Hyperkalaemia Following Blood Transfusion–a Systematic Review Assessing Evidence and Risks

Hyperkalaemia following transfusion is widely reported in the literature. Our objective was to critically review recent evidence on hyperkalaemia in association with transfusion and to assess whether specific aspects of transfusion practice can affect the likelihood of developing hyperkalaemia. We searched 9 electronic databases (including MEDLINE, Embase, and Transfusion Evidence Library) using a predefined search strategy, from 2010 to April 8, 2021. Three reviewers performed dual screening, extraction, and risk of bias assessment. We used Cochrane risk of bias (ROB) 2 for assessment of RCTs, ROBINS-I for non-RCTs, and GRADE to assess the certainty of the evidence. We report 7 comparisons of interest in n = 3729 patients from 28 studies (11 RCTs, 4 prospective cohort studies, and 13 retrospective cohort studies): (1) age of blood, (2) washing, (3) filtration, (4) irradiation, (5) fluid type, (6) transfusion vs no transfusion, (7) blood volume/rate. Of the 28 studies included, 25 reported outcomes of potassium (K+) concentration, 17 the number developing hyperkalaemia, 13 mortality, 10 cardiac arrest, and 10 cardiac arrhythmia. Only 16 studies provided analysable data suitable for quantitative analysis. Evidence addressing our outcomes was of very low certainty (downgraded for incomplete outcome data, baseline imbalance, imprecision around the estimate, and small sample size). While 5 studies showed a difference in K+ concentration up to 6 hours posttransfusion for 3 comparisons (age of blood, washing, and transfusion volume/rate), and 3 studies showed a difference in the diagnosis of hyperkalaemia for 2 comparisons (age of blood, and transfusion volume/rate), the evidence was inconsistent across all included studies. There was no difference in any reported outcomes for 4 comparisons (filtration, irradiation, fluid type, or transfusion vs no transfusion). Overall, the reported evidence was too weak to support identification of groups most at risk of hyperkalaemia or to support recommendations on use of short-storage RBC. For other commonly used risk mitigations for hyperkalaemia in transfusion medicine, the (low certainty) evidence was either conflicting or not supportive.