The Oral and Laryngeal Components of the Upper Airway Resistance During Mouth Breathing

Abstract

The upper airway resistance may be considered as consisting of two components: the oral component between the oral aperture and the pharynx, about one centimetre above the top of the epiglottis; and the laryngeal component, between this part of the pharynx and the sub-glottic space. These two components of the upper airway resistance were measured by introducing an additional point of measurement in the pharynx to the two used for determining the upper airway resistance as a whole. The mean oral resistance for 8 subjects at a flow of 0.5 1/sec was 0.5 cm H₂O/1/sec. The mean laryngeal resistance for 6 subjects at the same flow rate was 0.3 cm H₂O/1/sec. The value was the same for the 4 normal men and 2 male cases of unilateral cord paralysis composing this group. For 2 cases of bilateral cord paralysis the mean was 24 cm H₂O/1/sec. In view of the high oral resistance it would seem to be important in all kinds of examinations of the ventilatory capacity to standardize the space between the dental arches, and the posture of the head in relation to the body.