ABSTRACT
Ventilation is the movement of air in and out of the lungs. Failure of ventilation is, therefore, life-threatening, often necessitating ventilatory support. Two decades ago, this usually necessitated admission to intensive care units (ICUs) for invasive artificial ventilation, but rapid progress in bilevel NIV since then enables many patients with ventilatory failure to be cared for both in the community and in acute hospital wards. Before widespread availability of NIV, CPAP was developed from supports originally available on invasive ventilators. Technically, CPAP is not ventilation, as it hinders, rather than helps, expiration. However, as both useful respiratory support and a means to understand bilevel NIV, it is included. This chapter frequently refers to the authoritative RCP/BTS/ICS guidelines for NIV, which updates the classic 2002 BTS guidelines. NIV is used in community settings mainly to treat
n sleep apnoea.
