Changes of central venous oxygen saturation define fluid responsiveness in patients with septic shock: A prospective observational study

Abstract

PurposeTo evaluate whether the changes of central venous oxygen saturation (Scvo2) after fluid challenge can define fluid responsiveness in patients with septic shock. MethodsIn this prospective observational study, septic shock patients with invasive cardiac output monitoring requiring fluid challenge were included. Cardiac index (CI) and Scvo2 were measured before and after fluid challenges. The changes of CI (ΔCI) and the changes of Scvo2 (ΔScvo2) were calculated and analyzed using Pearson correlation. Receiver operating characteristics curve (ROC) analysis was used to classify fluid responders and nonresponders. Area under ROC was calculated. ResultsForty patients were included and 18 patients (45%) were fluid responders. In the responders, CI increased from 3.4±1.1 to 4.4±1.0 L min−1 m−2 and Scvo2 from 69.6%±9.8% to 77.1%±8.9% (both P<.001) after fluid challenge. In the nonresponders, neither CI nor Scvo2 changed (4.1±1.3 vs 4.1±1.3 L min−1 m−2, 71.0%±13.8% vs 70.6%±14.1%, both P>.05). The correlation between ΔScvo2 and ΔCI was significant (r=0.702, P<.001). The area under ROC of ΔScvo2 to define fluid responsiveness was 0.88 (95% confidence interval [95% CI], 0.76-0.99). A ΔScvo2 threshold value of 5.0% discriminated responders from nonresponders with sensitivity of 0.78 (95% CI, 0.52-0.93) and specificity of 0.95 (95% CI, 0.75-1.00). ConclusionsThe changes of Scvo2 correlate with the changes of CI, and the changes of Scvo2 define fluid responsiveness in patients with septic shock.