Validation of Novel Indirect Calorimetry System Based on Luminescence Quenching On-Airway Oxygen Sensor

Salt Lake Community College Student Center

Metabolic gas exchange monitors are frequently used in the intensive care unit to study the oxygen kinetics and appraise the nutritional requirements for acutely ill patients. In a method known as indirect calorimetry, energy expenditure information is obtained non-invasively by measuring the respiratory gases under resting conditions.1-3 A modified Weir equation relates the oxygen consumption (VO2) and the carbon dioxide production (VCO2) to the caloric burn rate.4 The resting energy expenditure (REE) represents approximately 70% of the total energy expenditure (TEE). Critical illness has been shown to alter metabolic rate and influence VO2. Inflammation, sepsis, seizures, and weaning from ventilation increase the VO2, while sedation, muscle paralysis, shock, and hypothermia decrease the VO2. Since underfeeding a patient may increase catabolism and overfeeding is associated with hyperglycemia, increased ventilation requirements, and lipogenesis, it is imperative for the patient’s recovery that the diet meets nutritional requirements.