A Novel Non-invasive Index of Cardiopulmonary Reserve for the Prediction of Failure of Weaning From Mechanical Ventilation.

Purpose: To develop an easy-to-implement prediction index of weaning failure for ICU patients. Materials and methods We developed a prediction index modifying respiratory exchange ratio (RER), Mod-RER, a parameter measured during the cardiopulmonary exercise test (CPET) based on respiratory quotient. The Mod-RER index is the ratio of partial pressure of CO in central venous blood over the difference of partial pressure of O in arterial and central venous blood (Mod-RER=PcvCO/PaO-PcvO where PcvCO = partial pressure of CO in central venous blood, PaO = partial pressure of O in arterial blood, and PcvO = partial pressure of O in central venous blood).