PT  - JOURNAL ARTICLE
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
TI  - Effect of heliox breathing on locomotor and respiratory muscle oxygen delivery during exercise in COPD patients with or without dynamic hyperinflation
DP  - 2011 Sep 01
TA  - European Respiratory Journal
PG  - 379
VI  - 38
IP  - Suppl 55
4099  - http://erj.ersjournals.com/content/38/Suppl_55/379.short
4100  - http://erj.ersjournals.com/content/38/Suppl_55/379.full
SO  - Eur Respir J2011 Sep 01; 38
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.