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

2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Jon-Émile S. Kenny ◽  
Igor Barjaktarevic ◽  
David C. Mackenzie ◽  
Mai Elfarnawany ◽  
Zhen Yang ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Stroke Volume ◽  
Doppler Ultrasound ◽  
Volume Change ◽  
Maximum Velocity ◽  
Human Model ◽  
Velocity Time Integral ◽  
Time Integral ◽  
Simulated Hemorrhage ◽  
Corrected Flow Time

Abstract Objective Doppler ultrasonography of the common carotid artery is used to infer stroke volume change and a wearable Doppler ultrasound has been designed to improve this workflow. Previously, in a human model of hemorrhage and resuscitation comprising approximately 50,000 cardiac cycles, we found a strong, linear correlation between changing stroke volume, and measures from the carotid Doppler signal, however, optimal Doppler thresholds for detecting a 10% stroke volume change were not reported. In this Research Note, we present these thresholds, their sensitivities, specificities and areas under their receiver operator curves (AUROC). Results Augmentation of carotid artery maximum velocity time integral and corrected flowtime by 18% and 4%, respectively, accurately captured 10% stroke volume rise. The sensitivity and specificity for these thresholds were identical at 89% and 100%. These data are similar to previous investigations in healthy volunteers monitored by the wearable ultrasound.

scholarly journals The feasibility of a novel, wearable Doppler ultrasound to track stroke volume change in a healthy adult

2020 ◽  
Vol 4 ◽  
pp. 17-17 ◽  
Author(s):  
Jon-Émile S. Kenny ◽  
Igor Barjaktarevic ◽  
Andrew M. Eibl ◽  
Matthew Parrotta ◽  
Bradley F. Long ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Doppler Ultrasound ◽  
Volume Change ◽  
Healthy Adult

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

2021 ◽  
Vol 8 (12) ◽  
pp. 203
Author(s):  
Jon-Émile Stuart Kenny ◽  
Geoffrey Clarke ◽  
Matt Myers ◽  
Mai Elfarnawany ◽  
Andrew M. Eibl ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Stroke Volume ◽  
Doppler Ultrasound ◽  
Bypass Surgery ◽  
Artery Bypass ◽  
Coronary Bypass ◽  
Clinically Significant ◽  
Set Up ◽  
Carotid Doppler ◽  
Proof Of Principle

Background: A novel, wireless, ultrasound biosensor that adheres to the neck and measures real-time Doppler of the carotid artery may be a useful functional hemodynamic monitor. A unique experimental set-up during elective coronary artery bypass surgery is described as a means to compare the wearable Doppler to trans-esophageal echocardiography (TEE). Methods: A total of two representative patients were studied at baseline and during Trendelenburg position. Carotid Doppler spectra from the wearable ultrasound and TEE were synchronously captured. Areas under the receiver operator curve (AUROC) were performed to assess the accuracy of changing common carotid artery velocity time integral (ccVTI∆) at detecting a clinically significant change in stroke volume (SV∆). Results: Synchronously measuring and comparing Doppler spectra from the wearable ultrasound and TEE is feasible during Trendelenburg positioning. In two representative cardiac surgical patients, the ccVTI∆ accurately detected a clinically significant SV∆ with AUROCs of 0.89, 0.91, and 0.95 when single-beat, 3-consecutive beat and 10-consecutive beat averages were assessed, respectively. Conclusion: In this proof-of-principle research communication, a wearable Doppler ultrasound system is successfully compared to TEE. Preliminary data suggests that the diagnostic accuracy of carotid Doppler ultrasonography at detecting clinically significant SV∆ is enhanced by averaging more cardiac cycles.

scholarly journals Diagnostic characteristics of 11 formulae for calculating corrected flow time as measured by a wearable Doppler patch

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Jon-Émile S. Kenny ◽  
Igor Barjaktarevic ◽  
David C. Mackenzie ◽  
Andrew M. Eibl ◽  
Matthew Parrotta ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Sensitivity And Specificity ◽  
Doppler Ultrasound ◽  
Flow Time ◽  
Cardiac Preload ◽  
Respiratory Cycle ◽  
Quiet Breathing ◽  
Diagnostic Characteristics ◽  
Corrected Flow Time ◽  
Corrected Flow

Abstract Background Change of the corrected flow time (Ftc) is a surrogate for tracking stroke volume (SV) in the intensive care unit. Multiple Ftc equations have been proposed; many have not had their diagnostic characteristics for detecting SV change reported. Further, little is known about the inherent Ftc variability induced by the respiratory cycle. Materials and methods Using a wearable Doppler ultrasound patch, we studied the clinical performance of 11 Ftc equations to detect a 10% change in SV measured by non-invasive pulse contour analysis; 26 healthy volunteers performed a standardized cardiac preload modifying maneuver. Results One hundred changes in cardiac preload and 3890 carotid beats were analyzed. Most of the 11 Ftc equations studied had similar diagnostic attributes. Wodeys’ and Chambers’ formulae had identical results; a 2% change in Ftc detected a 10% change in SV with a sensitivity and specificity of 96% and 93%, respectively. Similarly, a 3% change in Ftc calculated by Bazett’s formula displayed a sensitivity and specificity of 91% and 93%. FtcWodey had 100% concordance and an R2 of 0.75 with change in SV; these values were 99%, 0.76 and 98%, 0.71 for FtcChambers and FtcBazetts, respectively. As an exploratory analysis, we studied 3335 carotid beats for the dispersion of Ftc during quiet breathing using the equations of Wodey and Bazett. The coefficient of variation of Ftc during quiet breathing for these formulae were 0.06 and 0.07, respectively. Conclusions Most of the 11 different equations used to calculate carotid artery Ftc from a wearable Doppler ultrasound patch had similar thresholds and abilities to detect SV change in healthy volunteers. Variation in Ftc induced by the respiratory cycle is important; measuring a clinically significant change in Ftc with statistical confidence requires a large sample of beats.

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