End Tidal Carbon Dioxide Concentration and Depth of Anesthesia in Children

Carbon Dioxide (CO2) is a by-product of metabolism and is removed from the body when we breathe out. High levels of CO2 can affect the nervous system and cause us to be sleepy or sedated. Research suggests that high levels of CO2 may benefit patients who are asleep under anesthesia, such as by reducing infection rates, nausea, or recovery from anesthesia . CO2 may also reduce pain signals or the medication required to keep patients asleep during anesthesia; this has not been researched in children.

During general anesthesia, anesthesiologists keep patients asleep with anesthetic gases or by giving medications into a vein. These drugs can depress breathing; therefore, an anesthesiologist will control breathing (ventilation) with an artificial airway such as an endotracheal tube. Changes in ventilation can alter the amount of CO2 removed from the body. The anesthesiologist may also monitor a patient's level of consciousness using a 'Depth of Anesthesia Monitor' such as the Bispectral Index (BIS), which analyzes a patient's brain activity and generates a number to tell the anesthesiologist how asleep they are.

The investigator's study will test if different levels of CO2 during intravenous anesthesia are linked with different levels of sedation or sleepiness in children, as measured by BIS. If so, this could reduce the amount of anesthetic medication the child receives. Other benefits may be decreased medication costs, fewer side effects, and a positive environmental impact by using less disposable anesthesia equipment.