Editing Fick principle (section)

==Variables==
In Fick's original method, the following variables are measured:<ref>{{cite book| title= Essentials of Human Physiology| first= Thomas M. |last= Nosek| chapter=Section 3/3ch5/s3ch5_3 |chapter-url=http://humanphysiology.tuars.com/program/section3/3ch5/s3ch5_3.htm |archive-url=https://web.archive.org/web/20160324124828/http://humanphysiology.tuars.com/program/section3/3ch5/s3ch5_3.htm|archive-date=2016-03-24}} - "Indirect Measurement of Cardiac Output"</ref>

* V̇O<sub>2</sub>, oxygen consumption in mL of pure gaseous oxygen per minute. This may be measured using a [[spirometer]] within a closed rebreathing circuit incorporating a [[carbon dioxide|CO<sub>2</sub>]] absorber
* ''C<sub>a</sub>'', the oxygen content of blood taken from the [[pulmonary vein]] (representing oxygenated blood = [[arterial blood]])
* ''C<sub>v</sub>'', the oxygen content of blood from an intravenous [[cannula]] (representing deoxygenated blood)