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THE INFLUENCE OF LUNG SHRINKAGE ON BREATH HOLDING TIME
Author(s) -
Godfrey S.,
Edwards R. H. T.,
Warrell D. A.
Publication year - 1969
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1969.sp002012
Subject(s) - expiration , shrinkage , lung volumes , lung , volume (thermodynamics) , respiration , chemistry , respiratory system , anesthesia , medicine , anatomy , materials science , thermodynamics , physics , composite material
The influence of lung shrinkage on the breath holding time was studied in three normal males. The rate of shrinkage was increased two to three fold either by slow expiration or by reducing gas density in a hypobaric chamber. For any given lung volume the relationship between breath holding time and pCO 2 was defined by a rebreathing method which allowed breath holds to be performed at progressively increasing levels of pCO 2 . Hypoxia was avoided throughout and the ventilatory response to CO 2 remained constant irrespective of ambient pressure. The breath holding time for any given pCO 2 was usually longer the larger the lung volume. Increasing the rate of lung shrinkage by either method did not alter the relationship between breath holding time and pCO 2 . There was no constant relationship between the pCO 2 and the lung volume at the breaking point of a breath hold. These findings are discussed in the light of previous work and it is concluded that the sensation arising during breath holding cannot be fully explained in terms of any combination of pCO 2 , lung volume and lung shrinkage.