A nurse is assisting with the care of a client whose laboratory results show blood glucose 700 mg/dL, potassium 2.9 mEq/L, sodium 131 mEq/L, magnesium 1.0 mEq/L, anion gap 22 mEq/L, and positive urine ketones. Complete the following sentence by choosing the correct options: The client is at risk for cardiac dysrhythmias due to which of the following?

The scenario describes a client presenting with severe hyperglycemia, metabolic acidosis, and profound electrolyte imbalances indicative of diabetic ketoacidosis. The nurse must apply knowledge of cardiac electrophysiology and the specific role of intracellular ions in maintaining myocardial stability. Choice A rationale Hypokalemia increases myocardial excitability and prolongs the action potential, predisposing the heart to lethal ventricular arrhythmias. The normal serum potassium level is 3.5 to 5.0 mEq per liter, making 2.9 mEq per liter critically low. Choice B rationale Severe hyperglycemia causes osmotic diuresis and severe dehydration, but glucose molecules do not directly alter the electrical resting membrane potential of cardiomyocytes to trigger immediate, acute cardiac dysrhythmias. Choice C rationale An elevated anion gap above 12 mEq per liter signifies metabolic acidosis due to unmeasured ketoacids. While acidosis affects cellular function, it is less immediately arrhythmogenic than a critical serum potassium deficit of 2.9 mEq per liter. Choice D rationale Positive urine ketones confirm the presence of systemic acetoacetate and beta-hydroxybutyrate from lipolysis. Although ketones cause metabolic acidosis, they do not directly disrupt the cardiac electrical conduction pathway like severe hypokalemia does..