Humidifi ers during non-invasive ventilation: key topics and practical implications

Inadequate gas conditioning during non-invasive ventilation (NIV) can impair the anatomy and function of nasal mucosa. The resulting symptoms may have a negative eff ect on patients’ adherence to ventilatory treatment, especially for chronic use. Several parameters, mostly technical aspects of NIV, contribute to ineffi cient gas conditioning. Factors aff ecting airway humidity during NIV include inspiratory fl inspiratory oxygen fraction, leaks, type of ventilator, interface used to deliver NIV, temperature and pressure of inhaled gas, and type of humidifi er. The correct application of a humidifi cation system may avoid the eff ects of NIV-induced drying of the airway. This brief review analyses the consequences of airway dryness in patients receiving NIV and the technical tools necessary to guarantee adequate gas conditioning during ventilatory treatment. Open questions remain about the timing of gas conditioning for acute or chronic settings, the choice and type of humidifi cation device, the interaction between the humidifi er and the underlying disease, and the eff ects of individual humidifi cation systems on delivered humidity.