Research

High mixed venous oxygen saturation levels do not exclude fluid responsiveness in critically ill septic patients

Dimitrios Velissaris, Charalampos Pierrakos, Sabino Scolletta, Daniel De Backer and Jean L Vincent^*

• * Corresponding author: Jean L Vincent jlvincen@ulb.ac.be

Author Affiliations

Department of Intensive Care, Erasme Hospital, Université libre de Bruxelles, Route de Lennik 808, 1070 Brussels, Belgium

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Critical Care 2011, 15:R177 doi:10.1186/10326

Published: 26 July 2011

Abstract

Introduction

The aim of this study was to determine whether the degree of fluid responsiveness in critically ill septic patients is related to baseline mixed venous oxygen saturation (SvO₂) levels. We also sought to define whether fluid responsiveness would be less likely in the presence of a high SvO₂ (>70%).

Methods

This observational study was conducted in a 32-bed university hospital medicosurgical ICU. The hemodynamic response to a fluid challenge was evaluated in 65 critically ill patients with severe sepsis. Patients were divided into two groups (responders and nonresponders) according to their cardiac index (CI) response to the challenge (>10% or <10%).

Results

Of the 65 patients, 34 (52%) were fluid responders. Baseline SvO₂, CI, heart rate (HR) and mean arterial pressure (MAP) were not statistically different between groups. The responders had lower pulmonary artery occlusion pressure (PAOP) and central venous pressure (CVP) at baseline than the nonresponders. After the fluid challenge, there were no differences between the two groups in MAP, CVP, PAOP or HR. There was no correlation between changes in CI or stroke volume index and baseline SvO₂. Receiver operating characteristic analysis showed that SvO₂ was not a predictor of fluid responsiveness.

Conclusions

The response of septic patients to a fluid challenge is independent of baseline SvO₂. The presence of a high SvO₂ does not necessarily exclude the need for further fluid administration.