What are the possible metabolic complications of blood transfusion during liver transplantation?

Updated: Apr 19, 2019
  • Author: Vanessa A Olcese, MD, PhD; Chief Editor: Ron Shapiro, MD  more...
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Metabolic complications associated with blood transfusion during OLT include the following:

  • Benzodiazepine-associated encephalopathy

  • Metabolic alkalosis

  • Hypercalcemia

  • Hypomagnesemia

Zeneroli and colleagues described the exacerbation of hepatic encephalopathy in patients receiving OLT, which in some cases could be traced to benzodiazepines present in transfused blood products. [41] These researchers evaluated 14 OLT patients and found that 5 patients had increased levels of benzodiazepines after surgery despite no infusion of this class of drug.

The blood products were tested and found to contain commercially available benzodiazepines, including nordazepam, diazepam, lorazepam, and delorazepam. Additionally, patients exhibiting encephalopathy showed clinical improvement after treatment with the benzodiazepine antagonist flumazenil.

Metabolic alkalosis was reported in 5 patients who received large-volume transfusions. [42] Driscoll et al reported that the protracted alkalosis was not explained by sodium bicarbonate administration during the anhepatic phase, but it correlated with a rise in serum citrate levels; the patients had received a mean of 750 mEq citrate from the transfused blood.

Blood is treated with citrate to bind ionized calcium (Ca2+) and prevent its action as a cofactor in the coagulation cascade. Massive infusion of citrated blood products may cause hypocalcemia and hypomagnesemia, particularly in patients with poor hepatic function, neonates, and patients with hypothermia.

During OLT, patients are at increased risk of citrate toxicity and subsequent hypocalcemia because aconitase, a citrate-metabolizing enzyme, is not produced. Hypocalcemia is treated with intraoperative calcium as needed to prevent ventricular hypocontractility and decreased peripheral vascular resistance.

Citrate can cause important hypomagnesemia. Scott et al found significant decreases in plasma concentrations of ionized magnesium across time during OLT in 9 patients; these decreases were inversely related to serum citrate increases. [43] Mean total transfusion of whole blood, packed red blood cells (PRBCs), platelets, and fresh frozen plaza (FFP) was 33 units, all of which had been treated with citrate.

Ionized hypomagnesemia, which may be present in the setting of normal total magnesium concentrations, can result in loss of electrolyte pump control and intracellular hypercalcemia. These complications can lead to cell death, macroscopic dysrhythmia, and decreased cardiac inotropy.

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