A nurse is caring for a client who develops a pulmonary embolism. Which of the following interventions should the nurse implement first?

Choice A reason: Starting an IV infusion of lactated Ringer’s supports fluid status and may be needed for anticoagulation administration in pulmonary embolism. However, it does not address the immediate hypoxemia caused by the embolism’s ventilation-perfusion mismatch. Oxygen therapy is the priority to correct low oxygen levels and prevent tissue hypoxia. Choice B reason: Morphine IV may relieve pain and anxiety in pulmonary embolism, reducing oxygen demand. However, it does not directly address hypoxemia, the primary life-threatening issue. The ABCDE approach prioritizes breathing, making oxygen therapy the first intervention to stabilize the patient before pain management is considered. Choice C reason: Pulmonary embolism causes a ventilation-perfusion mismatch, reducing oxygen delivery to the blood, leading to hypoxemia. Administering oxygen therapy immediately increases alveolar oxygen, improving arterial PaO2 and preventing tissue hypoxia. In the ABCDE approach, breathing is prioritized, making oxygen therapy the first intervention to stabilize the client. Choice D reason: Cardiac monitoring assesses for arrhythmias or right heart strain in pulmonary embolism, which is important for ongoing management. However, it does not correct the immediate threat of hypoxemia. Oxygen therapy addresses the critical reduction in oxygen saturation, taking precedence in the ABCDE approach over monitoring in acute management.