The Measurement of Oxygen Consumption and Carbon Dioxide Production in Term and Preterm Infants by Mass Spectrometry and Metabolic Monitor

To investigate the effect of breast milk and formula feeds on the metabolic rate of term and preterm infants at differing post-natal ages. Using measurement of oxygen consumption (VO2) and carbon dioxide production (VCO2), it is possible to quantity the respiratory quotient (RQ) and the metabolic rate. Background: Measurement of oxygen consumption, carbon dioxide .production reflects biological oxidation of substrate utilized by the body and is dependent upon uptake of oxygen. Oxygen uptake and carbon dioxide production in infants depends on many factors. For example, body temperature changes which are closely related to environmental temperature significantly affect the oxygen consumption of the infants. In infants temperature regulation depends on the following mechanisms: (i) Heat production, which is a chemical process based on biological oxidation of nutrients inside the body. (ii) Heat loss from the body. (iii) Behavioural thermoregulation, a complex mechanism which depends on the neurodevelopment of the newborn infants. Many researchers in the past who investigated this mechanism came to the conclusion that an appropriate environmental temperature is important to maintain a normal body temperature for the infant. Oxygen consumption and carbon dioxide production measurement can be used to investigate the effects of changes in body temperatures due to above mechanisms. There are other factors important in the measurement of oxygen uptake and carbon dioxide production, these include state of sleep, type of nutrition, activity state. All these factors for instance can change the rate of oxygen uptake and carbon dioxide production. The measurement of oxygen uptake and carbon dioxide production accurately requires an appropriate and reproducible methodology. Method: We have investigated two methods to study the oxygen uptake, carbon dioxide production using the principle of indirect open method. The first involves the Delta Track Metabolic Monitor and the second by using mass spectrometer