Physiology. Humidification during high-flow oxygen therapy. Small volume nebulization. HME. Heated humidifier. Active versus passive humidification. Factors that influence the performance of humidification devices. Methods to evaluate the performance of humidification devices. Humidification during invasive mechanical ventilation. Practice of humidification. Humidification during non-invasive mechanical ventilation. Effects of oxygen inspiration in non-invasive mechanical ventilation. Invasive mechanical ventilation and/or VAP associated with humidification. Humidification devices and ventilator-associated pneumonia. Types of humidifier and the prevention of ventilator-associated pneumonia. A portable trachea spray for lower airway humidification in patients after tracheostomy. Problems with humidification. Artificial airway secretion management. Measurement of inspired gas temperature in the ventilated neonate. Indications and contraindications in home care. Pros and cons of humidification for CPAP therapy in the treatment of sleep apnea.