Inspiratory Muscle Training in Patients With Duchenne Muscular Dystrophy: Protocol
The catheters were perfused with distilled water at a constant flow of 25 ml/h. The proximal ends were coupled to pressure transducers (Could-Statham, P23ID, Cleveland). The catheter-pressure transducer system was described in detail previously. The Pdi was calculated by subtracting esophageal pressure (Pes) from the gastric pressure (Pga) by an electronic subtraction circuit. The Pes, Pga, and Pdi were displayed on-line on a four-channel paper recorder (Beckman 511 A, Fullerton, Calif). The Pes, Pga, and Pdi were arbitrarily assigned zero at the start of each sniff trial. Thus, only the change in pressure from the initial position was determined for each sniff. An interval of 30 to 40 s was allowed between e ach sniff and the best of a total of ten maneuvers was used for analysis. buy allegra
Inspiratory Muscle Endurance: The patients were instructed to breathe continuously in cycles at a certain level of inspiratory resistance for 1 min, followed by 20 s of rest. The test was terminated when the Pdi could not be sustained at the target level for three consecutive breaths or when a total of 20 resistive breathing cycles were completed by the patient. The cumulative time of these maneuvers (Те) served as a parameter for inspiratory muscle endurance. A single-lead ECG was monitored throughout the maneuvers. The blood gas values assessed immediately after the resistive breathing cycles showed no worsening in oxygen tension or increase in C02 tension in any patient.
Three months before and at the beginning of training, in the first and third month of training, at the end, and 6 months after its cessation, inspiratory muscle strength and endurance were assessed in both groups. Additionally, serum creatine kinase measurements were done to detect possible muscular damage caused by training. To analyze inspiratory muscle endurance, the initial resistance was adjusted in such a way that 70 percent of the Pdimax value had to be generated with each breath at normal resting flow rates. The Ve and fb had to correspond to the resting Ve and fb, which were assessed earlier over a 10-min time span, during which the patients breathed quietly through the unloaded circuit. The Pes, Pga, and Pdi were recorded online on the paper-recorder to ensure that 70 percent of the Pdimax was generated breath by breath. When the given resistance could be tolerated for more than 15 cycles, the level of resistance was increased to 80 percent of the Pdimax. When it was tolerated for less than 12 cycles, the level was decreased to 60 percent of the Pdimax. For the training patients, the level of resistance was adjusted each month anew, if the patients could meanwhile achieve higher Pdimax values or sustain more than 15 resistive breathing cycles. The hospital-adjusted level of resistance was used for the training at home.