Respiratory muscle fatigue and breathing pattern

M. Jeffery Mador, M.D., F.C.C.P

The respiratory muscles, like the heart, must work continuously with little opportunity to rest. Palmonary disease increases the load on the respiratory pump while at the same time decreasing the pressuregenerating capacity of the respiratory muscles. If the respiratory muscles are subjected to sufficiently high loads for a prolonged period of time, they will eventually fatigue.

It has been postulated that respiratory muscle fatigue causes the respiratory pump to fail resulting in hypercapnic ventilatory failure.’ This postulate has led to a tremendous interest in respiratory muscle fatigue. In this article, we will focus on the determinants of respiratory muscle fatigue, the effects of respiratory muscle fatigue, the effects of respiratory muscle fatigue on breathing pattern and the clinical signfficance of these changes in breathing pattern.