Experiences with triggered pulmonary exposures in children.

With conventional manual triggering technique pulmonary exposures expected to time and end-inspiration were made on 51 small children. These exposures showed a random distribution. Transthoracic impedance reflects the variations in the pulmonary air-fluid ratio during respiration. In 94 infants and small children the transthoracic impedance was monitored while pulmonary exposures were triggered by a pulse given at the level of end-inspiration or end-expiration. It was found that transthoracic impedance as a triggering device permitted precise matching of the exposures to end-inspiration or end-expiration.