2. Field exercise tests The pro’s and the Cons Sally Singh
University Hospitals of Leicester NHS Trust & Coventry University
3. Exercise tests & physical activity
4. Pro’s and Cons Why use an exercise test
What field tests are available
The pro’s (& their clinical usefulness)
8. ‘The gold standard’
9. Additional monitoring During exercise test
Metabolic & ventilatory responses
Heart rate monitoring
Additional performance measures
10. The six minute walk test (6MWT)
11. The six minute walk test (6MWT) Unobstructed course (variable distance)
Standardised instructions (own pace, ? habitual pace)
A least two practice walks
Supervise from behind
Monitor oximetry/ heart rate
End exercise Borg
Results in metres
14. 6 MWT or the SWT ? Aim – to compare pulmonary gas exchange response to the 6MWT and the ISWT.
Assumption- the ISWT may more accurately reflect maximum exercise capacity & the 6MWT endurance capacity.
Results – SWT linear increase with cardio-respiratory parameters, 6MWT exponential increase
- SWT provides data close to laboratory tests (peak VO2 r=0.86)
- if issues around endurance capacity , 6MWT may be test of choice
(? Comparison of the 6MWT and the ESWT)
Onorati P et al Eur J Appl Physiol 2003;89:331-336
15. Physiological responses to exercise tests
16. The Pro’s Simple to conduct
Response compares well to laboratory based test
But – are they clinically useful
17. Field exercise tests - Distance Definition of disability
Threshold for surgery
Prescription of exercise programme
Prescription of oxygen
Response to bronchodilators
19. Minimum clinically important difference Six minute walking test
54 m (95% CI: 37 to 71 m)- to stop rating themselves as "about the same" and start rating themselves as either "a little bit better" or "a little bit worse"
(n = 112, mean age = 67 yr, mean FEV1 = 975 ml)
Redelmeier DA et al Am J Crit Care Med 1997;155:1278-82
24. Comparison of the 6MWT & ESWT to pulmonary rehabilitation
26. Walking versus cycling: sensitivity to bronchodilation in chronic obstructive pulmonary disease Pepin V et al Am J Respir Crit Care Med 2005 No consensus for exercise testing to evaluate functional impact of bronchodilator therapy
N=17 ESWT and cycle endurance test at 80%
Prior administration of ipratropium bromide (randomised, double blind)
Cycling time did not improve, despite increase in FEV1
28. Assessment for surgery Walking distance may be a pre-operative indicator for surgery.
Prior to lung volume reduction surgery (LVRS) less than 200m on the 6MWT or 150m on the ISWT predicts an unacceptable operative risk.
29. Prognostic value of field exercise tests The 6 minute walk distance: change over time and value as a predictor of survival in severe COPD.
Pinto-Plata V et al Eur Respir J 2004 23:28-33
N= 198 patients with severe COPD, 41 age matched controls
Followed up for 2 years
6MWT distance decreased from 238m to 218m
Non survivors (42%) had a more pronounced change in distance
(-40m/year vs –22m/year) despite similar decline in FEV1
Conclusion- 6MWT independently predicts for survival after accounting for age, BMI , FEV1 and other co-morbidities
ILD – desaturation on exercise test below 88% associated with higher mortality (lama et al 2003)
CHF – SWT higher predictive value than the 6MWT for event free survival
32. The con’s
33. The problems
34. Variability in performance of timed walk tests in pulmonary rehabilitation programs Elpern EH et al Chest 2000;118:98-105
35. Variability in performance of timed walk tests in pulmonary rehabilitation programs Elpern EH et al Chest 2000;118:98-105
36. Six minute waking distance in chronic obstructive pulmonary disease- reproducibility and effect of walking course layout and length. Sciurba F et al Am J Resp Crit Care Med 2003;167:1522-1527 6 mwt completed on 761 pts for the NETT LVRS trial.
476 repeated test on a second day (mean difference 66.1 feet, p<0.0001, average 7.0%, 70% of patients increased. 14.9%)
Circular or oval course resulted in increase of 92.2ft compared to course back and forth along corridor!!