Clini E, Vitacca M, Scalvini S, Quadri A, Foglio K
Division of Pneumology, Salvatore Maugeri Foundation IRCCS, Medical Center of Rehabilitation, Gussago, Italy.
Monaldi Arch Chest Dis. 1996 Jun;51(3):194-8.
We tested measures of specific airway conductance (sGaw) and forced expiratory volume in one second (FEV1) versus transcutaneous oxygen tension (Ptc,O2) during inhaled methacholine bronchial challenge in 60 out-patients (38 males 22 females, mean age 33 +/- 13 yrs). The provocative doses of methacholine needed to produce a 35% decrease of sGaw (PD35,sGaw), a 20% fall in FEV1 (PD20,FEV1) and a 20% decrease in Ptc,O2 (PD20,O2) were simultaneously derived from the dose-response curves. Two groups were identified according to the PD20,FEV1 result ("responders" with a PD20,FEV1 < 2,000 micrograms methacholine and "nonresponders" with PD20,FEV1 > 2,000 micrograms methacholine). All three indices derived from the dose-response curves differed significantly between the groups (p < 0.00005). The relationship analysis showed a significantly better value for PD20,O2 versus PD35,sGaw (r = 0.98) than versus PD20, FEV1 (r = 0.62). We observed similar baseline levels and variations in arterial oxygen tension (Pa,O2) and Ptc,O2 during methacholine challenge (-25 and -27%, respectively) in 14 randomly studied responders. Thus, inhaled methacholine-induced hypoxaemia (PD20,O2) seems to reflect PD35,sGaw better than changes in FEV1. Our investigation supports the hypothesis that PD20,O2 could be useful in interpreting the methacholine inhaled challenge. It could be of help in clarifying the pathophysiological meaning of the concurrent hypoxaemia during this challenge, which should be further elucidated.
我们对60名门诊患者（38名男性，22名女性，平均年龄33±13岁）在吸入乙酰甲胆碱支气管激发试验期间的比气道传导率（sGaw）、一秒用力呼气容积（FEV1）与经皮氧分压（Ptc,O2）指标进行了检测。产生sGaw下降35%（PD35,sGaw）、FEV1下降20%（PD20,FEV1）和Ptc,O2下降20%（PD20,O2）所需的乙酰甲胆碱激发剂量同时从剂量反应曲线得出。根据PD20,FEV1结果分为两组（PD20,FEV1＜2000微克乙酰甲胆碱的“反应者”和PD20,FEV1＞2000微克乙酰甲胆碱的“无反应者”）。两组间从剂量反应曲线得出的所有三个指标均有显著差异（p＜0.00005）。相关性分析显示，PD20,O2与PD35,sGaw的相关性（r = 0.98）显著优于与PD20,FEV1的相关性（r = 0.62）。在14名随机研究的反应者中，我们观察到在乙酰甲胆碱激发试验期间动脉血氧分压（Pa,O2）和Ptc,O2有相似的基线水平和变化（分别为-25%和-27%）。因此，吸入乙酰甲胆碱诱发的低氧血症（PD20,O2）似乎比FEV1的变化能更好地反映PD35,sGaw。我们的研究支持了PD20,O2可用于解释吸入乙酰甲胆碱激发试验的假说。这可能有助于阐明该激发试验期间并发低氧血症的病理生理意义，对此应进一步阐明。
