Malo J L, Côté J, Cartier A, Boulet L P, L'Archevêque J, Chan-Yeung M
Department of Chest Medicine, Sacré-Coeur Hospital, West Gouin, Montreal, Canada.
Thorax. 1993 Dec;48(12):1211-7. doi: 10.1136/thx.48.12.1211.
Serial peak expiratory flow rate (PEF) recording has been advocated as a sensitive and specific means of confirming work related asthma. The optimum number of recordings per day to achieve the best between-reader and within-reader reproducibility and sensitivity/specificity ratio compared with the final diagnosis determined by specific inhalation challenges is unknown.
PEF recording was carried out every two hours in 74 subjects referred for possible occupational asthma. Specific inhalation challenges performed in a hospital laboratory or at the workplace (positive in 33 subjects and negative in 41) were considered the gold standard. The duration of monitoring at work and away from work was at least two weeks each. Graphs of PEF recordings were generated in four different ways: every two hours, four times/day, three times/day, and every morning and evening. The graphs were assessed by three readers in three different centres in a blind manner. Furthermore, one third of each type of graph was read blind by the same reader one week after the initial interpretation.
Agreement between the three readers was a little more frequent (82%) in the case of the every two hour readings than for the other types of readings (70% v 77%). Agreement between at least two of the three readers occurred in 73% of positive challenges (sensitivity) and in 78% of negative challenges (specificity) for every two hour readings. The figures varied from 61% to 70% for positive challenges and from 78% to 88% for negative challenges for the other types of readings. Within-subject reproducibility from one reading to the next (one week apart) was excellent (83% to 100%).
Recording PEF every two hours results in a slightly more satisfactory agreement between readers and in concordance in terms of sensitivity/specificity than less frequent PEF readings, although the four times a day assessment is almost as satisfactory.
连续呼气峰值流速（PEF）记录被认为是确诊职业性哮喘的一种敏感且特异的方法。与通过特异性吸入激发试验确定的最终诊断相比，为实现最佳的读者间和读者内重复性以及敏感度/特异度比值，每天的最佳记录次数尚不清楚。
对74名疑似职业性哮喘的受试者每两小时进行一次PEF记录。在医院实验室或工作场所进行的特异性吸入激发试验（33名受试者结果为阳性，41名受试者结果为阴性）被视为金标准。工作期间和非工作期间的监测时长均至少为两周。PEF记录图通过四种不同方式生成：每两小时一次、每天四次、每天三次以及每天早晚各一次。这些记录图由三个不同中心的三名读者进行盲法评估。此外，每种类型记录图的三分之一在初次解读一周后由同一名读者进行盲法重读。
对于每两小时一次的读数，三名读者之间的一致性（82%）比其他类型的读数（70%对77%）略高。对于每两小时一次的读数，在73%的阳性激发试验（敏感度）和78%的阴性激发试验（特异度）中，至少两名读者之间达成了一致。对于其他类型的读数，阳性激发试验的这一数字在61%至70%之间，阴性激发试验的这一数字在78%至88%之间。同一受试者在相隔一周的两次读数之间的重复性极佳（83%至100%）。
与PEF读数频率较低的情况相比，每两小时记录一次PEF在读者之间的一致性以及敏感度/特异度的一致性方面略更令人满意，尽管每天四次的评估几乎同样令人满意。
