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Abstract: FR-PO554

Activation of Blood Leak Alarm During Hemodialysis Secondary to Hydroxocobalamin Therapy of Cyanide Toxicity

Session Information

Category: Trainee Case Report

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Yancey, Justin Leonadus, University of Tennessee Center for Health Science, Memphis, Tennessee, United States
  • Wall, Barry M., Veterans Affairs Medical Center, Memphis, Tennessee, United States
  • Asif Siddiqui, Omer M., University of Tennessee Center for Health Science, Memphis, Tennessee, United States

Toxic levels of cyanide, which may develop with prolonged infusions of sodium nitroprusside, can be treated with hydroxocobalamin. A noted side effect of hydroxocobalamin is red discoloration of plasma and urine. Hydroxocobalamin may also lead to red discoloration of dialysate with activation of blood detector alarms during conventional hemodialysis.

Case Description

61 year old female with advanced renal disease due to poorly controlled hypertension presented with severe blood pressure elevation of 247/125 mmHg with imaging findings concerning for 5.6 cm abdominal aortic aneurysm with impending rupture. Sodium nitroprusside was started for blood pressure control at low dosages for 9 days. On the 9th day, she developed a wide anion gap metabolic acidosis: sodium 145, potassium 4.5, chloride 96, bicarbonate 18, BUN 24, SCr 2.52, and anion gap 31. Cyanide toxicity was diagnosed and treated with intravenous hydroxocobalamin. Conventional hemodialysis was initiated with a Fresinius FMC machine, but could not be performed due to activation of blood leak dectector alarms with visibly reddish colored dialysate. CVVHD was subsequently initiated through use of NxStage machine. The red discoloration of the dialysate gradually resolved over a 48 hr period, at which time intermittent hemodialysis was reinitiated with no further blood leak alarms.


Blood leak detection alarms on dialysis machines have been designed to cease operations when blood is detected in the dialysate. Fresenius dialysis machine contains blood leak alarm consisting of two-color light source transmitter/sensor (red light and green light) that monitor clarity of effluent dialysate. The photodetector is triggered when green light (wavelength 562–575 nm) is absorbed by blood. A leak detector is placed in dialysis solution outflow line, using sensor in dialysate effluent path. When blood leaks are detected, the alarm is activated and blood flow through dialyzer stops. NxStage CRRT machine does not have hydroxocobalamin-related false blood leak alarms. The blood leak detector of NxStage machine uses a single optical emitter with 880-nm wavelength designed to detect light scatter. It does not depend on light absorption, and, therefore, was not activated by discoloration of the dialysate by hydroxocobalamin, such that renal replacement therapy could be administered.