EFFECTS OF SEVOFLURANE ON INTRACRANIAL-PRESSURE, CEREBRAL BLOOD-FLOW AND CEREBRAL METABOLISM - A DOSE-RESPONSE STUDY IN PATIENTS SUBJECTED TO CRANIOTOMY FOR CEREBRAL-TUMORS

Background: Studies concerning the cerebrovascular effects of sevoflur ane in patients with space-occupying lesions are few. This study was c arried out as a dose-response study comparing the effects of increasin g sevoflurane concentration (1.5% (0.7 MAC) to 2.5% (1.3 MAC)) on cere bral blood flow (CBF), intracranial pressure (ICP), cerebrovascular re sistance (CVR), metabolic rate of oxygen (CMRO2) and CO2-reactivity in patients subjected to craniotomy for supratentorial brain tumours. Me thods: Anaesthesia was induced with propofol/fentanyl/atracurium and m aintained with 1.5% sevoflurane in air/oxygen at normocapnia. Blood pr essure was maintained constant by ephedrine. In group 1 (n = 10), the patients received continuously 1.5% sevoflurane. Subdural ICP, CBF and CMRO2 were measured twice at 30-min intervals. In group 2 (n = 10), s evoflurane concentration was increased from 1.5% to 2.5% after CBF1. C BF2 was measured after 20 min during 2.5% sevoflurane. Finally, CO2-re activity was studied in both groups. Results: In group 1, no time-depe ndent alternations in CBF, CVR, ICP and CMRO2 were found. In group 2, in increase in sevoflurane from 1.5% to 2.5% resulted in an increase i n CBF from 29+/-10 to 34+/-12 ml 100g(-1) min(-1) and a decrease in CV R from 2.7+/-0.9 to 2.3+/-1.2 mmHg ml(-1) min 100g (P<0.05), while ICP and CMRO2 were unchanged. CO2-reactivity was maintained at 1.5% and 2 .5% sevoflurane. Conclusion: Sevoflurane is a cerebral vasodilator in patients with cerebral tumours. Sevoflurane increases CBF and decrease s CVR in a dose-dependent manner. CO<INF>2</INF>-reactivity is preserv ed during 1.5% and 2.5% sevoflurane. (C) Acta Anaesthesiologica Scandi navica 42 (1998).<INF></INF>