A comparative study of stroke volume variation and plethysmography variability index as goal-directed fluid therapy...

Goal-directed fluid therapy with dynamic variables enhances tissue oxygen delivery. A prospective, randomized comparative study was designed with stroke volume variation (SVV) and plethysmography variability index (PVI) to study fluid responsiveness, fluid requirement, and postoperative complications.

A total of 68 patients undergoing major abdominal oncosurgeries were randomly allotted to the SVV or PVI group. SVV was measured with the FlotracEV1000 arterial pressure-based waveform analyzer, and for values >11, a colloid bolus of 200 mL was given. PVI was measured with a MasimoRad-97 plethysmography analyzer as variations in the pulse oximeter plethysmography waveform amplitude, and for values >11, a colloid bolus of 200 mL was given. Fluid response was noted in both groups.

Total fluids (P = 0.058) and colloids (P = 0.268) given were comparable in both groups. Crystalloids required were less in PVI versus SVV, with (P = 0.034). Fluid responsiveness for SVV (84.7%) and PVI (83.8%) was good and values statistically comparable (P = 0.884). In SVV, the receiver operating characteristic (ROC) (AUC) was 0.50, which implies that pre-bolus SVV cannot be considered as a predictor of sensitivity for fluid responsiveness. In PVI (AUC), it was 0.70, which implies that prebolus PVI can be considered as a predictor of sensitivity for fluid responsiveness. Postoperative serum lactate and creatinine values were normal, and SICU stay was short and statistically comparable between the two groups. Bowel sounds appeared earlier in PVI (P < 0.03) patients.

Both SVV and PVI are valid predictors for fluid responsiveness and guides for fluid therapy: reduced postoperative complications and length of stay noted in both groups. PVI is a more sensitive dynamic variable than SVV.