Department of Pulmonary and Critical Care Medicine, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China.
Centre for Clinical Science, Respiratory Medicine, Hull York Medical School, University of Hull, Castle Hill Hospital, Cottingham, East Yorkshire, UK.
Ther Adv Respir Dis. 2024 Jan-Dec;18:17534666241231117. doi: 10.1177/17534666241231117.
Fractional exhaled nitric oxide (FeNO) measured at multiple exhalation flow rates can be used as a biomarker to differentiate central and peripheral airway inflammation. However, the role of alveolar nitric oxide (CaNO) indicating peripheral airway inflammation remains unclear in gastroesophageal reflux-associated cough (GERC).
We aimed to characterize the changes in alveolar nitric oxide (CaNO) and determine its clinical implication in GERC.
This is a single-center prospective observational study.
FeNOs at exhalation flow rates of 50 and 200 ml/s were measured in 102 patients with GERC and 134 patients with other causes of chronic cough (non-GERC). CaNO was calculated based on a two-compartment model and the factors associated with CaNO were analyzed. The effect of anti-reflux therapy on CaNO was examined in 26 GERC patients with elevated CaNO.
CaNO was significantly elevated in GERC compared with that in non-GERC (4.6 ± 4.4 ppb 2.8 ± 2.3 ppb, < 0.001). GERC patients with high CaNO (>5 ppb) had more proximal reflux events (24 ± 15 9 ± 9 episodes, = 0.001) and a higher level of pepsin (984.8 ± 492.5 634.5 ± 626.4 pg/ml, = 0.002) in sputum supernatant than those with normal CaNO. More GERC patients with high CaNO required intensified anti-reflux therapy (χ = 3.963, = 0.046), as predicted by a sensitivity of 41.7% and specificity of 83.3%. Cough relief paralleled a significant improvement in CaNO (8.3 ± 3.0 4.8 ± 2.6 ppb, < 0.001).
Peripheral airway inflammation can be assessed by CaNO measurement in GERC. High CaNO indicates potential micro-aspiration and may predict a necessity for intensified anti-reflux therapy.
在多个呼气流量下测量的呼出气一氧化氮分数（FeNO）可用作区分中心和外周气道炎症的生物标志物。然而，在胃食管反流相关性咳嗽（GERC）中，肺泡一氧化氮（CaNO）作为外周气道炎症的指标的作用仍不清楚。
我们旨在描述肺泡一氧化氮（CaNO）的变化，并确定其在 GERC 中的临床意义。
这是一项单中心前瞻性观察性研究。
在 102 例 GERC 患者和 134 例其他慢性咳嗽（非 GERC）患者中测量了呼气流量为 50 和 200ml/s 时的 FeNO。根据双室模型计算 CaNO，并分析与 CaNO 相关的因素。在 26 例 CaNO 升高的 GERC 患者中检查了抗反流治疗对 CaNO 的影响。
与非 GERC 相比，GERC 患者的 CaNO 明显升高（4.6±4.4ppb 2.8±2.3ppb， < 0.001）。CaNO 升高（>5ppb）的 GERC 患者近端反流事件更多（24±15 9±9 次， = 0.001），痰上清液中胃蛋白酶水平更高（984.8±492.5 634.5±626.4pg/ml， = 0.002）。更多的 GERC 患者需要强化抗反流治疗（χ ²=3.963， = 0.046），这与 41.7%的敏感性和 83.3%的特异性相符。咳嗽缓解与 CaNO 的显著改善平行（8.3±3.0 4.8±2.6ppb， < 0.001）。
在 GERC 中可以通过 CaNO 测量来评估外周气道炎症。高 CaNO 表明潜在的微吸入，并可能预测需要强化抗反流治疗。
