PT  - JOURNAL ARTICLE
AU  - Kazuyuki Tabira
AU  - Jun Horie
AU  - Hiromasa Fujii
AU  - Toshio Aida
TI  - Skeletal muscle oxygenation during exercise in patients with chronic respiratory failure
DP  - 2012 Sep 01
TA  - European Respiratory Journal
PG  - P846
VI  - 40
IP  - Suppl 56
4099  - http://erj.ersjournals.com/content/40/Suppl_56/P846.short
4100  - http://erj.ersjournals.com/content/40/Suppl_56/P846.full
SO  - Eur Respir J2012 Sep 01; 40
AB  - Background: Muscle oxygenation correlates with systemic oxygen uptake (VO2) in normal subjects, however whether this relationship exists chronic respiratory failure (CRF) patients remains unclear.Objectives:The purpose of this study was to investigate the influence of skeletal muscle oxygenation on VO2 during exercise in CRF patients.Methods: Ten chronic obstructive pulmonary disease and two sequelae of pulmonary tuberculosis patients performed an incremental cycle ergometer exercise test. We measured ventilation, pulmonary gas exchange and SaO2. We also measured tissue oxygen saturation (StO2) in the vastus lateralis with continuous-wave near-infrared spectroscopy. We calculated the muscle oxygen extraction rate (MOER) based on SaO2 and StO2. In addition, we performed regression analysis to examine the relationships between the VO2 obtained during exercise testing and the mean values of SaO2, StO2, heart rate (HR), and MOER for each 30-second interval of the tests. Finally, we analysed the relationships between the peak value of oxygen uptake (VO2peak) and the slopes of HR/VO2, SaO2/VO2, StO2/VO2, and MOER/VO2.Results: With the increasing exercise intensity, many subjects showed a gradual decrease in StO2 and SaO2, but a gradual increase in HR and MOER. VO2 was negatively correlated with StO2 and SaO2, and was positively correlated with HR and MOER. However, VO2peak was not correlated with any of the slopes.Conclusions: VO2 is highly influenced by oxygen utilization in exercising muscles, as well as by blood oxygenation levels and cardiac function. However, the impact of skeletal muscle utilization during exercise on VO2peak varied greatly among the patients.