A client with atrial fibrillation is scheduled for an elective cardioversion.

The nurse prepares for the procedure by inserting two intravenous (IV) catheters and connecting the monitoring lead wires to the client.
Which action is most crucial for the nurse to take before initiating the cardioversion?

Clinical Rationale

Choice B (Correct): To ensure a proper seal and maintain the prescribed $FiO_2$, the mask must be secured over the bridge of the nose first, then pulled down to cover the mouth and chin. A snug fit prevents oxygen from leaking toward the eyes, which can cause irritation, and ensures the client receives the full benefit of the oxygen therapy.

Choice A (Incorrect): Simple face masks used in acute care are generally disposable, single-patient-use items. Cleaning them with soap and water is not standard practice and could introduce contaminants or moisture that compromises the equipment.

Choice C (Incorrect): A client with an oxygen saturation of 89% is hypoxic and requires continuous supplemental oxygen. Taking frequent "breaks" would cause the saturation to drop further, potentially leading to respiratory distress or cardiac strain.

Choice D (Incorrect): For an oxygen mask to be effective, it must cover both the nose and the mouth. Leaving the nose exposed allows the client to inhale room air (21% oxygen), which dilutes the supplemental oxygen and fails to reach the desired therapeutic level.

Choice E (Incorrect): Oxygen is a medication that requires a provider's order. While a nurse may titrate oxygen based on specific standing orders (e.g., "titrate to keep $SpO_2$ > 92%"), a nurse cannot unilaterally "adjust" levels without a protocol or direct order in place.

Choice A rationale
Comparing muscle strength bilaterally is not the most important intervention in this situation. While muscle weakness can be a symptom of hyperkalemia, it is not the most immediate concern. Hyperkalemia can lead to life-threatening cardiac dysrhythmias, which is a more immediate threat to the patient’s life.

Choice B rationale

Observing the color and amount of urine can provide information about the patient’s renal function, which is important in the regulation of potassium. However, this is not the most immediate concern when a patient’s serum potassium level is dangerously high.

Choice C rationale
Determining the apical pulse rate and rhythm is the most important intervention. Hyperkalemia can cause cardiac dysrhythmias, so the nurse should immediately assess the patient’s heart rate and rhythm. The nurse should also place the patient on a cardiac monitor, if not already done, and notify the healthcare provider immediately.

Choice D rationale
Assessing the strength of deep tendon reflexes can provide information about neuromuscular function, which can be affected by hyperkalemia. However, this is not the most immediate concern. The nurse’s priority is to assess and monitor for life-threatening cardiac dysrhythmias.