Resistive breathing training in severe chronic obstructive pulmonary disease. A pilot study.

We studied the effects of resistive breathing in 10 patients with long-standing, severe disabling COPD. Small increases in inspiratory resistive load resulted in diaphragmatic fatigue and failure in all patients. Fatigue was detected using the frequency spectrum analysis of an EMG signal obtained with surface electrodes. Failure was defined as an inward displacement of the abdomen during inspiration, i.e. incoordination of thoracoabdominal motion. The patients trained for one half hour daily for 4 weeks, breathing into a simple device, where they inspired against a resistive load that produced some incoordinated breaths. After 4 weeks this load was increased, if possible, and another 4-week training period started. All patients improved with training, i.e. higher resistances could be tolerated without signs of fatigue and failure. In addition most patients claimed that training had helped them in their daily living; they were able to do more without getting short of breath. The device helped expectoration, possibly owing to the effect of the small expiratory resistance.

Supraphysiological glucocorticoid treatment in hypoxic stress in dogs.

Effects of supraphysiologic methylprednisolone succinate doses on systolic time intervals, hemodynamic performance, and metabolism were studied in normal dogs during normoxia, after 60 min of normocapnic hypoxemia (PAO2 = 30 mm Hg), and reoxygenation. Bolus injections of 30 or 100 mg/kg methylprednisolone did not exert any positive inotropic action during normoxia. Cardiovascular and metabolic changes induced by hypoxia were modified only to a modest and statistically insignificant degree by sustained high levels of methylprednisolone.