Dickinson J W, Whyte G P, McConnell A K, Nevill A M, Harries M G
English Institute of Sport, Bisham Abbey High, Performance Centre, Bisham, Nr Marlow, Bucks SL7 1RT, UK.
Thorax. 2006 Feb;61(2):111-4. doi: 10.1136/thx.2005.046615. Epub 2005 Oct 14.
A fall in FEV(1) of > or =10% following bronchoprovocation (eucapnic voluntary hyperventilation (EVH) or exercise) is regarded as the gold standard criterion for diagnosing exercise induced asthma (EIA) in athletes. Previous studies have suggested that mid-expiratory flow (FEF(50)) might be used to supplement FEV(1) to improve the sensitivity and specificity of the diagnosis. A study was undertaken to investigate the response of FEF(50) following EVH or exercise challenges in elite athletes as an adjunct to FEV(1).
Sixty six male (36 asthmatic, 30 non-asthmatic) and 50 female (24 asthmatic, 26 non-asthmatic) elite athletes volunteered for the study. Maximal voluntary flow-volume loops were measured before and 3, 5, 10, and 15 minutes after stopping EVH or exercise. A fall in FEV(1) of > or =10% and a fall in FEF(50) of > or =26% were used as the cut off criteria for identification of EIA.
There was a strong correlation between DeltaFEV(1) and DeltaFEF(50) following bronchoprovocation (r = 0.94, p = 0.000). Sixty athletes had a fall in FEV(1) of > or =10% leading to the diagnosis of EIA. Using the FEF(50) criterion alone led to 21 (35%) of these asthmatic athletes receiving a false negative diagnosis. The lowest fall in FEF(50) in an athlete with a > or =10% fall in FEV(1) was 14.3%. Reducing the FEF(50) criteria to > or =14% led to 13 athletes receiving a false positive diagnosis. Only one athlete had a fall in FEF(50) of > or =26% in the absence of a fall in FEV(1) of > or =10% (DeltaFEV(1) = 8.9%).
The inclusion of FEF(50) in the diagnosis of EIA in elite athletes reduces the sensitivity and does not enhance the sensitivity or specificity of the diagnosis. The use of FEF(50) alone is insufficiently sensitive to diagnose EIA reliably in elite athletes.
支气管激发试验（等二氧化碳通气过度（EVH）或运动）后第1秒用力呼气容积（FEV(1)）下降≥10%被视为诊断运动员运动诱发哮喘（EIA）的金标准。既往研究提示，呼气中期流速（FEF(50)）可用于补充FEV(1)，以提高诊断的敏感性和特异性。本研究旨在调查精英运动员在EVH或运动激发试验后FEF(50)的反应，作为FEV(1)的辅助指标。
66名男性（36名哮喘患者，30名非哮喘患者）和50名女性（24名哮喘患者，26名非哮喘患者）精英运动员自愿参与本研究。在停止EVH或运动前以及停止后3、5、10和15分钟测量最大自主流速-容量环。FEV(1)下降≥10%和FEF(50)下降≥26%被用作EIA的诊断标准。
支气管激发试验后，DeltaFEV(1)与DeltaFEF(50)之间存在强相关性（r = 0.94，p = 0.000）。60名运动员FEV(1)下降≥10%，从而被诊断为EIA。仅使用FEF(50)标准导致这些哮喘运动员中有21名（35%）得到假阴性诊断。FEV(1)下降≥10%的运动员中，FEF(50)的最低下降值为14.3%。将FEF(50)标准降至≥14%导致13名运动员得到假阳性诊断。仅1名运动员在FEV(1)未下降≥10%（DeltaFEV(1) = 8.9%）的情况下FEF(50)下降≥26%。
在精英运动员EIA诊断中纳入FEF(50)会降低敏感性，且不会提高诊断的敏感性或特异性。单独使用FEF(50)对精英运动员EIA进行可靠诊断的敏感性不足。
