Laboratory techniques for evaluation of respiratory muscle structure, perfusion and metabolism
| Techniques | Invasiveness | Physiology laboratory required | Biology laboratory required | Purpose |
| Near-infrared spectroscopy | None | Yes | No | Muscle blood flow |
| Oxygen cost of breathing | None | Yes | No | Ventilation, oxygen uptake |
| Access to costal diaphragm muscle | Yes, thoracotomy | Yes, always in surgery room | No | Biological and histological analyses |
| Access to parasternal muscles | Yes, thoracotomy | Yes, always in surgery room | No | Biological and histological analyses |
| Access to external intercostals | Yes, open biopsy techniques | Yes, possible in surgery room | No | Biological and histological analyses |
| Immunohistochemical or immunofluorescence analyses | No | Yes | Muscle fibre type and morphometry | |
| Mitochondrial respiratory chain evaluation (respiration procedures) | None | No | Yes | Quantification of mitochondrial respiration (oxygen consumption) |
| Immunoblotting procedures | None | No | Yes | Quantification of protein levels in muscle specimens |
| Quantitative real-time PCR | None | No | Yes | Quantification of gene expression levels in muscle specimens |
| Specific activity assays including mitochondrial enzyme activities | None | No | Yes | Quantification of activity levels of enzymes in muscle specimens |