Koshy Aaron, Pellicori Pierpaolo, Clark Andrew L
Department of Academic Cardiology, Castle Hill Hospital, Cottingham, UK.
Heart. 2016 Apr;102(8):597-601. doi: 10.1136/heartjnl-2015-308932. Epub 2016 Feb 18.
Chronic heart failure is characterised by reduced exercise tolerance. We assessed the effects of different fractions of inspired oxygen (FiO2) on exercise capacity using cycle ergometry to see if there is a dose-response relationship between FiO2 and exercise performance.
This was a single-centre, randomised, single-blinded, cross-over study. Thirty-one patients with chronic heart failure undertook three maximal incremental exercise tests. For each test, a different FiO2 was used: room air (20.9%), 28% or 40%. The patient had to breathe in via a venturi mask allowing the investigator to control the FiO2 and maintain the patient's blinding. The three tests were carried out in random order with a minimum of 4 days' rest between any two tests.
Exercise time increased from (mean±standard deviations) 501±24.9 s on room air to 525±25.1 s (p=0.042) and 536±24.2 (p<0.001) seconds, with FiO2 of 28% and 40%, respectively. Maximal metabolic equivalents were 3.47±0.16 on room air and 3.67±0.16 (p=0.002) and 3.70±0.15 (p<0.001) on 28% and 40% oxygen, respectively. Maximal workload was 78.4±4.5 W on room air and 82.6±4.3 (p=0.021) and 84.2±4.2 (p=0.005) on 28% and 40% oxygen, respectively. Increasing FiO2 resulted in higher mean oxygen saturations during exercise. The mean heart rate during exercise was lower with FiO2 of 28% with no further drop at 40%. Changing FiO2 had no effect on blood pressure.
Increasing FiO2 to 28% or 40% acutely improves exercise capacity in patients with chronic heart failure.
Eudract number: 2014-003380-38; Results.
慢性心力衰竭的特点是运动耐力下降。我们使用自行车测力计评估了不同吸氧分数（FiO2）对运动能力的影响，以观察FiO2与运动表现之间是否存在剂量反应关系。
这是一项单中心、随机、单盲、交叉研究。31例慢性心力衰竭患者进行了三次最大递增运动试验。每次试验使用不同的FiO2：室内空气（20.9%）、28%或40%。患者必须通过文丘里面罩吸气，以便研究者控制FiO2并保持患者的盲态。三次试验按随机顺序进行，任意两次试验之间至少休息4天。
运动时间从室内空气条件下的（均值±标准差）501±24.9秒分别增加到FiO2为28%时的525±25.1秒（p = 0.042）和FiO2为40%时的536±24.2秒（p < 0.001）。最大代谢当量在室内空气条件下为3.47±0.16，在FiO2为28%时为3.67±0.16（p = 0.002），在FiO2为40%时为3.70±0.15（p < 0.001）。最大工作量在室内空气条件下为78.4±4.5瓦，在FiO2为28%时为82.6±4.3瓦（p = 0.021），在FiO2为40%时为84.2±4.2瓦（p = 0.005）。FiO2增加导致运动期间平均血氧饱和度升高。运动期间平均心率在FiO2为28%时较低，在FiO2为40%时无进一步下降。改变FiO2对血压无影响。
将FiO2急性增加到28%或40%可急性改善慢性心力衰竭患者的运动能力。
欧洲临床试验注册号：2014 - 003380 - 38；结果。
