The nurse is caring for four clients. Which client does the nurse identify at greatest risk of developing acute respiratory distress syndrome (ARDS)?

A. Blunt chest trauma and aspiration are direct lung injuries, which place the client at the highest risk for ARDS. Trauma damages the alveolar-capillary membrane, and aspiration of gastric contents triggers intense pulmonary inflammation, pulmonary edema, and impaired oxygen exchange. Direct lung insults are the most potent predictors of ARDS development. B. Alcohol abuse and chronic pancreatitis are indirect risk factors. Severe pancreatitis may lead to systemic inflammatory response syndrome (SIRS) and secondary ARDS, but the risk is lower compared with direct pulmonary injury. C. Postoperative heart valve surgery with a single unit transfusion has a low immediate risk of ARDS. While TRALI (transfusion-related acute lung injury) can occur, it is rare with only one unit, and surgical stress alone does not carry as high a risk as trauma with aspiration. D. Severe sepsis is an indirect cause of ARDS, as systemic inflammation can lead to capillary leak in the lungs, but it is generally less immediately high-risk than direct pulmonary injury. Close monitoring is required, but trauma with aspiration remains the greatest risk scenario.