The effect of selective brain cooling on intracerebral temperature during craniotomy

In this study we investigated the effect of topical application of cool irrigation fluid on brain tissue temperature during craniotomy. Eight patients were given a standard general anaesthetic for craniotomy. Distal oesophageal and nasopharyngeal temperatures were measured continuously and systemic normothermia was maintained. A sterile needle temperature probe was inserted 18 mm into the cerebrum to measure brain temperature. Brain temperatures were recorded for five minutes while the brain was irrigated with 1000 ml of normal saline at a temperature of 30 degrees C. Measurement continued until the brain temperature returned to baseline. The mean maximum decrease in cerebralparenchymal temperaturefollowing irrigation was 1.6 +/- 0.5 degrees C (P<0.01). The average time to return to baseline temperature after cessation of irrigation was 5.3 +/- 1.5 minutes. Cooling the brain has a marked protective effect after brain injury, but systemic hypothermia can produce significant harmful effects. This study demonstrates that the use of cool irrigation fluid during neurosurgery is a simple and effective method of cooling the brain whilst minimizing the use of systemic hypothermia.