Reduced hyperpnea-induced bronchospasm following repeated cold air challenge.
Reduced hyperpnea-induced bronchospasm following repeated cold air challenge.
复制标题
减少反复冷空气挑战后呼吸过度引起的支气管痉挛。
DOI：
10.1152/jappl.1986.61.1.210
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Axen,K
中科院分区：
文献类型：
--
作者：
Haas,F;Levin,N;Pasierski,S;Bishop,M;Axen,K
这项研究评估了12名哮喘受试者在冷空气刺激(CAP)5分钟后(干燥空气调节到大约0摄氏度)和在呼吸环境空气(大约21摄氏度和40%相对湿度)的情况下运动后(达到预计最大心率的85%)的呼气功能下降。这些评估是在以下培训方案之前和之后进行的。呼吸0度至-10℃的空气进行3次5分钟的等容冷空气高呼吸，间隔5分钟休息，持续36次，持续12周。正如预期的那样，训练前呼气功能在CAP和运动后均显著降低(P<0.001)。然而，在CAP和运动后，训练后呼气功能的下降明显不明显(最大P<0.05)。这些数据支持我们的假设，即反复的冷空气攻击会导致气道对冷空气的习服，从而减少运动引起的支气管痉挛。习服可直接通过呼吸道习惯化或血管扩张导致支气管血流量增加，从而减少呼吸道降温。然而，一个意想不到的发现是，反复的冷空气挑战也可能导致呼吸道的长期炎症变化。在训练期间，相当大比例的受试者经历了基线肺功能下降和哮喘症状的总体恶化。
This study assessed reduction in expiratory function in 12 asthmatic subjects both after 5 min of cold air provocation (CAP) with dry air conditioned to approximately 0 degrees C and after exercise (to 85% of predicted maximum heart rate) while breathing ambient room air (approximately 21 degrees C and 40% relative humidity). These assessments were done both before and after the following training protocol. Three 5-min periods of isocapnic cold air hyperpnea separated by 5-min rest periods were performed breathing 0 degrees to -10 degrees C air, for 36 sessions over 12 wk. As expected, pretraining expiratory function was significantly reduced (P less than 0.001) after both CAP and exercise. The posttraining reduction in expiratory function after CAP and exercise, however, was significantly less pronounced (largest P less than 0.05). These data support our hypothesis that repeated bouts of cold air challenge result in airway acclimatization to cold air and consequent decrease in exercise-induced bronchospasm. Acclimatization may result directly either by habituation of the airways or by vasodilation leading to increased bronchial blood flow and consequent reduced airway cooling. An unanticipated finding, though, is that repeated cold air challenge may also cause long-term inflammatory changes in the airways. A significant percentage of subjects experienced reduced base-line pulmonary function and overall exacerbation of asthma symptoms during the training period.