Forane (compound 469): 2. Biochemical effects of repeated administration to animals, response to bleeding, and compatibility with epinephrine.

Abstract

Biochemical Effects in Dogs Two groups of five mature, pedigreed, female beagles were used, having a mean body weight of 10.6 kg. Each of the dogs in one of these groups had an open liver biopsy taken, under thiopentone anaesthesia, a month before the experiment. These received 3 hours of anaesthesia a day on five consecutive days. The other group of beagles was anaesthetized for 4 hours a day on alternate days, up to a total of 16 hours. After food had been withheld for 12 hours, anaesthesia was induced by mask inhalation of <4 per eent Forane in oxygen, and the dogs were intubated. No premedication or muscle relaxant drugs were used. The animals were then eonneeted to a non-rebreathing system, using Fink valves, and maintained under surgical anaesthesia with spontaneous respiration for the appropriate periods by the administration of between 1.0 and 1.5 per cent Forane in oxygen. Fluotec vapourisers were used which had been recalibrated by gas chromatography. Arterial and venous blood samples were drawn immediately after induction and just before termination of anaesthesia, and these were analysed by standard techniques for the variables listed in Tables I and II. No intravenous fluids were given. The blood chemistry results were studied for evidence of changes occurring during a single day's anaesthesia, those seen between the 'start' samples on the first day and the 'start' samples on the last day, and the effects of serial removal of blood. 1,2 After the last anaesthetic, those dogs that received 3 hours of anaesthesia on five successive days were sacrificed by intravenous injection of a barbiturate, and tissue specimens of liver, kidney, pancreas, small bowel, spleen, lungs, and heart were taken for gross and microscopic examination.