AACN CCRN® (Adult)

The presentation most strongly supports pulmonary embolism: abrupt dyspnea with pleuritic chest pain, recent surgery with unilateral calf swelling (risk factors for venous thromboembolism), and clear lung sounds despite significant symptoms. The ABG pattern of hypoxemia (low PaO2) with low PaCO2 and alkalemia is consistent with acute hyperventilation from impaired oxygenation due to V/Q mismatch and increased physiologic dead space, which is characteristic of a pulmonary embolus. Emphysema and chronic bronchitis more commonly produce chronic airflow limitation with CO2 retention (especially chronic bronchitis) and do not typically present with sudden pleuritic pain and a strong thromboembolic risk profile. The choice stating acute respiratory failure is a physiologic syndrome rather than a specific etiology; the question asks for the most likely underlying condition causing these findings.

Hyperkalemia is most consistent with end-stage renal disease and the described ECG findings. Impaired renal excretion can cause potassium to accumulate, and elevated potassium classically produces tall, peaked T waves with progressive conduction slowing that can lead to a widened QRS and malignant dysrhythmias, often accompanied by weakness and palpitations. The choice mentioning hypocalcemia more commonly causes neuromuscular irritability (perioral numbness, tetany) and is associated with QT prolongation rather than peaked T waves. The choice mentioning hyponatremia typically presents with neurologic symptoms (headache, confusion, seizures) rather than peaked T waves and QRS widening. The choice mentioning hypomagnesemia can cause tremor, cramps, and ventricular irritability, but the most characteristic ECG associations are QT prolongation and torsades risk, not peaked T waves.

Respect for patient autonomy requires honoring a patient’s documented wishes when the patient lacks decision-making capacity. An advance directive communicates the patient’s preferences and should guide end-of-life decisions when it is valid and applicable. The nurse’s ethically appropriate role is to verify the directive, communicate and collaborate with the provider and team, and advocate for care aligned with comfort-focused goals, using structured escalation (such as an ethics or palliative care consult) when there is conflict with the family. The choices suggesting changing code status solely based on the family’s request, delaying goals-of-care decisions despite a known directive, or treating the family’s wishes as automatically overriding the patient’s documented preferences do not prioritize the patient’s expressed wishes and are inconsistent with ethical practice.