Carotid Flow as a Surrogate for Cardiac Output Measurement in Hemodynamically Stable Participants.

Area of Science:

• Cardiovascular Physiology
• Medical Ultrasound
• Hemodynamics

Background:

• Common carotid artery (CCA) blood flow assessment offers insights into patient hemodynamic status.
• Ultrasound is a non-invasive tool for evaluating blood flow dynamics.

Purpose of the Study:

• To assess the correlation between cardiac output and CCA hemodynamic parameters: systolic carotid flow (SCF), corrected flow time (CFT), and total carotid flow (TCF).
• To investigate the utility of leg compression maneuvers in simulating volume depletion and evaluating hemodynamic responses.

Main Methods:

• A pilot study involving 20 healthy volunteers.
• Hemodynamic parameters were measured in the CCA and heart at rest and during leg compression/passive leg raise maneuvers.
• Nonparametric Spearman correlation analysis was performed.

Main Results:

• A significant direct correlation was found between cardiac output and SCF (r=0.67, P<0.001).
• A significant direct correlation was observed between cardiac output and CFT (r=0.57, P<0.001).
• Total carotid flow (TCF) showed a weaker, non-significant correlation with cardiac output (r=0.41, P<0.06).

Conclusions:

• Carotid blood flow variations, particularly SCF and CFT, directly reflect changes in cardiac output and preload.
• Carotid flow parameters show potential as non-invasive surrogates for cardiac output monitoring.
• Further research is warranted to validate these findings for guiding fluid management and predicting fluid responsiveness.