The Correlation between Carotid Artery Corrected Flow Time and Velocity Time Integral during Central Blood Volume Loss and Resuscitation

Isabel Kerrebijn; Chelsea E Munding; Christine Horner; Sarah Atwi; Mai Elfarnawany; Andrew M Eibl; Joseph K Eibl; Jenna L Taylor; Chul Ho Kim; Bruce D Johnson; Jon-Émile S Kenny

doi:10.4103/jmu.jmu_80_23

The Correlation between Carotid Artery Corrected Flow Time and Velocity Time Integral during Central Blood Volume Loss and Resuscitation

J Med Ultrasound. 2023 Dec 7;31(4):309-313. doi: 10.4103/jmu.jmu_80_23. eCollection 2023 Oct-Dec.

Authors

Isabel Kerrebijn¹, Chelsea E Munding¹, Christine Horner¹, Sarah Atwi¹, Mai Elfarnawany¹, Andrew M Eibl^{1

2}, Joseph K Eibl^{1

2

3}, Jenna L Taylor^{4

5}, Chul Ho Kim⁴, Bruce D Johnson⁴, Jon-Émile S Kenny^{1

2}

Affiliations

¹ Flosonics Medical, Toronto, ON, Canada.
² Health Sciences North Research Institute, Sudbury, ON, Canada.
³ Northern Ontario School of Medicine, Sudbury, ON, Canada.
⁴ Department of Cardiovascular Diseases, Human Integrative and Environmental Physiology Laboratory, Mayo Clinic, Rochester, MN, USA.
⁵ School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia.

Abstract

Background: Doppler ultrasound of the common carotid artery is used to infer central hemodynamics. For example, change in the common carotid artery corrected flow time (ccFT) and velocity time integral (VTI) are proposed surrogates of changing stroke volume. However, conflicting data exist which may be due to inadequate beat sample size and measurement variability - both intrinsic to handheld systems. In this brief communication, we determined the correlation between changing ccFT and carotid VTI during progressively severe central blood volume loss and resuscitation.

Methods: Measurements were obtained through a novel, wireless, wearable Doppler ultrasound system. Sixteen participants (ages of 18-40 years with no previous medical history) were studied across 25 lower body-negative pressure protocols. Relationships were assessed using repeated-measures correlation regression models.

Results: In total, 33,110 cardiac cycles comprise this analysis; repeated-measures correlation showed a strong, linear relationship between ccFT and VTI. The strength of the ccFT-VTI relationship was dependent on the number of consecutively averaged cardiac cycles (R_{1 cycle} = 0.70, R_{2 cycles} = 0.74, and R_{10 cycles} = 0.81).

Conclusions: These results positively support future clinical investigations employing common carotid artery Doppler as a surrogate for central hemodynamics.

Keywords: Carotid artery; Doppler ultrasound; corrected flow time; functional hemodynamic monitoring; velocity time integral; wearable technology.