Which ECG change corresponds to potassium levels 7.5-8.5 mmol/L?

Prepare for the SNHD Paramedic Protocols Test. Utilize flashcards and multiple choice questions, with hints and explanations for each query. Ace your exam comfortably!

Multiple Choice

Which ECG change corresponds to potassium levels 7.5-8.5 mmol/L?

Explanation:
Potassium at this high level slows conduction through the ventricles because it inactivates some sodium channels and raises the resting membrane potential toward threshold. That slowing manifests on the ECG as widening of the QRS complex, which is the hallmark of more severe hyperkalemia. Earlier changes you might see include tall, peaked T waves, and as potassium climbs further you can lose P waves, with sine waves typically appearing only at extreme levels. So the QRS widening best matches the 7.5–8.5 mmol/L range.

Potassium at this high level slows conduction through the ventricles because it inactivates some sodium channels and raises the resting membrane potential toward threshold. That slowing manifests on the ECG as widening of the QRS complex, which is the hallmark of more severe hyperkalemia. Earlier changes you might see include tall, peaked T waves, and as potassium climbs further you can lose P waves, with sine waves typically appearing only at extreme levels. So the QRS widening best matches the 7.5–8.5 mmol/L range.

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