Inspiratory pressure support prolongs exercise induced lactataemia in severe COPD

Background-A physiological benefit from pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD) is more probable if exercise is perfo rmed above the lactate threshold. This study was undertaken to investigate whether it was possible to extend the lactataemia of exercise using non-inv asive inspiratory pressure support (IPS). Methods-Plasma lactate levels were measured in eight men with severe COPD w ho performed two treadmill walks at an identical constant work rate to a co ndition of severe dyspnoea; the second walk was supported by IPS. Results-Mean plasma lactate levels before the free and IFS assisted walks w ere 1.65 mmol/l and 1.53 mmol/l, respectively (p = NS). Lactate levels incr eased during both walks to 2.96 mmol/l and 2.42 mmol/l , respectively (p = 0.01 for each) but the duration of the IPS assisted walk was significantly greater than the free walk (13.6 minutes versus 5.5 minutes, p = 0.01). Conclusions-Patients with severe COPD can sustain exercise induced lactatae mia for longer if assited with IPS. This technique may prove to be at usefu l adjunct in pulmonary rehabilitation.