Ventilatory ¹³³Xenon Distribution Studies in the Duck(Anas platyrhynchos)

Summary

The distribution of an inspired bolus of the ¹³³Xe in air was measured in lightly anesthetized, spontaneously breathing ducks using a scintillation camera. Inspired gas enters the avian lungs and airsacs nearly simultaneously. The respiratory dead space appeared initially preferentially distributed to the posterior (abdominal) sacs. The pathway of gas from the posterior thoracic airsac during expiration was observed by injecting radioactive gas into this sac at end-inspiration. The posterior thoracic sac contents entered the lung during expiration which supports the unidirectional airflow hypothesis of avian respiration in so far as the lungs fill during inspiration and expiration.The relative compartmental ventilation rates were measured by determining at 0.1-s intervals the disappearance of ¹³³Xe when breathing room air. The lungs and posterior thoracic sac cleared more rapidly than the other compartments.