Terheggen-Lagro Suzanne W, Bink Marielle W, Vreman Hendrik J, van der Ent Cornelis K
Department of Pediatric Pulmonology, University Medical Center, Internal Postal Code KH 01.419.0, PO-Box 85090, 3508 AB Utrecht, The Netherlands.
Am J Respir Crit Care Med. 2003 Nov 15;168(10):1227-31. doi: 10.1164/rccm.200302-248OC. Epub 2003 Sep 4.
Several factors influence levels of end-tidal carbon monoxide (ETCO). We studied determinants of ETCO corrected for inhaled CO (ETCOc) levels in healthy control subjects and compared ETCOc levels and determinants between healthy control subjects and patients with cystic fibrosis (CF). Thirty healthy control subjects (mean +/- SD age, 23 +/- 6 years) and twenty clinically stable patients with CF, aged 13.5 +/- 3.5 years were included. ETCO was measured with the CO-STAT End-Tidal Breath Analyzer (Natus Medical, Inc., San Carlos, CA), and determinants included lung volume (measured with the multiple-breath helium wash-in method), CO-diffusion capacity, and different expiratory flow rates. In healthy control subjects we found a significant correlation between ETCOc and lung volume (r = 0.64, p < 0.05) and with CO-diffusion capacity uncorrected for VA (r = 0.48, p = 0.02). There was no expiratory flow rate dependency in either group. Patients with CF showed no difference in ETCOc levels compared with control subjects (mean 1.2 +/- 0.4 ppm vs. 1.3 +/- 0.4 ppm, p = 0.32), but patients with CF had lower total lung capacity-helium than healthy control subjects. ETCOc corrected for lung volume was significantly higher in patients with CF compared with control subjects (p < 0.001). We hypothesize that a possible increase in breath CO caused by airway inflammation might be masked by differences in lung volumes between control subjects and patients with CF.
多种因素会影响呼气末一氧化碳（ETCO）水平。我们研究了健康对照受试者中经吸入一氧化碳校正后的ETCO（ETCOc）水平的决定因素，并比较了健康对照受试者与囊性纤维化（CF）患者之间的ETCOc水平及决定因素。纳入了30名健康对照受试者（平均±标准差年龄，23±6岁）和20名临床稳定的CF患者，年龄为13.5±3.5岁。使用CO-STAT呼气末呼吸分析仪（Natus Medical，Inc.，圣卡洛斯，加利福尼亚州）测量ETCO，决定因素包括肺容量（用多次呼吸氦气吸入法测量）、一氧化碳弥散能力和不同的呼气流量。在健康对照受试者中，我们发现ETCOc与肺容量之间存在显著相关性（r = 0.64，p < 0.05），与未经VA校正的一氧化碳弥散能力之间也存在显著相关性（r = 0.48，p = 0.02）。两组中均不存在呼气流量依赖性。CF患者与对照受试者相比，ETCOc水平无差异（平均1.2±0.4 ppm对1.3±0.4 ppm，p = 0.32），但CF患者的肺总量-氦含量低于健康对照受试者。校正肺容量后的ETCOc在CF患者中显著高于对照受试者（p < 0.001）。我们推测，气道炎症导致的呼气一氧化碳可能增加可能被对照受试者与CF患者之间肺容量的差异所掩盖。
