[Methodology in non-invasive ventilation]

Objective during the application of noninvasive ventilation (NIV) in acute respiratory failure is, as occurs in conventional mechanical ventilation, to improve gas exchange. Expiratory pressure is applied to favour recruitment of collapsed alveoli, improving oxygenation. Inspiratory pressure use on airway aids respiratory muscle rest and decrease respiratory work, which has a direct repercussion in decreasing oxygen consumption. The NIV preserves defence mechanisms of the patients airway intact, which noticeably decreases appearance of mechanical ventilation associated pneumonia, with subsequent benefit in health care cost, stay and morbidity-mortality. We have reviewed the literature available regarding respiratory modes used in NIV, patient monitoring, humidification, and inhaled drug administration. However, the benefits of NIV are obtained when success of the technique is reached; this is depending on patients' collaboration, adequate indication, underlying disease, material resources available, and mainly, training and dedication of the personnel applying the respiratory support.