The value of stroke volume variation in prediction of responsiveness to fluid resuscitation in patients with septic shock

Objective To determine whether stroke volume variation (SVV) in relation to volume loading in mechanically ventilated patients with septic shock.Methods Data of thirty-two mechanically ventilated patients with septic shock admitted from Dec 2009 to May 2012 were prospectively analyzed.Cardiac index (CI),stroke volume (SV),systemic vascular resistance index (SVRI) and stroke volume variation (SVV) were measured by FloTrac/Vigileo before and after fluid resuscitation (250 mL saline in 10 min).Patients with an increase in SV (△SV) ≥ 10％ and ＜ 10％ after fluid volume loading were classified as responders and non-responders,respectively.The comparisons between these two sorts of patients were assessed by using two sample Student' s t-test,and comparisons between changes before and after fluid challenge were assessed by using a paired Student' s t-test.A Pearson' s correlation analysis was employed for evaluate the correlation between △SV and other haemodynamic variables.The roles of SVV,central venous pressure (CVP),mean artery pressure (MAP) and the changes of CVP (△CVP),MAP (△MAP) after fluid administration in predicting volume responsiveness were evaluated by receiver operating characteristic (ROC) curve.Results Thirty-two patients with septic shock were included in this study.There were 54 instances of fluid challenge performed,among which 35 instances were defined as response group.Significantly increased SV induced by fluid challenge was assigned into response group (83.6 ± 15.6) mL vs.(68.5 ± 14.2) mL,P ＜0.01,while in non-response group,there were no significant change in SV (P ＞0.05).SVV was significantly correlated with SV before fluid loading (r =0.522,P ＜ 0.01).The area under the ROC curve (AUC) for stroke volume variation (SVV) was 0.898 (95％ CI:0.796-1.000).Using SVV ≥ 11.5％ as the threshold to predict fluid responsiveness,the sensitivity was 94％ and specificity was 84％.Conclusions SVV can be used to predict fluid responsiveness in patients with septic shock. Key words: Septic shock;  Stroke volume variation;  Volume responseness;  Fluid challenge