[Electrophysiology of respiration]

Neurological respiratory insufficiency may be the primary cause of admission to an intensive care unit or may develop during care in an intensive care ward. Severe respiratory insufficiency due to nervous system causes either involves a lack of central drive or weakness of the respiration muscles. The former are induced by a wide variety of encephalopathies and the latter by diseases of anterior horn cells, peripheral nerve, the neuromuscular junction, or muscles of the chest wall or diaphragm. In an intensive care unit, it is often not possible clinically to determine whether there is a lack of central drive or a neuromuscular problem. It is now possible by electrophysiological methods to pinpoint the site of nervous system cause of respiratory insufficiency. This review will describe the various electrophysiological techniques currently available and describe how they have been successfully applied in investigating some conditions that cause severe respiratory failure.