RT Journal Article
SR Electronic
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
FD European Respiratory Society
SP 379
VO 38
IS Suppl 55
A1 Zafeiris Louvaris
A1 Vasilis Andrianopoulos
A1 Maroula Vasilopoulou
A1 Evgenia Cherouveim
A1 Stauroula Spetsioti
A1 Andrea Aliverti
A1 Helmut Habazettl
A1 Peter Wagner
A1 Spyros Zakynthinos
A1 Ioannis Vogiatzis
YR 2011
UL http://erj.ersjournals.com/content/38/Suppl_55/379.abstract
AB 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.