How to use 12-lead EKG, patient history to recognize hyperkalemia

This case illustrates the EKG changes from hyperkalemia secondary to missing dialysis


Article updated August 2, 2017

Medic 31 is dispatched for a "male not feeling well" and he has missed a dialysis appointment because he felt so bad.

Given the rapid decline in the patient’s EKG findings, mentation, circulation and history of renal insufficiency, you suspect acute hyperkalemia. You start two large bore IVs quickly with your partner’s assistance. You allow crystalloid solution to infuse rapidly as you bolus a gram of calcium chloride in one IV. In the other IV, you bolus 100 meq of sodium bicarbnonate. You ask your partner to start an albuterol nebulizer and prepare the BVM with the connectors, should you need to bag it in order to ventilate the patient. This gives you the opportunity to contact online medical control to provide a report. The physician on the radio suggests that you now begin a rapid transport to the closest major facility that is equipped for dialysis.

Enroute to the hospital, the patient’s condition ceases to worsen, although no improvement is apparent. The emergency department physician meets you at the door and listens to your report. As you move the patient into one of the larger rooms, you notice a dialysis machine and several nurses approaching from the intensive care unit. The physician and nursing staff commend you for your rapid detection and treatment of this patient.

Before you can complete the patient’s report, they advise you that the patient’s potassium level on arrival was 8.5 mmol/L and must have been much higher before you started treatment. They inform you later that the patient was admitted to the ICU and is expected to make a full recovery.

Recognition of hyperkalemia

If you recognized the signs of hyperkalemia, then you have completed the first step in properly treating this patient. It is critical to quickly evaluate patients at risk for acute renal failure or for those with renal insufficiency who have missed one or more dialysis treatments. For some of these patients, even a minor systemic infection, such as a urinary tract infection, can prove to be fatal in just a few days if left undetected or untreated.

Correctly recognizing the sine wave pattern of the EKG indicates that the condition has reached a critical level. While guessing the level of potassium may be academic, having the ability to recognize this unique feature will allow you to immediately begin treatment and potentially avoid impending cardiac arrest. In this case, the patient requires rapid treatment followed by transport to a hospital capable of providing emergent dialysis.

The following EKG is taken only three minutes after the initial EKG out while preparing to start an IV. The changes illustrate how rapidly conditions can worsen within a very short amount of time. You can see the patient’s level of consciousness decrease, his radial pulse weaken, and his skin color become ashen literally right before your eyes.

Second EKG (click for larger image):

The computed interpretation is:

Abnormal ECG **Unconfirmed**
Atrial fibrillation with rapid ventricular response with premature ventricular or aberrantly conducted complexes
Indeterminate axis
Low voltage QRS
Possible Lateral infarct, age undetermined

Complete your own interpretation of the second 12-lead EKG using the steps recommended by the EKG Club

Looking at the second 12-leadEKG, try to imagine shaping the EKG tracing out of a piece of string. As the level of potassium circulating in the blood increases, the ends of the string are gradually pulled together. In the sine wave pattern, the normal shapes have been replaced by a unique pattern. However, even these shapes start to lose their definition as it progresses, until a ventricular fibrillation or asystole cardiac arrest occurs. At that point, successful resuscitation will be extremely difficult with a very low probability.

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