Green Kent, Ejlertsen Jacob S, Madsen Astrid, Buchvald Frederik F, Kongstad Thomas, Kobbernagel Helene, Gustafsson Per M, Nielsen Kim G
Department of Pediatric and Adolescent Medicine, Danish PCD and chILD Centre, CF Centre Copenhagen, Pediatric Pulmonary Service, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
Research Unit on Women's and Children's Health, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
Pediatr Pulmonol. 2016 Jun;51(6):624-32. doi: 10.1002/ppul.23339. Epub 2015 Nov 23.
Nitrogen multiple-breath washout (N2 MBW) is a promising tool for assessing early lung damage in children with chronic obstructive pulmonary disease, but it can be a time-consuming procedure. We compared alternative test-shortening endpoints with the most commonly reported N2 MBW outcome, the lung clearance index, calculated as lung volume turnovers required to reach 2.5% of the starting N2 concentration (LCI2.5 ).
Cross-sectional study of triplicate N2 MBW measurements obtained in cystic fibrosis (CF) patients (N = 60), primary ciliary dyskinesia (PCD) patients (N = 28), and matched healthy controls (N = 48) aged 5-18 years. Bland-Altman analysis was used to compare LCI2.5 with earlier LCI endpoints (3%, 4%, 5%, 7%, and 9% of starting N2 concentration), Cn@TO6 (defined as % of N2 starting concentration when reaching six lung volume turnovers), and LCI derived from only two N2 MBW runs in each session. N2 MBW endpoints were analyzed as z-scores calculated from healthy controls.
In PCD, Cn@TO6 and LCI2.5 exhibited similar values (mean [95%CI] difference: 0.33 [-0.24; 0.90] z-scores), reducing the test duration by one-third (5.4 min; 95%CI: 4.0; 6.8). All other tested alternative endpoints exhibited increasing disagreement with increasing LCI2.5 . With an average reduction in test duration of 40%, LCI2.5 derived from two runs exhibited good agreement in all children.
Cn@TO6 may be suggested as a potential test-shortening endpoint in school children with PCD. In CF, early test termination may reduce measurement power with advancing pulmonary disease, suggesting differences in underlying pathophysiology. Two technically acceptable N2 MBW runs may be sufficient in school children irrespective of diagnosis with CF or PCD. Pediatr Pulmonol. 2016;51:624-632. © 2015 Wiley Periodicals, Inc.
氮多次呼吸洗脱（N2 MBW）是评估慢性阻塞性肺疾病患儿早期肺损伤的一种很有前景的工具，但它可能是一个耗时的过程。我们将替代的缩短测试终点与最常报告的N2 MBW结果——肺清除指数进行了比较，肺清除指数计算为达到起始N2浓度的2.5%所需的肺容积周转次数（LCI2.5）。
对年龄在5至18岁的囊性纤维化（CF）患者（N = 60）、原发性纤毛运动障碍（PCD）患者（N = 28）和匹配的健康对照者（N = 48）进行了三次重复N2 MBW测量的横断面研究。采用Bland - Altman分析将LCI2.5与更早的LCI终点（起始N2浓度的3%、4%、5%、7%和9%）、Cn@TO6（定义为达到六次肺容积周转时N2起始浓度的百分比）以及每次测量仅从两次N2 MBW运行得出的LCI进行比较。N2 MBW终点分析为根据健康对照者计算的z分数。
在PCD中，Cn@TO6和LCI2.5表现出相似的值（平均[95%CI]差异：0.33[-0.24; 0.90]z分数），将测试持续时间缩短了三分之一（5.4分钟；95%CI：4.0；6.8）。所有其他测试的替代终点与LCI2.5的差异随着LCI2.5的增加而增大。在所有儿童中，从两次运行得出的LCI2.5平均测试持续时间减少了40%，表现出良好的一致性。
对于患有PCD的学龄儿童，Cn@TO6可被建议作为潜在的缩短测试终点。在CF中，随着肺部疾病进展，早期终止测试可能会降低测量效能，提示潜在病理生理学存在差异。无论诊断为CF还是PCD，两次技术上可接受的N2 MBW运行对于学龄儿童可能就足够了。《儿科肺脏病学》。2016年；51：624 - 632。©2015威利期刊公司。
