Question: An adult patient is admitted to the ICU with severe pancreatitis. During the hospital stay, they develop sudden-onset severe dyspnea and hypoxemia requiring mechanical ventilation. Bilateral pulmonary infiltrates are seen on chest X-ray, and lab results show a decreased PaO2/FiO2 ratio. An echocardiogram is not indicative of heart failure. Which of the following best describes the primary mechanism behind refractory hypoxemia seen in this condition? Group of answer choices Decreased cardiac output Right-to-left cardiac shunt Mismatch of ventilation and perfusion (V/Q mismatch) Central nervous system depression