Alberts W M, Ferris M C, Brooks S M, Goldman A L
Division of Pulmonary, Critical Care, and Occupational Medicine, University of South Florida College of Medicine, Tampa.
Ann Allergy. 1994 Sep;73(3):221-5.
Nonspecific bronchial provocation testing is clinically useful in the evaluation of patients with symptoms suggestive of asthma. Testing is usually reserved for those with normal or near normal baseline spirometry. Although bronchial provocation testing is safe and widely available, the protocol is time consuming and not without expense. It has been reported that a reduced FEF25-75% in the context of an otherwise normal spirogram suggests that asthma should be considered. To evaluate this suggestion, we compared the baseline FEF25-75% (expressed as percent of predicted) with the results of the subsequent methacholine bronchial provocation test in 205 consecutive patients referred for testing. The mean baseline FEF25-75% in the 112 patients with normally responsive airways (ie, a negative bronchial provocation test) was 95.4 +/- 27.5%. In the 93 patients with a positive bronchial provocation test, the mean FEF25-75% was 77.6 +/- 27.2%. The mean FEF25-75% in those with hyperresponsive airways was significantly lower (t = 4.616, P < .0001). Of those patients with a positive bronchial provocation test, there was no significant correlation, however, between the baseline FEF25-75% and the degree of bronchial hyperresponsiveness as assessed by the PC20FEV1 (r = .154, P = .141). When a significant reduction in FEF25-75% was defined as less than 60% of predicted, the sensitivity of the prediction rule was 25.8%, the specificity was 92.0%, the positive predictive value was 72.7%, and the negative predictive value was 60.0%. From these results, we conclude that the FEF25-75% derived from simple spirometry may be useful in predicting the presence or absence, but not the degree, of bronchial hyperresponsiveness.
非特异性支气管激发试验在评估有哮喘疑似症状的患者时具有临床实用性。该试验通常适用于基线肺量计检查结果正常或接近正常的患者。尽管支气管激发试验是安全且广泛可用的，但试验方案耗时且费用不菲。据报道，在其他肺量图正常的情况下，FEF25 - 75%降低提示应考虑哮喘。为评估这一提示，我们比较了205例连续转诊接受检测患者的基线FEF25 - 75%（以预测值的百分比表示）与随后的乙酰甲胆碱支气管激发试验结果。112例气道反应正常（即支气管激发试验阴性）患者的平均基线FEF25 - 75%为95.4±27.5%。在93例支气管激发试验阳性的患者中，平均FEF25 - 75%为77.6±27.2%。气道高反应性患者的平均FEF25 - 75%显著更低（t = 4.616，P < .0001）。然而，在那些支气管激发试验阳性的患者中，基线FEF25 - 75%与通过PC20FEV1评估的支气管高反应程度之间无显著相关性（r = .154，P = .141）。当将FEF25 - 75%显著降低定义为低于预测值的60%时，预测规则的敏感性为25.8%，特异性为92.0%，阳性预测值为72.7%，阴性预测值为60.0%。从这些结果中，我们得出结论，简单肺量计得出的FEF25 - 75%可能有助于预测支气管高反应性的存在与否，但不能预测其程度。
