Biomedical subjects
Publications and source records attributed to Hermann J Theilen.
Cell membranes are not simply barriers separating intracellular from extracellular space. Rather, they represent a dynamic high-turnover system that adapts to current demands. During inflammation, prostaglandins and leukotrienes are formed from membrane-derived phospholipids. Encouraging improvements in critically ill patients were observed after nutritional replacement of long-chain omega-6 fatty acids with long-chain omega-3-fatty acids, contained in fish oil.
UNLABELLED: Hypertriglyceridemia is a possible unwanted effect during long-term propofol sedation while using a formulation containing long-chain triglycerides (LCT) from soybean oil. The use of propofol formulated in a solvent consisting of medium-chain triglycerides (MCT) and LCT might reduce the risk. Because a new solvent may affect the pharmacological profile of propofol, in this prospective, randomized, controlled, and double-blinded study we compared the pharmacodynamic and kinetic characteristics of propofol diluted in MCT/LCT fat solution with those of propofol formulated in LCT fat emulsion. In addition, serum triglyceride levels were measured during and after the administration of both drugs. Thirty patients likely to require mechanical ventilation over at least 48 h were randomized to receive either propofol 2% MCT/LCT (Group 1) or propofol 2% LCT (Group 2). Infusion rates of propofol (2.34 +/- 0.83 mg. kg(-1). h(-1) in Group 1 versus 2.31 +/- 0.6 mg. kg(-1). h(-1) in Group 2), the plasma propofol concentrations during infusion (0.95 +/- 0.53 versus 0.98 +/- 0.32 micro g/mL), and the concentrations and arousal behavior after discontinuation of the drug did not show significant differences. Plasma triglyceride concentrations during sedation did not differ between the groups, whereas there was a tendency toward a more rapid triglyceride elimination in Group 1 after termination of the propofol administration. IMPLICATIONS: Propofol diluted in an emulsion of medium- and long chain-triglycerides shows equivalent pharmacological properties during long-term sedation compared with its hitherto well known formulation containing long-chain triglycerides only. In addition, potential favorable effects on the plasma triglyceride profile could be found.
OBJECTIVE: To investigate a possible time-dependent effect of propofol sedation on electroencephalographic activity, we analyzed the electroencephalogram frequency behavior while keeping patients at a constant level of sedation. DESIGN: Prospective, controlled trial. SETTING: Intensive care unit of a university hospital. PATIENTS: Twenty patients without neurologic or metabolic disorders. MEASUREMENTS AND MAIN RESULTS: During sedation with propofol (1-4 mg x kg(-1) x hr(-1)), a bifrontally recorded processed electroencephalogram was obtained. For 48 hrs, sedation was kept constant at a level according to Ramsay Scale 3 while we adjusted the dosage of propofol given per hour. At hours 6, 18, 30, and 42, blood samples were taken to assess the plasma concentration of propofol. The electroencephalogram values of 60 mins obtained during 1 hr before blood sampling were taken for further calculation. From the data, relative band power of the beta-, alpha-, theta, and delta-bands, spectral median frequency, and spectral edge frequency 90 and 95 were computed. For statistical analysis, a polynomial three-factorial repeated-measures analysis of variance with covariates was performed. Relative power of beta- and alpha-wavebands showed a constant and significant decrease over time (beta, 15.5%, 10.3%, 10.3%, 7.6%; alpha, 14.8%, 13.4%, 10.0%, 8.3%), whereas relative delta power increased (delta, 56.4%, 63.4%, 70.7%, 72.3%). The theta-waveband remained unchanged. Accordingly, spectral edge frequency 90 and 95 and spectral median frequency decreased significantly. From hours 6 to 18, a significant increase of the plasma propofol concentration was found. Subsequently, the level remained constant. CONCLUSION: Despite constant sedation, a longer period of propofol application induces a time-dependent electroencephalogram frequency deceleration. The use of electroencephalogram derivatives to monitor depth of sedation in the intensive care unit thus should be regarded cautiously.