1. A 68-year-old male patient presents with sudden onset of dyspnea and pleuritic chest pain. Which of the following is the most likely diagnosis? A) Pneumonia B) Acute pulmonary embolus C) Chronic obstructive pulmonary disease (COPD) D) Asthma Correct Answer: B) Acute pulmonary embolus Rationale: The sudden onset of dyspnea and pleuritic chest pain are classic signs of an acute pulmonary embolus, which is a blockage in one of the pulmonary arteries in the lungs. 2. A patient with acute respiratory failure is exhibiting a PaO2 of 55 mmHg on room air. What is the most appropriate initial intervention? A) Initiate mechanical ventilation B) Administer a bronchodilator C) Provide supplemental oxygen