ICU Patients for Indirect Calorimetry

The purpose of this study is to utilize the new indirect calorimetry Q-NRG device to the measurement of energy expenditure (EE) throughout your intensive care unit (ICU) stay and ultimately address fundamental questions about metabolism and energy requirements for critically ill patients. The study will use a new, investigational calorimeter called the Q-NRG (the study device, supplied by Cosmed, Italy). The word "investigational" means the study drug or device or biologic is still being tested in research studies and is not approved by the U.S. Food and Drug Administration (FDA). A calorimeter is a device that connects to your breathing machine tubing for a short period (about 30 minutes) and helps to determine what nutrition you may need in your current condition. There are FDA approved calorimeters that have been used as the current standard of care. These devices and the new Q-NRG calorimeter measure oxygen consumption and carbon dioxide production (the gas you breathe out when you exhale) and calculate energy expenditure. Unfortunately, previously existing calorimeters are complicated to use, cumbersome and require time for measurements. It is hoped the new calorimeter will be easier and more practical to use and, through the measurements we take, we will have a better understanding of a patient's caloric needs for healing. Muscle mass and quality play a role in determining EE and metabolic needs. Massive loss of muscle mass and quality that occurs in critical illness significantly affects EE and nutritional needs and should be accounted for in clinical nutrition delivery. Imaging (standard of care abdominal CT and MSK ultrasound) will be used to assess muscle mass, and muscle quality (amount of intramuscular adipose content; IMAT).