Stroke output variations calculated by esophageal Doppler is a reliable predictor of fluid response

Abstract

Objective: Esophageal Doppler allows continuous monitoring of stroke volume index (SVI) and corrected flow time (FTc). We hypothesized that variations in stroke output index SOI (SVI/FTc) during volume expansion can predict the hemodynamic response to subsequent fluid loading better than the static values.

Design and setting: Prospective study in the intensive care unit of a university hospital.

Patients: Fifty-one patients with circulatory failure were monitored by esophageal Doppler.

Interventions: Patients who responded to a first fluid challenge received a second one. Patients who responded to both were classified as responders-responders, and those who did not respond to the second as responders-nonresponders. In these two groups we compared DeltaSVI, DeltaFTc, and DeltaSOI during each fluid challenge and also static values at the end of each fluid challenge.

Measurements and results: After the first fluid challenge DeltaSOI and DeltaSVI were significantly higher in patients who responded to subsequent volume expansion than in patients who no longer responded. ROC curves showed that DeltaSOI was a better predictor of fluid responsiveness than DeltaSVI. During volume expansion a DeltaSOI value of 11% discriminated between responders and nonresponders to subsequent volume expansion with a sensitivity of 91% and a specificity of 97%. There was no significant difference between the two groups for FTc value at the end of first fluid challenge.

Conclusions: Analysis of DeltaSOI during fluid challenge predicts response to subsequent fluid challenge and FTc is not a reliable indicator of cardiac preload.