Various intravenous (IV) insulin regimens are used to treat acute hyperkalemia. Now, a systematic review finds no significant differences in the potassium-lowering effect of common insulin doses and routes of administration.
In a hyperkalemic emergency, the standard recommendation is to administer 10 units of short-acting insulin as an IV bolus. The evidence supporting this method has been unclear, however. So Ziv Harel, MD, and Kamel S. Kamel, MD, of St. Michael’s Hospital in Toronto, conducted a review of randomized controlled trials and observational studies from 1946 to 2015. Perioperative hyperkalemia was excluded, as was hyperkalemia treated with other therapies, such as diuretics. The definition of hyperkalemia varied, with some studies using a floor of 5 mmol/L, and others a floor of 6 mmol/L. Some did not specify their criteria.
The researchers identified 11 studies: 7 examined an insulin regimen of 10 units (bolus or infusion), 3 an insulin regimen of 20 units infused over 60 minutes, and 1 an insulin regimen of 12 units infused over 30 minutes.
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Results showed no statistically significant difference in average decrease of serum potassium concentration at 60 minutes after the start of insulin between 20 units of insulin infused over 60 minutes and 10 units administered as a bolus (0.79 vs 0.78 mmol/L). Likewise, the study revealed no meaningful difference in potassium lowering between a 20 unit infusion and a 10 unit infusion (0.79 vs 0.39 mmol/L).
“Accordingly, 10 units of short acting insulin given intravenously may be used in cases of hyperkalemia,” Drs Harel and Kamel wrote in PLOS One. “Alternatively, 20 units of short acting insulin may be given as a continuous intravenous infusion over 60 minutes in patients with severe hyperkalemia (i.e., serum K+ concentration > 6.5 mmol/L) and those with marked EKG changes related to hyperkalemia (e.g., prolonged PR interval, wide QRS complex) as an alternative to 10 units of short acting insulin.”
Overall, 18% of patients experienced hypoglycemia. The investigators noted that more patients given a low dose of 25 g of glucose experienced hypoglycemia. Therefore, they recommend 60 g glucose with the administration of 20 units of insulin and 50 g glucose with the administration of 10 units of insulin to prevent hypoglycemia.
The researchers acknowledged a high degree of bias and heterogeneity among the studies and suggested a high-quality randomized controlled trial be performed in the future.
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