An Introduction to Hyperkalemia

Created and Presented by: Dr. Matthew Davis Dr. Michael Peddle Dr. Natalie Cram Christine Hardie PHCS, ACP

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Objectives

Upon completion of this webinar the paramedic will: • Recall the basic pathophysiology of hyperkalemia • Explain how illness, injury and other factors lead to hyperkalemia

• Explain the complications associated with hyperkalemia

• Recognize hyperkalemia in the pre-hospital setting using simulated patient care scenarios

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What is Hyperkalemia?

• Hyperkalemia is an elevated serum potassium level

• A normal serum potassium level is between 3.5 and 5.0 meq/L

• Potassium is an important electrolyte for maintaining normal cardiac and neuromuscular function

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Why is Potassium Important?

• Potassium is the major intracellular positively charged electrolyte

• The concentration of potassium inside the cell is approximately 140meq/L vs 4meq/L in the extracellular space or serum

• The difference in potassium concentration across the cell membrane contributes to an electrochemical gradient

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Where is Potassium Found?

• In the human body, 98% of potassium is contained INSIDE cells in the intracellular fluid

• It is found primarily in skeletal muscle, liver, and red blood cells

• The 2% of the body’s potassium that is extracellular is the potassium that is important for cardiac and neuromuscular function. This is the level that is measured in a serum potassium reading.

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Potassium Regulation

• Dietary sources of potassium are absorbed by the intestine

• Potassium is primarily excreted in the urine, with small amounts also being eliminated via feces and sweat

• The kidney plays a very important role in regulating potassium

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Common Causes of Hyperkalemia

• Renal failure: acute or chronic • Cell death: crush injuries, large burns, rhabdomyolysis, tumor lysis syndrome, hemolysis

• Drugs: spironolactone, NSAIDs, ACE inhibitors, ARBs, acute digitalis toxicity

• Acidosis: DKA, Addison’s disease, adrenal insufficiency

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ECG Changes Associated with Hyperkalemia

• Peaked T-waves • Long P-R interval • Flattening and loss of p-waves • Widened QRS • Sine wave pattern • Rhythm changes: ventricular tachycardia and fibrillation, PEA and asystole

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ECG Changes

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ECG Changes

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ECG Changes

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Treatment of Hyperkalemia

• Goals: 1) Stabilize the cardiac membrane

2) Shift potassium into the cells

3) Remove potassium from the body

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Treatment

• Stabilize the cardiac membrane:

• Calcium gluconate or calcium chloride is given to stabilize the cardiac membrane. This decreases the excitability of the cardiac cells, and therefore the likelihood of arrhythmia.

• Calcium increases cardiac conduction speed and narrows the QRS complex.

• Calcium DOES NOT lower potassium levels.

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Treatment

• Shift potassium back into cells:

• Beta2-agonists (ie. Ventolin)

• Insulin and glucose

• Bicarbonate

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Treatment

• Remove potassium from the body:

• Medications • Diuretics (ie. Lasix) • potassium-binding resins (ie. Kayexalate)

These medications work slowly over many hours and are not part of the acute management of hyperkalemia

• Hemodialysis

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Case Discussion

You are called to a residence for a 67 year old c/o feeling unwell. On ambulance arrival you observe a female patient who opens her eyes when you speak to her and she states she feels “very tired” A- Patent B- Spontaneous, regular, adequate C- Patient pale, slow carotid pulse present

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Case Discussion

S – Feeling unwell since she missed dialysis two days ago A - Penicillin M – Insulin, ramipril, metoprolol, ASA, amlodipine, lipitor P –Renal dysfunction, NIDDM, HTN L – Ate breakfast this am E – Pt describes increasing weakness and nausea since she missed dialysis two days ago

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Case Discussion

Vital Signs HR – 57, regular BP – 90/60 RR – 18 regular, full SpO2 – 99% EtCO2 – 45 cm H2O BGL – 24 mmol

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Case Discussion

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Discussion

Recognition of hyperkalemia can be improved by considering the diagnosis in patients most at risk: 1. Chronic kidney disease patients on hemodialysis that may have missed treatment(s) 2. Crush injuries, acid-base disturbances ie DKA, prolonged status seizures, major burns, prolonged immobilization.

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Signs and Symptoms of Hyperkalemia

1. CNS findings such as muscle twitches, cramps,

paresthesias

2. GI: abdominal cramps, diarrhea, nausea/vomiting

3. CVS: ECG changes, bradycardia, progression to hypotension, decreased LOC

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Discussion

How do we define a “peaked T-wave”?

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Discussion

What is a “sine wave” pattern on ECG? Wouldn’t a patient be pulseless with this rhythm?

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Discussion

If a patient with risk factors for hyperkalemia has a normal 12-lead ECG, can hyperkalemia be ruled out?

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Discussion

Given that hyperkalemia is not uncommon and can potentially be a life-threatening condition, is there something that paramedics can do in the pre-hospital setting to stabilize these patients?

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Hyperkalemia Medical Directive

This directive will address HIGH-RISK PATIENTS who are either in CARDIAC ARREST or in a PRE-ARREST STATE High-risk patients include those with:

• End-stage renal disease • Receiving dialysis • Historical or situational risk factors that could cause hyperkalemia (crush injury, prolonged immobilization or seizure, large burns etc)

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Hyperkalemia Medical Directive

Goals of pre-hospital treatment:

• Recognize possible hyperkalemia

• Stabilize the cardiac cell membrane

• Redistribute extracellular potassium back into cells

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Hyperkalemia Medical Directive

Details will be coming to a 2015/16 SWORBHP recert near you! Paramedics will administer pre hospital: • calcium gluconate • salbutamol

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Case Discussion 2 You respond to a farm for a 65 year old male who was found trapped under a large bail of hay. On arrival you observe the patient with the bail of hay resting on his lower limbs to the level of the pelvis. LOA –Fluctuating level of consciousness A- Patent B – Spontaneous, rapid, pt is in obvious pain C – Rapid radial pulse present

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Case Discussion 2

Your trauma assessment of the patient’s upper body is unremarkable. With the assistance of the FD you are able to remove the hay bail from atop the patient. You prepare your equipment and stretcher for rapid transport.

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Case Discussion 2

S – Loss of feeling in lower limbs, severe pain A – Morphine M – None P –None L – Unknown E – Pt’s son states the patient was working in the barn this morning before school (6 am) and he returned home finding him with a hay bail resting across his legs unable to move. Thinking about hyperkalemia? We hope so!!!

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When the Medical Directive Applies This directive will apply to HIGH-RISK PATIENTS who are either in CARDIAC ARREST or a PRE-ARREST STATE High-risk patients include those with:

• End-stage renal disease • Receiving dialysis • Historical or situational risk factors that could cause hyperkalemia (crush injury, prolonged immobilization or seizure, large burns etc)

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Some Strategies

• Be suspicious and identify patients at risk for hyperkalemia

• Take a thorough history and perform all necessary assessments i.e. 12-lead ECG

• Patients with renal insufficiency are at the highest risk for developing hyperkalemia

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Thank you!

If you have any questions regarding hyperkalemia or any of your medical directives, please contact your Regional Paramedic Educator. Christine Hardie – christine.hardie@lhsc.on.ca Dwayne Cottel – dwayne.cottel@lhsc.on.ca Peter Morassutti – peter.morassutti@lhsc.on.ca Jennifer Robson – jennifer.robson@lhsc.on.ca Michael Kennedy – michael.kennedy@lhsc.on.ca