Feasibility and Safety of Inducing Modest Hypothermia in Awake Patients With Acute Stroke Through Surface Cooling: A Case-Control Study

Abstract

Hypothermia reduces neuronal damage in animal stroke models. Whether hypothermia is neuroprotective in patients with acute stroke remains to be clarified. In this case-control study, we evaluated the feasibility and safety of inducing modest hypothermia by a surface cooling method in awake patients with acute stroke. We prospectively included 17 patients (cases) with stroke admitted within 12 hours from stoke onset (mean 3.25 hours). They were given hypothermic treatment for 6 hours by the "forced air" method, a surface cooling method that uses a cooling blanket with a flow of cool air (10 degrees C). Pethidine was given to treat compensatory shivering. Cases were compared with 56 patients (controls) from the Copenhagen Stroke Study matched for age, gender, initial stroke severity, body temperature on admission, and time from stroke onset to admission. Blood cytology, biochemistry, ECGs, and body temperature were monitored during hypothermic treatment. Multiple regression analyses on outcome were performed to examine the safety of hypothermic therapy. Body temperature decreased from t(0)=36.8 degrees C to t(6)=35.5 degrees C (P:<0.001), and hypothermia was present until 4 hours after therapy (t(0)=36.8 degrees C versus t(10)=36.5 degrees C; P:=0.01). Mortality at 6 months after stroke was 12% in cases versus 23% in controls (P:=0. 50). Final neurological impairment (Scandinavian Stroke Scale score at 6 months) was mean 42.4 points in cases versus 47.9 in controls (P:=0.21). Hypothermic therapy was not a predictor of poor outcome in the multivariate analyses. Modest hypothermia can be achieved in awake patients with acute stroke by surface cooling with the "forced air" method, in combination with pethidine to treat shivering. It was not associated with a poor outcome. We suggest a large, randomized clinical trial to test the possible beneficial effect of induced modest hypothermia in unselected patients with stroke.