Respiratory Unit, AOU Policlinico-Vittorio Emanuele, Department of Clinical and Experimental Medicine, University of Catania, Via Santa Sofia 78, I-95123, Catania, Italy.
Department of Pediatrics, Foundation IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy.
Respir Med. 2020 Apr;164:105906. doi: 10.1016/j.rmed.2020.105906. Epub 2020 Feb 19.
Nocturnal hypoxemia adversely affects outcomes in patients with cystic fibrosis (CF). Although an early detection of this abnormality may be desirable, still its predictability remains uncertain. The Lung Clearance Index (LCI) is a measure of lung ventilation distribution obtained from a multiple-breath washout technique (MBW), recently implemented in patients with CF. This study aimed to establish whether the LCI predicts nocturnal hypoxemia in patients with stable CF, with mild to moderate disease, and normal diurnal gas exchange.
31 stable patients (15 males, mean age 17.4 ± 5.2 years) with mild to moderate CF, normoxic when awake, were enrolled. In all patients we performed nocturnal cardio-respiratory polygraphy, lung function measurement, and MBW test to derive LCI values.
LCI was abnormal in most of the patients and inversely correlated with mean nocturnal SpO (r = -0.880 p < 0.01). A receiver operating characteristic (ROC) analysis, performed to assess whether LCI predicted nocturnal hypoxemia, revealed a high predictive accuracy of LCI for nocturnal desaturation (AUC = 0.96; Youden index = 0.79). Forced expiratory volume in 1 s (FEV) was predictive only in patients with more severe airway obstruction, with a moderate degree of accuracy (AUC 0.71).
The LCI showed a high effectiveness in predicting nocturnal hypoxemia in stable patients with CF, particularly when compared with a traditional parameter of lung function such as FEV.
夜间低氧血症会对囊性纤维化（CF）患者的预后产生不利影响。尽管早期发现这种异常可能是理想的，但它的可预测性仍然不确定。肺清除指数（LCI）是一种从多次呼吸冲洗技术（MBW）中获得的衡量肺通气分布的指标，最近已在 CF 患者中实施。本研究旨在确定 LCI 是否可预测稳定期 CF 患者、有轻度至中度疾病且日间气体交换正常的患者的夜间低氧血症。
纳入 31 例稳定期 CF 患者（15 名男性，平均年龄 17.4±5.2 岁），患者在清醒时均为氧合正常。所有患者均进行夜间心肺多导睡眠图、肺功能测量和 MBW 测试以得出 LCI 值。
大多数患者的 LCI 异常，且与平均夜间 SpO 呈负相关（r=-0.880，p<0.01）。为评估 LCI 是否预测夜间低氧血症而进行的受试者工作特征（ROC）分析显示，LCI 对夜间血氧饱和度降低的预测准确性较高（AUC=0.96；约登指数=0.79）。FEV 仅在气道阻塞更严重的患者中具有预测作用，且具有中等准确性（AUC 为 0.71）。
LCI 对稳定期 CF 患者夜间低氧血症的预测效果较好，尤其是与 FEV 等传统肺功能参数相比。
