[Effects of different positive end expiratory pressure levels on resting energy expenditure measured by indirect calorimeter in patients with pressure-controlled ventilation].

OBJECTIVE: To identify variations during measurements of resting energy expenditure (REE), oxygen consumption (VO2) and CO2 production (VCO2) by indirect calorimetry (IC) in patients with pressure-controlled ventilation and different levels of positive end expiratory pressure (PEEP). DESIGN: Prospective and comparative study. SETTING: Intensive care unit (ICU) of a university-affiliated hospital. MEASUREMENTS AND MAIN RESULTS: REE, VO2, and VCO2 were measured by IC in nine patients with pressure-controlled ventilation and different levels of PEEP. Paired t Wilcoxon and coeficient of variation tests for all measurements were carried out. Decrease in REE, VCO2, and VO2 was observed with increments in PEEP, these changes related with a concomitant reduction in VE. Coefficient of variation during IC was above 6%, and was lower in three patients who maintained the same VE throughout the study. CONCLUSIONS: Measurement of REE by IC is reliable at various levels of PEEP, and it improves if VE remains constant throughout measurement. Respiratory quotient (RQ) in this setting is not accurate.