Capnography is actually required for all intubated patients in many areas (and intubation is a standard step in the management of pre-hospital cardiac arrest patients). This is because (properly interpreted) capnography is one of the most definite ways to verify that the ET tube is headed for the lungs, not the stomach.

Given the increasing prevalence of capnography use in the field, I expect the next few years will see several studies into how it could be used to improve patient outcomes.