Introduction: Hyperkalemia is not an uncommon occurrence in complicated anesthetic cases that involve multiple units of blood transfusion. Calcium, insulin and glucose and furosemide have been considered the mainstay of treatment for this condition. This case demonstrates an effective alternative therapy to rapidly lower potassium and support hemodynamics simultaneously.
Case Report: A 29 year old male with a history of testicular cancer and extensive retroperitoneal metastasis status post 4 cycles of bleomycin and radiation presented for radical left nephrectomy and dissection of retroperitoneal lymph nodes and masses via thoracoabdominal incision.
Anesthetic considerations included low FiO2, careful titration of IV fluids and maintenance of normal hemodynamics. Induction was uneventful and general anesthesia was maintained with sevolfurane, cis-atricurium and fentanyl. Hemodynamics were initially maintained with lactated ringers. In the fifth hour of surgery, prior to blood transfusion, the patient developed hyperkalemia (6.5 mmol/L) and metabolic acidosis. He subsequently experienced rapid blood loss, with hemoglobin decreasing from 14mg/dl to 7mg/dl, hypotension and anuria. He was resuscitated with 2L of normal saline and several boluses of phenylephrine. Initial treatment of hyperkalemia included insulin, dextrose, 40mg furosemide and 2 ampules of bicarbonate. However, the EKG monitors continued to show peaked T waves and potassium levels remained elevated, limiting resuscitation with blood products. Furthermore, urine output was low and unresponsive to fluid boluses or furosemide.
A major transfusion concern in this hyperkalemic patient was further increases in potassium potentially resulting in cardiac arrest. It was decided to treat the patient with seven intermitted doses of epinephrine (25mcg). Within 35 minutes the potassium level dropped to 3.5 mmol/L. Additionally, EKG changes resolved and blood pressure stabilized. The patient was subsequently transfused 4 units of PRBCs further improving blood pressure and increasing urine output. Post transfusion potassium levels showed 4.5 mmol/L. The total operative time was 11 hours. Patient was successful extubated in the operating room without negative sequelae. Total blood loss was 2.5 L and total urine output was 3L.
Discussion: In cases of hyperkalemia resistant to conventional therapy, epinephrine is effective in shifting potassium intracellularly. Massive blood transfusion can cause hyperkalemia. In this case, small doses of epinephrine served a dual purpose: to support unstable hemodynamics and minimize the risk of cardiac arrest from hyperkalemia.
