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Protocols and clinical methodology

Protocols and clinical methodology. Paul W. Jones Professor of Respiratory Medicine St George’s Hospital Medical School London, UK. Purpose of cardiopulmonary exercise tests. Measure work (exercise) capacity Investigate breathlessness Measure effect of treatment.

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Protocols and clinical methodology

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  1. Protocols and clinical methodology Paul W. Jones Professor of Respiratory Medicine St George’s Hospital Medical School London, UK

  2. Purpose of cardiopulmonary exercise tests • Measure work (exercise) capacity • Investigate breathlessness • Measure effect of treatment

  3. Measures of exercise capacity • Peak work • Watts • VO2max • Lactate threshold (aerobic capacity) • Endurance

  4. VO2 max Oxygen consumption and work rate VO2 Unloaded pedaling 3 min Zero 0 Work Rate Increase

  5. Measurements every minute Easier to calibrate More reliable Suitable for most purposes Provides many measurements Complex Needs careful setup Suitable for ramp tests More expensive Gas measurements Mixing Chamber Breath-by-breath

  6. Ergometer methodologies

  7. Work rate 1 min Unloaded pedaling 3 min 5-25 watts Zero 0 10 Time (mins) Incremental work rate 0

  8. Ramp protocol (computer controlled ergometer) Work rate Unloaded pedaling 3 min Ramp equivalent to 5-25 watts/min Zero 0 10 Time (mins)

  9. Effect of work increment on peak work Debigaré et al. Medicine & Science in Sports and Exercise. 2000; 32: 1365

  10. Bruce protocol (treadmill) Stage 4 Stage 3 Work rate Stage 2 Stage 1 2-4 mets (about 50 watts) 5 mets Zero 0 10 Time (mins) 0

  11. Balke protocol (treadmill) Walk at constant 5.3 kph Work rate 1 min 1˚ increase in grade (inclination) 0 10 Time (mins) 0

  12. VO2 max Oxygen consumption and work rate VO2 Unloaded pedaling 3 min Zero 0 Work Rate Increase

  13. Symptom-limited VO2 max Oxygen consumption and work rate VO2 Unloaded pedaling 3 min Zero 0 Work Rate Increase

  14. Detection of anaerobic threshold Increased ventilation due to lactate accumulation VE Unloaded pedaling 3 min Zero 0 Anaerobic Threshold VO2

  15. Detection of anaerobic threshold (V-slope method) VCO2 Slope 2 Slope 1 Unloaded pedaling 3 min Zero VO2 0 Anaerobic Threshold

  16. Detection of anaerobic threshold (V-slope method breath-by-breath)

  17. Purpose of cardiopulmonary exercise tests • Measure work (exercise) capacity • Investigate breathlessness • Measure effect of treatment

  18. Incremental tests • Pattern of breathing • Tidal volume • Respiratory Rate • Arterial saturation • Heart rate

  19. COPD Normal Resp. rate Resp. rate Tidal volume Tidal volume Pattern of breathing with increasing work rate

  20. 95 85 75 65 55 45 0.0 0.5 1.0 1.5 Fall in arterial oxygen saturation with exercise SaO2 VO2 (l/min)

  21. Why did they stop? Symptom-limited VO2 max Oxygen consumption and work rate VO2 Unloaded pedaling 3 min Zero 0 Work Rate Increase

  22. Measuring breathlessness Borg CR10 scale Visual analogue scale Maximum imaginable 10 Maximal Very very severe (almost maximal) 8 7 Very severe 6 5 Severe 4 Somewhat severe 3 Moderate 2 Slight 1 Very slight 0.5 Very very slight (just noticeable) None 0 Nothing at all

  23. 7 6 5 4 3 2 1 0 Reasons for stopping exercise (COPD patients) Maximal 10 Perceived severity 9 Dyspnea 8 Legs Very Severe Severe 75% centile Moderate Median 25th centile Dyspnea Legs Both n=30 n=42 n=25 Reason for stopping exercise Killian et al Am Rev Respir Dis 1992; 146: 935-940

  24. Influence of work increment on dyspnoea Debigaré et al. Medicine & Science in Sports and Exercise. 2000; 32: 1365

  25. Steady state tests • Cycle or treadmill • 50-70% of maximum work achieved in incremental test • In practice achieves 50-90% of VO2max

  26. 1/time (sec) Critical Power (sustainable work) Neder et al. Am J Respir Crit Care Med Vol 200; 162: 497–504

  27. Critical Power (sustainable work) Neder et al. Am J Respir Crit Care Med Vol 200; 162: 497–504

  28. VO2 critical power (ml/min) VO2 peak (ml/min) VO2 critical power (ml/min) VO2 anaerobic threshold (ml/min) Critical Power (sustainable work) Controls COPD Neder et al. Am J Respir Crit Care Med Vol 200; 162: 497–504

  29. Dynamic hyperinflation in COPD O’Donnell Am J Respir Crit Care Med 2001; 164:770-7,

  30. Tiotropium Effect of tiotropium on dynamic hyperinflation during exercise Baseline O’Donnell. Eur Respir J 2004; 23: 832–840

  31. End-exercise Iso-time Effect of tiotropium on dyspnoea Baseline Tiotropium

  32. Effect of tiotropium on exercise duration in COPD Tiotropium Placebo O’Donnell et al Eur Respir J 2004; 23: 832–840

  33. Reduction in dynamic hyperinflation and improved exercise in COPD with supplemental oxygen Somfray et al Eur Respir J 2001; 18: 77–84.

  34. Summary • Use 1-minute incremental tests for most routine clinical evaluation • Use endurance tests at 70% maximum to test effects of treatment

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