Haemodynamic effects of octreotide in portal hypertensive rats receiving propranolol

Background: The aim of this study was to investigate short-term effects of propranolol (a non-selective beta-adrenergic antagonist), octreotide (a long-acting somatostatin analogue), or a combination of these substances on splanchnic and systemic haemodynamics and arterial blood gases in rats with portal vein stenosis. Methods: Splanchnic and systemic haemodynamics were measured using the radioactive microspheres method. Eight rats first received an i.v, infusion of isotonic saline (10 mu L/min for 15 min) and then an i.v. infusion of octreotide (8 mu g.h/kg for 15 min). Eight other rats first received a bolus i.v. injection of propranolol (2 mg) and an i.v. infusion of octreotide 15 min later. Results: Propranolol or octreotide alone significantly decreased portal pressure (both by 23%), portal tributary blood now (35 and 10%, respectively) and cardiac index (36 and 26%, respectively). Octreotide administration in rats pretreated with propranolol significantly decreased cardiac index but did not change portal and arterial pressures or portal tributary blood flow. Propranolol significantly increased arterial oxygen tension. Octreotide alone or combined with propranolol significantly decreased oxyhaemoglobin saturation and pH and increased carbon dioxide tension. Conclusions: In rats with portal vein stenosis, the somatostatin analogue, octreotide, accentuates the short-term decrease in cardiac index due to propranolol. In addition, octreotide altered arterial blood gases and acid-base status. In contrast, octreotide does not further decrease portal pressure in animals receiving propranolol.