The capnography extension uses infrared absorption spectroscopy to continuously measure CO₂ values. Designed to work with IntelliVue patient monitors and racks, the capnography extension provides CO₂ waveform and numeric values, plus temperature and 2 invasive pressure measurements on the IntelliVue patient monitor display. A digital signal processor located in the sensor measures either sidestream or mainstream etCO₂ and awRR for patients in surgery, in critical care, and during transport.