Capnography is useful for –
Uses of Capnography

It is the surest confirmatory sign of correct intubation in the trachea. Incorrect position of the tube in oesophagus instead of the trachea (oesophagal 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 hyperthermia → ETCO2 increases significantly (more than 100 mg Hg).