Journal of Applied Physiology, Vol 65, Issue 4 1520-1524, Copyright © 1988 by American Physiological Society
An assessment of nasal functions in control of breathing
Y. Tanaka, T. Morikawa and Y. Honda
Department of Surgery, School of Medicine, Chiba University, Japan.
Breathing pattern and steady-state CO2 ventilatory response during mouth
breathing were compared with those during nose breathing in nine healthy
adults. In addition, the effect of warming and humidification of the
inspired air on the ventilatory response was observed during breathing
through a mouthpiece. We found the following. 1) Dead space and airway
resistance were significantly greater during nose than during mouth
breathing. 2) The slope of CO2 ventilatory responses did not differ
appreciably during the two types of breathing, but CO2 occlusion pressure
response was significantly enhanced during nose breathing. 3) Inhalation of
warm and humid air through a mouthpiece significantly depressed CO2
ventilation and occlusion pressure responses. These results fit our
observation that end-tidal PCO2 was significantly higher during nose than
during mouth breathing. It is suggested that a loss of nasal functions,
such as during nasal obstruction, may result in lowering of CO2, fostering
apneic spells during sleep.
