Related Experiment Video
Updated: Jan 13, 2026
Noninvasive Determination of Vortex Formation Time Using Transesophageal Echocardiography During Cardiac Surgery
Published on: November 28, 2018
Comparison of the change in carotid corrected flow time and stroke volume variation for assessing volume
Yongyong Yang1,2, Min Li3, Chenlong Yang1,2
1Department of Anesthesiology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, No. 999, Huashan Rd, 350212, Fuzhou, China.
Background:
Accurately identifying surgical patients who will have an increase in stroke volume following fluid administration remains challenging when utilizing noninvasive bedside methods. This study aims to compare the value of using ultrasound to measure changes in corrected carotid artery flow time (ΔFTc) with that of using invasive measurements of stroke volume variation (ΔSVV) for assessing volume responsiveness in patients under general anesthesia and mechanical ventilation.
Methods:
A total of 91 patients undergoing elective abdominal surgery under general anesthesia were enrolled in this prospective observational study. Under general anesthesia and mechanical ventilation, the ΔFTc was measured using noninvasive bedside ultrasound, and the ΔSVV was measured using invasive hemodynamic monitoring, both before and after fluid administration. Fluid responders were defined as an increase in stroke volume of ≥ 10% after the fluid challenge.
Results:
A total of 47 (54.0%) patients were fluid responders. The ΔFTc was 14.5 ± 8.3 ms for responders and 5.7 ± 4.9 ms for non-responders, while the ΔSVV was 3.3 ± 1.4% for responders and 1.7 ± 0.7% for non-responders. The areas under the receiver operating characteristic curves for ΔFTc and ΔSVV were 0.85 (95% CI 0.77-0.92; P < 0.05) and 0.84 (95% CI 0.75-0.93; P < 0.05), respectively. The optimal cutoff values were 7.03 ms for ΔFTc (sensitivity 91.5%, specificity 69.8%) and 2.85% for ΔSVV (sensitivity 95.6%, specificity 72.6%). A narrower gray zone for ΔFTc, ranging from 7 ms to 12 ms and covering 27 patients, was observed compared with that for ΔSVV, which ranged from 1% to 3% and covered 41 patients.
Conclusions:
Both the ΔFTc and ΔSVV reliably assessed fluid responsiveness in patients undergoing general anesthesia and mechanical ventilation. Noninvasive bedside ultrasound measurement of ΔFTc can serve as an accurate assessment parameter, reflecting the presence of volume responsiveness following rapid fluid administration and showing greater clinical applicability.
Trial Registration:
www.chictr.org.cn (ChiCTR2500101114); registered 21 April 2025.
Related Concept Videos
01:22Cardiac Output II: Effect of Stroke Volume on Cardiac Output
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...
01:11Cardiac Output and Stroke Volume
In an average resting adult male, the typical cardiac...
01:27Regulation of Stroke Volume
Preload refers to the degree of stretch on the heart before it contracts. It's analogous to the stretching of a rubber band; the more it's stretched, the more forcefully it snaps back. This concept is encapsulated in the Frank-Starling law of the...