Prognostic value of respiratory quotients in severe polytrauma patients with nutritional support

•Indirect calorimetry could have a new clinical application in polytrauma patients.•Respiratory quotient (RQ) and nonprotein respiratory quotient (npRQ) related to the clinical outcomes such as length of stay in the intensive care unit and duration of mechanical ventilation in polytrauma patients with nutritional support.•Severe polytrauma patients without nutritional support had significantly lower RQ and npRQ compared with fasting control patients who had similar anthropometric characteristics. Resting energy expenditure of these compared groups did not differ significantly.•In patients with nutritional support, energy expenditure was significantly higher, whereas RQ and npRQ were very similar to those in fasting controls. The association between energy metabolism and prognosis in polytrauma patients has not yet been defined. The aim of this study was to describe energy metabolism and analyze the prognostic value of respiratory quotient (RQ) and nonprotein respiratory quotient (npRQ) in fasting polytrauma patients (fPP) and polytrauma patients with nutritional support (nsPP). Twenty-two polytrauma patients (before and after parenteral nutrition administration) and 22 healthy controls (after overnight fasting) were examined on day 4 (median) after admission to the intensive care unit. To evaluate energy expenditure in nsPP and resting energy expenditure in fPP and controls with RQ and npRQ in all groups, we used indirect calorimetry. With regression analysis, the descriptive models of intensive care unit (ICU) length of stay (LOS) and mechanical ventilation time (VT) were derived. RQ and npRQ were significantly lower in fPP than in controls (P