The dynamic distribution of pulmonary ventilation was studied both theoretically and experimentally. The human lungs were simulated as two compartments driven by independent cyclic pleural pressures. The distribution of tidal volume depended primarily on the regional pressures, but dissimilar pressure swings generated sequential flows. A model of the tracer dynamics in the lung during a breath showed that the ventilation per unit volume was proportional to the time derivative of krypton-81m activity normalized by the activity itself. In gamma camera measurements, the average flow distribution was independent of frequency and tidal volume, but the flow per unit volume in left lateral decubitus subjects was greater in the dependent than the non-dependent lung, and sequential flows were evident. However, lung sound amplitudes were in phase over the dependent and non-dependent regions, varying as the square of the airflow at the mouth. The frequency composition of the sounds remained constant. Thus, nonhomogeneous pleural pressure swings appear to control the dynamic distribution of ventilation. This time-varying quantity can be measured using a short-lived isotope but not directly with lung sounds.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.71993 |
| Date | January 1984 |
| Creators | Shykoff, Barbara Ellen. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000219006, proquestno: AAINL20856, Theses scanned by UMI/ProQuest. |
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