Ventilatory support during training improves training benefit in severe chronic airway obstruction.

Background: One mechanism that may limit training effect in chronic obstructive pulmonary disease is the ventilatory limitation and associated dyspnea. Objectives: To minimize ventilatory limitation during training of patients with severe COPD by applying bi-level positive pressure ventilation during training in order to augment training intensity (and effect). Methods: The study group comprised 19 patients (18 males, 1 female) with a mean age of 64 ′ 9 years. Mean forced expiratory volume in 1 second was 32 ′ 4% of predicted, and all were ventilatory-limited (exercise breathing reserve 3 ′ 9 L/min, normal >15 L/min). The patients were randomized: 9 were assigned to training with BiPAP and 10 to standard training. All were trained on a treadmill for 2 months, twice a week, 45 minutes each time, at maximal tolerated load. Incremental maximal unsupported exercise test was performed before and at the end of the training period. Results: BiPAP resulted in an increment of 94 ′ 53% in training speed during these 2 months, as compared to 41 ′ 19% increment in the control group (P < 0.005). Training with BiPAP yielded an average increase in maximal oxygen uptake of 23 ′ 16% (P < 0.005), anaerobic threshold of 11 ′ 12% (P < 0.05) and peak O 2 pulse of 20 ′ 19% (P < 0.05), while peak exercise lactate concentration was not higher after training. Interestingly, in the BiPAP group, peak exercise ventilation was also 17 ′ 20% higher after training (P < 0.05). Furthermore, contrary to our expectation, at any given work rate, ventilation (and tidal volume) in the BiPAP group was higher in the post-training test as compared to the pre-training test, and the end tidal partial pressure of CO 2 at 55 watts was lower, 40 ′ 4 and 38 ′ 4 mmHg respectively (P < 0.05). No improvement in exercise capacity was observed after this short training period in the control group. Conclusion: Pressure-supported ventilation during training is feasible in patients with severe COPD and it augments the training effect. The improved exercise tolerance was associated with higher ventilatory response and therefore lower P E T CO 2 at equal work rates after training.