Eur Heart J. 2017 Apr 14;38(15):1159-1168. doi: 10.1093/eurheartj/ehx099.
The purpose of the current trial was to test the hypothesis that breathing oxygen-enriched air increases exercise performance of patients with pulmonary arterial or chronic thrombo-embolic pulmonary hypertension (PAH/CTEPH) and to investigate involved mechanisms.
Twenty-two patients with PAH/CTEPH, eight women, means ± SD 61 ± 14 years, resting mPAP 35 ± 9mmHg, PaO2 ambient air >7.3 kPa, underwent four bicycle ergospirometries to exhaustion on different days, while breathing oxygen-enriched (FiO2 0.50, hyperoxia) or ambient air (FiO2 0.21, normoxia) using progressively increased or constant load protocols (with 75% maximal work rate under FiO2 0.21), according to a randomized, sham-controlled, single-blind, cross-over design. ECG, pulmonary gas-exchange, arterial blood gases, cerebral and quadriceps muscle tissue oxygenation (CTO and QMTO) by near-infrared spectroscopy were measured. In ramp exercise, maximal work rate increased from 113 ± 38 W with normoxia to 132 ± 48 W with hyperoxia, mean difference 19.7 (95% CI 10.5-28.9) W, P < 0.001. Constant load exercise endurance increased from 571 ± 443 to 1242 ± 514 s, mean difference 671 (95% CI 392-951) s, P < 0.001. At end-exercise with hyperoxia PaO2, CTO, QMTO, and PaCO2 were increased, and ventilatory equivalents for CO2 were reduced while the physiological dead space/tidal volume ratio remained unchanged.
In patients with PAH/CTEPH, breathing oxygen-enriched air provides major increases in exercise performance. This is related to an improved arterial oxygenation that promotes oxygen availability in muscles and brain and to a reduction of the excessive ventilatory response to exercise thereby enhancing ventilatory efficiency. Patients with PAH/CTEPH may therefore benefit from oxygen therapy during daily physical activities and training.
clinicaltrials.gov Identifier: NCT01748474.
本试验旨在验证吸入富氧空气可提高肺动脉高压或慢性血栓栓塞性肺动脉高压（PAH/CTEPH）患者运动能力这一假说，并探讨其相关机制。
22 名女性 PAH/CTEPH 患者（平均年龄 61±14 岁，静息肺动脉压 35±9mmHg，环境空气中 PaO2＞7.3kPa），采用随机、假对照、单盲、交叉设计，分别在不同天内使用递增或恒负荷方案（在 FiO2 0.21 下使用 75%最大工作率），进行 4 次自行车运动直至力竭。患者分别在吸入富氧（FiO2 0.50，高氧）或环境空气（FiO2 0.21，常氧）时进行试验。试验过程中，连续监测心电图、肺气体交换、动脉血气、近红外光谱测定的脑和股四头肌组织氧饱和度（CTO 和 QMTO）。在斜坡运动中，常氧下的最大工作率从 113±38 W 增加到高氧下的 132±48 W，平均差值为 19.7（95%CI 10.5-28.9）W，P＜0.001。恒负荷运动耐力从 571±443 s 增加到 1242±514 s，平均差值为 671（95%CI 392-951）s，P＜0.001。高氧下运动结束时，PaO2、CTO、QMTO 和 PaCO2 增加，CO2 通气当量降低，而生理无效腔/潮气量比保持不变。
在 PAH/CTEPH 患者中，吸入富氧空气可显著提高运动能力。这与动脉血氧合改善有关，改善的动脉血氧合可促进肌肉和大脑的氧供应，并减少运动时过度的通气反应，从而提高通气效率。PAH/CTEPH 患者可能受益于日常体力活动和训练时的氧疗。
clinicaltrials.gov 标识符：NCT01748474。
