Editing Biofeedback (section)

===Capnometer===
A [[capnometer]] or [[capnograph]] uses an infrared detector to measure end-tidal {{chem|CO|2}} (the partial pressure of carbon dioxide in expired air at the end of expiration) exhaled through the nostril into a latex tube. The average value of end-tidal {{chem|CO|2}} for a resting adult is 5% ({{convert|36|torr|kPa|abbr=on|disp=or}}). A capnometer is a sensitive index of the quality of patient breathing. Shallow, rapid, and effortful breathing lowers {{chem|CO|2}}, while deep, slow, effortless breathing increases it.<ref name="Peper, E. 2008"/>

Biofeedback therapists use capnometric biofeedback to supplement respiratory strain gauge biofeedback with patients diagnosed with anxiety disorders, asthma, chronic pulmonary obstructive disorder (COPD), essential hypertension, panic attacks, and stress.<ref name = Yucha2008/><ref name="Fried, R. 1987"/><ref>{{cite book | vauthors = Fried R | date = 1993 | title = The psychology and physiology of breathing | location = New York | publisher = Plenum Press }}</ref>