Drug nebulizing system for medical ventilators of the volume-limited type

摘要

An all-pneumatic medical ventilator of the volume-limited type is provided with a pneumatically driven drug nebulizer for injecting medication into the patient's breathing circuit in response to a cyclic pressure signal from the ventilator. The nebulizer is driven either directly or indirectly, according to the desired mode of use, from the pressurized oxygen source of the ventilator. In a preferred mode, a given portion of the tidal volume of gas is temporarily withdrawn from the breathing circuit during inhalation and subsequently forcibly returned by way of the nebulizer to the breathing circuit. This takes place during the same inhalation period so that nebulized medication is added to the patient's breathing circuit without changing either the predetermined oxygen concentration or tidal volume of the breathing gas.