apnography is used for assessment of ?

Ans. is 'c' i.e., Ventilation of lung after intubation Capnographv Capnography is the continuous measurement of end tidal CO2 (ETCO2), i.e., CO2 in exhaled air. Normal value is 35-45 mm Hg (4% to 6%). Capnography works on the principle that infrared light is absorbed by carbon dioxide. A beam of infrared light is passed across the gas sample to fall on to a sensor. The presence of CO2 in the gas leads to a reduction in the amount of light falling on the sensor which changes the voltage in the circuit. Uses of Capnography It is the surest confirmatory sign of correct intubation in trachea. Incorrect position of tube in esophagus instead of trachea (esophageal intubation) will yield ETCO2 = 0. Intraoperative displacement of endotracheal tube ---> ETCO2 will become zero. Obstruction or disconnections of endotracheal tube ---> ETCO2 will fall. Diagnosing malignant hypehermia ETCO2 increases significantly (more than 100 mg Hg).