Prediction of fluid responsiveness in septic shock patients: comparing stroke volume variation by FloTrac/Vigileo and automated pulse pressure variation.

OBJECTIVES: The aim of this study was to assess and compare the ability of the automatically and continuously measured stroke volume variation (SVV) obtained by FloTrac/Vigileo, and pulse pressure variation (PPV) measured by an IntelliVue MP monitor, to predict fluid responsiveness in mechanically ventilated septic shock patients.

METHOD: We conducted a prospective study on 42 septic shock patients. SVV, PPV and other haemodynamic data were recorded before and after fluid administration of 500 ml of 6% hydroxyethyl starch. Responders were defined as patients with an increase in stroke volume index of at least 15% after fluid loading.

RESULTS: Twenty-four (57.1%) patients were classified as fluid responders. The baseline SVV correlated with the baseline PPV (r=0.96, P<0.001). SVV and PPV were significantly higher in responders than in nonresponders (15.5±4.5 vs. 8.2±3.3% and 16.4±5.2 vs. 8.3±3.5, respectively, P<0.001 for both). There was no difference between the area under the receiver operating characteristic curves of SVV [0.92, 95% confidence interval 0.832-1.00] and PPV (0.916, 95% confidence interval 0.829-1.00). The optimal threshold values in predicting fluid responsiveness were 10% for SVV (sensitivity 91.7% and specificity 83.3%) and 12% for PPV (sensitivity 83.3% and specificity 83.3%). Our results were independent of the site of arterial catheterisation.

CONCLUSION: The SVV, obtained by FloTrac/Vigileo, and the automated PPV, obtained by the IntelliVue MP monitor, showed comparable performance in terms of predicting fluid responsiveness in passively ventilated septic shock patients, with a regular cardiac rhythm and a tidal volume not less than 8 ml kg(-1).