Danish PCD Center and Pediatric Pulmonary Service, Department of Pediatrics, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.
Thorax. 2012 Jan;67(1):49-53. doi: 10.1136/thoraxjnl-2011-200726. Epub 2011 Sep 26.
The lung clearance index (LCI) derived from the multiple breath inert gas washout (MBW) test reflects global ventilation distribution inhomogeneity. It is more sensitive than forced expiratory volume in 1 s (FEV(1)) for detecting abnormal airway function and correlates closely with structural lung damage in children with cystic fibrosis, which shares features with primary ciliary dyskinesia (PCD). Normalised phase III slope indices S(cond) and S(acin) reflect function of the small conducting and acinar airways, respectively. The involvement of the peripheral airways assessed by MBW tests has not been previously described in PCD.
A cross-sectional MBW study was performed in 27 children and adolescents with verified PCD, all clinically stable and able to perform lung function tests. LCI, S(cond) (n=23) and S(acin) (n=23) were derived from MBW using a mass spectrometer and sulfur hexafluoride as inert marker gas. MBW indices were compared with present age, age at diagnosis and spirometry findings, and were related to published normative values.
LCI, S(cond) and S(acin) were abnormal in 85%, 96% and 78% of patients with PCD and in 81%, 93% and 79%, respectively, of 13/27 subjects with normal FEV(1). LCI and S(acin) correlated significantly while S(cond) did not correlate with any other lung function parameters. None of the lung function measurements correlated with age or age at diagnosis.
PCD is characterised by marked peripheral airway dysfunction. MBW seems promising in the early detection of lung damage, even in young patients with PCD. The relationship of MBW indices to the outcome of long-term disease and their role in the management of PCD need to be assessed.
从多呼吸惰性气体洗脱（MBW）试验中得出的肺清除指数（LCI）反映了全球通气分布的不均匀性。它比 1 秒用力呼气量（FEV1）更敏感，用于检测气道功能异常，与囊性纤维化（CF）儿童的结构性肺损伤密切相关，CF 与原发性纤毛运动障碍（PCD）具有共同特征。正常化的相位 III 斜率指数 S（cond）和 S（acin）分别反映了小传导气道和腺泡气道的功能。MBW 试验评估的周围气道受累在 PCD 中尚未被描述过。
对 27 名确诊的 PCD 患儿和青少年进行了横断面 MBW 研究，所有患儿均处于临床稳定状态，能够进行肺功能测试。使用质谱仪和六氟化硫作为惰性标记气体，从 MBW 中得出 LCI、S（cond）（n=23）和 S（acin）（n=23）。将 MBW 指数与当前年龄、诊断年龄和肺功能检查结果进行比较，并与已发表的正常值进行比较。
在 85%、96%和 78%的 PCD 患者中，LCI、S（cond）和 S（acin）异常，而在 13/27 名 FEV1 正常的患者中，分别有 81%、93%和 79%异常。LCI 和 S（acin）显著相关，而 S（cond）与任何其他肺功能参数均不相关。肺功能测量与年龄或诊断年龄均无相关性。
PCD 的特点是明显的周围气道功能障碍。MBW 似乎有望在早期发现肺损伤，即使是在年轻的 PCD 患者中。需要评估 MBW 指数与长期疾病结局的关系及其在 PCD 管理中的作用。
