Department of Pediatrics, University of Florence, Florence, Italy.
Pediatr Pulmonol. 2010 Jul;45(7):633-8. doi: 10.1002/ppul.21210.
To determine and validate a cut-off value for bronchodilation using the interrupter resistance (Rint) in preschool children.
Rint was measured in 60 healthy children (age range 2.7-6.4 years) before and after salbutamol inhalation (200 microg). Four potential methods for assessing BDR were evaluated: percent change from baseline, percent change of predicted values, absolute change in Rint, and change in Z-score. These cut-off values, determined as the fifth percentile of the healthy group, were applied to children referred for the assessment of recurrent wheezing, classified on the basis of acute symptoms and/or abnormal chest examination into symptomatic (n = 60, age range 2.9-6.1 years) and asymptomatic (n = 60, age range 2.5-5.7 years) groups.
The cut-off values for bronchodilation calculated in healthy children were: -32% baseline; -33% predicted; -0.26 kPa L(-1) sec; and -1.25 Z-scores. Assessing BDR in children with a history of wheezing by either a decrease in absolute Rint or a decrease in Z-score gave sensitivity, specificity, negative predictive value, and positive predictive value all >80% for detecting children with current respiratory symptoms.
Both a decrease in Rint > or =0.26 kPa L(-1) sec and a decrease in Z-score of > or =1.25 are appropriate for assessing BDR in preschool children with a history of recurrent wheezing. As Z-score is a more general solution, we recommend using a change in Z-score to determine BDR in preschool children. Further longitudinal studies will be required to determine the clinical utility of measuring BDR in managing lung disease in such children.
确定并验证学龄前儿童使用呼吸中断阻力（Rint）来衡量支气管扩张的截断值。
在沙丁胺醇吸入（200 微克）前后，对 60 名健康儿童（年龄 2.7-6.4 岁）进行了 Rint 测量。评估了 4 种潜在的 BDR 评估方法：与基线相比的百分比变化、与预测值相比的百分比变化、Rint 的绝对值变化和 Z 分数变化。这些截断值是通过将健康组的第 5 个百分位确定的，然后应用于因反复喘息而接受评估的儿童，根据急性症状和/或异常胸部检查将他们分为有症状组（n=60，年龄 2.9-6.1 岁）和无症状组（n=60，年龄 2.5-5.7 岁）。
健康儿童计算出的支气管扩张截断值为：-32%基线；-33%预测值；-0.26 kPa L(-1) sec；-1.25 Z 分数。通过绝对 Rint 降低或 Z 分数降低来评估有喘息病史的儿童的 BDR，对于检测有当前呼吸道症状的儿童，其灵敏度、特异性、阴性预测值和阳性预测值均>80%。
对于有反复喘息病史的学龄前儿童，Rint 降低>或=0.26 kPa L(-1) sec 和 Z 分数降低>或=1.25 均适用于评估 BDR。由于 Z 分数是一种更通用的解决方案，我们建议使用 Z 分数的变化来确定学龄前儿童的 BDR。需要进一步的纵向研究来确定在管理此类儿童的肺部疾病时测量 BDR 的临床实用性。
