呼气末二氧化碳分压评估特发性肺动脉高压与慢性血栓栓塞性肺动脉高压严重程度的价值

End tidal PCO2 for evaluation of severity of disease in idiopathic pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

目的观察特发性肺动脉高压（IPAH）和慢性血栓栓塞性肺动脉高压（CTEPH）患者的呼气末二氧化碳分压（PETCO2），分析PETCO2评估疾病严重程度的价值。方法回顾性分析2011年10月至2014年10月上海市肺科医院住院治疗的患者120例，其中男45例，女75例，68例为IPAH，52例为CTEPH。所有患者均行右心导管检查、肺功能测试及心肺运动试验，采用病例对照研究方法比较2组患者疾病严重程度，根据世界卫生组织心功能分级（WHO-FC）将2组患者细分为Ⅰ-Ⅱ级亚组和Ⅲ-Ⅳ级亚组，观察PETCO2差异。结果IPAH组平均肺动脉压（mPAP）和肺血管阻力（PVR）[（60±16）mmHg（1mmHg=0．133kPa）、（13±6）Wood U]均高于CTEPH组[（46±12）mmHg、（9±4）Wood U，t值分别为4．90和4．83，均P〈0．01]，峰值摄氧量占预计值％和峰值脉搏氧占预计值％[（45±15）％、（60±22）％]均低于CTEPH组[（53±16）％、（68±21）％，t值分别为-2．42和-1．96，均P〈0．05]。IPAH组PETCO2静息期[（27±5）mmHg]、无氧阈期[（28±7）mmHg]及峰值[（25±7）mmHg]均高于CTEPH组[（24±4）、（23±6）、（21±6）mmHg，t值为3．22-4．54，均P〈0．01]。IPAH组WHO-FC Ⅰ-Ⅱ级和Ⅲ-Ⅳ级亚组间比较无氧阈期和峰值PETCO2差异有统计学意义（t值分别为2．55和2．60，均P〈0．05）；CTEPH组仅PETCO2无氧阈期亚组间有显著差异（t=2．39，P〈0．05），峰值亚组间差异不明显（t=1．71，P〉0．05）。IPAH组PETC02无氧阈期与NT-proBNP呈中度负相关（r=-0．58，P〈0．01），而CTEPH组仅呈弱负相关性（r=-0．34，P=0．02）。结论与CTEPH患者相比，IPAH患者的运动耐力低，PETCO2高，PETCO2在2组患者中均可反映疾病严重程度，但对IPAH患者评估价值更高，PETCO2无氧阈期反映通气效率优于峰值。

Objective To explore the difference in end tidal PCO2 （PET CO2 ） between idiopathic pulmonary arterial hypertension （IPAH） and chronic thromboembolic pulmonary hypertension （CTEPH） , and to analyze the correlation between PET CO2 and the indexes of disease severity in IPAH and CTEPH patients. Methods Data were retrieved from 68 IPAH patients and 52 CTEPH patients who all had received right-heart catheterization, pulmonary function test and cardiopuimonary exercise testing at Shanghai Pulmonary Hospital from October 2011 to October 2014. In addition, other clinical parameters were alsocollected. Results The IPAH group had a significantly higher mPAP, PVR [ （60 ± 16 ） mmHg （1 mmHg =0. 133 kPa）, （13±6） Wood U ] than the CTEPH group [ （46 ± 12） mmHg, （9 ±4） Wood U, t = 4. 90, 4. 83, all P 〈 0. 01 ]. Meanwhile, the IPAH group had a lower percentage of predicted peakVO2, oxygen pulse [ （45 ± 15 ） %, （ 60 ± 22 ） % ] compared with the CTEPH group [ （ 53 ±16 ） %, （68±21）%, t= -2.42, -1.96, allP〈0.05]. The value of PETCO2 at rest, AT, peak in thelPAH patients [ （27 ±5）, （28 ±7）, （25±7） mmHg] were higher than those in the CTEPH patients [ （24±4） mmHg, （23 ±6） mmHg, （21 ±6） mmHg, t =3.22 -4.54, all P 〈0.01]. There was a significantly difference in PETCO2 at AT and peak between WHO-FC Ⅰ-Ⅱ and Ⅲ-Ⅳ subgroups in IPAH （ t = 2. 55, 2. 60, all P 〈0. 05） and CTEPH （t =2. 39, P 〈0. 05）, except for PETCO2 at peak in the CTEPH patients （t = 1.71, P 〉 0. 05 ）. A moderately inverse correlation was found between PET CO2 at AT and NT-proBNP in the IPAH group （r = -0. 58, P 〈 0. 01 ）, meanwhile PETCO2 at AT in the CTEPH group was weakly correlated with NT-proBNP （ r = - 0. 34, P 〈 0. 05 ）. Condusions Compared with the CTEPH patients, the IPAH patients had significantly decreased exercise capacity and increased PETCO2. PETCO2 could reflect the disease severity in both IPAH and CTEPH patients, being superior in IPAH than in CTEPH. Furthermore, PETCO2 at AT might be better than PETCO2 at peak in reflecting the ventilatory efficiency.