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The pattern of stimulated breathing in man during non‐elastic expiratory loading.
Author(s) -
Garrard C S,
Lane D J
Publication year - 1978
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1978.sp012328
Subject(s) - tidal volume , ventilation (architecture) , lung volumes , breathing , resistive touchscreen , cardiology , volume (thermodynamics) , medicine , respiratory system , anesthesia , respiration , respiratory minute volume , expiration , airway resistance , lung , anatomy , physics , quantum mechanics , electrical engineering , thermodynamics , engineering
1. The pattern of breathing expressed as the relationship between tidal volume and the components of breath interval was studied in normal subjects during CO2 rebreathing, both under unloaded conditions and following the introduction of a non‐elastic expiratory resistance. 2. Under unloaded conditions end‐expiratory thoracic gas volume (FRC) measured plethysmographically did not alter during the course of the rebreathing experiment. Maximum tidal volume attained (VT, max.) was equal to or just less than the inspiratory capacity of the subject measured at rest. Expiratory reserve volume was not encroached upon even at the highest levels of ventilation. 3. Under loaded conditions the pattern of breathing was altered. VT, max. was diminished in all subjects and FRC showed a progressive rise during rebreathing which was proportional to the resistive load afforded by the artificial resistance. There were no consistent differences in the components of breath duration either at rest or on maximal ventilatory stimulation between the loaded and unloaded states. 4. It is suggested that the pattern of breathing adopted under conditions of expiratory non‐elastic loading is influenced more by the secondary effects of breathing at an elevated lung volume, than by the effect of the non‐elastic load per se.