Chang A B, Phelan P D, Holst D, Robertson C F
Department of Thoracic Medicine, Royal Children's Hospital, Parkville, Melbourne, Victoria, Australia.
Pediatr Pulmonol. 1997 Jun;23(6):412-6. doi: 10.1002/(sici)1099-0496(199706)23:6<412::aid-ppul3>3.0.co;2-k.
Recurrent cough and asthma are common problems in children. In the evaluation of children with recurrent cough, the sequential measurements of airway responsiveness (AR) and capsaicin cough receptor sensitivity may be useful. However, the effect of capsaicin on AR induced by an indirect stimulus such as hypertonic saline (HS) is not known. Current evidence suggests that a common pathway is involved in both capsaicin and HS challenges. This study was designed to determine whether inhalation of capsaicin for the cough receptor sensitivity test before HS challenge will alter AR of asthmatic and non-asthmatic children to that challenge. Twenty-one children (12 asthmatics, 9 non-asthmatics; mean age, 11.3 years) performed the HS challenge alone or 2 min after capsaicin inhalation on 2 different days in random order. The end point of the capsaicin inhalation was when > or = 5 coughs were stimulated from a single inhalation. The power of the study was > 90% at a significance level of 0.05. Capsaicin inhalation prior to HS challenge did not alter the AR of normal children. In the asthmatic group, the PD15 (provocation dose causing a fall in forced expiratory volume in 1 s of > or = 15% from the baseline) without prior inhalation of capsaicin (mean, 2.44 +/- SEM 1.21 ml) was not significantly different from that when HS challenge was performed after capsaicin inhalation (mean, 2.19 +/- SEM 0.83 ml). The mean of the difference in log PD15 of the HS challenge with and without capsaicin was -0.02 (95% CI, -0.16, 0.12), i.e. within the equivalence range of the HS challenge in children with asthma. We conclude that in normal and asthmatic children, capsaicin inhalation does not alter AR to HS; consequently the capsaicin cough sensitivity test can be performed validly before an HS challenge.
反复咳嗽和哮喘是儿童常见的问题。在评估反复咳嗽的儿童时，气道反应性（AR）和辣椒素咳嗽受体敏感性的连续测量可能有用。然而，辣椒素对由间接刺激如高渗盐水（HS）诱导的AR的影响尚不清楚。目前的证据表明，辣椒素和HS激发试验涉及共同的途径。本研究旨在确定在HS激发试验前吸入辣椒素进行咳嗽受体敏感性测试是否会改变哮喘和非哮喘儿童对该激发试验的AR。21名儿童（12名哮喘患者，9名非哮喘患者；平均年龄11.3岁）在2个不同的日子里，以随机顺序单独进行HS激发试验或在吸入辣椒素2分钟后进行。辣椒素吸入的终点是单次吸入刺激产生≥5次咳嗽。在显著性水平为0.05时，该研究的检验效能>90%。在HS激发试验前吸入辣椒素并未改变正常儿童的AR。在哮喘组中，未预先吸入辣椒素时的PD15（引起第1秒用力呼气量较基线下降≥15%的激发剂量）（平均，2.44±标准误1.21 ml）与吸入辣椒素后进行HS激发试验时的PD15（平均，2.19±标准误0.83 ml）无显著差异。有和没有辣椒素时HS激发试验的log PD15差异的平均值为-0.02（95%可信区间，-0.16，0.12），即在哮喘儿童HS激发试验的等效范围内。我们得出结论，在正常和哮喘儿童中，吸入辣椒素不会改变对HS的AR；因此，辣椒素咳嗽敏感性测试可在HS激发试验前有效进行。
