General introduction to the clinical application of non-invasive respiratory aids

Intermittent positive pressure ventilation via tracheostomy has been the most common method of providing ventilatory support for patients with respiratory failure since the late 1950s. It is the standard procedure for individuals who suffer from acute respiratory failure, impaired consciousness, and severe restrictive lung disease. However, numerous adverse complications from these invasive techniques have been reported in those who are long-term ventilator users. This paper describes the evolution and current application of non-invasive respiratory aids in both acute and long-term settings. The respiratory function can be aided by applying forces to the body or intermittent pressure to the air ways. The devices are negative pressure body ventilators which act on the body by creating negative pressure around the thorax and abdomen such devices effectively maintain the ventilation of individuals with respiratory failure, but have the shortcomings of bulkiness, high expense, and limitation on the users' activities. The non-invasive positive pressure ventilator applies intermittent pressure directly to the airway by a non-invasive interface; namely mouthpiece, nasal, or face masks. In this way, it can prevent patients from requiring either tracheostomy or endotracheal tube, but is not effective enough to ventilate patients with markedly decreased lung compliance because the high airway resistance provides air leakage from the non-invasive interface. Non-invasive respiratory aids should be the first choice to maintain ventilation for patients with respiratory failure secondary to neuromuscular disorder, because of their benefits of easy application, satisfactory results, fewer complications and early active rehabilitation. Increased understanding of non-invasive respiratory aids should assist in the management of patients with chronic respiratory failure.