Hemodialysis-associated methemoglobinemia in acute renal failure

Patients on maintenance hemodialysis are vulnerable to chloramine toxicity if chloramines are inadequately removed. We report two critically ill patients with acute renal failure who developed methemoglobinemia during hemodialysis in the intensive care unit. During the same period, methemoglobin levels measured from 30 patients in the outpatient dialysis facility were undetectable. Methemoglobin levels normalized when the carbon filtration system of the portable dialysis machine was replaced with a larger unit to remove chloramines more effectively. Causes, treatment, and prevention of chloramine toxicity in patients receiving dialysis in the intensive care unit are discussed.