Respiratory Medicine Department, University of Thessaly Medical School, Larissa, Greece.
Respir Res. 2011 May 22;12(1):67. doi: 10.1186/1465-9921-12-67.
Endogenous airway acidification, as assessed by exhaled breath condensate (EBC) pH, is present in patients with stable COPD. The aim of this study was to measure EBC pH levels in a large cohort of COPD patients and to evaluate associations with functional parameters according to their smoking status.EBC was collected from 161 patients with stable COPD and 112 controls (current and ex-smokers). EBC pH was measured after Argon deaeration and all subjects underwent pulmonary function testing.EBC pH was lower in COPD patients compared to controls [7.21 (7.02, 7.44) vs. 7.50 (7.40, 7.66); p < 0.001] and ex-smokers with COPD had lower EBC pH compared to current smokers [7.16 (6.89, 7.36) vs 7.24 (7.09, 7.54), p = 0.03]. In ex-smokers with COPD, EBC pH was lower in patients with GOLD stage III and IV compared to patients with stage I disease (p = 0.026 and 0.004 respectively). No differences were observed among current smokers with different disease severity. EBC pH levels in ex-smokers were associated with static hyperinflation (as expressed by IC/TLC ratio), air trapping (as expressed by RV/TLC ratio) and diffusing capacity for carbon monoxide, whereas no associations were observed in current smokers.Endogenous airway acidification is related to disease severity and to parameters expressing hyperinflation and air trapping in ex-smokers with COPD. The possible role of EBC pH in COPD needs to be further evaluated in longitudinal studies.
内源性气道酸化，通过呼出气冷凝液（EBC）pH 值来评估，存在于稳定期 COPD 患者中。本研究的目的是测量大量 COPD 患者的 EBC pH 值，并根据吸烟状况评估其与功能参数的相关性。
收集了 161 例稳定期 COPD 患者和 112 例对照者（现吸烟者和既往吸烟者）的 EBC。在氩气脱气后测量 EBC pH 值，所有受试者均进行肺功能测试。
与对照组相比，COPD 患者的 EBC pH 值更低[7.21（7.02，7.44）比 7.50（7.40，7.66）；p<0.001]，且与 COPD 合并现吸烟者相比，EBC pH 值更低的既往吸烟者更多[7.16（6.89，7.36）比 7.24（7.09，7.54），p=0.03]。在 COPD 合并既往吸烟者中，EBC pH 值在 GOLD 分期 III 和 IV 患者中低于 I 期疾病患者（p=0.026 和 0.004）。在不同疾病严重程度的现吸烟者中，未观察到差异。EBC pH 值在既往吸烟者中与静态过度充气（以 IC/TLC 比值表示）、空气潴留（以 RV/TLC 比值表示）和一氧化碳弥散量相关，而在现吸烟者中未观察到相关性。
内源性气道酸化与疾病严重程度以及 COPD 合并既往吸烟者的过度充气和空气潴留参数相关。EBC pH 值在 COPD 中的可能作用需要在纵向研究中进一步评估。
