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

Purpose: To evaluate whether the changes of central venous oxygen saturation (Scvo(2)) after fluid challenge can define fluid responsiveness in patients with septic shock. Methods: In this prospective observational study, septic shock patients with invasive cardiac output monitoring requiring fluid challenge were included. Cardiac index (CI) and Scvo(2) were measured before and after fluid challenges. The changes of CI (Delta CI) and the changes of Scvo(2) (Delta Scvo(2)) 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. Results: Forty 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 Scvo(2) from 69.6% +/- 9.8% to 77.1% +/- 8.9% (both P < .001) after fluid challenge. In the nonresponders, neither CI nor Scvo(2) 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 Delta Scvo(2) and Delta CI was significant (r = 0.702, P < .001). The area under ROC of Delta Scvo(2) to define fluid responsiveness was 0.88 (95% confidence interval [ 95% CI], 0.76-0.99). A Delta Scvo(2) threshold value of 5.0% discriminated responders from nonresponders with sensitivity of 0.78 (95% Cl, 0.52-0.93) and specificity of 0.95 (95% Cl, 0.75-1.00). Conclusions: The changes of Scvo(2) correlate with the changes of CI, and the changes of Scvo(2) define fluid responsiveness in patients with septic shock. (C) 2016 Elsevier Inc. All rights reserved.