Measurements of the Air Conditioning Capacity of the Nose During Normal and Pathological Conditions and Pharmacological Influence

Abstract

A simple method is introduced for measuring the air conditioning capacity of the nose. A flow of 8 1/min dry air is introduced by a catheter into the nasopharynx, while 5 l/min is sucked out from the investigated nasal cavity through a psychrometer. The additional 3 l/min passes down into the pharynx, thus reducing the intermingling with expiratory air. By using CO₂ as a tracer, this error was found to be maximally 15% and often about 1%. The three different enthalpy factors: increase in enthalpy of dry air, vaporization, and increase in enthalpy of water vapour, were calculated separately and the vaporization was found to be the dominant factor. The calculated total supply of humidity showed that the method presented causes at least a slight stress on the humidifying capacity. Pharmacological studies have shown that subcutaneously injected atropine decreased the total enthalpy and that of water vapour, while nasal administration of oximetazoline also decreased the total enthalpy. Nasal administration of homatropine or pilo-carpine had no effect on the air conditioning. In comparison with normal subjects, those with vasomotor rhinitis had an increased enthalpy of the air, while the same enthalpy factor was reduced in cases with atrophic rhinitis. Laryngectomized patients had no significant difference in the air conditioning capacity of the nose in relation to normal subjects, while patients operated with partial maxillectomy had a considerable reduction in vaporization and total enthalpy.