Intravenous potassium: medication error and hyperkalemia

A 72-year-old woman with heart failure and chronic kidney disease takes furosemide and is hospitalized for decompensation. The morning potassium came back at 3.1 mmol/L, and the doctor prescribed intravenous potassium chloride replacement by slow infusion. At night, because of a pump programming error, the solution runs much faster than prescribed. Two hours later, she says her legs are weak and her heart is "failing". The monitor shows a rate of 48 beats per minute, and the ECG has tall, peaked T waves and a widened QRS. Serum potassium comes back at 7.2 mmol/L. The scene is fictional and was written for teaching.

This text uses the case as a clinical reasoning scenario for nursing. It brings together two topics that are usually taught separately: safety in preparing and administering intravenous potassium and recognition of hyperkalemia at the bedside. The text does not replace your institution's protocol or the medical prescription. If you play the case of the day in NEXO, you will recognize the challenge: linking a vague complaint to a concrete cause before it becomes serious.

Key points

• Concentrated potassium chloride is a high-alert medication; errors in labeling, dilution and rate have already caused deaths.
• Weakness, bradycardia or palpitations in someone receiving potassium call for an ECG and serum potassium right away.
• The ECG helps, but it can be normal even with very high potassium.
• Intravenous calcium protects the heart within minutes, but it does not lower potassium.
• Insulin with glucose and salbutamol move potassium into the cells; dialysis or binders remove it from the body.
• After insulin, blood glucose must be monitored for hours, because hypoglycemia is common.

Why this is a reasoning scenario

Hyperkalemia is an emergency because it can cause fatal arrhythmias. A review on the treatment of severe hyperkalemia sums up the requirement: monitor the ECG and potassium, start therapies that act together and in sequence, and repeat doses at the right time (Abuelo, 2018). The scene adds one element: the cause is a medication error, and nursing is the team at the pump.

The scenario is good for training because the presentation is vague. Leg weakness in an older woman in hospital can be tiredness, a diuretic effect, a drop in blood pressure or simple anxiety. What changes the reading is the question about what is going in through the vein. The post on signs, symptoms and history shows how to read vague complaints, and the post on clinical decision-making discusses how to choose the test that changes management.

What the scene teaches

The scene trains four habits. The first is checking the pump when the patient changes: the programmed rate, the volume already delivered and the solution hanging. The second is knowing that hyperkalemia affects muscle and heart. The third is knowing the treatment sequence, so you can prepare the material before the prescription arrives. The fourth is monitoring blood glucose after insulin.

Intravenous potassium: a high-alert medication

Concentrated potassium chloride is among the high-alert medications, alongside chemotherapy drugs, anticoagulants, opioids and neuromuscular blockers (Salman et al., 2020). Between 1996 and 1998, the American hospital accreditation commission found 10 deaths from wrong administration of potassium chloride, six of them due to identical labels, and recommended that the concentrated product not be available outside the pharmacy without specific safeguards (Kothari et al., 2012).

The causes cited are familiar from routine practice: similar names, similar vials and ampoules, labels of the same color, identical packaging, improper handling, haste and human error in administration (Kothari et al., 2012). In a study with 2,363 nurses from 29 hospitals in Pakistan, prompted by the death of a 9-month-old baby after rapid administration of 15 percent potassium chloride, about 84 percent of participants scored below 70 percent on a test about high-alert medications (Salman et al., 2020).

The potassium bolus

Potassium concentrated in an intravenous bolus can stop the heart. A French report describes a 20-year-old nursing student found in asystole after injecting potassium chloride into herself; beside her were 50 mL syringes and empty 20 mL ampoules at 10 percent (Battefort et al., 2012). The case is extreme, but it shows why potassium should never be pushed as a bolus.

Extravasation

Speed is not the only risk. A Chinese report describes a patient with potassium of 2.4 mmol/L who was supposed to receive potassium chloride diluted through the central venous catheter, but the solution ran through a peripheral vein at 12 mEq per hour for about an hour, until the nurse noticed dark red skin along the path (Yan, 2021). The author recalls that potassium solutions are hypertonic and toxic to tissues and that the prescription should state clearly whether the route is peripheral or central only (Yan, 2021).

Barriers that work

Kothari et al. gather recommendations for pharmacists and multidisciplinary teams on potassium chloride (Kothari et al., 2012). In nursing practice, they come down to simple questions before hanging the bag. Is the solution the one prescribed, and is it diluted? Is the route the indicated one? Was the pump programmed and checked by a second person, if the protocol requires it? Is the patient monitored, if the dose or the rate require it? The table organizes these checkpoints.

Moment	Question	Why it matters
Storage	Is the concentrate kept outside the ward?	Similar labels and ampoules have already caused deaths
Preparation	Are the dilution and volume the prescribed ones?	A concentrated solution is toxic to the vein
Route	Peripheral or central only?	Extravasation can cause necrosis
Pump	Are rate and volume checked?	A programming error changes the dose per hour
During the infusion	Are there symptoms, bradycardia or pain at the access site?	Early signs of hyperkalemia or infiltration

Table sources: (Kothari et al., 2012) and (Yan, 2021).

How hyperkalemia appears on the ECG

High potassium changes the heart's electrical activity. A review describes the progression: increased T wave amplitude (peaked T), PR and QRS prolongation, loss of the P wave, delayed atrioventricular conduction, fusion of the QRS with the T wave into a sine wave pattern and, finally, asystole (Mushiyakh et al., 2011). Clinically, the patient may have palpitations, syncope and sudden death (Mushiyakh et al., 2011).

The review by Lindner et al. recalls that tall, peaked T waves can be early signs, but that the ECG is not very sensitive for detecting hyperkalemia, and that severe hyperkalemia can exist without changes in the tracing (Lindner et al., 2020).

The ECG can be normal

A Japanese case illustrates the warning. A 77-year-old man with kidney disease had potassium of 8.5 mEq/L with a normal ECG; days later, with potassium of 8.6 mEq/L, he presented sine wave ventricular tachycardia (Ryuge et al., 2017). The authors suggest that ECG changes depend not only on the potassium level but also on how fast it rises (Ryuge et al., 2017). This matters in the scene setting, where potassium rises quickly because of the rapid infusion.

In a Hungarian emergency department study, 46 percent of patients with high potassium and 24 percent of patients with normal potassium had some ECG change suggestive of hyperkalemia (Varga et al., 2019). Wide QRS, peaked T, first-degree atrioventricular block and bradycardia were more frequent in severe hyperkalemia (Varga et al., 2019). The lesson is twofold: a normal ECG does not rule it out, and an altered ECG does not confirm it. The blood test remains necessary.

Differential diagnosis

Weakness and bradycardia in a hospitalized older woman have several causes. The table organizes the hypotheses of the scene.

Hypothesis	Clues	What nursing checks
Hyperkalemia	Intravenous potassium in progress, kidney disease	Pump, ECG, serum potassium
Effect of beta-blocker or digitalis	Medication list	Prescription, timing of doses
Hypotension	Diuretic, dehydration	Blood pressure, perfusion
Hypoglycemia	Diabetes, insulin	Capillary glucose
Coronary syndrome	Chest pain, risk factors	ECG, immediate communication

The post about differential diagnosis with clues shows how to organize this list without losing the most dangerous hypothesis.

First minutes: what nursing does

When the nurse suspects that potassium entered too fast, the first measure is to stop the potassium infusion. Then come the safety measures defined by the local protocol: call for help, put the patient on the monitor, perform an ECG, collect serum potassium and keep a working venous access for emergency medications. Abuelo's review reminds us that management requires monitoring the ECG and potassium throughout the entire treatment (Abuelo, 2018).

Communicate clearly

A structured message helps: "72-year-old patient with heart failure and kidney disease, receiving intravenous potassium chloride. The pump ran above the prescribed rate for about two hours. Now leg weakness, rate of 48, ECG with peaked T waves and wide QRS. I stopped the infusion, she is on the monitor, I collected potassium. I request immediate evaluation." This sentence puts cause, severity and what has already been done in seconds.

Prepare the material

While the doctor arrives, nursing can set aside what is usually used in the first hours: intravenous calcium, regular insulin, hypertonic glucose, salbutamol for nebulization and a glucose meter. Setting aside is not administering. Each medication depends on the prescription and the local protocol, but having everything at hand saves minutes.

Treatment on three fronts

Acute treatment of hyperkalemia follows three fronts: protect the heart, shift potassium into the cells and remove potassium from the body (Celebi Yamanoglu and Yamanoglu, 2022). The review by Lindner and colleagues brings an algorithm for the emergency department based on a 2010 systematic review and an observational study; the authors warn that the thresholds for each action are based on opinion (Lindner and colleagues, 2020).

Protect the heart: calcium

Calcium stabilizes the membrane of heart cells and acts in 1 to 3 minutes; another dose can be given in 5 to 10 minutes if there is no effect (Lindner and colleagues, 2020). The algorithm offers two options: 3 times 1 g of calcium gluconate (3 times 10 mL of the 10 percent solution) or 1 g of calcium chloride (10 mL of the 10 percent solution), which contains about three times more calcium per milliliter (Lindner and colleagues, 2020). The European Resuscitation Council recommends 10 mL of 10 percent calcium chloride over 2 to 5 minutes in hyperkalemia with ECG changes (Lindner and colleagues, 2020). When potassium is known and there is no ECG or monitor immediately available, the authors suggest giving calcium to all patients with potassium above 6.5 mmol/L (Lindner and colleagues, 2020).

Two limits matter. Calcium does not lower potassium, and its effect lasts 30 to 60 minutes (Lindner and colleagues, 2020). In a Turkish prospective study with 111 patients, calcium gluconate improved some rhythm disturbances, but not the other ECG changes (Celebi Yamanoglu and Yamanoglu, 2022). Therefore, calcium buys time; it does not solve.

Shift potassium into the cells

Insulin shifts potassium into the cells. A systematic review concluded that 10 units of insulin lower potassium as much as 20 units, with less hypoglycemia, and that 25 to 50 g of glucose should be given intravenously together with insulin (Lindner and colleagues, 2020). Studies with 5 units of insulin showed no difference in potassium drop compared to 10 units, with less hypoglycemia (Lindner and colleagues, 2020). In the algorithm, 5 units of intravenous regular insulin with 25 g of glucose (50 mL of 50 percent glucose) are as effective as 10 mg of nebulized salbutamol, and the two can have an additive effect (Lindner and colleagues, 2020). With blood glucose above 200 mg/dL (11.1 mmol/L), insulin can be given without additional glucose (Lindner and colleagues, 2020).

Hypoglycemia after insulin

Here nursing plays a central role. A scoping review of 62 studies found hypoglycemia in 17.2 percent of hospitalized adults treated with insulin for hyperkalemia, with a median of 124 minutes after the insulin (Chothia et al., 2022). The authors note that hypoglycemia can appear up to six hours after treatment and that glucose must be measured frequently (Chothia et al., 2022). In an Australian study, the incidence was 21 percent with the regimen of 10 units of insulin and 25 g of glucose; a filtration rate below 60 was associated with more risk (odds ratio of 2.47), and the episodes clustered between 60 and 150 minutes (Crnobrnja et al., 2020). In a study of patients on hemodialysis, 13 percent of the episodes treated with insulin ended in hypoglycemia, more often in those without diabetes and in those with lower glucose before treatment (Apel et al., 2014).

The patient in the scene has kidney disease, which increases the risk. Measuring glucose at set times in the following hours is a nursing task that changes the outcome.

Removing potassium from the body

The measures that remove potassium include diuretics, potassium binders and dialysis (Celebi Yamanoglu and Yamanoglu, 2022). The Lindner algorithm lists sodium polystyrene sulfonate and sodium zirconium cyclosilicate as binders and points to hemodialysis as the preferred modality when removal is needed (Lindner et al., 2020). Abuelo argues that bicarbonate, polystyrene sulfonate and hemodialysis with a low-potassium dialysate remain useful in the treatment of severe hyperkalemia (Abuelo, 2018). A review of records at one hospital showed that, in 71 percent of patients, the exchange resin was given without an adequate indication, without other measures or when contraindicated (Mushiyakh et al., 2011).

Step-by-step reasoning in the case

First, the suspicion: an older woman with kidney disease receiving intravenous potassium, with weakness and bradycardia. The first question is what is running in the pump.

Second, the immediate action: stop the potassium infusion, call for help, monitor, ECG and serum potassium.

Third, the severity: peaked T waves and a wide QRS, potassium of 7.2 mmol/L. This is severe hyperkalemia, above 7 mmol/L (Crnobrnja et al., 2020).

Fourth, the sequence: calcium to protect the heart, insulin with glucose and salbutamol to shift the potassium into the cells, and a strategy to remove it, as prescribed.

Fifth, the monitoring: continuous ECG, repeat potassium and glucose in the following hours.

Sixth, the cause and the record: a pump programming error, reported as a high-alert medication event.

Common errors

The first error is attributing the weakness to tiredness without looking at the pump.

The second error is relying on a normal ECG to rule out hyperkalemia (Ryuge et al., 2017).

The third error is thinking the calcium solved it, when it only protects for 30 to 60 minutes (Lindner et al., 2020).

The fourth error is forgetting glucose after the insulin, especially in kidney disease (Crnobrnja et al., 2020).

The fifth error is treating the episode and not reporting the medication error, which leaves the same failure ready for the next patient.

After the episode

The report is not meant to blame the colleague who programmed the pump. It is meant to understand what made the error easier: the pump without a medication library, the double check that did not happen, the prescription that did not state the maximum rate. Recommendations on potassium chloride insist on safeguards in storage, preparation and administration (Kothari et al., 2012). The post about diagnostic pause shows how to stop and review the picture before going on.

How NEXO helps train this reasoning

To use the case of the day as training, try three habits. Before your first guess, ask what the patient is receiving and whether that would explain the picture. With each clue, ask whether it speaks of cause or of severity. After the result, note the clue you ignored because it seemed trivial.

Three exercises with cases

Link the medication to the symptom. In each case, list the medications and solutions that could explain the picture.

Order the treatment. Write the sequence of measures and the reason for each one.

Plan the monitoring. Say what you will measure, and when, over the next six hours.

The post on simulation of care shows how to train patient assessment, and the post on interprofessional clinical reasoning discusses how nursing, medicine and pharmacy decide together. The post on case-based learning in clinical practice shows how cases help fix these habits, and the post on diagnostic uncertainty discusses how to decide when the data still do not add up.

The limits on using the game are described on the NEXO Economy page. If you research the teaching of clinical reasoning, the page for Researchers explains how to get in touch. Professionals who write or review cases find information on Curator and Creators, and institutions can learn about the proposal on the partnerships page.

Frequently asked questions

Does a normal ECG rule out hyperkalemia?

No. The ECG is not very sensitive, and there are cases of potassium above 8 with a normal tracing (Lindner et al., 2020) (Ryuge et al., 2017).

What is the calcium dose?

The Lindner algorithm gives 3 times 10 mL of 10 percent calcium gluconate or 10 mL of 10 percent calcium chloride, with a new dose in 5 to 10 minutes if there is no effect (Lindner et al., 2020). Follow the prescription.

What is the insulin and glucose dose?

The algorithm gives 5 units of regular intravenous insulin with 25 g of glucose; the review cited by the authors uses 10 units with 25 to 50 g of glucose (Lindner et al., 2020).

For how long should blood glucose be monitored?

Hypoglycemia appears most often around two hours after insulin and can arise up to six hours later (Chothia et al., 2022).

Can potassium be given as a bolus?

No. Concentrated potassium as a bolus can cause cardiac arrest (Battefort et al., 2012).

Final checklist

• I checked the solution, dilution, route and rate before starting potassium.
• When faced with weakness, bradycardia or palpitations, I looked at the pump first.
• I stopped the infusion, called for help, monitored and did an ECG and serum potassium.
• I did not rely on a normal ECG to rule out hyperkalemia.
• I prepared calcium, insulin, glucose and salbutamol according to protocol.
• I monitored blood glucose in the hours after insulin.
• I repeated the potassium and kept the monitor on.
• I reported the medication error.

Want to practice reasoning with progressive clues? Play the case of the day.

References

1. Abuelo JG. Treatment of Severe Hyperkalemia: Confronting 4 Fallacies. Kidney Int Rep. 2018. PMID 29340313.
2. 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. PMID 25852884.
3. Battefort F, Dehours E, Vallé B, et al. Suicide attempt by intravenous potassium self-poisoning: a case report. Case Rep Emerg Med. 2012. PMID 23326708.
4. Celebi Yamanoglu NG, Yamanoglu A. The effect of calcium gluconate in the treatment of hyperkalemia. Turk J Emerg Med. 2022. PMID 35529029.
5. Chothia MY, Humphrey T, Schoonees A, et al. Hypoglycaemia due to insulin therapy for the management of hyperkalaemia in hospitalised adults: A scoping review. PLoS One. 2022. PMID 35552566.
6. Crnobrnja L, Metlapalli M, Jiang C, Govinna M, Lim AKH. The Association of Insulin-dextrose Treatment with Hypoglycemia in Patients with Hyperkalemia. Sci Rep. 2020. PMID 33328554.
7. Kothari D, Kothari S, Agrawal J. Potassium chloride: A high risk drug for medication error. Indian J Anaesth. 2012. PMID 22529434.
8. Lindner G, Burdmann EA, Clase CM, et al. Acute hyperkalemia in the emergency department: a summary from a Kidney Disease: Improving Global Outcomes conference. Eur J Emerg Med. 2020. PMID 32852924.
9. Mushiyakh Y, Dangaria H, Qavi S, et al. Treatment and pathogenesis of acute hyperkalemia. J Community Hosp Intern Med Perspect. 2011. PMID 23882341.
10. Ryuge A, Nomura A, Shimizu H, Fujita Y. Warning: The ECG May Be Normal in Severe Hyperkalemia. Intern Med. 2017. PMID 28781297.
11. Salman M, Mustafa ZU, Rao AZ, et al. Serious Inadequacies in High Alert Medication-Related Knowledge Among Pakistani Nurses: Findings of a Large, Multicenter, Cross-sectional Survey. Front Pharmacol. 2020. PMID 32765259.
12. Varga C, Kálmán Z, Szakáll A, et al. ECG alterations suggestive of hyperkalemia in normokalemic versus hyperkalemic patients. BMC Emerg Med. 2019. PMID 31151388.
13. Yan G. Extravasation of Concentrated Potassium Chloride: A Case Report. Curr Ther Res Clin Exp. 2021. PMID 34745392.