Pulmonary Rehabilitation in Patients with COPD (6)
The EMG signals were amplified 3,000 to 10,000 times (Tonnies amplifier) and subsequently passed through a band-pass filter of 10 to 400 Hz. To minimize the influence of the electrocardiogram, especially the QRS complex, samples of 250 ms were taken 100 ms after the detection of a QRS complex. Cheap Diskus Advair
A Fourier analysis of the EMG signal provides a histogram of the contribution of the various frequencies to the total electrical power of the EMC. The peak of this histogram is the centroid frequency (Fc). As a muscle fatigues, the contribution of the lower frequencies to the total power increases. As a result, Fc decreases. The rate of decline per unit of time (seconds) can be quantified by the tangent of Fc/time (tgFc) and can be used as an EMG-derived parameter of muscle fatigue. The more negative tgFc, the faster a muscle fatigues.
With each sample, Fc of the power spectrum of the diaphragm (FCDIA) and the intercostal muscles (FJC) was calculated.
Endurance Test of the Inspiratory Muscles: After measuring PImax, the patients were instructed to make static inspiratory maneuvers into an almost occluded mouthpiece, which was connected to the manometer (Validyne). A small leak prevented the patients from using their buccal muscles for generating negative pressures.