An indirect calorimetry system for ventilator dependent very low birthweight infants.
Open Access
- 1 March 1992
- journal article
- research article
- Published by BMJ in Archives of Disease in Childhood
- Vol. 67 (3), 315-319
- https://doi.org/10.1136/adc.67.3.315
Abstract
With neurodevelopmental outcome of very low birthweight (VLBW) infants being adversely affected by inadequate nutrition during the first few weeks of life, there is an urgent need for more specific nutritional data on the sick VLBW ventilator dependent infant. The development of a new mass spectrometry gas analysis indirect calorimetry system which is non-invasive and can operate over several hours or days is described. Technical evaluation of each of the components of the system indicates a total random error of less than 5%. Systematic error was determined using gas infusions which simulated carbon dioxide production and oxygen consumption. The relative error in the measurement of carbon dioxide production was less than or equal to 1.5% (coefficient of variation (CV) 6.0%)) with carbon dioxide infusion rates ranging from 3.86 to 13.98 ml/min. The relative error in oxygen 'consumption' was less than or equal to 4.3% (CV 2.8%) for infusions of oxygen at rates of 7.5 to 14.80 ml/min. With nitrogen infusions simulating oxygen consumptions of 2.0 and 5.5 ml/min the relative error in the calculated nitrogen infusion was 1.5% (CV 4.1%) and 1.4% (CV 5.7%) respectively. Clinical studies on 10 infants demonstrated a mean energy expenditure of 161.7 kJ/kg/day and a respiratory quotient in excess of 1.0. The energy expenditure of ventilated VLBW infants may be less than previously indicated and the energy mix and nitrogen content of parenteral nutrition regimens recommended for these infants may be inappropriate.Keywords
This publication has 10 references indexed in Scilit:
- 56 CAN RESPIRATORY WATER LOSS AND OXYGEN CONSUMPTION BE MEASURED ACCURATELY DURING VENTILATOR AND CPAP TREATHENTPediatric Research, 1990
- Percutaneous carbon dioxide excretion in the newborn infantEarly Human Development, 1990
- Early diet in preterm babies and developmental status in infancy.Archives of Disease in Childhood, 1989
- Total parenteral nutrition in the newborn: impact of the quality of infused energy on nitrogen metabolismThe American Journal of Clinical Nutrition, 1988
- Calculation of Metabolic Expenditure and Substrate Utilization from Gas Exchange MeasurementsJournal of Parenteral and Enteral Nutrition, 1988
- Neurodevelopmental outcome in babies weighing less than 2001 g at birth.BMJ, 1987
- Measurement of Carbon Dioxide Production Rate in Sick Ventilated Premature InfantsNeonatology, 1987
- Dietary Composition and Macronutrient Storage in Preterm InfantsPediatrics, 1983
- New methods for calculating metabolic rate with special reference to protein metabolismThe Journal of Physiology, 1949