Intraoperative mild hypothermia therapy in patients scheduled for neurosurgical procedures

Deliberate mild hypothermia has been proposed as a means of providing cerebral protection during neurosurgicals procedures complicated by cerebral ischaemia. Our prospective study was designed to examine the safety of deliberate mild hypothermia and to evaluate our techniques for cooling and rewarming.

With institutional approval, 20 patients scheduled for elective neurosurgery were enrolled into our prospective study. After the induction of anaesthesia, the core temperature was measured by urinary catheters with probes (Kendall). The patients were cooled (temperature of blankets set at 15 degrees C) and rewarmed (temperature set at 40 degrees C) by two circulating water blankets (Blanketrol III, Cincinnati Sub-Zero, Cincinnati). The variables are expressed as a mean +/- standard deviation.

The time of anaesthesia was 316+/-53 min. The core temperature was 36.5+/-0.4 degrees C at the start of anaesthesia. The minimal temperature reached 34.4+/-0.4 degrees C. The patients were cooled at a rate of 1.1+/-0.3 degrees C/h and rewarmed at a rate of 0.9+/-0.4 degrees C/h. The temperature was 35.8+/-0.5 degrees C after the neurosurgical procedure. Deliberate mild hypothermia with rewarming did not cause delays in emerging from anaesthesia. On the control CT scan, no ischaemic changes were observed after surgery.

Our findings indicate that patients can be cooled and rewarmed by two circulating water blankets, and core temperatures about 34 degrees C were easily achieved. The deliberate mild hypothermia is together with careful anaesthesia management a safe technique of cerebral protection from ischaemic insult during elective neurosurgical procedures. (Tab. 1, Ref. 11.).