Journal of Applied Physiology, Vol 39, Issue 3 367-371, Copyright © 1975 by American Physiological Society
Effect of hypoxia on immediate ventilatory load response in dogs
P. Lynne-Davies, J. A. Bowden and W. Giles
The effective elastance of the respiratory system (which has been
previously shown to provide an index of the ability of the respiratory
musculature to compensate rapidly for transient mechanical ventilatory
loads) was measured in six hypoxic dogs to determine whether hypoxia
hindered immediate load-compensatory mechanisms. The effective elastance
value was computed from measurements of control tidal volume and the
pressure developed at the airway opening during the first inspiratory
effort following airway occlusion at FRC. The mean effective elastance was
197 cmH2O/l while the animals were breathing room air and did not change
significantly when the animals were rendered hypoxic by reducing the
inspired oxygen concentration, in five dogs, or by controlled hemorrhage,
in two dogs. It was concluded that inasmuch as effective elastance
measurements remain constant during hypoxia, the stability of ventilation
is not significantly impaired in this situation.
