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 (PtcO(2)) response to 1.0 FiO(2. )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 FiO(2 )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 10min-OCT ((PtcO(2 )after 10 minutes on inspired 1.0 oxygen) - (baseline PtcO(2))), and the oxygen challenge index ((10min-OCT)/(PaO(2 )on inspired 1.0 oxygen - baseline PaO(2))) during the OCT. RESULTS: The PI was significantly correlated with baseline PtcO(2), 10min-OCT and oxygen challenge index (OCI) in all the patients. The control group had a higher baseline PtcO(2), 10min-OCT and PI than the septic shock group. In the sepsis group, the macro hemodynamic parameters and ScvO(2 )showed no differences between survivors and nonsurvivors. The nonsurvivors had a significantly lower PI, 10min-OCT and OCI, and higher arterial lactate level. The PI, 10min-OCT and OCI predicted the ICU mortality with an accuracy that was similar to arterial lactate level. A PI <0.2 and a 10min-OCT <66mmHg 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.