Gina Bartlett examines hyperkalemia, an uncommon medical emergency that EMS providers should know how to manage.
Scenario
You are requested to respond to a residence for a female found unresponsive. The patient’s son is on scene and tells dispatch that his mother is “out of it and not responding appropriately.”
When you arrive on scene, you find the patient lying in her bed covered in feces. The patient has a GCS of 10 and is responsive to painful stimuli. Her medical history consists of Addison’s disease, colon cancer, a stroke and a brain tumor. When you check the patient’s blood sugar, it is within normal limits. The patient’s four lead shows sinus tachycardia. Radial pulses are absent and both automatic and manual blood pressures are unobtainable. A 12-lead EKG is done and is unremarkable. The patient does not have any veins suitable for venous access, so an IO is placed in the left tibia and is flushed with 40mg Lidocaine to numb the area. A one-liter bag of fluid is pressure infused and the patient is moved to the stretcher. She then becomes unresponsive.
You load her into the back of the ambulance and begin to prepare push dose epinephrine to attempt to increase her blood pressure when your partner says to you, “take a look at her EKG – something changed.” You notice a sine-wave pattern and the patient’s heart rate has decreased to 70 beats per minute. You instruct your partner to drive emergent to the hospital while you call a doctor for a medical consult. He tells you he is concerned about hyperkalemia and instructs you to slowly administer one gram of calcium chloride through the IO. After hanging up with the physician, the patient’s rhythm changes to asystole on the monitor and a carotid pulse is no longer present. CPR is initiated as you’re pulling into the ambulance bay. Care is transferred to the receiving facility and you’re left wondering what happened to your patient.
Hyperkalemia
Potassium is an incredibly important ion in the human body. It is an electrolyte that aids in the function of our nerves and muscles.1 It also helps regulate our heart’s electrical activity and maintain normal fluid levels.1 It is mostly intracellular, and this property is maintained by the sodium-potassium pump.2 Changes in the extracellular potassium level, no matter how small, can have significant effects on both the cardiovascular and neuromuscular systems, potentially leading to hyperkalemia.
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Hyperkalemia is defined as “a measured serum potassium of 5.0 mEq/L.3 It can be categorized as either mild, moderate, or severe.3 Normal potassium levels are between 3.5-5.1 mEq/L.4 Mild hyperkalemia consists of potassium levels between 5.2-5.9 mEq/L, moderate hyperkalemia is 6.0-7.0 mEq/L, and severe hyperkalemia is considered anything above 7.0 mEq/L.4 Typically, most patients can live at any of these three levels and be asymptomatic.3 When symptomatic, a patient may complain of the following symptoms: generalized fatigue, weakness, paresthesia, paralysis and palpitations.2 In patients with severe hyperkalemia, palpitations, shortness of breath, chest pain, nausea, or vomiting may occur.5 If left untreated, severe hyperkalemia may cause ventricular fibrillation or asystole, resulting in cardiac arrest.4
Hyperkalemia has a few different causes. One cause is decreased or impaired potassium excretion. This insufficiency is seen in patients with acute or chronic renal failure, sickle cell disease, Addison’s disease, and systemic lupus erythematosus.2 Another cause is excess potassium in the intracellular space, which can be caused by potassium supplements, rhabdomyolysis and hemolysis.2 Additionally, the transmembrane shifts that occur during acidosis and from medications such as beta-blockers and succinylcholine can result in hyperkalemia.2 Finally, crush syndrome can cause hyperkalemia in trauma patients. Crush syndrome occurs when toxins are released from crushed muscle tissue.6 The onset of symptoms is typically delayed by four-to-six hours but can occur as soon as 60 minutes after the incident.6 Crush syndrome can ultimately result in kidney failure, causing potassium to be excreted from the damaged cells and result in hyperkalemia.6 Identification of this electrolyte imbalance in the prehospital setting is challenging but possible if the prehospital care provider knows what to look for.
Identification
The signs and symptoms of hyperkalemia are not unique to this condition, which can make it difficult for the prehospital care provider to identify. However, a major tool the provider has at their disposal is the 12-lead EKG.
EKG changes are not uncommon in hyperkalemic patients, especially as their potassium levels continue to rise. These changes occur due to the effect the increased potassium has on the heart’s myocytes.7 Peaked T waves, widening of the QRS complex, prolonged PR interval, bradycardia, first-degree AV block, and a sine-wave pattern are all indicative of hyperkalemia.4 Certain changes, such as wide QRS, bradycardia, peaked T waves, and first-degree AV block are more common in severely hyperkalemic patients.4 Peaked T waves are considered to be the earliest sign that the patient’s potassium level might be elevated.4 A wide QRS complex is the most common EKG change in these patients.4 Once a patient’s potassium level surpasses 8.0 mEq/L, the EKG will take on the sine-wave pattern.7
Management
While mild hyperkalemia is not typically life-threatening, severe hyperkalemia is and should be treated as such. Treatment in the prehospital setting is not as aggressive as it would be in the emergency department, but for certain patients it could mean the difference between life and death.
The goal when treating the hyperkalemic patient is to reverse the transmembrane shift that occurred due to excess potassium. EMS providers carry three pharmacological agents that may work: calcium chloride, albuterol, and sodium bicarbonate.3 These drugs will stabilize the patient while en route to the receiving facility.
Calcium chloride “stabilizes the cardiac membrane and reduces myocardial irritability.”3 It acts quickly and is considered the first line of treatment when severe hyperkalemia is suspected.2 As previously mentioned, hyperkalemia can have a negative influence on the myocytes of the heart, which is why it’s important to attempt to stabilize these cells.
Albuterol is a beta-adrenergic agonist and works to reverse the transmembrane shift by increasing the plasma insulin concentration.2,3 In hyperkalemic patients, it is important to give a dose that is two to four times the typical amount that would be given to respiratory patients.2
Sodium bicarbonate is an alkalinizing agent and is beneficial for these patients as it can help with acidosis.3 It also assists in reversing the transmembrane shift by neutralizing the hydrogen ions and increasing the pH.2,3
While none of these drugs are the final treatment for hyperkalemia, they will have a positive impact on the patient and stabilize them long enough to get them to definitive care.
Conclusion
While hyperkalemia is not a common medical emergency most providers encounter, it is important to know what it is, how to identify it, and how to manage it. The 12-lead EKG has been proven to be a great diagnostic tool for this condition. It is also important to know that certain diseases or injuries can increase an individual’s chances of becoming hyperkalemic. All of this information, in addition to medical command physicians, can work to provide a field diagnosis of hyperkalemia. Treatment will be administered sooner, and for some patients that could be the difference between life and death.
References
1. U.S. National Library of Medicine. (2021, November 19). Potassium. MedlinePlus. Retrieved March 28, 2022, from https://medlineplus.gov/potassium.html
2. Garth, D. (2021, July 22). Hyperkalemia in emergency medicine treatment & management: Prehospital Care, emergency department care, consultations. Hyperkalemia in Emergency Medicine Treatment & Management: Prehospital Care, Emergency Department Care, Consultations. Retrieved February 25, 2022, from https://emedicine.medscape.com/article/766479-treatment
3. Barrow, M. (2020, September). EMS Treatment of Hyperkalemia. EMS World. Retrieved February 25, 2022, from https://www.hmpgloballearningnetwork.com/site/emsworld/article/1224770/ems-treatment-hyperkalemia
4. Varga, C., Kálmán, Z., Szakáil, A., Drubits, K., Koch, M., Bánhegyi, R., Oláh, T., Pozsgai, É., Fülöp, N., & Betlehem, J. (2019). ECG alterations suggestive of hyperkalemia in normokalemic … BMC Emergency Medicine. Retrieved February 25, 2022, from https://bmcemergmed.biomedcentral.com/track/pdf/10.1186/s12873-019-0247-0.pdf
5. What is hyperkalemia? National Kidney Foundation. (2022, March 7). Retrieved March 28, 2022, from https://www.kidney.org/atoz/content/what-hyperkalemia
6. Parrish, A., Tagore, A., Ariyaprakai, N., Hohbein, J. L., DiCorpo, J. E., & Merlin, M. A. (2021, August 31). Managing the toxic chemical release that occurs during a crush injury – jems: EMS, emergency medical services – training, paramedic, EMT News. JEMS. Retrieved March 5, 2022, from https://www.jems.com/patient-care/trauma/managing-the-toxic-chemical-release-that-occurs-during-a-crush-injury/
7. Zaher, M., & Lafferty, J. (2009, July 7). Electrophysiologic basis of the EKG changes of hyperkalemia. HCPLive. Retrieved March 28, 2022, from https://www.hcplive.com/view/electrophysiologic_basis
8. Lederer, E. (2021, October 17). What are the typical ECG findings in severe hyperkalemia (high serum potassium levels)? Latest Medical News, Clinical Trials, Guidelines – Today on Medscape. Retrieved February 25, 2022, from https://www.medscape.com/answers/240903-11015/what-are-the-typical-ecg-findings-in-severe-hyperkalemia-high-serum-potassium-levels
