What is Hyperkalemia ?
If we break down the word Hyperkalemia, we will get our answer:
Hyper- is the Greek name for "high."
Kal- is from kali (qali), the Arabic name for potassium
and -emia is the Greek name for "blood."
Hyperkalemia or HyperK for short means: “high potassium in the blood.” (1)
Potassium is vital for regulating the normal electrical activity of the heart. Increased extracellular potassium reduces myocardial excitability, with depression of both pacemaking and conducting tissues.
Progressively worsening Hyperkalaemia leads to suppression of impulse generation by the SA node and reduced conduction by the AV node and His-Purkinje system, resulting in bradycardia and conduction blocks and ultimately cardiac arrest. (2)
EKG indications of Hyperkalemia (from ALS-PCS v4.9):
Wide and bizarre QRS complexes [³120 ms]
Peaked T waves
Loss of P waves
and/or QRS complex with a “sine wave” appearance
EKG indications of Hyperkalemia (other):
Blocks (any/all: the full spectrum of 1st à 3rd)
EKG Tip: Think of a Tall T – then piece of sting being pulled:
-the PR lengthens, the P wave widens, then disappears, Conduction blocks set in, QRS widens, and continues to widen into sine pattern – then disappears (asystole!!)
*note however that Hyperkalemia may manifest any of the ECG changes at any point, not necessarily in this order or succession (or manifest no ECG changes at all!)
Who to look out for? (from ALS-PCS v4.9):
“Suspected Hyperkalemia in patients at high risk, including: Currently on dialysis; OR History of end-stage renal disease; OR Relevant incident history (i.e. Prolonged crush injury) AND One of the following clinical situations: Cardiac Arrest OR Pre-arrest with 12-lead ECG changes associated with Hyperkalemia”