Obstructive jaundice blunts myocardial contractile response to isoprenaline in the dog: a clue to the susceptibility of jaundiced patients to shock?

Abstract

1. Patients with obstructive jaundice are susceptible to postoperative shock. To clarify the mechanism of this phenomenon, we compared the contractile response to isoprenaline of isolated ventricular preparations from three groups of dogs: (a) dogs with chronic bile-duct ligation (CBDL), (b) dogs with choledochocaval anastomosis (CDCA) and (c) sham-operated dogs (SO). 2. Isolated ventricular muscles from CBDL and CDCA dogs showed a depressed contractile response to isoprenaline as compared with SO dogs. Mechanical performance was spared in the CBDL and CDCA dogs. 3. There were no differences in the contractile responses of SO and CBDL dogs, either to ouabain or to changes in the rates of stimulation (force-frequency relationships). These data demonstrate that, in the dog, obstructive jaundice and/or cholaemia are associated with blunted contractile response to β-adrenoreceptor stimulation in the face of intact basic mechanical performance. 4. Similar inotropic refractoriness to β-adrenoreceptor stimulation could contribute to the susceptibility to postoperative shock in patients with obstructive jaundice.