The use of volumetric capnography in critically ill patients admitted in intensive care has not been studied widely, we used the NICO monitor as a volumetric capnography and its parameters were compared with changes in hemodynamics and ventilator settings in 100 patients admitted in surgical intensive care unit in Massachuseets General Hospital order to describe a pattern of volumetric CO2 change during the course of mechanical ventilation and to test the hypothesis that volumetric CO2 changes are predictive of ventilatory and hemodynamic change.The main findings of this prospective observational study can be summarized as follows:1) Hemodynamic and volumetric CO2 parameters among ICU population do not widely vary. 2) There was a meaningful correlation between MAP changes and volumetric CO2 parameters 3) Also meaningful correlation between changes in ventilation setting (except PEEP level) and volumetric CO2 parameters 4) Despite such correlation among ICU population, most of these variables were comparable among survivors and non survivors 5) Variables that differed among survivors and non survivors were body weight, hospital stay and PeCO2 (mixed expired).