Correlation of Carotid Doppler Flowmetry with Fluid Responsiveness in Mechanically Ventilated Patients Undergoing Coronary Artery Bypass Grafting -- A Popular Grey Zone

The authors conducted a prospective, observational study to evaluate the correlation of fluid responsiveness with commonly used carotid doppler-derived indices like carotid artery blood flow (CBF), carotid corrected flow time (FTc), respirophasic variation in carotid artery blood flow peak velocity (ΔVpeak) in patients undergoing CABG. They claimed that altough only ΔVpeak demonstrated some predictive power with areas under receiver operating characteristic (AUROC) of 0.671, carotid doppler ultrasound indices were found to be not dependable as a substitute for invasive methods to assess fluid responsiveness. The presence of studies advocating quite different sentiments in the literature regarding feasibility and reliability show that there is a long way gone and a long way to go.