An aerosol is defined as a suspension of liquid or solid particles in air or oxygen; the process of forming an aerosol is called nebulization. The purpose of aerosols in the treatment of asthma is to deposit these particles on the respiratory epithelium where a high local concentration can be achieved and exert its pharmacological effect.Aerosol medications have become commonplace in the treatment of acute and chronic asthma but are often poorly used. This presentation will discuss the use of water vapor in mist tents and other forms of inhalation therapy, available aerosolized medications for the treatment of asthma, the proper use of aerosol inhalers, aerosolized drugs that should be available in the immediate future, and also the types of equipment available for administration of these medications by mask in the home.Water mist may be administered either by means of a steam vaporizer, high-humidity tent, or cool-mist nebulizer. Water mist has been advocated to liquefy the thick secretions of the tracheobronchial tree. It also tends to decrease mucosal edema. Although mist is generally considered a benign form of treatment, it is not always so for young infants. A problem unique to the small infant is the hazard of water intoxication from moisture absorbed in the process of nebulization.Oxygen has a marked ability to produce drying and desiccation of the respiratory mucosa. Therefore oxygen should be administered always with humidity. Concentrations of O2 approaching 100% have also been found to alter the histology of alveolar cells and to impair ciliary action, irritate the bronchial mucosa, and damage pulmonary capillaries. These changes can lead to pulmonary edema, generalized atelectasis, and alveolar capillary block in less than 24 hours.'In six healthy adults and eight patients with cystic fibrosis, the distribution of inhaled mist was assessed by labelling aerosol from an ultrasonic nebulizer with 99'11T~ and measuring the distribution of radioactivity in a subject who breathed the aerosol for an hour in the mist tent. Less than 5% of the activity nebulized and distributed in the tent entered the body. Of this, 90% of the inhaled radioactivity initially lodged in the nasopharynx and rapidly appeared in the stomach. Very little activity was detected over the lungs. These results indicate that very little aerosol fluid from a mist tent is directly deposited in the terminal airways of the lung.3 This and similar studies
