KDIGO Clinical Practice Guideline for Acute Kidney Injury
Mannitol

Mannitol

Mannitol has been frequently used in the past for prevention of AKI; however, most of the studies are retrospective, underpowered, and, overall, the studies did not meet the criteria of the Work Group to be included in formulation of recommendations. Prophylactic mannitol has been promoted in patients undergoing surgery. While in most of these instances mannitol increases urine flow, it is highly probable that mannitol does not convey additional beneficial effects beyond adequate hydration on the incidence of AKI.

In radiocontrast-induced nephropathy, loop diuretics and mannitol in one study have been shown to exacerbate ARF.¹⁹¹ Weisberg et al.,¹⁹⁷ randomized patients undergoing contrast-medium investigations to receive saline or one of three renal vasodilator/diuretic drugs (dopamine [2 µg/kg/min], mannitol [15 g/dl in a one-half isotonic saline solution given at 100ml/h] or atrial natriuretic peptide). Dopamine, mannitol, and atrial natriuretic peptide were associated with a much higher incidence of renal dysfunction in diabetic subjects compared to patients receiving saline alone.

Mannitol is often added to the priming fluid of the cardiopulmonary bypass system to reduce the incidence of renal dysfunction, but the results of these studies are not very convincing.¹⁹⁸ Two small randomized trials—one in patients with pre-existing normal renal function,¹⁹⁹ the second in patients with established renal dysfunction²⁰⁰—did not find differences for any measured variable of renal function. More convincing are the results obtained with the preventive administration of mannitol, just before clamp release, during renal transplantation.^201,202 The sparse controlled data available have shown that 250 ml of mannitol 20% given immediately before vessel clamp removal reduces the incidence of post-transplant AKI, as indicated by a lower requirement of post-transplant dialysis. However, 3 months after transplantation, no difference is found in kidney function compared to patients who did not receive mannitol.²⁰³

It has also been suggested that mannitol is beneficial in rhabdomyolysis by stimulating osmotic diuresis and by lowering the intracompartmental pressure in the affected crushed limbs^204-206; again, these studies were either not randomized or underpowered. A separate guideline on crush injury associated with disasters, mainly earthquake victims, is under preparation by the ISN Renal Disaster Relief Task Force.

In summary, despite experimental animal data and the anecdotal human evidence for the beneficial effects of mannitol, there are no adequately powered prospective RCTs comparing mannitol vs. other strategies. Based on these considerations, the Work Group concludes that mannitol is not scientifically justified in the prevention of AKI.