TY - JOUR T1 - Effect of heliox breathing on locomotor and respiratory muscle oxygen delivery during exercise in COPD patients with or without dynamic hyperinflation JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - 379 AU - Zafeiris Louvaris AU - Vasilis Andrianopoulos AU - Maroula Vasilopoulou AU - Evgenia Cherouveim AU - Stauroula Spetsioti AU - Andrea Aliverti AU - Helmut Habazettl AU - Peter Wagner AU - Spyros Zakynthinos AU - Ioannis Vogiatzis Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/379.abstract N2 - Background: Dynamic hyperinflation and large intrathoracic pressure swings induce negative hemodynamic effects during exercise in COPD. Heliox breathing reduces the degree of dynamic hyperinflation thereby improving peripheral muscle oxygen delivery. Whether this effect also applies to patients who do not hyperinflate during exercise, is unknown.Methods: 17 COPD patients (n=8 hyperinflators [FEV1=37±4% pred] and n=9 non-hyperinflators [FEV1=48±4% pred]) performed two constant-load exercise tests to the limit of tolerance in air and whilst breathing heliox.Results: The improvement in exercise tolerance by heliox was not different between hyperinflators and non-hyperinflators (by 3.8±1.9 and 4.2±2.0 min, respectively).This is probably due to the finding that systemic oxygen delivery significantly improved in both hyperinflators (from 1.48±0.10 to 1.70±0.13 l/min) and non-hyperinflators (from 1.68±0.12 to 1.93±0.15 l/min); however, the mechanism of improvement was different as heliox improved cardiac output in non-hyperinflators (from 9.3±0.5 to 10.4±0.5 l/min) whilst arterial oxygen content increased only in hyperinflators (from 160±3 to 177±4 mlO2/l). Nonetheless, quadriceps and intercostal muscle oxygen delivery (measured by NIRO+ICG method with arterial sampling) improved significantly and by the same magnitude in both hyperinflators (by 16.6±7.4 and 4.0±1.1 mlO2/min/100g, respectively) and non-hyperinflators (by 17.6±8.2 and 4.5±1.2 mlO2/min/100g, respectively).Conclusion: Heliox improves peripheral and respiratory muscle oxygen delivery in all COPD patients regardless of the occurrence of exercise-induced dynamic hyperinflation. ER -