Carotid doppler indices do not predict fluid responsiveness in mechanically ventilated patients undergoing coronary...

Area of Science:

• Cardiovascular Anesthesiology
• Critical Care Medicine
• Hemodynamic Monitoring

Background:

• Fluid responsiveness assessment is crucial in mechanically ventilated patients undergoing major surgery.
• Non-invasive hemodynamic monitoring is desirable to guide fluid therapy.
• Coronary artery bypass grafting (CABG) surgery requires careful hemodynamic management.

Purpose of the Study:

• To evaluate the predictive value of carotid artery blood flow (CABF), corrected carotid flow time (CFT), and respiratory variation in carotid peak systolic velocity (DVPeakCA) for fluid responsiveness.
• To correlate these carotid doppler indices with changes in stroke volume index (SVI) after fluid administration in CABG patients.

Main Methods:

• Prospective, interventional, before-after study of 45 adult patients undergoing CABG.
• A fluid challenge (6 mL/kg crystalloid) was administered over 10 minutes.
• Hemodynamic parameters including CABF, CFT, and DVPeakCA were measured before and after the fluid bolus.

Main Results:

• 22 patients (48.9%) were classified as fluid responders (SVI increase >15%).
• Area under the ROC curves for CABF (0.516), CFT (0.502), and DVPeakCA (0.671) showed poor predictive value for fluid responsiveness.
• Correlation coefficients (r) between carotid doppler indices and SVI changes were <0.2, indicating very weak correlations.

Conclusions:

• Carotid doppler-derived indices (CABF, CFT, DVPeakCA) are unreliable for assessing fluid responsiveness in this patient population.
• These non-invasive indices cannot replace invasive methods for preload optimization.
• No significant correlation was found between carotid doppler indices and SVI alterations post-fluid bolus.