A nurse is caring for a client who develops a pulmonary embolism. Which of the following interventions is the priority for the nurse to take?

A. Begin oxygen therapy: The priority for a client with a pulmonary embolism is to maintain adequate oxygenation. Hypoxemia can develop rapidly due to impaired gas exchange, making oxygen therapy the first and most critical intervention. B. Start an IV infusion of lactated Ringer's: While maintaining IV access is important for medication administration or fluid replacement, it does not immediately address hypoxia or the life-threatening effects of a pulmonary embolism. C. Initiate cardiac monitoring: Cardiac monitoring is important because a pulmonary embolism can cause arrhythmias or right-sided heart strain. However, monitoring alone does not improve oxygenation or stabilize the patient’s airway and breathing. D. Administer IV morphine: Morphine may help relieve pain and anxiety associated with dyspnea but can also depress respiratory drive. Pain management is secondary to ensuring adequate oxygenation and gas exchange in the acute phase.