Introduction to noninvasive ventilation

Noninvasive ventilation (NIV), also known as noninvasive positive pressure ventilation, is ventilatory support given by a mask (most commonly an oro-nasal mask, but can also be a nasal or total face mask, or a helmet) rather than by endotracheal intubation.

Noninvasive ventilation may be given acutely or long term. It may consist of continuous positive airway pressure (CPAP), or bilevel positive airway pressure (BPAP), in which a higher pressure is given during inspiration (inspiratory positive airway pressure [IPAP]) and a lower pressure is given during expiration (expiratory positive airway pressure [EPAP]), often with a backup respiratory rate. IPAP provides pressure support for inspiration, which increases alveolar ventilation and assists in reducing carbon dioxide. EPAP improves aeration of the lungs.

Noninvasive ventilation is supportive therapy, used only in addition to first-line therapy directed at the underlying condition.

Acute noninvasive ventilation has approximately 20% failure rate. Before starting any form of ventilatory support, a decision should be made as to whether intubation and invasive mechanical ventilation will be undertaken if noninvasive ventilation fails.

Adequately trained staff are needed to administer and monitor acute noninvasive ventilation, usually in a critical care environment or a high-dependency unit.

Noninvasive ventilation is an aerosol-generating procedure, which has implications for infection control; consider use of:

• devices, circuits and masks that reduce aerosol dispersion (eg single-limb device with filtered vented mask, dual-limb device with nonvented mask)
• increased personal protective equipment
• appropriate ward setting (eg single room with negative pressure ventilation).