Abstract 3942: Mild Controlled Hypothermia Induction is Safe and Feasible for the Treatment of Intracranial Hypertension in Patients with Aneurysmal Subarachnoid Hemorrhage.

Abstract

Introduction Hypothermia has been increasingly used for cerebral resuscitation in comatose survivors of cardiac arrest. A large number of studies have been undertaken in patients with traumatic brain injury to asses the efficacy of hypothermia for reduction of intracranial hypertension. Hypothermia has also been shown to reduce mortality and increase functional outcome if used for longer duration in patients with severe traumatic brain injury. Due to the risk of rebound cerebral edema during re-warming, medical complications and other factors, hypothermia has not been widely utilized for other neurologic catastrophes. To determine the safety and feasibility of hypothermia to treat intracranial hypertension in patients with aneurysmal subarachnoid hemorrhage (SAH), we performed this study. Methods Retrospective analysis was performed on 11 consecutive patients with poor grade (Hunt and Hess IV and V) SAH who had high intracranial pressure that was either non responsive or poorly responsive to conventional methods (head of bed at 30 degrees, sedation, CSF drainage and osmotherapy). All patients had intracranial pressure (ICP) monitoring via an external ventriculostomy drain (EVD) catheter. Hypothermia was induced non-invasively via surface cooling pads (Artic Sun Temperature Management System). Intravenous sedation and paralysis was used via intravenous infusion to control shivering. Hypothermia (target temperature of 32 to 34 degree C) was maintained until ICP normalized. Results Duration of hypothermia ranged from 79 hours to 190 hours. One patient required re-induction due to rebound increase in ICP during re-warming. Modified rankin scale was recorded at 3 month after the ictus. Eight patients (72%) survived with good recovery, one patient (9%) survived with severe disability and two patients (18%) died. The most common side effect was electrolyte imbalance seen in seven patients (63%), thrombocytopenia in three patients (27%), and pneumonia in four patients(36%). All complications were successfully treated and major consequences of complications (bleeding diathesis, septic shock syndrome and death) were not observed in any of these patients. Two patients had decompressive hemicraniectomy prior to hypothermia induction. Out of nine patients who did not undergo hemi-craniectomy, two died and seven did not require surgical intervention after induction of hypothermia. Conclusions Mild hypothermia induction for 72 hours or more for the treatment of intracranial hypertension refractory to other conventional methods in patients with SAH appears safe and feasible. Hypothermia may potentially be an earlier treatment option than currently recommended. This study serves as a template for future efficacy trials.