Journal article
A gradient-layer calorimeter for measurement of energy expenditure of infants
American journal of physiology. Regulatory, integrative and comparative physiology, Vol.266(3), pp.R1052-R1060
03/01/1994
DOI: 10.1152/ajpregu.1994.266.3.R1052
PMID: 8160854
Abstract
We have developed and validated a gradient-layer calorimeter for direct measurement of energy expenditure of preterm infants. Infant calorimeters must be operated and tested differently from adult calorimeters, because the calorimeter must be warmed during operation to limit heat loss from the infant, the calorimeter wall temperature (which is selected on the basis of the infant's maturity) must be precisely controlled, and energy expenditure (heat output) is typically < 10 W. We calibrated our calorimeter by varying the heat produced by a dry source (manikin or light bulb) with airflow (n = 42) and without airflow (n = 8) at various water jacket temperatures (n = 7) and by a wet source (combustion of ethyl alcohol) with airflow (n = 9). With no air moving, qc = 0.740 Vc + 0.029 Twj-0.697, where qc (W) is the estimated output of the heat source measured by the calorimeter, Vc (mV) is the gradient-layer voltage of the calorimeter, and Twj (degree C) is the temperature of the water jacket surrounding the walls of the device. From this equation and enthalpy calculations, the slope and intercept of the regression line relating the estimated heat production to the actual heat produced from alcohol combustion are 1.029 +/- 0.046 and -0.549 +/- 0.484 (SE), respectively. The slope is not significantly different from unity, and the intercept is not significantly different from zero. Thus we can accurately estimate the energy expenditure of preterm infants from the equations describing our calorimeter, and we can accurately resolve the total heat output into a dry (nonevaporative) component and a wet (evaporative) component.
Details
- Title: Subtitle
- A gradient-layer calorimeter for measurement of energy expenditure of infants
- Creators
- Steven J Meis - University of IowaEdwin L. Dove - University of IowaEdward F Bell - University of IowaCharlotte M Thompson - University of IowaMargit-Andrea Glatzl-Hawlik - University of IowaAmy L Gants - University of IowaWon K Kim - University of Iowa
- Resource Type
- Journal article
- Publication Details
- American journal of physiology. Regulatory, integrative and comparative physiology, Vol.266(3), pp.R1052-R1060
- DOI
- 10.1152/ajpregu.1994.266.3.R1052
- PMID
- 8160854
- ISSN
- 0363-6119
- eISSN
- 1522-1490
- Language
- English
- Date published
- 03/01/1994
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Stead Family Department of Pediatrics; Family and Community Medicine; Neonatology
- Record Identifier
- 9984353947602771
Metrics
21 Record Views