Anaesthetic management for endovascular treatment of unruptured intracranial aneurysms.

BACKGROUND: Endovascular techniques for treatment of intracranial aneurysms are increasingly commonly applied. In general, the procedures are short, require general anaesthesia and complete immobilisation of patients. The aim of the present study was to assess the usefulness of general anaesthesia with propofol and laryngeal mask airway for endovascular management of intracranial aneurysms based on analysis of haemodynamic stability. METHODS: The study encompassed 26 patients undergoing endovascular treatment of intracranial aneurysms. The mean arterial pressure (MAP), heart rate (HR), bispectral index (BIS), end-tidal CO2(E(T)CO2) and haemoglobin saturation with oxygen (SpO2 ) were determined at eight measurement points: T1 - before anaesthesia induction, T2 - after induction, T3 - after LMA insertion, T4 - during arteriography, T5 - during "coiling" , T6 - at completion of propofol infusion, T7 - before LMA removal, T8 - after LMA removal. RESULTS: MAP and HR were found significantly reduced between T2 and T1 . To maintain BIS within the range of 40-60, the following propofol infusion rates (in mg kg b.w.⁻¹ h⁻¹ ) were required: T2 - 4.5 ± 0.3; T3 - 4.6 ± 0.7; T4 - 4.5 ± 0.8 and T5 - 4.4 ± 0.6. E T CO2 and SpO2 were not demonstrated to be changed. The mean duration of anaesthesia and of recovery was 64.3 ± 21.8 and 8.9 ± 4.8 min, respectively. CONCLUSIONS: General anaesthesia with propofol and LMA ensures suitable conditions for endovascular treatment of intracranial aneurysms.

Effect of sevoflurane on cerebral perfusion pressure in patients with internal hydrocephalus.

BACKGROUND: Due to its confirmed neuroprotective properties, sevoflurane is one of a few anaesthetics used for neuroanaesthesia. Its effects on the cerebral and systemic circulations may be of particular importance in patientswith intracranial pathology. This study aimed to evaluate the effect of sevoflurane at concentrations lower than 1 MAC on cerebral perfusion pressure (CPP) in patients with internal hydrocephalus. METHODS: The study was conducted on14 patients with internal hydrocephalus, who underwent ventriculo-peritoneal shunt implantation. After inserting the catheter into the lateral cerebral ventricle, sevoflurane, at 1.1 and 2.2 vol%, was initiated at two successive 15-minute intervals. The intracranial pressure (ICP) was continuously measured; special attention was focused on the values prior to and at the end of each observation period. The following parameters were monitored: mean arterial pressure (MAP), CPP, heart rate, end-tidal CO2 concentration, core body temperature, and the inspiratory and end-expiratory concentrations of sevoflurane. RESULTS: The HR and MAP decreased during successive observation intervals compared to baseline values. Likewise, the CPP decreased from 75.6 ± 2.8 mm Hg to 72.2 ± 2.6 mm Hg to 70.2 ± 0.8 mm Hg. The baseline value for ICP was 16.3 ± 0.6 mm Hg and increased to 17.7 ± 0.8 and 18.9 ± 0.5 mm Hg during the next observation periods. CONCLUSIONS: Sevoflurane administered ata concentration below 1MAC to patients with internal hydrocephalus increases the ICP and decreases the MAP, which leads to adecrease in CPP. The CPP decrease is more dependent on depressing the systemic circulatory system than an increased ICP.