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Medication Errors During Insulin Administration for Patients with Hyperkalemia

Hyperkalemia is a serious, potentially lethal electrolyte disturbance that requires medical treatment without delay if it is severe enough to cause disturbances in cardiac conduction. Although hyperkalemia treatment guidelines in the literature vary,1 many organizations begin treatment with the administration of one or more intravenous (IV) bolus doses of 50% dextrose and an IV bolus dose of 10 units of insulin. Some organizations use a rapid-acting insulin (i.e., insulin aspart, insulin lispro) rather than short-acting insulin (i.e., regular insulin) because it may decrease the incidence of hypoglycemia, given its shorter half-life.1

Errors When Treating Hyperkalemia

When treating hyperkalemia, the potential for errors and patient harm is significant due to the urgency of the treatment, the difficulty in measuring and administering bolus doses of IV insulin, and the risk of treatment-induced hypoglycemia. A 2017 analysis of almost 200 adverse events associated with hyperkalemia treatment showed that delayed treatment and administration of insulin by the wrong route or the wrong dose (mostly overdoses) were the most common types of errors.1 The analysis also showed that, despite the administration of dextrose, hypoglycemia was still a relatively common occurrence often linked to the variability in dextrose and insulin dosing, the type of insulin used, duration of the dextrose and insulin infusion, the sequence of administering the dextrose and insulin, and patient factors such as renal dysfunction. Some episodes of hypoglycemia have also been caused by administering only the insulin portion of the treatment and not the glucose component.2

Causes of Errors

Delays. Most delays have occurred because treatment was postponed until patients were transferred to another unit, or there were no immediate signs of changes on a patient’s electrocardiogram (EKG). Although the effects of hyperkalemia can be detected on an EKG as peaked T waves, a prolonged PR-interval, and a widened QRS-interval,1 an EKG is a poor indicator of hyperkalemia severity; thus, patients with hyperkalemia who meet criteria for treatment based on their potassium level should be treated without delay even in the absence of EKG changes, because even benign changes can quickly progress to lethal arrhythmias.3 

Wrong route. Some insulin wrong route errors have occurred during order entry when IV insulin was prescribed by the subcutaneous route. This was sometimes caused by an automatic default to the subcutaneous route for routine insulin prescribed outside of standard order sets that had been developed for IV insulin. In these cases, the prescriber did not use the hyperkalemia order set to prescribe the insulin, or no such order set existed. In other cases, the IV insulin was mistakenly administered subcutaneously, perhaps because it was a more familiar route of administration. Insulin should be given IV when treating hyperkalemia to promote consistent bioavailability.1,4

Dosing errors. Most dosing errors have involved measuring insulin doses in mL instead of units (e.g., 10 mL instead of 10 units), misreading the measurement markings on syringes, and not understanding the differences between insulin syringes and other parenteral syringes. Some dosing errors have occurred because practitioners failed to recognize that the U-100 strength of insulin equates to 100 units in each mL, and they were either practicing outside of their scope of practice or had never been taught to administer insulin IV.2,3 Providing the required insulin in vials rather than the exact dose, particularly without directions for measuring the dose, has also contributed to errors. In a 2011 analysis, we found that human error (e.g., mental slips, lapses, forgetfulness) associated with insulin dose measurement and hyperkalemia treatment was a predominant cause of dosing errors.2

However, at the crux of many of these errors is the lack of a luer-compatible insulin syringe without a needle that can be used to measure and administer IV insulin via needleless access devices and lines. Most insulin syringes in hospitals have an attached needle appropriate for subcutaneous administration of medications. Also, some hospitals are only using insulin pens, which are likewise an inappropriate device to measure and administer IV insulin doses via a needleless system. This has resulted in several unsafe practices, including: 1) distribution of hyperkalemia treatment kits that, instead of insulin syringes without a needle, contain a tuberculin syringe and vial of rapid- or short-acting insulin; 2) calculating the volume of insulin needed for each dose so a luer-compatible (non-insulin) syringe can be used for administration, which has resulted in calculation and measurement errors; and 3) measuring doses in an insulin syringe, and then transferring the dose to a parenteral syringe for IV administration, which can lead to dose inaccuracies and infection control breaches.

Examples of Recent Errors

Several recent insulin errors during hyperkalemia treatment have been reported to ISMP or have appeared in the literature. For example, just this month, we learned about an error in which a nurse correctly calculated the volume needed for a 10 unit dose of insulin lispro, but accidentally measured out 20 units of insulin using a 10 mL non-insulin syringe. A physician prescribed treatment that included calcium gluconate 1 g IV, insulin lispro 10 units IV, and dextrose 50% IV. The nurse calculated that she would need 0.1 mL of the insulin for the 10 unit dose, and a nurse manager verified the calculation. Using a 10 mL syringe, she drew the insulin lispro into the syringe up to the first gradation mark, believing this represented 0.1 mL. But the first syringe marking was actually 0.2 mL. The nurse manager did not verify the dose in the syringe prior to administration. The error was quickly discovered when a clinical nurse specialist asked the nurse, who had just completed orientation, to demonstrate how she had measured the insulin dose in a 10 mL syringe. The patient’s blood glucose was monitored, and she experienced no adverse effects.

Another event appeared in recent literature involving a medical resident working in interventional radiology (IR) who gave the wrong dose of insulin to a hemodialysis patient with hyperkalemia.3 The hospitalized patient was scheduled for replacement of her dialysis access in IR. On the day of the procedure, her potassium level was 5.9 mmol/L, and she was treated with KAYEXALATE (sodium polystyrene sulfonate). A repeat potassium level was drawn, and the result, 6.9 mmol/L, was reported to IR during the procedure. Because the patient was stable without EKG abnormalities, treatment was delayed until after the procedure.

When the procedure had been completed, a resident went to the pharmacy to request the medications needed for hyperkalemia treatment, including 10 units of regular insulin. The pharmacy dispensed a 3 mL vial of U-100 regular insulin without clarification that only 0.1 mL would be needed for a 10 unit dose. The resident mistakenly administered the entire vial of insulin (300 units) instead of 10 units. He had little prior experience measuring and preparing insulin doses since medication administration of this type was not within his scope of practice.

When the dosing error was identified, a rapid response team was called. The patient was treated with a 10% dextrose infusion along with 4 bolus doses of 50% dextrose in the first 30 minutes, and then dialysis. The patient was transferred to an intensive care unit (ICU) and able to tolerate meals with carbohydrates to provide a more physiological delivery of glucose. Glucose and potassium levels stabilized, and the patient was transferred out of the ICU within 2 days.

Recommendations

Treatment protocols. Establish standard hyperkalemia protocols that specify the threshold for treatment based on severity (e.g., potassium level above which to act), the corresponding pharmacological and clinical interventions, and monitoring parameters to gauge the patient’s response to the treatment. Ensure adequate monitoring of glucose levels and signs and symptoms of hypoglycemia during treatment, even if dextrose is being administered, and for several hours after insulin administration. Hypoglycemia may occur up to 6 hours after dextrose and insulin administration, especially if the patient has renal dysfunction.1,5

In the protocols, also specify the insulin type, dose, and route of administration, and how to flush the IV line or access site, if necessary, to ensure the small volume of insulin has been fully administered; the concomitant dextrose concentration, volume, and route of administration; and specific doses and administration for all other pharmacological interventions (e.g., sodium bicarbonate, calcium chloride/gluconate, furosemide).

Standard order sets. Create standard order sets for hyperkalemia treatment and require their use. Treatment should only be prescribed using a standard order set that is automatically populated with the correct dose and route of administration for the required medications, including insulin. If the insulin dose is to be administered IV push via a syringe, include on the order set a reminder to use a luer-compatible insulin syringe without a needle, and to flush the line or access site if necessary to ensure the small volume of insulin has been fully administered. These reminders should also appear on the medication administration record.

Treat at threshold. Do not delay treatment of hyperkalemia based on the absence of symptoms or EKG changes once an established severity threshold for treatment has been reached. If transfer to another unit is necessary, accomplish the handoff as soon as possible so treatment can begin.

Pharmacy preparation or kits. Have pharmacy prepare, label, and dispense IV insulin doses in a ready-to-use form, either in a luer-compatible insulin syringe that can connect to a needleless system, or diluted in a small minibag. Although hyperkalemia is a medical emergency, the administration of insulin, in most circumstances, can wait until a pharmacist prepares a stat dose. If 24-hour pharmacy service is not available, stock hyperkalemia treatment kits on patient care units in automated dispensing cabinets (ADCs). The kits should contain 50% dextrose injection along with a 3 mL vial of rapid- or short-acting insulin (to lessen the potential amount of insulin a patient could receive in error), a luer-compatible insulin syringe, a removable needle or transfer device to withdraw the insulin from the vial to the syringe, a label for the syringe (to apply after preparation but before administration), a vial or syringe of a compatible flush solution, alcohol swabs, and directions for preparing and administering the dose. Other medications needed for hyperkalemia treatment can typically be obtained from a code cart or ADC but may be provided in the kit if necessary.

Luer-compatible insulin syringes. Carefully evaluate whether luer-compatible needleless insulin syringes are needed in certain patient care units (e.g., critical care, emergency department). BD and Monoject offer these syringes; for an example, click here. Due to the risk of inadvertent use for subcutaneous insulin doses that could then be accidentally administered IV, limiting use of these syringes for pharmacy-dispensed insulin doses or in hyperkalemia kits is preferred. If the syringes are made available in certain units, separate their storage from other insulin and parenteral syringes (e.g., stock only in code carts, away from other syringes) so they are less likely to be inadvertently mixed up, and ensure they are not automatically removed from stock due to low use.

Double check. Require an independent double check of all IV insulin doses to confirm the patient and the insulin type, concentration, dose, amount in the syringe, route of administration, and indication prior to administration.

Education. Provide education to all practitioners and students who might prescribe, dispense, and administer medications used to treat hyperkalemia, including IV insulin. Don’t assume that all practitioners are knowledgeable and skilled with measuring doses and administering IV insulin. Cover the types and concentration of insulin used during treatment, recognition of safe dosage ranges, the availability of luer-compatible insulin syringes, the differences between insulin syringes and other parenteral syringes, how to measure insulin doses, and how to administer IV insulin. Clearly define the scope of practice for practitioners that allows or disallows IV insulin administration, and restrict insulin preparation and/or administration to those who have demonstrated competency.

References

  1. Lawes S, Gaunt M, Grissinger M. Treating hyperkalemia: avoiding additional harm when using insulin and dextrose. Pa Patient Saf Advis. 2017;14(3).
  2. ISMP. Misadministration of IV insulin associated with dose measurement and hyperkalemia treatment. ISMP Medication Safety Alert! 2011;16(16):1-3.
  3. Hewitt DB, Barnard C, Bilimoria KY. Insulin dosing error in a patient with severe hyperkalemia. JAMA. 2017;318(24):2485-6.
  4. Kes P. Hyperkalemia: a potentially lethal clinical condition. Acta Clin Croat. 2001;40(3):215-25.
  5. Apel J, Reutrakul S, Baldwin D. Hypoglycemia in the treatment of hyperkalemia with insulin in patients with end-stage renal disease. Clin Kidney J. 2014;7(3):248-50.