Indirect calorimetry in critical ill patients: validity of measurement for ten minutes

GOAL: There are no gold standards on the duration and frequency of the measurement of indirect calorimetry, a fact of importance in daily clinical practice. An assessment of is made of the degree of concordance between energy expenditure at rest (EER) measured over a short interval (10 minutes) versus another prolonged measurement (1 hour). PATIENTS: Sixty critically-ill patients, under sedation and analgesia with connection to mechanical ventilation, were studied. INTERVENTIONS: EER values were determined by means of a metabolic computer analysis (Engstrom Eliza) at rest. The reproducibility and the degree of concordance were assessed in the measurements made with both periods. RESULTS: The mean values of the EER determinations at 10 and 60 minutes were 1,818 +/- 319 kilocalories/day and 1,815 +/- 318 Kcal/day. The limits of the concordance between both times were -101 and +117 kilocalories/day and the correlation was significant (r = 0.98, p < 0.0001). CONCLUSIONS: In critically-ill patients under sedation and with mechanical ventilation, the measurement of EER may be taken over short periods of time (10 minutes) providing that baseline examination conditions are met, thus giving greater availability of the resources used to study indirect calorimetry.