Background and purpose: We undertook this study to evaluate the feasibility of inducing and maintaining moderate hypothermia with the use of endovascular rather than surface cooling.
Methods: Six patients with severe acute ischemic stroke were treated with moderate hypothermia. This was induced and maintained by circulating temperature-adjusted normal saline in a closed-loop system entailing 3 balloons located near the tip of a central line, which dwelled in the inferior vena cava.
Results: The mean+/-SD initial temperature of the patients was 37+/-1 degrees C (range, 35.5 degrees C to 38.4 degrees C). The pace of cooling was 1.4+/-0.6 degrees C/h, and target temperature was reached after 3+/-1 hours (range, 2 to 4.5 hours). During hypothermia, the maximal temperature observed was 33.4 degrees C, and the minimal temperature was 32.2 degrees C. Temperature deviations >0.2 degrees C or >0.3 degrees C were observed during 21% or 10% of the hours under hypothermia, respectively. Singultus was the only device-related complication encountered. Pulmonary infection, arterial hypotension, bradycardia, arrhythmia, and thrombocytopenia were the most common side effects.
Conclusions: Induction and maintenance of hypothermia with an intravenous cooling device are feasible. The safety of this approach remains to be evaluated.