[The significance of different predictive equations for resting energy expenditure in patients receiving invasive mechanical ventilation]. To calculate resting energy expenditure (REE) in patients receiving invasive mechanical ventilation and compare different predictive equations with indirect calorimetry(IC). A total of 60 patients in intensive care unit(ICU) were enrolled.  Measure calculating daily REE in the first week included IC, Harris-Benedict formula, Penn State formula and Swinamer formula.  Daily REE did not exhibit significant difference in the first week of mechanical ventilation by IC (all P>0.05). All patients' REE values by IC were higher than those by Harris-Benedict formula (all P<0.01).  By Penn State formula, REE in day l, 2, and 5 were comparable (all P>0.05) with those by IC, whereas the consistency between the two methods was poor.  Similarly, daily REE by Swinamer formula calculation in the first week did not show significant difference (all P>0.05), with acceptable consistency as IC.  Resting energy expenditure in patients receiving invasive mechanical ventilation dose not significantly change during the first week.  Swinamer formula is more accurate than other equations when IC is considered as the standard method.
IC
Measure calculating daily REE in the first week included IC, Harris-Benedict formula, Penn State formula and Swinamer formula.  All patients' REE values by IC were higher than those by Harris-Benedict formula (all P<0.01). 
Harris-Benedict formula
Measure calculating daily REE in the first week included IC, Harris-Benedict formula, Penn State formula and Swinamer formula.  By Penn State formula, REE in day l, 2, and 5 were comparable (all P>0.05) with those by IC, whereas the consistency between the two methods was poor. 
Penn State formula
Measure calculating daily REE in the first week included IC, Harris-Benedict formula, Penn State formula and Swinamer formula.  Similarly, daily REE by Swinamer formula calculation in the first week did not show significant difference (all P>0.05), with acceptable consistency as IC.  Swinamer formula is more accurate than other equations when IC is considered as the standard method.
Swinamer formula