Capnography is the act of using a capnograph to measure the exhaled carbon dioxide from a patient. The capnograph is a device that fits on the end of a patient’s endotracheal tube (ET tube) and is used with every patient that is undergoing general anesthesia. Measuring exhaled carbon dioxide gives the technician a lot of information on a patient under general anesthesia.  It lets us know that the patient is getting enough oxygen, is breathing often and large enough to exhale all the carbon dioxide produced in the body.  This means that the red blood cells are able to carry the much-needed oxygen to the tissues. If the patient isn’t breathing sufficiently while under general anesthetic the technician will manually breathe for them to make sure they are getting enough oxygen and breathing off the excess carbon dioxide.