Table IV.

NPV indications and contraindications.

Indications	Contraindications
Severe facial decubitus	Sleep-apnoea syndrome
Mask intolerance	Severe obesity
Facial deformity	Severe kyphoscoliosis
Inability to fit mask	Rib fractures
Severe hypercapnic encephalopathy	Recent abdominal surgery
Severe respiratory acidosis	Claustrophobia or poor compliance