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% trichloroethylene and 1% halothane anaesthesia in a control group of five dogs, chronically implanted with cardiovascular flow- and pressure-measuring apparatus and compared them with a similar group of six dogs pretreated for 3 weeks with oral propranolol (20 mg/kg/day). The effects of graded haemorrhage of 25% of the estimated blood volume and re-transfusion were studied. Cardiovascular function was satisfactory at all stages of the study except during trichloroethylene anaesthesia in the beta-blocked dogs when the response to blood loss was impaired severely. Therefore the use of trichloroethylene in the presence of propranolol may not be advisable in clinical practice.