Predicting fluid responsiveness in septic shock patients by using 3 dynamic indices: is it all equally effective?

To evaluate the effectiveness and accuracy of three dynamic indices, currently available in intensive care monitoring devices, which are pulse pressure variation (PPV), stroke volume variation (SVV) and pulse oximetry plethysmographic waveform variation (POPV) in septic patients.

This prospective clinical trial was conducted in 20 deeply sedated septic patients 18 years of age and older who had invasive blood pressure monitoring with an intraarterial cannula. PPV, SVV and POPV (%) were calculated using five consecutive snapshots from every patient's monitor. Statistical analysis compared using linear regression, paired t-test or student t-test, and receiver operating characteristic (ROC) curve analysis.

The authors found that, strong correlation existed of PPV for the detection of percent cardiac index change (r2 = 0.794, p < 0.001). A respiratory variation in POPV exceeding 14% (sensitivity of 72%, specificity of 90%), SVV exceeding 11% (sensitivity 90%, specificity 92%) allowed detection of PPV exceeding 12% (sensitivity 84%, specificity 96%).

Comparing of PPV, SVV and POPV, PPV is the most correlate with percent change in cardiac index and the most effective dynamic index for predict fluid responsiveness in adult septic critically ill patients who are on controlled mechanical ventilator, followed by SVV and POPV.