Effects of the aldosterone receptor antagonist potassium canrenoate on renal blood flow and urinary output during prolonged increased intraabdominal pressure (IAP) in pigs

Background: Increased intraabdominal pressure can be found after major abdominal trauma and necrotizing pancreatitis and is used during laparoscopic surgery. The purpose of this study was to investigate the effect of the aldosterone receptor antagonist (potassium canrenoate) on renal hemodynamics and urinary output in pigs during increased intraabdominal pressure (IAP). Methods: The IAP was kept at 30 mmHg for 3 h by instillation of Ringer's solution into the peritoneal cavity. Eight animals were treated with potassium canrenoate and eight animals served as controls. Renal blood flow, hormones in femoral artery blood, and the urinary output were measured. Results: The administration of potassium canrenoate was followed by increased aldosterone concentrations in arterial blood, increased blood concentration of potassium, and increased concentration of sodium in the urine, indicating satisfactory inhibition of aldosterone. Potassium canrenoate did not cause changes in cardiac output and arterial pressure. It did not affect the renal vascular resistance that increased at an IAP of 30 mmHg, or the renal blood flow that remained constant during the experiments. The group treated with potassium canrenoate had higher mean urinary Output than the controls, but the difference was not significant. Conclusion: Increased IAP in pigs is associated with markedly reduced urinary output and increased serum concentrations of aldosterone. Although the urinary output did not increase significantly, the increased sodium concentration in the urine of canrenoate-treated animals suggests that the high blood level of aldosterone contributes to the oliguria under Increased IAP.