Background

Patients with unrepaired cyanotic congenital heart disease (CHD) suffer from aggravated hypoxemia during exercise. We tested the hypothesis that supplemental oxygen improves exercise performance in these patients.

Methods

In this randomized, sham-controlled, single-blind, cross-over trial cyanotic CHD-patients underwent four cycle exercise tests to exhaustion, while breathing either oxygen-enriched (FiO₂ 0.50, oxygen) or ambient air (FiO₂ 0.21, air) using incremental (IET) or constant work-rate (CWRET) exercise test protocols (75% of maximal work rate achieved under FiO₂ 0.21). Pulmonary gas-exchange, electrocardiogram, arterial blood gases, oxygen saturation (SpO₂), cerebral and quadriceps muscle tissue oxygenation (CTO and QMTO) by near-infrared spectroscopy were measured.

Results

We included seven patients with cyanotic CHD (4 Eisenmenger syndrome, 3 unrepaired cyanotic defects, 4 women) median (quartiles) age 36 (32;50) years, BMI 23 (20;26) kg/m² and SpO₂ at rest 87 (83;89) %. When comparing supplemental oxygen with air during exercise, maximal work-rate in IET increased from 76 (58;114) Watts to 83 (67;136) Watts, median difference 9 (0;22) W (p = 0.046) and CWRET-time increased from 412 s (325;490) to 468 s (415;553), median increase 56 (39;126) s (p = 0.018). In both IET and CWRET SpO₂ was significantly higher and ventilatory equivalent for carbon dioxide significantly lower at end-exercise with oxygen compared to air, whereas CTO and QMTO did not significantly differ.

Conclusions

Patients with cyanotic CHD significantly improved their exercise performance, in terms of maximal work-rate and endurance time along with an improved arterial oxygenation and ventilatory efficiency with supplemental oxygen compared to air.

中文翻译：

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氧疗对紫绀型先天性心脏病患者运动表现的影响：随机对照试验

背景

未修复的紫绀型先天性心脏病（CHD）患者在运动过程中会出现严重的低氧血症。我们检验了补充氧气可以改善这些患者的运动表现的假设。

方法

在这项随机、假对照、单盲、交叉试验中，紫绀型 CHD 患者在呼吸富氧（FiO ₂ 0.50，氧气）或环境空气（FiO ₂ 0.21，空气) 使用增量 (IET) 或恒定工作率 (CWRET) 运动测试协议（在 FiO ₂ 0.21 下达到的最大工作率的 75%）。通过近红外光谱测量肺气体交换、心电图、动脉血气、氧饱和度 (SpO ₂ )、脑和股四头肌组织氧合 (CTO 和 QMTO)。

结果

我们纳入了 7 名紫绀型 CHD 患者（4 名 Eisenmenger 综合征，3 名未修复的紫绀缺陷，4 名女性）中位（四分位数）年龄 36 (32;50) 岁，BMI 23 (20;26) kg/m ²和 SpO ₂休息时 87 (83;89) %。比较运动期间补充氧气与空气时，IET 的最大工作率从 76 (58;114) 瓦增加到 83 (67;136) 瓦，中位数差异 9 (0;22) W ( p  = 0.046) 和 CWRET-时间从 412 s (325;490) 增加到 468 s (415;553)，中位数增加 56 (39;126) s ( p  = 0.018)。在 IET 和 CWRET中，与空气相比，在运动结束时，氧气的 SpO ₂显着更高，二氧化碳的换气当量显着降低，而 CTO 和 QMTO 没有显着差异。

结论

与空气相比，紫绀型 CHD 患者的运动表现显着提高，包括最大工作率和耐力时间，以及改善动脉氧合和补充氧气的通气效率。