下気道に対する Air Conditioner としての鼻腔機能

呼吸様式および鼻腔形態の違いが鼻腔の加温,加湿能に与える影響についての検討

抄録

Many research works have been published on the efficiency of the nose for conditioning of respiratory air. Since the temperature and humidity of the respiratory air show cyclic fluctuation with respiratory movement, accuracy of measurement is influenced markedly by the response time of the measuring instruments. With recent development of the medical electronics, these measurements have become easier and more accurate. To evaluate influence of morphological features of the nasal cavity and modes of respiration on the air conditioning capacity of the nose, experiments were performed in normal subjects, patients with atrophic rhinitis and in tracheotomized subjects. The temperature and humidity of, the respiratory air were measured by fine thermocouples and a respiratory Mass Spectrometer (Varian Matt M3-BA). The temperature and humidity of experimental environment were 21-24°C and 14.08mmHg. The present experiments revealed the following:
1. In normal sbujects inspiratory air temperature increase in the mesopharynx was as follows. Each value represents temperature increase divided by temperature difference between the environmental air and body temperature. nasal resting breathing: 75.5%, nasal deep breathing: 67.3% oral resting breathing: 58.4%, oral deep breathing: 46.7% In the cervical trachea temperature increase was as follows. nasal resting breathing: 80.7%, nasal deep breathing: 70.8% oral resting breathing: 71.8%, oral deep breathing: 58.6%
2. In subjects with atrophic rhinitis the inspiratory air temperature increase in the mesopharynx was as follows. nasal resting breathing: 65.0%, nasal deep breathing: 53.2% oral resting breathing: 57.0%, oral deep breathing: 42.3% In the cervical trachea, temperature increase was as follows. nasal resting breathing: 76.6%, nasal deep breathing: 67.8% oral resting breathing: 70.4%, oral deep breathing: 53%
3. The expiratory air temperature in the nasal vestibulum was 3.7-C below the body temperature in the normal and 1.9°C below in the nose with atrophic rhinitis which corresponded 23.8% and 13.4% of the difference between the body and environmental air temperature.
4. In normal subjects the humidity of the expiratory air showed marked difference between nasal breathing (34.8-38.7mmHg) and oral breathing (43.6-44.3mmHg). But in subjects with atrophic rhinitis, the difference was minimal. The inspiratory air humidity in the cervical trachea in the normal was 43.3-46.8mmHg and difference between nasal and oral breathing was minimal ranging 1.6-2.2mmHg.
5. Relative humidity is directly influenced by temperature change. Depending on the difference in respiratory modes and morphological features of the nasal cavity, the extent of the respiratory mucosa participating in conditioning of inspiratory air differs and the lower portion of the respiratory tract becomes involved in certain conditions.