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SummaryWe have studied core temperature changes occurring during induction of general anaesthesia and surgery in 18 patients undergoing elective aortic aneurysm repair. In the operating theatre, all patients were warmed with a forced-air warmer and a warming mattress, and received warmed (37 ЊC) intravenous fluids. Despite this, mean (SD) [range] core temperatures in the anaesthetic room decreased by 1.5 (0.3)[1.1-2.2] ЊC, while intravascular lines, epidural and urinary catheters were inserted before the introduction of warming methods in theatre. In one-third of patients, the core temperature was still below 36 ЊC at the end of surgery. The overall temperature decrease correlated significantly with the duration of time between induction of general anaesthesia and surgical incision (R 2 0.6912), when the patients were not being warmed. Hypothermia may thus be prevented by minimising the period that the patient is anaesthetised without being warmed. Vascular lines, urinary and epidural catheters should be inserted before the induction of general anaesthesia or, alternatively, warming methods should be introduced in the anaesthetic room. Peri-operative hypothermia is common during major vascular surgery [1], due to factors such as redistribution of blood following induction of general anaesthesia, the abolition of central thermoregulatory mechanisms [2] and the administration of cold intravenous fluids. A patient undergoing aortic surgery is at particular risk of developing hypothermia as the abdomen may be open for a considerable time, there is a period of reduced perfusion of the lower body and fluid losses may be significant. Maintenance of body temperature peri-operatively is desirable as postoperative hypothermia has significant detrimental effects, including coagulopathy and blood loss [3], greater postoperative fluid requirements, increased need for vasopressors and inotropes, increased mortality [4], increased postoperative infection rate [5] and a higher incidence of myocardial ischaemia [6].Several different methods have been used to prevent peri-operative hypothermia [7], including the use of warmed intravenous fluids, forced-air warmers, warming mattresses, radiant heaters and the administration of heated and humidified anaesthetic gases. Of these, the most efficient is the forced-air warmer [8], the use of which has become routine in many institutions.At our hospital, all patients undergoing prolonged (b 2 h) surgery receive prophylactic warming measures in the operating theatre. These include the use of a forced-air warmer, a warming mattress and warmed intravenous fluids wherever possible. Despite this attention to warming techniques, patients undergoing aortic aneurysm repair still become hypothermic by 2 ЊC or more and often do not reach normothermia by the end of surgery, with the result that tracheal extubation may be delayed. We hypothesised that significant heat loss occurs in the anaesthetic room, after induction of anaesthesia and before the introduction of any of these warming methods. We...

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Laser microdissection (LMD) with subsequent reverse transcription-PCR analysis is a powerful histochemical technique subserving the molecular characterization of specific cell types. We developed an efficient method for selective sampling of specific cell populations using immunohistochemistry coupled with LMD. The cerebral cortex of adult rats was cut into serial thin sections. Some sections were immunostained for parvalbumin. The adjacent sections were mounted on Cell Support Film for LMD and stained with neutral red. By comparison of the two adjacent sections, neuronal profiles representing parts of parvalbumin-immunopositive somata were identified in the neutral red-stained sections. These neuronal profiles were safely captured with LMD and analyzed on reverse transcription-PCR using extracted RNA. The method presented here can be applied to cell-type-specific characterizations using fixed cells under RNase-free conditions.