Box 1:

Glossary of terms

Continuous positive airway pressure (CPAP) – the additional pressure applied to the lungs (alveoli) above atmospheric pressure throughout the respiratory cycle. This applies a single, fixed pressure throughout inspiration and expiration, which does not vary, via a tightly fitted nasal or whole face mask to the spontaneously breathing, conscious patient without the need for intubation and sedation. This is not a form of ventilation
High-flow nasal cannula oxygen therapy (HFNCO) – this is an oxygen supply system capable of delivering up to 100% humidified and heated oxygen at a flow rate of up to 60 liters per minute via nasal cannulae
Non-invasive ventilation (NIV) – this delivers mechanically supported breaths via a tightly fitted nasal or whole face mask to the spontaneously breathing, conscious patient without the need for intubation and sedation. The patient usually triggers the inspiratory cycle. Expiration is passive, by elastic recoil. The pressure delivered varies during the respiratory cycle, being higher in inspiration than expiration. This is a form of ventilation
IPAP – Inspiratory positive airway pressure, the inspiratory pressure set on the non- invasive ventilator
EPAP – Expiratory positive airway pressure, the expiratory pressure set on the non-invasive ventilator
Positive end expiratory pressure (PEEP) – the additional pressure applied to the lungs (alveoli) above atmospheric pressure at the end of expiration
Vacuum-insulated evaporator (VIE) – the common method for hospital storage of liquid oxygen. The inner shell is of stainless steel and is separated from the outer carbon shell by a vacuum. The contents are at a pressure of 700–1000 KPa and a temperature of −160 C to −180 C (the critical temperature for oxygen is −118 C)