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SummaryWe compared the effects of indomethacin (bolus of 0.2 mg.kg )1 followed by an infusion of 0.2 mg.kg )1 .h )1 ) and placebo on intracranial pressure and cerebral haemodynamics in 30 patients undergoing craniotomy for supratentorial brain tumours under propofol and fentanyl anaesthesia.

The aim of the current study was to examine the effects of 10 degrees reverse Trendelenburg position (rTp) on subdural intracranial pressure (ICP), cerebral perfusion pressure (CPP), and dural tension. Additionally, the relationship between preoperative Hunt and Hess (H and H) grade and the subdural ICP in patients scheduled for cerebral aneurysm surgery was investigated. Twenty-eight consecutive patients with a cerebral aneurysm were subjected to craniotomy in propofol/fentanyl or propofol/remifentanil anesthesia. Subdural ICP was measured after opening of the bone flap and exposure of dura. After reference measurements of subdural ICP and mean arterial blood pressure (MABP), the measurements were repeated during 10 degrees rTp. No significant differences between the anesthetic groups were disclosed. During 10 degrees rTp, a significant decrease in MABP, ICP, and jugular bulb pressure was observed whereas CPP remained unchanged. In H and H 0 patients (unruptured aneurysm), the ICP decreased from 2.9 +/- 2.6 mmHg to 0.4 +/- 2.2 mmHg at 10 degrees rTp. In H and H I to II patients, the ICP decreased from 9.3 +/- 3.8 mmHg to 4.6 +/- 3.3 mmHg at 10 degrees rTp. A significant difference in the mean baseline subdural ICP and DeltaICP (change in ICP) was found between patients with unruptured aneurysm and patients with subarachnoid hemorrhage (H&H I and II). Furthermore, the relationship between the subdural ICP at neutral position and DeltaICP was significant. In patients without intracranial hypertension, 10 degrees rTp decreases subdural ICP and dural tension in patients with ruptured as well as patients with unruptured cerebral aneurysm; CPP is unchanged.

These findings indicate that endothelin receptor stimulation is not involved in indomethacin-induced cerebral vasoconstriction or maintenance of cerebrovascular tone in the anaesthetized pig. However, our results suggest that the increase in MABP is mediated through endothelin receptors.

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