Article

Although the six-minute walk test (6MWT) is widely used in cardiac
rehabilitation, little is known about the ventilatory strategies adopted by older
patients who have recently undergone median sternotomy, in order to meet the
increased metabolic demand in the 6MWT. METHODS: Using a portable gas-analyser we
assessed the breathing patterns in the 6MWT before and after a 3-week
rehabilitation programme in 84 older patients, 58 men and 26 women, mean age 71
years (standard deviation (SD) 6 years), who had undergone median sternotomy.
RESULTS: After rehabilitation, patients increased end-test ventilation (33.1 l
(SD 9.8) vs. 30.9 l (SD 8.4), p < 0.001) by increasing tidal volume (1.158 l (SD
0.298) vs. 1.065 l (SD 0.255), p < 0.001), while breathing frequency remained
unchanged (29.9 bpm (SD 5.4) vs. 30.2 bpm (SD 5.8), p = 0.621). As a consequence,
the ventilatory equivalent for CO2, was significantly improved (39.9 (SD 5.3) vs.
43.5 (SD 7.4), p < 0.001). Furthermore, the improvement in ventilatory efficiency
was significantly (p < 0.001) correlated with the improvement in the distance
walked on the 6MWT. CONCLUSION: Older patients who have undergone median
sternotomy meet the increased metabolic demand on the 6MWT after cardiac
rehabilitation by increasing tidal volume. Accordingly, we should consider
including as a routine specific exercises for inspiratory muscle training in
current rehabilitation programmes to reduce inspiratory muscle effort and further
improve ventilatory efficiency.

Langue : ANGLAIS