Respiratory Gas Conditioning and Humidification

Abstract

The term humidity describes the amount of water in a vaporous state contained in a gas. Under-humidification of inhaled medical gas mixtures may have adverse pulmonary and systemic effects. Standards on minimum levels of humidity differ with respect to the applied respiratory support modality. A wide variety of device brands for humidification is commercially available. Their efficiency differs substantially. Heated humidifiers are standard of care for longterm invasive ventilation in infants. Air leaks around the upper airway preclude the use of heat and moisture exchanges during noninvasive ventilatory techniques. Nebulization of water and irrigation of the airway may not replace the provision of appropriately warmed and humidified medical gas. Knowledge of the basic physics of humidity and working principles of active and passive humidifiers may help clinicians to better recognize humidity deficits during respiratory care.