Intracranial hypertension and brain oedema in albino rabbits. Part 3: Effect of acute simultaneous diuretic and barbiturate therapy.

Increased intracranial pressure due to brain oedema was produced in albino rabbits by combining a cryogenic lesion in the left hemisphere with the intraperitoneal administration of 6-aminonicotinamide (cytotoxic agent). The following parameters were assessed: intracranial pressure (ICP), systolic arterial pressure (SAP), central venous pressure (CVP), EEG, brain water and electrolyte content, gross pathology, and blood brain barrier integrity. Acute therapy to reduce ICP was performed by administering a bolus of mannitol (1 gm/kg) and 30 minutes later, also in bolus, frusemide (5 mg/kg). Immediately following the administration of mannitol an infusion of pentobarbitone was commenced; this was continued for one hour so that a total of 10 mg/kg was administered. There was a 50% reduction of ICP at one hour from initiation of treatment. The brains of the animals were extracted immediately upon cessation of therapy (pentobarbitone) and they revealed a significant reduction of water content for the right, uninjured, hemisphere only, when compared to controls; a slight but not significant reduction of the brain sodium and potassium was noted in both hemispheres. There was no change noted in the gross pathology and extent of blood brain barrier breakdown. In all animals epinephrine infusion had to be administered for between 20 and 30 minutes to maintain a SAP over 80 torr. There seems to be no advantage in the simultaneous administration of barbiturates and diuretics for the control of ICP due to brain oedema.