Daviskas E, Anderson S D, Gonda I, Eberl S, Meikle S, Seale J P, Bautovich G
Dept of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, Australia.
Eur Respir J. 1996 Apr;9(4):725-32. doi: 10.1183/09031936.96.09040725.
Hyperosmolarity of the airway surface liquid (ASL) has been proposed as the stimulus for hyperpnoea-induced asthma. We found previously that mucociliary clearance (MCC) was increased after isocapnic hyperventilation (ISH) with dry air, and we proposed that the increase related to transient hyperosmolarity of the ASL. We investigated the effect of increasing the osmolarity of the ASL on MCC, by administering an aerosol of concentrated salt solution. MCC was measured using 99mTc-sulphur colloid, gamma camera and computer analysis in 12 asthmatic and 10 healthy subjects on three separate days, involving administration of each of the following: 1) ultrasonically nebulized 14.4% saline; 2) ultrasonically nebulized 0.9% saline; and 3) no aerosol intervention (control). The (mean +/- SD) volume of nebulized 14.4% saline was 2.2 +/- 1.2 mL for asthmatics and 3.2 +/- 0.7 mL for healthy subjects. This volume was delivered over a period of 5.4 +/- 1.3 and 6.4 +/- 0.7 min for asthmatic and healthy subjects, respectively. The airway response to 14.4% saline was assessed on a separate visit and the fall in forced expiratory volume in one second (FEV1) was 22 +/- 4% in the asthmatic and 3 +/- 2% in the healthy subjects. Compared to the MCC with the 0.9% saline and control, the hypertonic aerosol increased MCC in both groups. In asthmatic subjects, MCC of the whole right lung in 1 h was 68 +/- 10% with 14.4% saline vs 44 +/- 14% with 0.9% saline and 39 +/- 13% with control. In healthy subjects, MCC of the whole right lung in 1 h was 53 +/- 12% with 14.4% saline vs 41 +/- 15% with 0.9% saline and 36 +/- 13% with control. We conclude that an increase in osmolarity of the airway surface liquid increases mucociliary clearance both in asthmatic and healthy subjects. These findings are in keeping with our previous suggestion that the increase in mucociliary clearance after isotonic hyperventilation with dry air is due to a transient hyperosmolarity of the airway surface liquid.
气道表面液体（ASL）的高渗状态被认为是导致通气过度诱发哮喘的刺激因素。我们之前发现，在吸入干燥空气进行等碳酸血症性通气过度（ISH）后，黏液纤毛清除功能（MCC）增强，我们推测这种增强与ASL的短暂高渗有关。我们通过给予高浓度盐溶液气雾剂，研究了ASL渗透压升高对MCC的影响。在12名哮喘患者和10名健康受试者中，分三天使用99mTc-硫胶体、γ相机和计算机分析测量MCC，每次涉及给予以下物质之一：1）超声雾化14.4%盐水；2）超声雾化0.9%盐水；3）无气雾剂干预（对照）。哮喘患者雾化14.4%盐水的（平均±标准差）体积为2.2±1.2 mL，健康受试者为3.2±0.7 mL。哮喘患者和健康受试者分别在5.4±1.3分钟和6.4±0.7分钟内完成该体积盐水的输送。在另一次就诊时评估对14.4%盐水的气道反应，哮喘患者一秒用力呼气量（FEV1）下降22±4%，健康受试者下降3±2%。与使用0.9%盐水和对照时的MCC相比，高渗气雾剂使两组的MCC均增加。在哮喘患者中，14.4%盐水组1小时内右肺整体的MCC为68±10%，0.9%盐水组为44±14%，对照组为39±13%。在健康受试者中，14.4%盐水组1小时内右肺整体的MCC为53±12%，0.9%盐水组为41±15%，对照组为36±13%。我们得出结论，气道表面液体渗透压升高会增加哮喘患者和健康受试者的黏液纤毛清除功能。这些发现与我们之前的推测一致——吸入干燥空气进行等渗通气过度后黏液纤毛清除功能增强是由于气道表面液体的短暂高渗。
