Hyperbaric oxygen therapy for consciousness disturbance following head injury in subacute phase.

Background: Hyperbaric oxygen (HBO) therapy has been shown to improve outcome after brain injury, however its mechanisms are not understood. The purpose of the present study was to investigate the effect of hyperbaric oxygen (HBO) therapy on the cerebral circulation and metabolism of patients with disturbances in consciousness after head injury in the subacute phase.

Methods: Seven head injury patients underwent HBO treatment after leaving the intensive care unit. Oxygen (100% O2, 2.7 atm absolute) was delivered to patients in a hyperbaric chamber for 60 min every 24 h (total five treatments/patient). Cerebral circulation monitoring (mean flow velocity: mFV, and pulsatility index: PI at horizontal portion of middle cerebral artery by transcranial Doppler) and cerebral metabolism monitoring (arterio-jugular venous difference of oxygen: AJDO2 and jugular venous lactate: lac-JV) before and after the series of treatments were evaluated.

Findings: Both PI and lac-JV were significantly decreased after HBO theatment, while there were no significant changes in mFV and AJDO2. The decreased PI and lac-JV after HBO therapy might indicate that this treatment couples cerebral circulation and metabolism.

Conclusions: The measurement of cerebral circulation and metabolism parameters, especially PI and lac-JV, is useful for estimation of effect of HBO therapy in patients with distubances in consciousness after head injury in the subacute phase.