Bussamra Maria Helena, Cukier Alberto, Stelmach Rafael, Rodrigues Joaquim Carlos
Unidade de Pneumologia do Instituto da Criança, University of São Paulo Medical School, São Paulo, SP, Brazil.
Chest. 2005 Feb;127(2):530-5. doi: 10.1378/chest.127.2.530.
Bronchodilator response criteria have been determined in adults; however, data applicable to children and adolescents are scarce. We measured pulmonary function in asthmatic patients to determine the bronchodilator response.
A blind study.
Outpatient clinic of Pneumology Unit, Instituto da Crianca and Center of Asthma Care and Research, University Hospital, University of Sao Paulo Medical School.
Sixty patients aged 6 to 20 years (median, 12 years).
Spirometry and plethysmography were performed before and after blind placebo and bronchodilator inhalation (400 mug salbutamol by metered-dose inhaler).
Approximately 90% of the patients had mild-to-moderate persistent asthma. The mean FEV(1) at baseline was 79.6% of the predicted value. Distribution of variations of the different pulmonary function parameters was analyzed after placebo inhalation. The 95th percentile was adopted as a criterion for a significant bronchodilator response. After the bronchodilator test, the patients were classified based on criteria derived from the placebo inhalation and the American Thoracic Society guidelines. Parameters established as cutoff values were 265 mL, 14.2% and 10% FEV(1) expressed as absolute volume, percentage compared with that at baseline and percentage of the predicted value, respectively, and 55% specific airway conductance (sGaw) expressed as a percentage compared with that at baseline. Based on the spirometric data, 37 patients (61%) had reversibility of obstruction, while 48 patients (80%) were classified as responders based on the analysis of variations in sGaw. The classifications based on variations in FEV(1) expressed as absolute volume and percentage of the predicted value showed a substantial correlation with the international classification.
The cutoff values established for the assessment of the bronchodilator response in the present population agree with those reported in the literature. sGaw was the most sensitive parameter for the identification of changes in airway caliber.
支气管扩张剂反应标准已在成人中确定；然而，适用于儿童和青少年的数据却很少。我们测量了哮喘患者的肺功能以确定支气管扩张剂反应。
一项盲法研究。
圣保罗大学医学院儿童研究所肺病科门诊及哮喘护理与研究中心、大学医院。
60名年龄在6至20岁（中位数为12岁）的患者。
在盲法给予安慰剂和吸入支气管扩张剂（通过定量吸入器吸入400μg沙丁胺醇）前后进行肺量计和体积描记法检查。
约90%的患者患有轻度至中度持续性哮喘。基线时的平均第一秒用力呼气容积（FEV₁）为预测值的79.6%。在吸入安慰剂后分析了不同肺功能参数变化的分布情况。采用第95百分位数作为支气管扩张剂显著反应的标准。在支气管扩张剂试验后，根据从安慰剂吸入得出的标准和美国胸科学会指南对患者进行分类。确定为临界值的参数分别为：以绝对容积表示为265mL、以相对于基线时的百分比表示为14.2%、以相对于预测值的百分比表示为10%的FEV₁，以及以相对于基线时的百分比表示为55%的比气道传导率（sGaw）。根据肺量计数据，37名患者（61%）存在阻塞性可逆性，而根据sGaw变化分析，48名患者（80%）被分类为反应者。以绝对容积和相对于预测值的百分比表示的FEV₁变化的分类与国际分类显示出高度相关性。
本研究人群中为评估支气管扩张剂反应所确定的临界值与文献报道一致。sGaw是识别气道管径变化最敏感的参数。
