Related Experiment Video
Updated: Mar 10, 2026
Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge
Published on: January 20, 2023
The diagnostic utility of sonographic carotid flow time in determining volume responsiveness
Hamid Shokoohi1, Grant W Berry1, Murteza Shahkolahi1
1Department of Emergency Medicine, The George Washington University, Washington, DC.
Objective:
We aimed to predict volume responsiveness and to assess the diagnostic accuracy of carotid flow time (FTc) with the change in hydration status before and after a passive leg raise (PLR) maneuver.
Methods:
Participants who presented at a community health fair in a dehydrated state following a prolonged fast while observing the month of Ramadan were recruited. Sonographic FTc measurements were obtained in the semi-Fowler position and after a PLR maneuver while participants were in a fasting state and repeated approximately 3 hours after breaking their fast.
Results:
In total, 123 participants with mean age of 47±14 years, 55% male, were enrolled. Participants had fasted for an average of 16.9 hours and consumed an average of 933 mL between the 2 ultrasound measurements. Mean FTc values were significantly lower in the fasting state compared with the nonfasting state (312±22 vs 345±25milliseconds, P value < .001). Relative increases in FTc following a PLR maneuver demonstrated strong discrimination of volume status (area under the receiver operating curve: 0.86 [95% confidence interval, 0.81-0.91]).
Conclusions:
The use of point-of-care ultrasound to measure FTc may provide a noninvasive alternative to determine fluid status. Percentage change in FTc of ≥5% provides a reliable diagnostic accuracy for predicting fluid status.
