A person’s forced vital capacity (FVC) as determined by a Pulmonary Function Test is largely what determines if a BiPAP machine is necessary. BiPAP is often used for people who have experienced pneumothorax (or collapsed lung) and as a result have loss of ability of the air sacs at the outermost portions of the lungs.
BiPAPs are usually used while a person is sleeping. It is used for conditions other than just cystic fibrosis. Sleep apnea sufferers for example, are often fitted with a BiPAP machine and face mask. Unlike supplemental oxygen, BiPAP masks are worn so that they completely enclose the mouth and nose. Most manufacturers of BiPAP face masks have different models available and all are designed to be as comfortable as possible.