Written by Thomas Davis
Administering 10 units of IV regular insulin plus 25g of IV dextrose causes highly variable changes in blood sugar. Delayed hypoglycemia is common, requiring frequent glucose monitoring.
Why does this matter?
Among patients with hyperkalemia, insulin is one of the most effective methods of pushing potassium back into the cells. However, IV dextrose generally only lasts about 1 hour whereas IV insulin will last 2-3 hours. Several studies have shown that giving insulin with only 25g of IV dextrose often leads to hypoglycemia. But just how much of a drop in blood glucose can you expect?
That’s an upstairs problem (or at least it should be).
This was a multicenter, retrospective cohort study at three hospitals. They evaluated 90 patients who received 10 units of IV insulin plus 25g of IV dextrose. Patients were excluded if they received albuterol, dextrose infusions, or insulin injections in the preceding 24 hours. Baseline glucose was 119 mg/dL (IQR 91 – 160) and creatinine clearance was 19 mL/min (IQR 11- 33). All patients had at least one follow-up glucose check within 6 hours. 51% had two glucose checks, and 31% had three glucose checks. There was a transient increase in blood glucose during the first hour followed by a decrease in glucose in the subsequent hours. Median blood glucose change was -24 mg/dL (IQR -53 to +6). In all, 22% developed hypoglycemia. Although the study is limited by its retrospective design, it is a good reminder to vigilantly monitor for hypoglycemia in the hours following insulin administration and to consider giving additional dextrose beyond the traditional 25g bolus.
Blood glucose reduction in patients treated with insulin and dextrose for hyperkalaemia. Emerg Med J. 2019 Oct 25. pii: emermed-2019-208744. doi: 10.1136/emermed-2019-208744. [Epub ahead of print]
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Reviewed by Clay Smith