A Carotid Doppler Patch Accurately Tracks Stroke Volume Changes During a Preload-Modifying Maneuver in Healthy Volunteers

Jon-Émile S Kenny; Igor Barjaktarevic; Andrew M Eibl; Matthew Parrotta; Bradley F Long; Joseph K Eibl; Frederic Michard

doi:10.1097/CCE.0000000000000072

A Carotid Doppler Patch Accurately Tracks Stroke Volume Changes During a Preload-Modifying Maneuver in Healthy Volunteers

Crit Care Explor. 2020 Jan 29;2(1):e0072. doi: 10.1097/CCE.0000000000000072. eCollection 2020 Jan.

Authors

Jon-Émile S Kenny¹, Igor Barjaktarevic², Andrew M Eibl¹, Matthew Parrotta¹, Bradley F Long^{1

3}, Joseph K Eibl^{1

3}, Frederic Michard⁴

Affiliations

¹ Health Sciences North Research Institute, Sudbury ON, Canada.
² Division of Pulmonary and Critical Care, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA.
³ Northern Ontario School of Medicine, Sudbury ON, Canada.
⁴ michardconsulting.com, Denens, Switzerland.

Abstract

Objectives: Detecting instantaneous stroke volume change in response to altered cardiac preload is the physiologic foundation for determining preload responsiveness.

Design: Proof-of-concept physiology study.

Setting: Research simulation laboratory.

Subjects: Twelve healthy volunteers.

Interventions: A wireless continuous wave Doppler ultrasound patch was used to measure carotid velocity time integral and carotid corrected flow time during a squat maneuver. The Doppler patch measurements were compared with simultaneous stroke volume measurements obtained from a noninvasive cardiac output monitor.

Measurements and main results: From stand to squat, stroke volume increased by 24% while carotid velocity time integral and carotid corrected flow time increased by 32% and 9%, respectively. From squat to stand, stroke volume decreased by 13%, while carotid velocity time integral and carotid corrected flow time decreased by 24% and 10%, respectively. Both changes in carotid velocity time integral and corrected flow time were closely correlated with changes in stroke volume (r ² = 0.81 and 0.62, respectively). The four-quadrant plot found a 100% concordance rate between changes in stroke volume and both changes in carotid velocity time integral and changes in corrected flow time. A change in carotid velocity time integral greater than 15% predicted a change in stroke volume greater than 10% with a sensitivity of 95% and a specificity of 92%. A change in carotid corrected flow time greater than 4% predicted a change in stroke volume greater than 10% with a sensitivity of 90% and a specificity of 92%.

Conclusions: In healthy volunteers, both carotid velocity time integral and carotid corrected flow time measured by a wireless Doppler patch were useful to track changes in stroke volume induced by a preload-modifying maneuver with high sensitivity and specificity.

Keywords: carotid ultrasound; corrected flow time; fluid responsiveness; stroke volume; velocity time interval.