A study of humidification in tracheostomized dogs.

In order to determine the optimal conditions for humidification of inspired air through a tracbeostomy, tracheostomized dogs were allowed to breathe humidified air, the temperature of which was deliberately varied between 15C and 40°C. At 15°C, the air was saturated lower than 40% but was fully saturated at the other temperatures. Measurements of alveolar ventilation, functional residual capacity, lung compliance, alveolar/arterial Po2 difference, pulmonary shunt ratio, cardiac output and oxygen consumption suggest that satisfactory conditions of lung function obtained when the animals breathed fully saturated air administered at a temperature between 20°C and 30°G