PMC5570114_01
Etiology and management of hyperkalemia.. Note. ECMO = extracorporeal membrane oxygenation; CVVHDF = continuous venovenous hemodiafiltration.
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The hyperkalemia (8.2 mmol/L) was refractory despite the administration of low-dose dopamine, encouraging urine output with diuretics, optimizing ECMO circuit flows to minimize hemolysis, minimizing nephrotoxic medications, and giving medications for hyperkalemia (sodium bicarbonate, diuretics, insulin and dextrose, and salbutamol, all within a 6-hour window) (Figure 1).
Circuit setup.. Note. CVVHDF = continuous venovenous hemodiafiltration; IHD = intermittent hemodialysis; ECMO = extracorporeal membrane oxygenation.
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We introduced CVVHDF to the ECMO circuit proximal to the oxygenator using the Prismaflex system (Figure 2). Prismaflex has broad flow rate capabilities for blood flows, dialysate, and replacement rates and can deliver up to 8000 mL/h of dialysate (replacement plus PBP). Potassium levels did not improve, so we elected to add IHD to improve the potassium balance (Figure 2).
Serum potassium in the week following admission.. Note. The patient only remained normokalemic on CRRT for a few hours. "Renal dose" dopamine was then started, ventolin was given, nephrotoxic drugs were discontinued, sodium bicarbonate was given via IV, and high doses of furosemide (3 mg/kg in repeated boluses), insulin, and dextrose were administered. As these initiatives were unsuccessful, the dialysis rate of the Prismaflex machine was increased to 6.0 L/h for a total flow rate of 8000 mL/h (dialysate, replacement plus PBP) until day 4 of the CRRT treatment. As none of these concurrent measures were able to lower the patient's potassium level, additional IHD was started with 4-hour treatment cycles interrupted by an 8-hour break; the second treatment caused hypokalemia, so the treatment was stopped. CVVHDF was discontinued after 4.5 days. The patient then received CVVHD until day 13 and was then continued on IHD for a total of 7 weeks, until the AKI resolved. IV = intravenous; CRRT = continuous renal replacement therapy; ECMO = extracorporeal membrane oxygenation; CVVHDF = continuous venovenous hemodiafiltration; CVVHD = continuous venovenous hemodialysis; PBP = pre-blood pump; IHD = intermittent hemodialysis; AKI = acute kidney injury.
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We were successful in reducing potassium levels (Figure 3), and the ECG changes normalized with the additional hemodialysis.