Respiratory Drive Response in COPD Patients During Exercise With Non Invasive Ventilation (NIV).

"Patients will perform 10 minutes, constant load, exercise in a cycloergometer. To set the load, a baseline incremental effort test will be performed previously (VISIT 1).~Then, in a separate day (VISIT 2), the subject will perform 10 minutes cycling at the 75% load of that determined as maximum in VISIT 1, at a constant rate of 30 to 35 pedal revolutions per minute, in spontaneous breathing, with low flow oxygen through conventional nasal cannula adjusted to achieve SpO2 between 92to 94%"

VISIT 2 Non invasive mask ventilation: parameters will be titrated during a free cycling period at the end of the spontaneous breathing exercise. Then, in a separate day (VISIT 3), with the same constant load, cycling cadence and under NIV, the patient will perform 10 min of cycling.

With constant flows of 50 lpm and with FiO2 adjusted according to SPO2, to obtain a constant saturation between 92 and 94%. The same pedaling load and frequency will be maintained, with similar variables collected.