Could Duplex carotid ultrasound be useful in the assessment of volume status and fluid responsiveness?

Although the ultrasound assessment of inferior vena cava diameters and their respiratory variations have been suggested as a tool for fluid management, recent reports do not confirm its validity in predicting fluid responsiveness in spontaneously breathing patients [ 1 Long E. Oakley E. Duke T. Franz E. Babl F.E. Does respiratory variation in inferior vena cava diameter predict fluid responsiveness: a systematic review and meta-analysis. SHOCK. 2017; 47: 550-559 Crossref PubMed Scopus (70) Google Scholar , 2 Bentzer P. Griesdale D.E. Boyd J. MacLean K. Sirounis D. et al. Will this hemodynamically unstable patient respond to a bolus of intravenous fluids?. JAMA. 2016; 316: 1298-1309https://doi.org/10.1001/jama.2016.12310 Crossref PubMed Scopus (101) Google Scholar , 3 Orso D. Paoli I. Piani T. Cilenti F.L. Cristiani L. Guglielmo N. Accuracy of ultrasonographic measurements of inferior vena cava to determine fluid responsiveness: a systematic review and meta-analysis. J Intensive Care Med. 2018; (885066617752308)https://doi.org/10.1177/0885066617752308 Crossref PubMed Scopus (38) Google Scholar ].