ABSTRACT
Reports on undesirable side effects of halothane in patients undergoing anaesthesia and in persons with long-term exposure in the operation theatre require establishment of safe upper limits and of methods for monitoring. The main metabolite trifluoroacetic acid is most suitable for biological monitoring. During systematic exposure with graded halothane concentrations (8, 24 and 50 ppm, 6 hours daily, 5 days weekly, for one and two weeks) trifluoroacetic acid concentrations in blood and urine were determined regularly. It was shown that for biologic monitoring estimation in blood is clearly preferential to estimation in urine because of a narrower scatter. At the end of one week of exposure a steady state concentration is found in blood. There is a linear relation between its height and the inhalation concentration of halothane. A trifluoroacetic acid concentration of 2.5 micrograms/ml is considered as a risk-free value. This corresponds to a maximal theatre air concentration of 5 ppm halothane.
Subject(s)
Halothane , Operating Rooms , Halothane/adverse effects , Humans , Maximum Allowable Concentration , Monitoring, Physiologic , Trifluoroacetic Acid/blood , Trifluoroacetic Acid/urineSubject(s)
Trichloroethylene , Carbon Monoxide , Chemical Phenomena , Chemistry , Chloral Hydrate , Drug Stability , Epoxy Compounds , Formates , Glyoxylates , Trichloroacetic Acid , WaterABSTRACT
The antidote efficacy of liquid paraffin in oral solvent intoxications was investigated in dogs. Groups of 3 to 4 animals each received 1 ml/kg of methylchloroform, 0.3 ml/kg of benzene, or 3 ml/kg of a synthetic gasoline mixture (hexane/heptane/octane, ratio 30:50:20) by gastric intubation. After a prolonged interval the same animals were given 5 ml/kg of liquid paraffin by a separate tube in addition to one of the above solvents. The solvent concentrations in the blood were determined by gas chromatography at appropriate intervals. Administration of liquid paraffin in conjunction with methylchloroform does not significantly affect the absorption process. In the case of benzene and the synthetic gasoline mixture, however, liquid paraffin produces a distinct reduction in the rate of absorption. It is thus concluded that in the therapy of oral solvent-intoxication, liquid paraffin exhibits favorable antidote properties which may however differ from one solvent to the other. In clinically relevant situations involving coadministration of purgatives, the antidote effect must be assessed as being of a higher order than in our animal experiments in which purgatives had to be omitted for external reasons.
