Capnography is a noninvasive method for monitoring the level of carbon dioxide in exhaled breath (EtCO2) to assess a patient’s ventilatory status. An inherent property of CO2 is to absorb infrared radiation at a very specific wavelength. Capnographs contain sensors that produce infrared sources of blackbody radiation at these wavelengths. These sensors enable the calculation of CO2 levels in a breath sample. Capnographs produce both waveforms and numeric values of the patient’s exhaled breath and are used to identify adverse ventilation events. This helps clinicians diagnose specific medical conditions, leading to important treatment decisions.