abstract: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.
If a capnograph is used, the presence of a normal shape of thecapnographic curve indicates that the number displayed for end-tidal carbon dioxideis likely to represent a trueend-expiratorysample.
When Mr. Goodman and his co-workers hooked Mr. Snitzer up to the capnograph upon their arrival, they were impressed with his CO2: It was in the low 30s.