Carotid Doppler Imaging as a Marker for Fluid Responsiveness

Area of Science:

• Critical Care Medicine
• Cardiovascular Physiology
• Point-of-Care Ultrasound (POCUS)

Background:

• Hemodynamic instability management requires accurate fluid responsiveness assessment.
• Traditional static measures like central venous pressure (CVP) have limitations.
• Cardiac ultrasound (US), specifically carotid Doppler POCUS, shows potential for noninvasive fluid responsiveness evaluation.

Purpose of the Study:

• To evaluate the correlation between carotid ultrasound (US) parameters and pulmonary artery catheter (PAC)-derived cardiac output (CO) in postcardiac surgery patients.
• To assess the utility of carotid POCUS in identifying fluid-responsive patients.

Main Methods:

• Prospective cohort study of 50 postcardiac surgery patients.
• Carotid US and PAC CO measurements taken at four intervals around a passive leg raise (fluid challenge).
• Pearson's correlation, linear regression, and Cohen's kappa used for analysis.

Main Results:

• No significant correlation found between changes in carotid US parameters (ΔCDPV, FTc, carotid blood flow) and PAC cardiac index (CI).
• A moderate correlation (r = 0.41, p = 0.005) observed between carotid blood flow and FTc at one hour post-fluid challenge.
• Regression and sensitivity analyses revealed no significant associations.

Conclusions:

• Carotid US parameters did not demonstrate correlation with PAC-derived CO following a passive leg raise.
• The study did not validate carotid POCUS as a reliable tool for fluid responsiveness assessment in this patient cohort.
• Further research is necessary to establish the role of carotid POCUS in managing hemodynamic instability.