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: 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.