Effect and Feasibility of Controlled Rewarming After Moderate Hypothermia in Stroke Patients With Malignant Infarction of the Middle Cerebral Artery

Abstract

Background and Purpose-Moderate hypothermia has been found to reduce intracranial pressure (ICP) significantly in patients who have severe middle cerebral artery infarction. However, during passive rewarming, ICP continuously rises and some patients suffer transtentorial herniation. Methods-We investigated the question of whether slower rewarming leads to slower increase in ICP and slower decrease in cerebral perfusion pressure (CPP). Furthermore, we studied feasibility of slow, controlled rewarming. ICP, CPP, and core body temperature were monitored continuously. Achievement of rewarming protocol was assessed by hit rate of temperature target intervals. Side effects of hypothermia were assessed. Results-Rates of change of both ICP and CPP were correlated significantly with increase in temperature (ICP rϭ0.62, Pϭ0.002; CPP rϭϪ0.50, Pϭ0.017). In feasibility analysis of 13 controlled rewarmed patients, hit rate of temperature target intervals was 63% (median; range 48% to 81%); hit rate within the target interval or below was 79% (median; range 62% to 94%). Conclusions-Slow, controlled rewarming is feasible and may be used for ICP and CPP control after moderate hypothermia for space-occupying infarction. Key Words: stroke, ischemic Ⅲ brain edema Ⅲ intracranial pressure Ⅲ hypothermia A bout 3% to 10% of patients with middle cerebral artery (MCA) territory infarction develop space-occupying hemispheric edema with increases in intracranial pressure (ICP), subsequent transtentorial herniation, and brain stem compression. 1 Moderate hypothermia (body temperature 32°C to 33°C for 48 to 72 hours) has been found to reduce ICP significantly in these patients. 2 However, during rewarming, ICP continuously rises and some patients suffer transtentorial herniation.Until 1998, rewarming took place in a passive manner; ie, after hypothermia, the cooling system was stopped and the rewarming process ensued without induction of any cooling or rewarming device within the next 17 to 24 hours (median 18 hours). 2 We refer to this rewarming protocol as "passive rewarming." To address the question of whether prolonged and controlled rewarming would lower risk of critical rewarming, we studied modified controlled rewarming. Feasibility of the protocol was analyzed by hit rates of the target interval (HTI) for the temperature. Subjects and MethodsWe studied a consecutive series of 15 patients with malignant MCA infarction who underwent therapeutic hypothermia for 72 hours.Patients with any previous disabling neurological diseases or terminal illness were excluded from the protocol, which was approved by the local ethics committee. "Controlled rewarming" was defined as an increase in temperature of 0.1°C to 0.2°C over 2 to 4 hours ( Figure 1) and was achieved by actively slowing down the process of passive rewarming. The cooling blanket (Polar Bair, Augustine Medical) or mattress (Hico-Variotherm 530, Hirtz) was switched on and off to achieve the planned increase in temperature. ICP, cerebral perfusion pressure (CPP), and core temperature...

Hypothermia Reduces Perihemorrhagic Edema After Intracerebral Hemorrhage

“…This finding is remarkable because rewarming of the patients could have led to a delayed increase of edema and associated increase of ICP, as seen in large cerebral infarcts. 25,26 Using this regimen, hypothermia was a highly effective anti-edematous therapy. Because the edema essentially stopped growing, no patient had episodes of critical ICP increase during the 14-day observation period.…”

Guidelines for the Management of Spontaneous Intracerebral Hemorrhage in Adults

“…92 There also appears to be a risk for rebound intracranial hypertension when induced hypothermia is reversed too quickly. 67 …”

Reprint

“…66 A significant rebound in ICP also appears to occur when induced hypothermia is reversed. 67 The exact frequency of increased ICP in patients with ICH is not known. Many patients with smaller ICHs will likely not have increased ICP and require no measures to decrease ICP, as is the case for many patients with ischemic stroke.…”