Postural relief of dyspnoea is associated with improved neuromechanical coupling in patients with advanced COPD

Background Patients with advanced chronic obstructive pulmonary disease (COPD) often report that adopting a specific body posture improves their dyspnoea. Exploring the underlying mechanisms could enhance our understanding of the origin of this symptom and approaches towards its alleviation. Methods Pulmonary function tests and detailed sensory-mechanical measurements, including gastroesophageal catheter-based crural diaphragm electromyography (surrogate for inspiratory neural drive) and respiratory manometry, were performed in 16 patients (9M; age: 66±7 years) with advanced COPD (FEV 1 =36±16% predicted; residual volume/total lung capacity: 55±11%) while adopting their most favourable (MF) and least favourable (LF) postures. Results The MF postures included sitting upright (56%), sitting with arms on knees in a forward-leaning position (25%), standing (13%), and lying with three pillows (6%). About two-thirds of patients choose the supine posture as the LF posture. There were no significant differences in minute ventilation and inspiratory capacity between MF and LF postures ( p >0.05). Compared to LF, MF postures were associated with a) increased dynamic lung compliance, b) lower transdiaphragmatic pressures, and c) reduced total work of breathing, leading to d) decreased inspiratory neural drive to the diaphragm and e) improved neuromechanical and neuroventilatory coupling (all p <0.05). The decrease in the “ difficulty breathing in ” dyspnoea qualifier when assuming the MF posture correlated with corresponding improvements in neuromechanical (r=0.62, p=0.01) and neuroventilatory uncoupling (r=0.57, p=0.02). Conclusion Healthcare professionals should evaluate the benefits of positional therapy for reducing dyspnoea in patients with COPD. Incorporating postural interventions into rehabilitation or using them at night may help lessen symptoms and improve quality of life.