Respiratory Research Group, Faculty of Medicine and Human Sciences, The University of Manchester, Manchester Academic Health Science Centre, Manchester, England.
Applied Immunobiology and Transplantation Research Group, Institute of Cellular Medicine, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne, England.
Chest. 2012 Oct;142(4):958-964. doi: 10.1378/chest.12-0044.
Microaspiration is often considered a potential cause of cough. The aim of this study was to investigate the relationship between microaspiration, the degree and type of gastroesophageal reflux, and the frequency of coughing in patients with chronic cough.
One hundred patients with chronic cough (mean [± SD] age, 55.8 years [± 11.0 years]; 65 women) and 32 healthy volunteers (median age, 43.5 years [interquartile range (IQR), 30-50.8 years]; 16 women) were recruited. Patients with chronic cough performed 24-h objective cough frequency with simultaneous esophageal impedance/pH monitoring and measurement of pepsin concentrations in sputum and BAL. Twelve healthy volunteers underwent bronchoscopy/BAL, and 20 underwent impedance/pH monitoring.
Patients with chronic cough had significantly more reflux episodes than healthy volunteers (median, 63.5 reflux episodes [IQR, 52.5-80.0] vs 59.0 [IQR, 41.8-66.0]; P = .03), although the absolute difference was small, and there was no difference in numbers of events extending into the proximal esophagus (median, 17.2% [IQR, 8.0%-26.0%] vs 20.3% [IQR, 5.1%-32.1%]; P = .36). BAL pepsin levels were also similar in chronic cough to control subjects (median, 18.2 ng/mL [range, 0-56.4 ng/mL] vs 9.25 ng/mL [range, 0-46.9 ng/mL]; P = .27). Sputum but not BAL pepsin weakly correlated with the number of proximally occurring reflux events (r = 0.33, P = .045) but was inversely related to cough frequency (r = −0.52, P = .04). Sputum pepsin was, therefore, best predicted by combining the opposing influences of cough and proximal reflux (r = 0.50, P = .004).
Proximal gastroesophageal reflux and microaspiration into the airways have limited roles in provoking chronic cough. Indeed, coughing appears to be protective, reducing pepsin concentration in the larger airways of patients with chronic cough.
微吸入常被认为是咳嗽的潜在原因。本研究旨在探讨微吸入、胃食管反流的程度和类型与慢性咳嗽患者咳嗽频率之间的关系。
招募了 100 名慢性咳嗽患者（平均年龄[±标准差]55.8 岁[±11.0 岁]；65 名女性）和 32 名健康志愿者（中位年龄 43.5 岁[四分位距（IQR），30-50.8 岁]；16 名女性）。慢性咳嗽患者进行 24 小时客观咳嗽频率检测，同时进行食管阻抗/pH 监测和痰液及 BAL 中胃蛋白酶浓度的测量。12 名健康志愿者接受支气管镜检查/BAL，20 名志愿者接受阻抗/pH 监测。
与健康志愿者相比，慢性咳嗽患者的反流发作次数明显更多（中位数，63.5 次反流发作[IQR，52.5-80.0] vs 59.0[IQR，41.8-66.0]；P=0.03），尽管差异较小，且延伸至近端食管的事件数量无差异（中位数，17.2%[IQR，8.0%-26.0%] vs 20.3%[IQR，5.1%-32.1%]；P=0.36）。BAL 中的胃蛋白酶水平在慢性咳嗽患者和对照组之间也相似（中位数，18.2 ng/mL[范围，0-56.4 ng/mL] vs 9.25 ng/mL[范围，0-46.9 ng/mL]；P=0.27）。痰中但不是 BAL 中的胃蛋白酶与近端反流事件的数量呈弱相关（r=0.33，P=0.045），但与咳嗽频率呈负相关（r=-0.52，P=0.04）。因此，通过结合咳嗽和近端反流的相反影响，可更好地预测痰中胃蛋白酶（r=0.50，P=0.004）。
近端胃食管反流和微吸入进入气道在引发慢性咳嗽方面的作用有限。事实上，咳嗽似乎具有保护作用，可降低慢性咳嗽患者大气道中的胃蛋白酶浓度。
