Series Distribution of Airway Collapsibility in Situ in Dogs

• Published in: Nihon Kyōbu Shikkan Gakkai zasshi Vol. 19; no. 2; pp. 84 - 91
• Main Authors: Nakamura, Masao, Sasaki, Hidetada, Sekizawa, Kiyohisa, Ishii, Munehiko, Takishima, Tamotsu
• Format: Journal Article
• Language: Japanese
• Published: Japan The Japanese Respiratory Society 01.02.1981
• Subjects: Animals; Bronchi - physiology; Dogs; Respiration; Trachea - physiology
• ISSN: 0301-1542; 1883-471X
• DOI: 10.11389/jjrs1963.19.84

We compared series distribution of airway collapsibilities in situ in dogs. Four major segments were compared: trachea, extrapulmonary bronchi, intrapulmonary main lobar bronchi and intrapulmonary small bronchi. The pressure-volume relations of the isolated trachea and extrapulmonary bronchi in the closed chest of 6 dogs were measured by glued beads of 6-22mm OD with the cannulation to provide airflow routes to the lobes. The pressure-volume relations of the isolated intrapulmonary large and small bronchi of 9.66 and 3.11mm OD (mean) at PL 30cmH2O, respectively, were measured from tantalum dust bronchograms in 6 lobes of excised dog lungs. The isolated intrapulmonary large bronchi were made by glued 10-15 beads of 2-9mmOD as described previously by Takishima et al. The isolated intrapulmonary small bronchi were made by 50-60 glued beads of 1mmOD. Twenty retrograde catheters were inserted into the lobe arround the perimeter and the lobe was inflated by positive pressure through the retrograde catheters. Airway collapsibilities were compared under the constant lung volumes at PL 30, 10 and 5cmH2O. At PL 30cmH2O, the extrapulmonary bronchi were more collapsible than the intrapulmonary large bronchi and trachea. At PL 10 and 5cmH2O, the intrapulmonary small bronchi were more collapsible than the other airways, and the peripheral airways were more collapsible than the large airways. It was concluded that during the maximum expiration as the most collapsible segment moved into the peripheral airway at low lung volumes, it might be possible that the flow limiting segment moved from the trachea towards the peripheral airway during maximum expiratory flow volume maneuvers.