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Updated: Apr 28, 2026
Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge
Published on: January 20, 2023
Correlation of corrected flow time in the carotid artery with changes in intravascular volume status
David J Blehar1, Scott Glazier1, Romolo J Gaspari1
1University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA 01655.
Insights
Doppler analysis of carotid artery blood flow, using corrected flow time (FTc), can effectively assess hydration status in critically ill patients. This method shows significant changes in FTc after fluid resuscitation, even when vital signs remain unchanged.
Area of Science:
- Critical Care Medicine
- Cardiovascular Physiology
- Medical Ultrasound
Background:
- Assessing patient volume status is crucial yet challenging in critical care settings.
- Current methods for volume status assessment may be limited in accuracy or invasiveness.
Purpose of the Study:
- To investigate the correlation between Doppler waveform analysis of carotid artery blood flow and changes in volume status.
- To determine if corrected flow time (FTc) can serve as a reliable indicator of volume status.
Main Methods:
- Ultrasound examination with Doppler analysis of the carotid artery was performed on dehydrated patients receiving intravenous fluid boluses.
- Measurements of corrected flow time (FTc), mean arterial pressure, and pulse rate were taken before and after fluid administration.
- Statistical analysis using Wilcoxon matched-pairs signed rank test compared pre- and post-fluid administration values.
Main Results:
- Fifty-six patients received an average of 1110 mL of fluid.
- Corrected flow time (FTc) significantly increased post-fluid resuscitation (P<.0001), from a mean of 299 ms to 340 ms.
- No significant changes were observed in mean arterial pressure or heart rate post-fluid administration.
Conclusions:
- Intravenous fluid administration led to significant changes in carotid artery FTc in dehydrated patients.
- Carotid artery Doppler waveform analysis, specifically FTc, shows potential as a non-invasive tool for assessing volume status in volume-depleted patients.
- FTc changes indicate volume status alterations independently of traditional vital signs.
Purpose:
Assessment of volume status remains a challenge in critical care. Our purpose was to determine if Doppler waveform analysis of carotid artery blood flow correlates with changes in volume status.
Materials And Methods:
Dehydrated patients receiving an intravenous fluid bolus were enrolled with exclusions including age less than 18 years, pregnancy, vasopressor administration, or atrial fibrillation. Ultrasound examination with Doppler analysis of the carotid artery was performed with measurements taken to calculate corrected flow time (FTc). Corrected flow time, mean arterial pressure, and pulse rate before and after fluid administration were compared using Wilcoxon matched-pairs signed rank test.
Results:
Fifty-six patients were enrolled with mean fluid administration of 1110 mL. Corrected flow time increased with fluid resuscitation from prefluid mean of 299 milliseconds (95% confidence interval [CI], 282-317 milliseconds) to a postfluid mean of 340 milliseconds (95% CI, 323-358 milliseconds) (P<.0001). Mean percentage change in FTc was 14.9% (95% CI, 8.4-21.3). There were no significant changes in mean arterial pressure or heart rate from pre- to post-fluid administration.
Conclusion:
Intravenous fluid administration in dehydrated patients resulted in significant changes in FTc in the carotid artery despite no change in vital signs. Corrected flow time measured from carotid arterial blood flow may be a useful means of assessing volume status in volume-depleted patients.
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