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Influence of smooth muscle tone and longitudinal tension on the collapsibility of immature airways
Author(s) -
Penn Raymond B.,
Wolfson Marla R.,
Shaffer Thomas H.
Publication year - 1988
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1950050303
Subject(s) - plethysmograph , medicine , compliance (psychology) , acetylcholine , airway resistance , pulmonary compliance , small airways , anatomy , anesthesia , cardiology , airway , respiratory system , psychology , social psychology
Mechanical properties and pressure‐flow relationships of tracheae excised from very premature lambs were studied in a plethysmograph. Control (Group 1) data revealed the tracheae to be extremely compliant, collapsible airways, with an inflation compliance (Si) of 0.033 (±0.004 SE) mmHg −1 , collapsing compliance (Sc) of 0.026 (± 0.001 SE) mmHg −1 , and pressure‐flow relationships similar to those of a Starling resistor. Acetylcholine administration (Group II) lowered both Si, 0.026 (± 0.003 SE) mmHg −1 and Sc, 0.022 (± 0.003 SE) mmHg −1 , asdid longitudinal stretch (Group III): Si, 0.021 (±.003 SE) mmHg −1 , and Sc, 0.017 (± 0.002 SE) mmHg −1 . Alterations in tracheal collapsibilty were also evidenced by significant reductions in resistance to airflow when the tracheae were subjected to compressive forces. Altering both smooth muscle tone (acetylcholine administration) and longitudinal length simultaneously (Group IV) produced results similar to those obtained for Group III. These data help to define the functional characteristics of immature airways and may provide insight for more effective clinical management of the premature infant.