Intravenous calcium salts for hyperkalemia-associated ECG abnormalities: a systematic review

Background: Intravenous (IV) calcium salts are recommended for hyperkalemia with electrocardiographic (ECG) abnormalities to stabilize myocardial excitability. The clinical evidence support this practice is limited and heterogeneous. We aimed to systematically review articles about IV calcium salts, calcium gluconate or calcium chloride, for hyperkalemia associated ECG abnormalities. Methods: A PRISMA based systematic review was designed for PubMed, Scopus, and Web of Science. Eligible studies were original human studies, prospective, retrospective cohorts, case series, and case reports, about hyperkalemia associated ECG abnormalities and administration of IV calcium salts with reported ECG or short term response. Reviews, editorials, and purely non-interventional ECG association studies were excluded. We extract data about study design, patient characteristics, potassium level, ECG findings, calcium salt, dose, co-interventions, and reported response. Results: Ten original studies were included. Most reports used IV calcium gluconate, one case show early calcium chloride IV push, and one recurrent arrest episode included calcium chloride during resuscitation. In case reports, ECG abnormalities included third degree AV block, severe bradyarrhythmia, sinus arrest with escape rhythms, QRS widening, and conduction disturbances in BRASH syndrome. Clear immediate clinical improvement associated with IV calcium was described in several cases as shock reversal, QRS narrowing, and rhythm stabilization, but attribution was confounded by concurrent insulin dextrose, beta agonists, bicarbonate, and dialysis. The largest prospective cohort found no significant effect on non-rhythm ECG abnormalities but a significant improvement in a subset of rhythm disorders. Conclusions: IV calcium salts for hyperkalemia associated ECG abnormalities is dominated by low level evidence plus one single center prospective observational study showing limited benefit in rhythm disturbances.