Fluid responsiveness

Fluid responsiveness (FR) is defined as the ability of the left ventricle to increase its stroke volume (SV) in response to fluid administration.

Sixty patients 1-3 years of age undergoing major neurosurgery received 10 ml/kg of Ringer's solution over 10 min after anesthesia induction. Aortic blood flow peak velocity (∆Vpeak), plethysmographic variability index (PVI), FloTrac/Vigileo-derived stroke volume variation (SVV), and dynamic arterial elastance (Eadyn ), and pulse pressure variation (PPV) were measured before and following fluid loading. An increase in cardiac index (CI) of ≥10% following fluid loading identified fluid “responders”.

Twenty-six (43.3%) patients were fluid responders. Baseline ∆Vpeak was an excellent predictor of a CI increase following fluid loading with an area under the receiver operating characteristic curve (AUROC) of 0.982 (P < 0.001). PVI showed fair diagnostic accuracy for CI-fluid responsiveness (AUROC 0.775, P < 0.001). Baseline ∆Vpeak and PVI cutoff values were 9.6% and 15%, respectively. PPV, SVV, and Eadyn were not or poor predictors for CI-fluid responsiveness (AUROC 0.669, 0.653, and 0.533, respectively).

Volume-based PVI and ∆Vpeak showed acceptable reliabilities for fluid responsiveness prediction in young children undergoing major neurosurgery, while pressure-based SVV using FloTrac/Vigileo, Eadyn , and PPV not ¹⁾