Measurement of neural respiratory drive in patients with COPD

Respir Physiol Neurobiol. 2005 Apr 15;146(2-3):165-74. doi: 10.1016/j.resp.2004.12.014.


Assessment of neural respiratory drive may be useful in patients with chronic obstructive pulmonary disease (COPD) for diverse clinical and academic reasons. We hypothesised that the oesophageal diaphragm EMG during CO2 rebreathing and treadmill exercise could be used for this purpose. The oesophageal catheter consisted of nine consecutive recording electrode coils, which formed five pairs of electrodes with an inter-electrode distance 3.2 cm within a recording pair. Each coil was 1cm in length and the gap between adjacent coils was 0.5 mm. Maximal isometric contractions at functional residual capacity (FRC) and maximal voluntary inspirations from FRC to total lung capacity (TLC) were performed. All subjects performed CO2 rebreathing until end-tidal CO2 was approximately 9% or they became intolerably breathless. There was a good linear relationship between peak of root mean square (RMS) of the diaphragm EMG and end-tidal CO2 (r = 0.92 +/- 0.06) during CO2 rebreathing. The method was also shown to be feasible during exercise. It is concluded that the diaphragm EMG recorded from an oesophageal electrode is a useful technique to assess neural respiratory drive in patients with COPD.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Carbon Dioxide / pharmacology
  • Diaphragm / physiopathology*
  • Dose-Response Relationship, Drug
  • Electrodes
  • Electromyography / methods
  • Exercise / physiology
  • Exercise Test / methods
  • Female
  • Functional Residual Capacity
  • Humans
  • Lung Volume Measurements / methods
  • Male
  • Maximal Voluntary Ventilation / drug effects
  • Maximal Voluntary Ventilation / physiology
  • Middle Aged
  • Muscle Contraction / drug effects
  • Muscle Contraction / physiology
  • Pulmonary Disease, Chronic Obstructive / physiopathology*
  • Respiratory Mechanics / physiology*
  • Signal Detection, Psychological
  • Total Lung Capacity / physiology


  • Carbon Dioxide