Helium–oxygen: A versatile therapy to “lighten the load” of chronic obstructive pulmonary disease (COPD)

Breathing helium–oxygen mixtures has a number of favorable physiological effects that could be beneficial in the treatment of both stable and unstable patients with chronic obstructive pulmonary disease (COPD). Helium–oxygen breathing reduces airway resistance, duty cycle, end-expiratory lung volume and intrinsic positive end-expiratory pressure, all leading to a reduction in the work of breathing in patients with airflow limitation. Important hemodynamic effects directly related to the reduction in the work of breathing also occur through enhanced lung–heart interaction. In the unstable patient, these physiological effects may decrease the need for intubation, reduce extubation failure and improve patient outcome. In the stable patient, similar effects lead to reduced dyspnea and improved exercise capacity, potentially enhancing the outcomes of exercise rehabilitation. To date, studies frequently include small sample sizes and less than rigorous methodology, so conclusive evidence regarding the effectiveness of breathing helium–oxygen mixtures for improving health outcomes in patients with COPD remains limited.