A volume-controlled continuous mandatory ventilation was simulated with a constant inspiratory flow, a tidal volume of 0.65 L, a breathing frequency of 15 breaths per minute, an inspiration time of 1.3 seconds, a post-expiratory pause of 0.3 seconds, and an expiration time of 2.4 seconds.
They were divided into two groups based on postbronchodilator (Post BD) forced expiratory volume in one second, PostBDFEV1 % predicted: ≥70% (Non-Fixed Obs) and < 70% (Fixed Obs).
Patients with New York Heart Association (NYHA) class I-III HF [ 45] and moderate-severe COPD (defined as post bronchodilator Forced Expiratory Volume (FEV1) in 1 sec < 80% predicted, FEV1/Forced Vital Capacity ratio < 70% and history of smoking) were eligible for inclusion.
Lung function parameters including post-bronchodilator forced expiratory volume in one second (FEV1), post-bronchodilator forced vital capacity (FVC), and the ratio of FEV1/FVC were reduced in the cases compared to controls.
* change from the post-bronchodilation baseline value FEV1 = post-bronchodilation forced expiratory volume in one second; ΔSpO2 = oxygen saturation average changes; MRC = Medical Research Council; 6MWT = six minutes walking test; ΔBorg6MWT = Borg dyspnea score change after 6MWT.
At screening, they were required to have a post-bronchodilator forced expiratory volume in 1 s (FEV1) ≥30%and<80%0% predicted normal and post-bronchodilator FEV1/forced vital capacity (FVC) ratio <0.70.
Criteria for enrolment included age between 40 75 years, post-bronchodilator forced expiratory volume in one second (FEV1) < 80% of normal predicted, post-bronchodilator FEV1/forced vital capacity (FVC) ≤ 0.7 and smoking history ≥ 10 pack-years.
To be eligible, patients were required to be aged between 40 and 80 years, exhibiting a clinical history of COPD, have a smoking history of ≥10 pack-years, a post-bronchodilator forced expiratory volume in one second (FEV1)/forced vital capacity ratio of ≤0.70 and a post-bronchodilator FEV1 ≥40%and≤80%0% predicted (GOLD stage II/III).
Patients aged ≥40 years with COPD and a smoking history of >10 pack-years could be recruited if they had a post-bronchodilator forced expiratory volume in 1 s (FEV1) of ≥30% and <80% of the predicted normal and a post-bronchodilator FEV1/forced vital capacity (FVC) of <70% at screening (Global initiative for chronic Obstructive Lung Disease [GOLD] 2 3).
Results: Mean age was 60.6 (S.D. 9.5) years, post-bronchodilator forced expiratory volume in 1 s (FEV1) 65.6 (S.D. 15.7) % predicted.
Post-bronchodilator Forced Expiratory Volume in one second (FEV1), Forced Vital Capacity (FVC) and FEV1/FVC ratio are assessed.
