Nitrous oxide is contraindicated in patients with pneumothorax, pneumopericardium or intestinal obstruction because it :
N2O use is contraindicated in pneumothorax and volvulus because it may lead to the development of high pressure in the closed cavities in the body (like an obstructed loop of bowel, intraocular air bubble, a pulmonary bulla, pneumothorax, ob­structed middle ear, air embolus, intracranial air and pneumoperitoneum).
Depresses an already compromised myocardium
Permits the use of limited FIO2 only
Is less soluble than nitrogen
Causes the expansion of air filled body cavities