Factors affecting the development of hypokalemia during apheresis in healthy donors

Despite being generally safe, apheresis for peripheral blood stem cell collection potentially disrupts electrolyte balance owing to the use of citric acid as an anticoagulant. As prior research has primarily studied hypocalcemia, information on the kinetics of potassium levels during apheresis in healthy donors is scarce. We investigated the fluctuation in potassium levels during apheresis and the risk factors for hypokalemia. This subanalysis used data from an open-label, randomized controlled trial of "oral calcium supplementation versus placebo in mitigating citrate toxicity" conducted between January 2021 and July 2022, at Okayama University Hospital. Potassium levels were significantly reduced after 5-day granulocyte colony-stimulating factor (G-CSF) administration (p < 0.0001), with seven patients (16.7 %) given oral potassium administration before apheresis because the treating physician deemed potassium levels potentially unsafe and three (7.1 %) presenting with hypokalemia at apheresis. Potassium levels after apheresis were significantly lower than those before apheresis (baseline; p < 0.0001), and 28 of 42 donors (66.7 %) experienced biochemical, clinically unapparent hypokalemia immediately after the completion of apheresis. A > 15 % reduction in potassium levels from baseline was associated with age and the acid citrate dextrose solution A (ACD-A) volume in univariate analysis. In the multivariable analysis, both factors were associated (hazard ratio [HR], 11.60; 95 % confidence interval [CI], 1.60-83.70; p = 0.02 and HR, 17.50; 95 % CI, 1.07-136.00; p = 0.04). In conclusion, G-CSF administration and apheresis ultimately induced hypokalemia in two-thirds of the donors. Older age and higher ACD-A volume may affect potassium levels during apheresis in healthy donors. Clinical Trial registration: jRCTs061200035.