ABSTRACT
Ultrasonic nebulizers use ultrasonic energy to convert liquid, usually an aqueous solution, into an aerosol for inhalation. They are used to deliver b2-agonists, corticosteroids, antiallergics, anticholinergics, and antiviral and mucolytic agents to the respiratory tract. Ultrasonic nebulizers were first developed in the 1960s and were initially used for air humidification in respiratory care units. Ultrasonic nebulizers exist in a number of basic designs that differ in the configuration of the piezoelectric crystal transducer, nebulizer chamber, baffles, and auxiliary airflow systems. Ultrasonic devices typically produce a much larger fluid output per unit of time than do jet nebulizers. Most nebulizer formulations are solutions, but a few corticosteroid suspension formulations have been marketed. In general, ultrasonic nebulizers are less efficient and more variable in delivering suspensions than are air-jet nebulizers. Although most ultrasonic devices share a basic design, some novel devices have been developed.
