If the primary assessment indicates signs of impending cerebral herniation, hypertonic osmostic solutions (e.g. hypertonic saline, mannitol) may be administered urgently. In addition, tracheal intubation and mechanical ventilation are commenced to protect the airway, avoid hypoxaemia and to avoid hypercarbia – usually by instituting mild hyperventilation (PaCO2 35 mmHg / 4.7 kPa approximately). Deep sedation is desirable while avoiding arterial hypotension. To prevent cerebral hypoperfusion and secondary brain injury, arterial blood pressure is maintained at normal to upper normal values (e.g. mean arterial pressure of 90 mmHg or higher) - often achieved with infusion of a vasopressor. In the situation where these urgent measures are being taken to treat impending cerebral herniation, urgent consultation with neurosurgery with a view to possible specific e.g. surgical intervention is indicated.