Aronsson David, Tufvesson Ellen, Bjermer Leif
Department of Respiratory Medicine and Allergology, Institution of Clinical Medicine and Science, Lund, Sweden.
Clin Respir J. 2011 Jan;5(1):10-8. doi: 10.1111/j.1752-699X.2009.00183.x.
Testing for airway hyperresponsiveness with indirect stimuli as exercise or mannitol has been proposed to better reflect underlying airway inflammation, as compared with methacholine (MCh), believed to act directly on airway smooth muscle cells.
To investigate whether different direct and indirect stimuli induces different patterns of obstruction, recorded as central and peripheral resistance, and to see whether baseline resistance could predict a positive response to direct or indirect provocation.
Thirty-four mild asthmatics and 15 controls underwent MCh, mannitol and eucapnic voluntary hyperventilation (EVH) challenge tests. The response was evaluated with spirometry and impulse oscillometry (IOS).
Twenty-three out of 34 asthmatics were positive to either EVH (22) or mannitol (13). Those positive to mannitol had a significant increased baseline value of IOS parameters such as ΔR5-R20 and AX. Twelve of the asthmatics had a 10% fall or more in forced expiratory volume in 1 s (FEV(1)) in all three challenge tests. However, the response pattern measured by IOS did not differ between the tests. When the limit for a positive mannitol provocation was set to 10% fall in FEV(1), 16 out of 19 mannitol-positive patients were also positive to EVH.
Even in mild asthmatics, a substantial number had a positive indirect test. Mannitol FEV(1) provocative dose to decrease FEV(1) by 10% from baseline (PD10) was closely associated to EVH10%. No difference in bronchoconstrictive pattern could be seen between the different provocation tests, but those positive to mannitol had more peripheral airway involvement at baseline. This supports the idea that peripheral airway involvement is an important predictor of asthma airway reactivity.
与被认为直接作用于气道平滑肌细胞的乙酰甲胆碱（MCh）相比，有人提出用运动或甘露醇等间接刺激物来测试气道高反应性，以更好地反映潜在的气道炎症。
研究不同的直接和间接刺激物是否会诱发不同的阻塞模式（记录为中心和外周阻力），并观察基线阻力是否能预测对直接或间接激发试验的阳性反应。
34名轻度哮喘患者和15名对照者接受了MCh、甘露醇和等容呼气末二氧化碳分压下的自主过度通气（EVH）激发试验。通过肺量计和脉冲振荡法（IOS）评估反应。
34名哮喘患者中有23名对EVH（22名）或甘露醇（13名）呈阳性反应。对甘露醇呈阳性反应者的IOS参数（如ΔR5-R20和AX）基线值显著升高。12名哮喘患者在所有三项激发试验中第1秒用力呼气容积（FEV(1)）下降10%或更多。然而，IOS测量的反应模式在各试验之间没有差异。当甘露醇激发试验阳性的标准设定为FEV(1)下降10%时，19名甘露醇阳性患者中有16名对EVH也呈阳性反应。
即使在轻度哮喘患者中，也有相当一部分人间接试验呈阳性。使FEV(1)从基线下降10%的甘露醇FEV(1)激发剂量（PD10）与EVH10%密切相关。不同激发试验之间未见支气管收缩模式有差异，但对甘露醇呈阳性反应者在基线时外周气道受累更多。这支持了外周气道受累是哮喘气道反应性重要预测指标的观点。
