Overview of indications for non-invasive respiratory support A K Simonds
Indications in acute respiratory failure 2
Physiological rationale 2
Epidemiology in practice 3
Long-term use 5
Spontaneous ventilation can be assisted or replaced by delivering intermittent positive pressure to the airway or applying intermittent negative pressure to the chest wall. The physiological and clinical aims of mechanical ventilation are listed in Table 1.1. Ventilatory methods are described as invasive if the airway is intubated or internal placement of electrodes is required, as in diaphragm pacing. Non-invasive modes avoid airway intubation and are therefore less suitable in individuals with impaired airway reﬂexes, excessive bronchial secretions or complete ventilatory dependence.