[Diuretic effects of aminophylline in patients after cardiac surgery]

Diuretic effects of aminophylline in patients after cardiac surgery were studied by using the local renal thermodilution catheter (Goodman Co. Ltd.). The subjects were 11 patients who underwent cardiac surgery in our hospital. All patients had shown almost normal renal and endocrine function. On the day of operation, we indwelld renal thermodilution catheter into the left renal vein under fluoroscopy. After operation, when the urinary volume decreased below 1 ml.kg-1.hr-1, we administered aminophylline at a rate of 2 ml.kg-1.hr-1. We measured HR, BP, CO, PAP, CVP, renal blood flow, urinary volume, urinary electrolytes, plasma renin activity, angiotensin II, aldosteron, ADH and alpha hANP just before and after infusion of aminophylline. The urine volume, renal blood flow and renal blood flow distribution rate showed significant increases of about 70%, 40% and 35% respectively. But hemodynamic parameters including HR, mean BP and CO increased for 5%, 10% and 8% respectively after administration of aminophylline. In the endocrine system, only angiotensin II increased significantly but aminophylline did not cause any change in endocrine system. The results suggest that diuretic effect of aminophylline is mainly achieved by increasing renal blood flow.