Author(s): LE PORCHOU, L., CHEHERE, B., SOULET, A., PAGLIA, O., SIMON, B., GIROUX-METGES, M.A., MANSOURATI, J., Institution: UNIVERSITÉ DE BREST - CHRU DE BREST - ORPHY EA 4324, Country: FRANCE, Abstract-ID: 691

INTRODUCTION:
Exercise tests are routinely used to assess the evolution of exercise tolerance following a rehabilitation in patients with cardiopulmonary diseases. Among all these tests, it was previously reported that walking endurance time (the time a person is able to walk at a constant, personalized intensity) is the most sensitive endurance parameter to assess the effects of rehabilitation. Difficulty lies in the feasibility of the method: it must be quick to set up for care teams and should last less than 10 minutes. The reference method (Endurance Shuttle Walk Test [ESWT]) is time-consuming as the walking speed is determined following two Incremental Shuttle Walk Test (ISWT). In this study, we propose a walking endurance test using the average speed measured during the 6-minute walk test (6MWT) which is already performed routinely and less time-consuming. The aims of this study are (1) to compare the walking speed and the feasibility of the two methods: ESWT using the two ISWT (SWTISWT) versus ESWT using the 6MWT (SWT6MWT), (2) to compare the cardiorespiratory adaptations during the tests and (3) to assess the reproducibility and learning effect of the SWT6MWT.
METHODS:
Forty-four patients (age: 64 ± 10 years) with heart failure (n=16, Left Ventricle Ejection Fraction: 41 ± 10 %) or chronic obstructive pulmonary disease (n=28, Forced Expiratory Volume in the 1st second: 53 ± 14 %predicted) were recruited from Brest University Hospital and underwent 4 visits over a 4-week period:
- Visit 1: two 6MWT,
- Visit 2: two ISWT and one ESWT using the ISWT (SWTISWT),
- Visits 3 and 4: two ESWT using the 6MWT (SWT6MWT).
For each test, endurance time, heart rate (HR), respiratory rate (RR), tidal volume (VT), minute ventilation (VE), pulse oxygen saturation (SpO2), dyspnea and fatigue (modified Borg scale) were assessed.
RESULTS:
(1) The SWT6MWT showed a higher speed when compared to SWTISWT (5.1 ± 1.1 vs. 4.3 ± 0.7 km.h-1, respectively; p<0.001); a smaller duration (263 ± 196 vs. 995 ± 338 sec, respectively; p<0.001) and a higher proportion of patients with endurance time under 10 minutes (71% vs. 19%, respectively; p<0.001).
(2) The SWT6MWT showed a higher SpO2 when compared to SWTISWT (92 ± 4 % vs. 90 ± 5 %, respectively; p=0.006); a higher RR (32 ± 6 vs. 30 ± 5 cycles.min-1, respectively; p=0.017) and a higher dyspnea score (5 ± 1 vs. 4 ± 1, respectively; p=0.002).
(3) The four SWT6MWT, whether separated by recovery time (30 minutes) or several days, were not significantly different (p=0.820).
CONCLUSION:
Using the 6MWT to personalize the endurance test intensity can be achieved for cardiorespiratory patients. The SWT6MWT seems to be a quick to set up and a feasible method with a higher proportion of patients having an endurance time under 10 minutes that of SWTISWT. The higher speed of SWT6MWT compared to SWTISWT means a higher RR and dyspnea score but also allows patients to desaturate less during their test. Finally, the SWT6MWT is a reproducible method with no learning effect.