Purpose: The purpose of this study is to compare the resting energy expenditure (REE) obtained by indirect calorimetry (IC) to the REE calculated by predictive equations (Brandi and Liggett) using the oxygen consumption (VO2) obtained by Fick's method in septic patients.
Methods: Prospective study in septic patients admitted in an intensive care unit of a university hospital. Fifteen adult patients (11 men and four women) were studied. VO2 measurements were made using a portable metabolic cart connected to a respirator and a pulmonary artery catheter.
Results: The APACHE II at admission was 22.6+/-7.2 with a mortality risk of 46.1+/-27.7%. The mean REE obtained by IC and by the Brandi and Liggett equations were 1699+/-271, 1815+/-355 and 1361+/-277 kcal.day-1 respectively. There were no statistically significant differences between the two methods, with the two means showing a difference of 8.7%. REE values were close for IC x BRANDI (r=0.80), but the IC x LIGGETT correlation was only 0.58.
Conclusions: The results suggest that REE can be easily calculated by obtaining VO2 with the Swan-Ganz catheter and using the Brandi equation even for septic patients under mechanical ventilation.