The EE formula is almost equivalent to the MR formula. First, it calculates CaO2 and CvO2 from Hb and the O2 saturations (arterial and venous). Then, it calculates VO2 from CO and the O2 contents, and finally it computes the EE in kcal/d.
This is the Fick equation and is used in patients who have a pulmonary artery catheter in place.