Abstract
The measurements of pulmonary mechanics were made on twenty unselected cases with varying degrees of nasal obstruction during both nasal and oral breathing.
Values for transnasal pressure and resisitance in various parts of the respiratory system were calculated from Rohrer's equation.
At a flow rate of 0.5l/sec, nasal resistance was greater during inspiration, while the resistances between nose and pleural surface and between mouth and pleural surface were increased during expiration.
The resistance of the conducting airways below the pharynx is obtained as the total less the nasal resistance. A correlation between changes of the transnasal pressure and the resistance below the pharynx was detected. Whenever the transnasal pressure changed, the resistance of the lower part of the respiratory system including the larynx also changed and most frequently in the same direction. In addition, these changes are observed during mouth breathing as well as nose breathing, and are in direct relation to the degree of transnasal pressure.However, the site of increased lower airway resistance is not known.
