In a health care environment, mechanical ventilation is used to support patients during acute illness and surgery. Mechanical ventilation is the process by which the patient’s respiratory function is artificially supported using a respirator. During mechanical ventilation, it is necessary to ensure the adequacy of ventilation. The patient is thus monitored for several ventilatory parameters. The end-tidal CO2 (EtCO2) is one of the primary monitoring parameters. EtCO2 is the partial pressure or maximal concentration of carbon dioxide (CO2) at the end of an exhaled breath, which is expressed as a percentage of CO2 or mmHg . Capnography is the technique that graphs out expired CO2 as a function of time and measures EtCO2. The measuring device is called a capnometer and the waveform displayed by the capnograph is called capnogram.