Considerations in Humidification by Nebulization

¹ Research Fellow, University of Texas Southwestern Medical School.
² Assistant Professor of Medicine, University of Texas Southwestern Medical School.

Available information plus knowledge of the physical processes involved in respiratory air conditioning provide a rational basis for the use of therapeutic humidification. Definite indications for humidification of dry air include gross drying of the upper airways, respiration by tracheostomy, and the presence of thick tracheo-bronchial exudate or decreased ability to move exudate and secretions through the trachea. Medication may be important in the treatment of airway drying, but its effects should not be confused with that of humidification.

With one exception, the nebulizers tested were found to produce total humidities of 30 to 60 per cent B.H.; this seems sufficient for most therapeutic needs. If near body humidity is required, nebulizers must be heated. Some of the variables concerned with final liquid humidity delivery in nebulization are: design, gas flow rate, apparatus used for delivery, and the patients' airways.

The usual side stream nebulization technique is not adequate in continuous IPPB assistance. A mainstream nebulization technique which provides adequate humidity is described.

The convenient absolute humidity expression "per cent body humidity" is proposed for use in respiratory physiology.

Extension of experimental work and further application of evaporative process principles to respiratory air conditioning in disease states are indicated to confirm and amplify the conclusions of this study. Further knowledge of the humidity provided in various inhalation therapy situations would be desirable.