Capnograph

A capnograph is an instrument used to measure the carbon dioxide (CO2) concentration in an air sample. It does this by measuring the absorption of infrared light, which is absorbed particularly well by carbon dioxide.

Capnographs (or capnometer) are frequently used in medicine for capnography, measuring the carbon dioxide content in inspired and expired air. It is a non-invasive device that measures the concentrations of respired gases using an infrared beam of light. The amount of light absorbed depends on the number of carbon dioxide molecules present in the exhaled and inhaled air. A capnograph is useful in detecting changes in carbon dioxide concentrations in patients who are hemodynamically stable, but not critically ill.

See capnography.