MedGem hand-held indirect calorimeter is valid for resting energy expenditure measurement in healthy children

Objective: To assess the validity of a new hand-held indirect calorimeter [MedGem (MG)] in the determination of resting energy expenditure (REE; kilocalories per day) in children. Research Methods and Procedures: One hundred male (n = 54) and female (n 46) children (10.6 +/- 3.2 years, 43.9 +/- 19.0 kg, 146.1 +/- 18.8 cm, 19.6 +/- 4.9 kg/m(2)) participated. Children arrived at the University of Oklahoma body composition laboratory between 5:30 Am and 6:15 Am after an overnight fast. On arrival, subjects voided and remained quietly in the supine position for 15 minutes before testing. REE was measured by indirect calorimetry (in random order), with both the MG (sitting upright) and the criterion Delta Trac II (DT) (supine). Data are reported as the mean +/- standard deviation. Results: The mean MG REE (1452 +/- 355 kcal/d) was significantly higher than DT REE (1349 +/- 296 kcal/d, p < 0.001). Bland-Altman analysis revealed a mean bias (MG DT) of 104 kcal/d, with limits of agreement of -241 to +449 kcal/d. To examine the difference in subject positioning, an independent sample of 38 subjects performed the MG in its normal position (sitting) and holding the MG in a supine position. REE by the MG in the sitting position (1475 +/- 350 kcal/d) was significantly (p < 0.05) higher than the MG in the supine position (1419 +/- 286 kcal/d). Discussion: The mean difference in REE between MG and DT was relatively small (103 kcal/d) but significant; however, a portion of this difference may have been related to differences in subject positioning. These preliminary data indicate that the MG shows promise as a valid tool in the assessment of REE in children.