Hyperventilation and head injury: controversies and concerns.

The use of hyperventilation for the treatment of severe head injuries has been the standard of care for more than two decades in the prehospital, emergency department and critical care settings. Controversy has surrounded its use, even when advocates recommended use for all unconscious, head-injured patients. Autoregulation, cerebral acidosis control, reduction of elevated intracranial pressure and the "steal phenomenon" were thought to be beneficial effects of hyperventilation therapy. Current researchers and developments in technology, however, have provided controversial information which suggests that hyperventilation therapy can be harmful, warranting the need for careful monitoring and selective treatment. This information calls into question the use of unmonitored hyperventilation therapy in the prehospital and early hospital settings.