No abstract

Propofol concentrations in the cerebrospinal fluid in neurosurgical patients Propofol concentration in cerebrospinal fluid of investigated patients decreased significantly after starting intraventricular drainage, despite relatively steady blood propofol concentrations. These results supplement the limited information about propofol pharmacokinetics in the human central nervous system.

In order to describe the changes of propofol concentration in whole blood and in its components during the blood storage we examined venous blood samples collected from patients anaesthetized either with or without propofol. Blood samples from patients anaesthetized without propofol were spike with propofol 45 min before analysis. Propofol concentration was examined in whole blood, plasma, rinsed formed elements and rinsed and lysed formed blood elements by means of HPLC after 1, 4, 7, 13, 21, 25 and 28 days of storage. There was significant decrease in plasma concentration of propofol during the first few days of sample storage followed by its increase during subsequent days. The opposite phenomenon was observed for formed blood elements. The findings support the hypothesis that propofol distribution between blood components changes in time.

One of the least explored subjects in the research on the metabolism of a widely used anaesthetic, propofol, is its excretion in an unchanged form. According to literature, the estimated percentage of applied propofol eliminated intact via kidneys is lower than 0.3%. The present study shows the amount of propofol excreted in an unchanged form with urine collected during the first 48 h after anaesthesia in five patients undergoing elective intracranial procedures. The drug was concentrated and selectively isolated from urine samples by supported liquid membrane technique and determined by HPLC with fluorescence detection. The amount of unchanged propofol eliminated with urine was approximately (0.004 +/- 0.002)% of the total applied dose. The obtained results may suggest that propofol in an unchanged form is not excreted by kidneys at all provided that all propofol determined in presented study originated from conjugates hydrolysis.

Background. A pulse oximeter is a standard device for perioperative monitoring. It is well known that the early detection of tissue hypoxia is of great importance. It has been made easier due to a new generation pulse oximetry device from Masimo. This enables measurements of the peripheral perfusion index (PI) in real time. It has been found that volatile anaesthetics such as sevoflurane and desflurane increase the perfusion index. As we know, no data is available about perfusion index during propofol/remifentanil total intravenous anaesthesia. Methods. ASA I and II class women scheduled for elective gynaecological surgery were eligible for the study. Patients were divided into two groups: group P receiving propofol/remifentanil intravenous anaesthesia and group D receiving desflurane/fentanyl general anaesthesia. PI was noted before anaesthesia, after remifentanil/fentanyl injection, after endotracheal intubation, at the beginning of surgery, during the procedure at ten minute intervals, at the end of the procedure, after awakening, after extubation and before discharge to the ward. Results. Eighty-three patients were enrolled to the study. In both groups, PI increased significantly from the start to the end of surgery. There was a significant correlation between PI and end-tidal desflurane concentration (r = 0.807; P = 0.001). No correlation was found between propofol or remifentanil concentrations and PI. Conclusion. Both intravenous propofol/remifentanil and desflurane/fentanyl general anaesthesia increase peripheral perfusion. An increase in end-tidal desflurane concentration raises peripheral perfusion.

Background: Synchronous independent lung ventilation (ILV) is the treatment of choice for unilateral pathology of lung parenchyma. Numerous studies have documented the improved blood oxygenation and clinical efficacy of this procedure. The aim of the present study was to evaluate the effects of ILV on the selected biomechanical parameters of the lungs. Method: The study involved ASA I-II patients undergoing thoracic surgery in the lateral decubitus position under the standard conditions of general anaesthesia with the thoracic cavity closed. ILV with equal separation of the tidal volume was performed with a prototype volume separator, using incremental a PEEP of 0−15 cm H 2 O in the dependent lung. Peak pressures, dynamic compliance and airway resistance of both lungs were evaluated. Results: The study included 36 patients. In all of the patients, a PEEP of 5−15 cm H 2 O in one lung increased its peak pressures, dynamic compliance and resistances, and variably affected the biomechanical parameters of the other lung. Irrespective of patient positioning on the right or left side, the highest compliance was recorded at a PEEP of 10 cm H 2 O. Conclusions: In ILV, peak pressures and airway resistances are higher in the dependent lung compared to compliances in the non-dependent lung. ILV with a PEEP of 5−15 cm H 2 O increases the biomechanical parameters of the dependent lung while variably influencing the parameters in the non-dependent lung.

Intracranial pathology may influence CSF propofol concentration. However, the observed discrepancies may also result from quantitative differences in CSF composition and from restricted diffusion of the drug in the CSF.

Vascular access is usually achieved through a femoral arterial puncture using a modified Seldinger technique. However, selective catheterization of the great cerebral vessels by femoral approach fails completely when the vessel is tortuous or atheromatous. In case of posterior vascular circulation aneurysms, transbrachial approach or direct puncture of the vertebral artery (VA) is an alternative. The aneurysms of the posterior cerebral artery (PCA) are reported to be rare. Due to unfavorable anatomic location, the PCA aneurysms are difficult to reach during surgical procedure. Endovascular embolization is at present considered to be more effective and safer treatment of the PCA aneurysms arising from different segments, offering a viable alternative to the surgical approach. We report the case of the giant left PCA aneurysm, located at the junction of P1/P2 segments, successfully treated by parent artery occlusion achieved after the direct puncture of the right VA which was used because both VAs were tortuous, irregular and their ostia were not accessible by femoral approach. According to different authors, parent artery occlusion appears to be safe in the treatment of P2 segment aneurysms, whatever the location of the occlusion. In our case we decided to perform this kind of treatment believing it was the only possible one.