Functional Hemodynamic Monitoring With a Wireless Ultrasound Patch

Abstract

In this Emerging Technology Review, a novel, wireless, wearable Doppler ultrasound patch is described as a tool for resuscitation. The device is designed, foremost, as a functional hemodynamic monitor-a simple, fast, and consistent method for measuring hemodynamic change with preload variation. More generally, functional hemodynamic monitoring is a paradigm that helps predict stroke volume response to additional intravenous volume. Because Doppler ultrasound of the left ventricular outflow tract noninvasively measures stroke volume in realtime, it increasingly is deployed for this purpose. Nevertheless, Doppler ultrasound in this manner is cumbersome, especially when repeat assessments are needed. Accordingly, peripheral arteries have been studied and various measures from the common carotid artery Doppler signal act as windows to the left ventricle. Yet, handheld Doppler ultrasound of a peripheral artery is susceptible to human measurement error and statistical limitations from inadequate beat sample size. Therefore, a wearable Doppler ultrasound capable of continuous assessment minimizes measurement inconsistencies and smooths inherent physiologic variation by sampling many more cardiac cycles. Reaffirming clinical studies, the ultrasound patch tracks immediate SV change with excellent accuracy in healthy volunteers when cardiac preload is altered by various maneuvers. The wearable ultrasound also follows jugular venous Doppler, which qualitatively trends right atrial pressure. With further clinical research and the application of artificial intelligence, the monitoring modalities with this new technology are manifold.

Carotid artery velocity time integral and corrected flow time measured by a wearable Doppler ultrasound detect stroke volume rise from simulated hemorrhage to transfusion

“…Inferring change in stroke volume (SV) is the bedrock of functional hemodynamic monitoring [ 1 , 2 ]. Yet measuring SV change (SV ∆ ) is clinically challenging, so surrogates like the common carotid artery Doppler pulse have been proposed [ 3 , 4 ] with some conflicting data [ 5 ].…”

A wireless optoelectronic skin patch for light delivery and thermal monitoring

“…2015b ). Several wearable devices for blood flow monitoring have been developed based on electrical ( Etemadi et al., 2015 ; Rosa et al, 2019 ; Cluff et al., 2017 ), mechanical ( Etemadi et al., 2015 ; Wiens et al., 2014 ), acoustic ( Rosa et al, 2019 ; Kenny 2021 ; Kenny et al., 2020 ), and optical ( Abtahi et al. 2016 ; Saikia and Mankodiya 2018 ) approaches.…”

“…2020a ). Clinical validation studies will be required to establish the performance of the wearable optoelectronic device compared with the gold standard, such as Doppler ultrasound for blood flow monitoring ( Kenny 2021 ; Kenny et al., 2020 ). Additional modalities, such as impedance cardiography ( Cluff et al., 2017 ) and reflectometry ( Saikia and Mankodiya 2018 ), can also be incorporated to improve sensing accuracy.…”

A Wireless Wearable Doppler Ultrasound Detects Changing Stroke Volume: Proof-of-Principle Comparison with Trans-Esophageal Echocardiography during Coronary Bypass Surgery

“…We have previously described a wireless Doppler ultrasound patch that adheres to the neck over the common carotid artery, maintains a constant angle of insonation, and accurately measures Doppler metrics such as the velocity time integral (VTI) and corrected carotid flow time (ccFT) [ 1 ]. One clinical application of this unique biosensor, particularly within the sphere of acute care medicine, is functional hemodynamic monitoring (FHM) [ 2 ]. FHM is predicated upon accurately measuring change in—rather than absolute values of—stroke volume (SV) [ 3 , 4 ].…”