Comparison of the Cosmed K4 b(2) and the Deltatrac II metabolic cart in measuring resting energy expenditure in adults.
OBJECTIVE
The objective of the study was to compare data obtained from the Cosmed K4 b(2) and the Deltatrac II metabolic cart for the purpose of determining the validity of the Cosmed K4 b(2) in measuring resting energy expenditure.


METHODS
Nine adult subjects (four male, five female) were measured. Resting energy expenditure was measured in consecutive sessions using the Cosmed K4 b(2), the Deltatrac II metabolic cart separately and the Cosmed K4 b(2) and Deltatrac II metabolic cart simultaneously, performed in random order. Resting energy expenditure (REE) data from both devices were then compared with values obtained from predictive equations.


RESULTS
Bland and Altman analysis revealed a mean bias for the four variables, REE, respiratory quotient (RQ), V CO(2), V O(2) between data obtained from Cosmed K4 b(2) and Deltatrac II metabolic cart of 268+/-702 kcal/day, -0.0+/-0.2, 26.4+/-118.2 and 51.6+/-126.5 ml/min, respectively. Corresponding limits of agreement for the same four variables were all large. Also, Bland and Altman analysis revealed a larger mean bias between predicted REE and measured REE using Cosmed K4 b(2) data (-194+/-603 kcal/day) than using Deltatrac metabolic cart data (73+/-197 kcal/day).


CONCLUSIONS
Variability between the two devices was very high and a degree of measurement error was detected. Data from the Cosmed K4 b(2) provided variable results on comparison with predicted values, thus, would seem an invalid device for measuring adults.
Littlewood
R A
RA
Department of Paediatrics and Child Health, University of Queensland, Australia.
White
M S
MS
Bell
K L
KL
Davies
P S W
PS
Cleghorn
G J
GJ
Grote
R
R
D000328:Adult; D001481:Basal Metabolism; D002138:Calibration; D002153:Calorimetry, Indirect / Q000379:methods; D002245:Carbon Dioxide / Q000032:analysis* / Q000378:metabolism; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen / Q000032:analysis*; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D012123:Pulmonary Ventilation; D015203:Reproducibility of Results; D013686:Telemetry
D002245:Carbon Dioxide; D010100:Oxygen