Role of sodium bicarbonate or mannitol or diuretics to prevent kidney injury in rhabdomyolysis
Should sodium bicarbonate or mannitol or diuretics be given to prevent kidney injury in rhabdomyolysis?
Urinary alkalinization in animal models has been shown to increase the solubility of the myoglobin-THP complex and inhibit reduction-oxidation cycling of myoglobin and lipid peroxidation.
Some experts advocate for the administration intravenous sodium bicarbonate (aiming for a urine pH greater than 6.5), in addition to volume expansion with normal saline.
However, alkalinization may lower serum ionized calcium levels as a result of enhanced binding to albumin (but not change total calcium) in patients who are already hypocalcemic.
Retrospective studies have shown that bicarbonate administration does not improve outcomes with regard to kidney failure, the need for dialysis, or mortality in most patients, although there may be benefit in the subgroup with severe rhabdomyolysis (CK level >30,000 U/L).
Loop diuretics may increase urinary flow but have not been shown to protect against Acute Kidney Injury.
Mannitol is an osmotic diuretic and a weak free-radical scavenger.
Unfortunately, mannitol may worsen Acute Kidney Injury by causing osmotic nephrosis and can accumulate if the urine output falls; it is now rarely used.
Notably, any diuretic therapy should be limited to patients who have been resuscitated and are volume replete.