Cold air-induced late-phase bronchoconstriction in horses.
Cold air-induced late-phase bronchoconstriction in horses.
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冷空气引起马的晚期支气管收缩。
DOI：
10.1111/j.2042-3306.2006.tb05600.x
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Marlin,D
中科院分区：
文献类型：
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作者：
Davis,MS;Royer,CM;McKenzie,EC;Williamson,KK;Payton,M;Marlin,D
进行研究的原因：在正常静息条件下，吸入的空气被加热至体温，并被上气道粘膜充分加湿。在每分钟通气量增加的情况下或当吸入的空气异常寒冷时，上气道可能无法完成这种调节过程，从而导致下呼吸道表面冷却和干燥。肺内气道的过多热量和水分流失被认为是运动诱导的支气管收缩（运动后立即发生）和相关晚期气道阻塞（运动后几小时发生）的刺激因素。假设：呼吸冷空气时运动导致马气道阻塞。方法：8匹健康马在随机交叉设计中进行了15分钟的次极量运动挑战。自变量为激发期间的吸入空气温度（25或-5 °C）。因变量为总呼吸阻抗，阻力，电抗在5，24和48小时后运动challenge，表示为prechallenge baseline.Results的百分比：没有显着的影响，发现吸入空气温度对任何呼吸力学参数5小时后运动的挑战。然而，冷吸入的空气与较高的呼吸阻抗和阻力48 h后的运动challenges.Conclusions：这些研究结果支持这一假设，亚极量运动，而呼吸冰点以下的空气会对正常马的呼吸机械性能产生不利影响。然而，发展异常的呼吸机械性能的时间过程比在其他mammals.Clinical相关性：运动在寒冷的天气可能是一个常见的原因下呼吸道疾病的马。
Reason for performing study:Inspired air is warmed to body temperature and fully humidified by the upper airway mucosa under normal resting conditions. This conditioning process may not be completed by the upper airways during conditions of increased minute ventilation or when the inspired air is unusually cold, resulting in cooling and desiccation of lower respiratory surfaces. Excess heat and water loss from intrapulmonary airways is believed to be the provocative stimulus for exercise‐induced bronchoconstriction (occurring immediately after exercise) and associated late phase airway obstruction (occurring a few hours after exercise).Hypothesis:Exercise while breathing cold air results in airway obstruction in horses.Methods:Eight healthy horses performed a 15 min submaximal exercise challenge in a random crossover design. Independent variable was inspired air temperature during the challenge (25 or ‐5°C). The dependent variables were total respiratory impedance, resistance, and reactance at 5, 24 and 48 h post exercise challenge, expressed as a percentage of the prechallenge baseline.Results:No significant effect of inspired air temperature was found on any respiratory mechanical parameter 5 h after exercise challenge. However, cold inspired air was associated with higher respiratory impedance and resistance 48 h after the exercise challenges.Conclusions:These findings support the hypothesis that submaximal exercise while breathing subfreezing air can adversely affect respiratory mechanical properties in normal horses. However, the timecourse for development of abnormal respiratory mechanical properties is longer than that reported in other mammals.Clinical relevance:Exercise in cold weather may be a common cause of lower airway disease in horses.