland–Altman plot. This paper thus details the development of a simple and validated mechanical design to measure PPW using arterial tonometry.