Hypokalemia & Hyperkalemia as a H&T Reversible Cause
Regardless if a rhythm is shockable or not, part of managing every cardiac arrest includes considering reversible causes. To make things a little easier to remember, these can be listed as Hs & Ts. Hypokalemia & hyperkalemia is something we should consider early based on the patient’s history and easy to identify changes to the T wave on the ECG. Hypo or hyperkalemia as a reversible cause of cardiac arrest is today’s Pass ACLS tip topic.
Heart muscle contraction and repolarization is dependent on Sodium, Calcium, Magnesium, and Potassium ions crossing cellular membranes.
When a patient’s potassium levels get too low or too high, hypokalemia or hyperkalemia results respectively.
Two things that may lead us to suspect hypo or hyperkalemia include:
- The patient’s medical history; and
- Changes to the T wave on the ECG.
Medical History
Some medical conditions related to the kidneys such as acute kidney failure or chronic kidney disease can affect potassium levels.
Common causes of Hypokalemia include: diuretic medications used to treat high blood pressure or CHF; prolonged diarrhea; and excessive use of laxatives or enemas.
Hyperkalemia may be the result of: kidney injury or disease; DKA; and ACE inhibitors or ARB medications used to treat high blood pressure.
End-stage renal failure patients receiving dialysis are prone to hypo and hyperkalemia.
ECG Changes
Patients with hypokalemia may have saggy, low amplitude T waves on the ECG while patients with hyperkalemia may have tall T waves.
Critical Labs
If you suspect hypokalemia or hyperkalemia get labs STAT. A serum potassium less than 3 or greater than 6 should be treated as a reversible cause.
ACLS Intervention
Hypokalemia is treated by potassium replacement via a very slow IV push or a potassium drip.
Hyperkalemia is treated by stabilizing cardiac membranes with administration of Calcium followed by an attempt to shift potassium into cells with administration of Insulin with Glucose.
Close monitoring of a patient’s potassium should be part of post-arrest care if hypo or hyperkalemia was identified before or during an arrest.
Additional FOAMed information on hypokalemia and hyperkalemia can be found on:
- The June 30, 2022 Ninja Nerd Podcast; and
- “Why do we give calcium for hyperkalemia” presented by the Curious Clinicians.
