The peripheral perfusion index and transcutaneous oxygen challenge test are predictive of mortality in septic patients after resuscitation

INTRODUCTION The peripheral perfusion index (PI) is a noninvasive numerical value of peripheral perfusion, and the transcutaneous oxygen challenge test (OCT) is defined as the degree of transcutaneous partial pressure of oxygen (PtcO2) response to 1.0 FiO2. The value of noninvasive monitoring peripheral perfusion to predict outcome remains to be established in septic patients after resuscitation. Moreover, the prognostic value of PI has not been investigated in septic patients. METHODS Forty-six septic patients, who were receiving PiCCO-Plus cardiac output monitoring, were included in the study group. Twenty stable postoperative patients were studied as a control group. All the patients inspired 1.0 of FiO2 for 10 minutes during the OCT. Global hemodynamic variables, traditional metabolic variables, PI and OCT related-variables were measured simultaneously at 24 hours after PiCCO catheter insertion. We obtained the 10 min-OCT ((PtcO2 after 10 minutes on inspired 1.0 oxygen)--(baseline PtcO2)), and the oxygen challenge index ((10 min-OCT)/(PaO2 on inspired 1.0 oxygen--baseline PaO2)) during the OCT. RESULTS The PI was significantly correlated with baseline PtcO2, 10 min-OCT and oxygen challenge index (OCI) in all the patients. The control group had a higher baseline PtcO2, 10 min-OCT and PI than the septic shock group. In the sepsis group, the macro hemodynamic parameters and ScvO2 showed no differences between survivors and nonsurvivors. The nonsurvivors had a significantly lower PI, 10 min-OCT and OCI, and higher arterial lactate level. The PI, 10 min-OCT and OCI predicted the ICU mortality with an accuracy that was similar to arterial lactate level. A PI<0.2 and a 10 min-OCT<66 mmHg were related to poor outcome after resuscitation. CONCLUSIONS The PI and OCT are predictive of mortality for septic patients after resuscitation. Further investigations are required to determine whether the correction of an impaired level of peripheral perfusion may improve the outcome of septic shock patients.