Prevention and early management of acute renal failure

Effect of "renal-dose" dopamine on renal function following cardiac surgery

The efficacy of renal-dose dopamine to improve renal function or reduce renal impairment was studied in 52 patients undergoing elective coronary artery bypass surgery. The patients were prospectively randomised in a double-blind fashion to receive dopamine at 200 micrograms/min (group D) or placebo (group P) from induction for 24 hours. Although dopamine improved haemodynamics, there was no effect on urine output at 4 hours (D = 917, P = 1231 ml: P = 0.066); urine output at 24 hours (D = 3659, P = 3304 ml: P = 0.36); creatinine clearance at 0-4 hours (D = 104, P = 127 ml/min: P = 0.27); creatinine clearance on admission to ICU-4 hours (D = 94.8, P = 83.4 ml/min: P = 0.48); creatinine clearance at 20-24 hours (D = 91.2, P = 107 ml/min: P = 0.48); free-water clearance at 0-4 hours (D = 29.6, P = -59.8 ml/hr: P = 0.069); free-water clearance at 20-24 hours (D = 43.2, P = -48.9 ml/hr: P = 0.55). The incidence of transient renal impairment was similar in both groups (D = 36%, P = 50%: P = 0.65). Our study failed to demonstrate that routine prophylactic renal-dose dopamine is associated with improvement in renal function, or with prevention of transient renal impairment in patients undergoing coronary artery bypass surgery.

Dopamine hydrochloride in oliguric states

Low-dose dopamine infusion (1 microgram/kg/min) produced a diuresis in early oliguric acute tubular necrosis. No complications were encountered during or after the infusion.

Can mannitol reduce amphotericin B nephrotoxicity? Double-blind study and description of a new vascular lesion in kidneys

Eleven patients with systemic mycotic infections were treated with amphotericin B, 1 mg/kg, on alternate days. Five patients also received mannitol (M), 1 g/kg, in the amphotericin infusion, while six served as controls (C). Renal function studies prior to therapy were repeated at a total cumulative amphotericin B dosage of 25 mg/kg; renal biopsies were obtained from 10 patients. Inulin and creatinine clearances decreased in both the C and M groups, significantly so in the latter. Urinary concentrating ability of five patients (2C, 3M) decreased as did the capacity of three (1C, 2M) to acidify urine after an acid load. Neither the peak and valley levels of amphotericin B in serum nor the urinary excretion thereof differed between the C and M groups. Striking vacuolization of smooth muscle cells, previously unrecognized, was observed in the media of arterioles and arteries in all renal biopsies. Tubular calcification was present in both groups. In summary, M therapy (1 g/kg) did not protect against the nephrotoxicity of amphotericin B. A unique lesion of the renal vasculature secondary to amphotericin B is described.

Excretion urography in acute renal failure

High-dose excretion urography has been carried out in 32 patients presenting with non-obstructive acute oliguric or non-oliguric renal failure. An early, dense, persisting nephrogram has been observed in all patients with acute uncomplicated tubular necrosis and in patients with acute oliguric pyelonephritis. This appearance is modified by the presence of pre-existing renal disease. Different patterns have been observed in patients with acute glomerular disease, severe renal ischaemia, and chronic glomerular disease. The study demonstrates that careful analysis of the evolution of the nephrogram in patients with acute renal failure provides valuable information as to the nature of the parenchymal disease.

Body water and electrolyte composition in acute renal failure

Body water and electrolyte contents have been measured by means of muscle biopsy analysis in 11 patients with untreated acute renal failure and in one patient during the diuretic recovery phase of his illness. Patients with acute oliguric renal failure show two main types of imbalance. One group shows evidence of a reduction in extracellular sodium and chloride with normal intracellular water and electrolytes. These findings are thought to be due to a combination of excess urinary salt loss during the development of oliguric renal failure, and inadequate replacement of extrarenal electrolyte losses. A second group shows overhydration of both extra- and intracellular phases, associated with an excess of sodium and chloride. The intracellular potassium concentration is reduced, owing to the intracellular water excess. The patient studied during the diuretic recovery phase of acute renal failure showed a marked loss of sodium and chloride, which emphasizes the necessity to replace urinary electrolyte losses at this stage of the illness. It is often extremely difficult to assess fluid and electrolyte balance in patients presenting with acute renal failure, and muscle biopsy analysis or isotope dilution studies may be required before accurate replacement therapy is possible.