Chest Department, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium.
J Breath Res. 2019 Apr 1;13(3):036002. doi: 10.1088/1752-7163/ab0a14.
Besides its role as an inflammatory marker in asthma, fractional exhaled nitric oxide (FNO) provides information on the extent of the airway obstruction process through evaluating its change after bronchodilation.
To investigate whether FNO change after bronchodilation can identify different sites of airway obstruction in COPD patients.
FNO, FEV and the slopes (S) of the alveolar plateau of the single breath washout test (SBWT) were measured in 61 stable COPD patients (FEV 34.5% predicted) before and after the inhalation of 400 μg salbutamol. SBWT used Helium (He), and sulfur-hexafluoride (SF). Obstruction relief occurring in pre-acinar and intra-acinar small airways is expected to decrease S and S, respectively. Indices changes (Δ) after bronchodilation were expressed as a percentage of pre-bronchodilation values.
FNO stability (∣ΔFNO∣ ≤ 11%) was observed in 19 patients [-2.7(6.7)%] [mean (SD)] (NO = group); ΔFNO > 11% [+37.4(27.7)%] in 20 patients (NO+ group) and ΔFNO < -11% in 22 patients [-31.2(9.8)%] (NO- group). A similar ΔFEV (p = 0.583; [+9.4(9.6)%]) was found in the three groups. In NO = and NO+ groups, neither S nor S changed; in NO- both S [-12.4(27.5)%, p = 0.007] and S [-20.2(20.4)%, p < 0.001] significantly decreased.
Different patterns of FNO response to β -agonists were observed in COPD most likely depending on the extent of the dilation process. A profile of airway obstruction with an extensive β -agonist response down to lung periphery is identified by FNO reduction after acute bronchodilation in 30% of COPD patients. The clinical relevance of this profile requires further investigation.
除了作为哮喘中的炎症标志物之外，呼出气一氧化氮分数（FENO）通过评估支气管扩张后其变化还可以提供气道阻塞过程程度的信息。
研究支气管扩张后 FENO 的变化是否可以识别 COPD 患者不同部位的气道阻塞。
61 例稳定期 COPD 患者（FEV 预测值 34.5%）吸入 400μg 沙丁胺醇前后，分别测量其呼出气一氧化氮（FENO）、用力肺活量（FEV）和单次呼吸氦气（He）或六氟化硫（SF）肺量计冲洗试验（SBWT）的肺泡平台斜率（S）。预计支气管扩张后，前腺泡和腺泡内小气道的阻塞缓解会分别降低 S 和 S。支气管扩张后指标的变化（Δ）表示为与支气管扩张前的百分比。
19 例患者（NO 组）FENO 稳定（∣ΔFENO∣≤11%）[-2.7（6.7）%] [平均值（标准差）]；20 例患者（NO+组）ΔFENO>11%[+37.4（27.7）%]；22 例患者（NO-组）ΔFENO<-11%[-31.2（9.8）%]。三组患者的 FEV 变化相似（p=0.583；[+9.4（9.6）%]）。NO=和 NO+组的 S 和 S 均无变化；NO-组的 S [-12.4（27.5）%，p=0.007]和 S [-20.2（20.4）%，p<0.001]均显著降低。
COPD 患者对β-激动剂的 FENO 反应存在不同模式，这可能取决于支气管扩张的程度。在 30%的 COPD 患者中，急性支气管扩张后 FENO 降低，识别出一种气道阻塞模式，其特征是β-激动剂作用广泛，延伸至肺外周。这种表型的临床相关性需要进一步研究。
