Inspiratory muscle training followed by non-invasive positive pressure ventilation in patients with severe chronic obstructive pulmonary disease: a randomized controlled trial / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of inspiratory muscle training followed by non-invasive positive pressure ventilation in patients with severe chronic obstructive pulmonary disease (COPD).</p><p><b>METHODS</b>This investigator-initiated randomized, controlled trial recruited 88 patients with stable GOLD stage IV COPD, who were randomized into 4 equal groups to continue oxygen therapy (control group) or to receive inspiratory muscle training followed by non-invasive positive pressure ventilation (IMT-NPPV group), inspiratory muscle training only (IMT group), or noninvasive positive pressure ventilation only (NPPV group) for at least 8 weeks. The outcomes of the patients were assessed including the quality of life (SRI scores), maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), dyspnea (MRC scores), 6-min walking distance (6MWD) and lung function.</p><p><b>RESULTS</b>s Compared to baseline values, SRI scores, 6MWT and MRC scores increased significantly after 8 weeks in IMT-NPPV, IMT and NPPV groups, and the improvements were significantly greater in IMT-NPPV group than in IMT and NPPV groups (P<0.05 for all). In IMT-NPPV and IMT groups, MIP and MEP increased significantly after the training (P<0.05), and the improvement was more prominent in IMT-NPPV group (P<0.05). No significant changes were found in pulmonary functions in the groups after 8 weeks of treatment (P>0.05).</p><p><b>CONCLUSION</b>Inspiratory muscle training followed by non-invasive positive pressure ventilation, compared with inspiratory muscle training or non-invasive positive pressure ventilation alone, can better enhance the quality of life, strengthen the respiratory muscles, improve exercise tolerance and relieve the dyspnea in patients with COPD.</p>

Effects of inhaled short-acting bronchodilators on diaphragm function and neural respiratory drive during maximal isocapnic ventilation in patients with chronic obstructive pulmonary disease / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of inhaled short-acting bronchodilators on diaphragm function and neural respiratory drive in patients with chronic obstructive pulmonary disease (COPD) during maximal isocapnic ventilation (MIV).</p><p><b>METHODS</b>Forty-seven patient with moderate to severe COPD were randomized into 4 groups: placebo group (n=12), salbutamol group (n=13), ipratropium group (n=10), and combined group (salbutamol and ipratropium, n=12). Each subject received an initial MIV for 3 min at baseline and inhaled placebo (400 µg), salbutamol (400 µg), ipratropium (80 µg), or both salbutamol and ipratropium, followed 30 min later by another 3 min of MIV. The parameters of diaphragm function and neural respiratory drive were monitored continuously and calculated during MIV.</p><p><b>RESULTS</b>During the initial MIV, all the patients experienced a linear increase in root mean square (RMS) of diaphragm electromyogram with a gradual decrease in transdiaphragmatic pressure (Pdi), minute ventilation (VE), and VE/RMS, and these parameters all improved significantly after inhalation of the bronchodilators. Compared with the placebo group at the same time point, the 3 bronchodilator-treated groups showed significantly decreased RMS and Borg score and increased Pdi, VE and VE/RMS; VE/RMS was the highest in the combined treatment group (P<0.05). The Delta Borg was significantly correlated with Delta Pdi, Delta VE, Delta RMS, and Delta VE/RMS (P<0.05).</p><p><b>CONCLUSIONS</b>In COPD patients, inhaled short-acting bronchodilators can alleviate diaphragm fatigue during MIV, increase lung ventilation, reduce neural respiratory drive, and improve neuro-ventilatory coupling to relieve dyspnoea, and the combination of β-2 agonists and anti-muscarinic antagonists produces a stronger efficacy.</p>