A client is diagnosed with a large pulmonary embolism. When explaining what has happened to cause respiratory distress to the client's family, which information will the nurse include?

Choice A reason: Thick secretions blocking airways are characteristic of conditions like chronic obstructive pulmonary disease or pneumonia, not pulmonary embolism. In pulmonary embolism, a clot obstructs pulmonary arteries, reducing blood flow to alveoli, not airflow. This leads to ventilation-perfusion mismatch, causing hypoxemia despite adequate breathing, making this explanation incorrect. Choice B reason: A pulmonary embolism blocks pulmonary arteries, reducing blood flow to certain lung regions despite normal ventilation. This creates a ventilation-perfusion mismatch, where alveoli are ventilated but not perfused, leading to hypoxemia and respiratory distress. This is the primary mechanism of pulmonary embolism, making it the correct explanation for the family. Choice C reason: This option suggests adequate blood flow but inadequate air to alveoli, which describes conditions like airway obstruction or atelectasis, not pulmonary embolism. In pulmonary embolism, the issue is reduced blood flow due to arterial obstruction, not insufficient air reaching alveoli, as breathing remains adequate, making this incorrect. Choice D reason: Thickened alveolar-capillary membranes, impairing oxygen diffusion, occur in conditions like pulmonary fibrosis or edema, not pulmonary embolism. In pulmonary embolism, the primary issue is vascular obstruction, not membrane thickness, leading to reduced perfusion and hypoxemia despite normal alveolar structure, rendering this explanation scientifically inaccurate.