Ann Olol 85: 1976
AIR HUMIDITY AND MUCOCILIARY ACTIVITY U. MERCKE, M.D. N. G. TOREMALM, M.D. MALMO, SWEDEN
SUMMARY - The relationship between varying humidity levels in the surrounding air and the mucociliary activity in rabbit trachea has been investigated. At a relative humidity (RH.) above 70% the risk for ciliestasis is very small in the temperature range between 34 C and 40 C. At 37 C ciliestasis is not obtained until a relative humidity (RH.) of 50% has been reached. The critical border is reached already at 60% RH. if the temperature is 40 C. At 37 C and a decrement from 90% to 60% RH. the mucociliary wave frequency was reduced by 30%, but at 40 C the corresponding reduction was 60%.
The mucociliary defense mechanism of the upper respiratory tract is influenced by the temperature and humidity of the surrounding air. In human beings the shape of the nasal cavities, and especially the nostrils, plays an important role for the conditioning of inhaled air. Contact between the airstream and the nasal mucous membrane is regulated by the degree of turbulence in the air flow. The air conditioning capacity of the nose under normal conditions is surprisingly high. For example, inhaled air with an external temperature of -12 C can be warmed to +25 C during its rapid passage through the nose.' The relative humidity (RH.) of the inhaled air is also considerably increased from about 35% (ordinary room air) to 98% when it passes the subglottic space." The influence of temperature changes on mucociliary activity has been documented experimentally by a great number of authors.v" The correlation between the temperature of the air and the mucociliary wave pattern has recently been systematically analyzed in vitro on rabbit trachea under standardized conditlons.s-" Reduced RH. of the inhaled air and incomplete conditioning during its pas-
sage through the nose produce clinical problems in the sphere of otorhinolaryngology, especially for tracheotomized patients and for patients immediately after laryngectomy. «The only natural enemy known to cilia in their line of function is excessive drying."lO The clinical importance of an adequate degree of humidity for retained mucociliary function has been mentioned by many authors mainly in anesthesiology.P'
AIR HUMIDITY AND MUCOCILIARY ACTIVITY U. MERCKE, M.D. N. G. TOREMALM, M.D. MALMO, SWEDEN
SUMMARY - The relationship between varying humidity levels in the surrounding air and the mucociliary activity in rabbit trachea has been investigated. At a relative humidity (RH.) above 70% the risk for ciliestasis is very small in the temperature range between 34 C and 40 C. At 37 C ciliestasis is not obtained until a relative humidity (RH.) of 50% has been reached. The critical border is reached already at 60% RH. if the temperature is 40 C. At 37 C and a decrement from 90% to 60% RH. the mucociliary wave frequency was reduced by 30%, but at 40 C the corresponding reduction was 60%.
The mucociliary defense mechanism of the upper respiratory tract is influenced by the temperature and humidity of the surrounding air. In human beings the shape of the nasal cavities, and especially the nostrils, plays an important role for the conditioning of inhaled air. Contact between the airstream and the nasal mucous membrane is regulated by the degree of turbulence in the air flow. The air conditioning capacity of the nose under normal conditions is surprisingly high. For example, inhaled air with an external temperature of -12 C can be warmed to +25 C during its rapid passage through the nose.' The relative humidity (RH.) of the inhaled air is also considerably increased from about 35% (ordinary room air) to 98% when it passes the subglottic space." The influence of temperature changes on mucociliary activity has been documented experimentally by a great number of authors.v" The correlation between the temperature of the air and the mucociliary wave pattern has recently been systematically analyzed in vitro on rabbit trachea under standardized conditlons.s-" Reduced RH. of the inhaled air and incomplete conditioning during its pas-
sage through the nose produce clinical problems in the sphere of otorhinolaryngology, especially for tracheotomized patients and for patients immediately after laryngectomy. «The only natural enemy known to cilia in their line of function is excessive drying."lO The clinical importance of an adequate degree of humidity for retained mucociliary function has been mentioned by many authors mainly in anesthesiology.P'
