Comparison of Energy Requirements of Patients with Brain Injury of the Intensive Care Unit: Indirect Calorimetry vs. Predictive Equations

ABSTRACT

Purpose@#The metabolic activity and demand usually increase in seriously ill patients, especially in patients with a brain injury (BI). These nutritional demands have been traditionally satisfied using predictive equations (PEs). Recently, indirect calorimetry (IC) has been used widely because it is more accurate than other methods. This study measured the energy expenditures (EE) using IC (GE, CARESCAPE B650, Helsinki, Finland) and calculated the PEs simultaneously in patients with BI. @*Methods@#This study was conducted on 55 patients with a BI for three years (2017.7∼2020.8), who were mechanically ventilated within a hospital for ≤seven days. The EE values using IC were measured once in each patient, and the EE values using PE were calculated using 5 PEs (ESPEN, Harris-Benedict, HB; Frankenfield, FK; Penn state, PS; and Faisy) at the same time.The 55 patients were divided into two groups, acute group (39 patients; ≤3 hospital days group, AG) and subacute group (16 patients; ＞3 hospital days group, SG) according to the time, and the values were obtained. @*Results@#There were no differences in the patient’s characteristics between the two groups, including age, gender, severity of the condition (Simplified Acute Physiology Score II), and anthropometric parameters. In AG, the energy expenditure values using PEs were significantly lower than those using IC in the three PEs (IC 1,712.0±476 kcal, ESPEN 1,558.6±324 kcal, P=0.038, HB 1,582.4±273 kcal, P=0.037, PS 1,530.8±340 kcal, P=0.005). In SG, the EE value using PEs did not differ significantly from that using IC. @*Conclusion@#An accurate assessment of EE is critical for seriously ill patients. These results showed that the previously well-known PEs might not be correct, particularly in acute patients with BI. Therefore, it is recommended that the EE values be obtained using IC, at least in acute patients with BI.