Moderate hypothermia for uncontrolled intracranial hypertension in acute liver failure

Background Increased intracranial pressure as a complication of acute liver failure has a mortality of about 90% in patients who do not respond to tre atment with mannitol and ultrafiltration. We investigated the safety and ef ficacy of moderate hypothermia for uncontrolled increase in intracranial pr essure in patients with acute liver failure. Methods We studied seven consecutive patients aged 16-46 years (five women, four candidates for orthotopic liver transplantation [OLT]) with acute liv er failure who fulfilled criteria for poor-prognosis liver failure and had increased intracranial pressure that was unresponsive to two treatments wit h mannitol and ultrafiltration. We used cooling blankets to lower the patie nts' core temperature to 32-33 degrees C. Patients who were not suitable ca ndidates for OLT (patients 1-3) were cooled for 8 h and then gradually rewa rmed over 1 h to 8 baseline temperature of 37 degrees C. Patients who were suitable candidates for OLT (patients 4-7) were cooled before and during th e OLT procedure; We measured cerebral blood flow and metabolic indices befo re and after cooling. Findings The four patients who were candidates for OLT were successfully ma intained until transplantation with 13 (range 10-14) h of hypothermia. The three patients who were unsuitable candidates for OLT died after rewarming. Intracranial pressure before cooling was 45 (25-49) mm Hg and was reduced in all patients to 16 (13-17) mm Hg (p<0.05). Cerebral blood flow decreased from 103 (25-134) mt 100 g(-1) min(-1) before cooling to 44 (24-75) mt 100 g(-1) min(-1) after cooling (p<005). The corresponding changes for cerebra l perfusion pressure was an increase from 45 (37-56) mm Hg to 70 (60-78) mm Hg (p<0.05) and for cardiac index a decrease from 9.8 (7-13) to 5.1 (4.3-6 .1) L per min per m(2) of body surface area. During hypothermia there was n o significant relapse of increased intracranial pressure. Arterial ammonia and cerebral uptake of ammonia were significantly reduced with cooling. No adverse effects of hypothermia were observed. Interpretation Moderate hypothermia is useful in the treatment of uncontrol led increase in intracranial pressure in patients with acute liver failure and may serve as a bridge to OLT.