HAEMODYNAMIC INTERACTIONS OF HIGH-DOSE PROPRANOLOL PRETREATMENT AND ANAESTHESIA IN THE DOG III: THE EFFECTS OF HAEMORRHAGE DURING HALOTHANE AND TRICHLOROETHYLENE ANAESTHESIA

We have examined the haemodynamic effects of 0.8% trichloroethyleneand 1% halothane anaesthesia in a control group of five dogs,chronically implanted with cardiovascular flow- and pressure-measuringapparatus and compared them with a similar group of six dogspretreated for 3 weeks with oral propranolol (20 mg/kg/day).The effects of graded haemorrhage of 25% of the estimated bloodvolume and re-transfusion were studied. Cardiovascular functionwas satisfactory at all stages of the study except during trichloroethyleneanaesthesia in the beta-blocked dogs when the response to bloodloss was impaired severely. Therefore the use of trichloroethylenein the presence of propranolol may not be advisable in clinicalpractice.