If you have not read our blog "The Trickster," I highly encourage you check it out before reading this blog; it is a good refresher on hyperkalemia emergencies. We will be using what we learned from "The Trickster" blog to show how we suspect hyperkalemia. IMPORTANT REMINDER: do not wait until you have point of care electrolyte results to treat this emergency; if we have high suspicion we must not delay treatment. Waiting can put the patient at risk of cardiovascular collapse. Let's jump right into it with our first case!
Case 1:
EMS is dispatched to an 72 year old with chief complaint of stroke/possible diabetic issue. On arrival you note the patient is alert and oriented and appears weak with a fast respiratory rate. Stroke exam is negative. Patient has been having trouble with his insulin pump and has turned it off. Vitals assessed finding BP 154/76 mmHg, HR 98, RR 42, SpO2 99%, lung sounds clear, BG "high," 12 lead is shown below. Patient, despite looking ill, states "I feel fine." Patient later admits generalized weakness. Patient has a history of HTN, high cholesterol, diabetes type 1, no stroke or MI history.
What is going on with this patient? What do you think of the EKG?
We quickly determine the patient is in DKA based on our assessment. And of course since this blog is all about hyperkalemia that is what we see signs of on this EKG. Note that we can see occasional p waves with some irregularity and "really wide" QRS complexes especially in V1-V3. The QRS is more than one big box wide in some places. Note the sine wave appearance. The monitor interpreted this as "MEETS ST ELEVATION MI CRITERIA." How do we know this is not an MI? We go back to the story and have to know that DKA can cause a host of electrolyte shifting. This patient was treated for hyperkalemia and did not have an MI. Potassium was 6.5 mEq/L. This case shows that we cannot predict what the potassium level will be based on the EKG changes, we can only identify when it is affecting the heart.
Suspicion to treat based on: history (diabetic), kussmaul breathing, BG reading, patient in DKA, EKG findings.
Case 2:
69 year old presents to the ER with AMS and difficulty urinating. Patient had no additional complaints. Patient assessed and labs obtained. I only have some information on this patient but the vitals were fairly normal; however the BG was 20. The doctor compared the EKG to a previous EKG and found the patient has a new onset RBBB. Patient BG treated with no change in AMS. History of diabetes, renal insufficiency, benign prostate hyperplasia (enlarge prostate that makes urination difficult), no cardiac history. Labs came back finding the patient's potassium to be 8.4 mEq/L. This is an extremely high potassium level.
Why is this patient hyperkalemic? What about his EKG suggests this?
This patient's BPH caused urinary retention leading to acute kidney injury and causing encephalopathy (which is why the patient is altered). The AKI combined with the already existing renal insufficiency is why the patient is hyperkalemic; they are not urinating and therefore holding onto their potassium. Whew! The patient was treated for hyperkalemia and recovered.
The EKG shows again a "very wide" QRS that is starting to run into the p wave. The t waves are not very tall but they are "peaked." And a new onset RBBB. All this together is suspicious for hyperkalemia.
Do we have enough information to treat this patient before labs come back; we do but it requires some critical thinking to get there.
Suspicion to treat based on: History of renal failure, urinary retention, AKI, EKG findings.
Case 3:
EMS responds to a person in their 30s dispatched as "unresponsive." They arrive to find the patient in cardiac arrest with the initial rhythm being PEA. EMS crew worked the arrest for several minutes giving calcium, epinephrine, and sodium bicarbonate before getting a pulse back. The EKG below is from EMS and was transmitted to the hospital. Cath lab was activated, but cardiology refused the patient after hearing the history/story. Patient has a chronic drug use problem and it is presumed that he had a prolonged amount of time on the floor before being found by a friend. Hospital found the patient to be in rhabdomyolisis and had lower extremity compartment syndrome. Potassium level was 7.9 mEq/L.
(Dr. Smith EKG Blog, 2021)
The EKG shows ST elevation in avL, V1-V3 and depression in II, III, and avF. What else do you see though? Yes! Very tall and peaked t waves and a borderline wide QRS. Hyperkalemia is a STEMI mimic and this is a great example of that. We do not have the PEA rhythm but I would assume it was most likely a wide complex PEA.
Upon getting the potassium level the patient was given calcium and insulin resulting in this EKG:
(Dr. Smith EKG Blog, 2021)
The ST segment elevation and depression is almost completely resolved. Further testing resulted in no evidence of an MI.
I am not sure what the physical exam findings looked like for this patient. But with there being compartment syndrome we can assume there is some discoloration in the lower extremity. Difficult case but we can be super aggressive with our hyperkalemia treatment with this patient due to them having a cardiac arrest event and EKG findings showing classic "tall and peaked t waves."
Suspicion to treat based on: Cardiac arrest, young patient, EKG findings.
Case 4:
This next case I do not have a significant amount of information. An adult patient arrived to ER with complaint of SOB. Patient looked well to staff and had no additional complaints. Patient vitals were: BP 150/45, HR 33, the rest is unknown. History included: renal failure, diabetes, and hypertension. Patient is on dialysis and missed their last dialysis appointment. Initial EKG below.
What do you see?
(Dr. Smith EKG Blog, 2014)
The EKG shows a junctional rhythm with tall and peaked t waves. Patient was immediately treated for hyperkalemia while waiting for lab results and given a total of 6 grams of calcium gluconate with no change in rhythm. Potassium level was 7.5 mEq/L. Patient later received emergent dialysis and recovered.
This is a tricky rhythm but it is important to note that hyperkalemia can cause junctional rhythms and a very slow HR. The t waves can be mistaken as being hyperacute but we usually will have some degree of ST elevation with hyper acute t waves. Notice there is no ST segment elevation here.
Suspicion to treat based on: Dialysis patient (missed dialysis), EKG findings (bradycardic with tall and peaked t waves).
When suspecting hyperkalemia all we have in the prehospital environment is: history, presentation, vitals, EKG, our previous experiences, and our ability to critically think. It is challenging, but with practice and continued learning we can identify this life threatening emergency and treat it aggressively. I truly believe the more dire the situation the less evidence we need to start treatment; sometimes we do not have much to go on. When we can get a complete history/story and have EKG changes consistent with hyperkalemia trust yourself! Know that if the patient does not indeed have hyperkalemia your treatment will NOT cause harm. It is safe which is why we can be aggressive.
References:
Meyers, P. M. (2021, May 14). What are these ST elevations, ST depressions, and tall T waves diagnostic of. Dr. Smith ECG Blog. https://hqmeded-ecg.blogspot.com/
Smith, S. S. (2014, July 13). Bradycardia, SOB, in a Dialysis Patient. Dr. Smith ECG Blog. http://hqmeded-ecg.blogspot.com/2014/07/bradycardia-sob-in-dialysis-patient.html
Add comment
Comments