A patient on high FiO2 develops a nonproductive cough, substernal chest pain, and crackles; these are early signs of what complication?

• A. Oxygen toxicity
• B. Pneumothorax
• C. Pulmonary edema
• D. Atelectasis

Answer: (A)

High concentrations of supplemental oxygen over time can cause oxygen toxicity, and these early signs fit that complication. When FiO2 is kept very high, oxygen can generate reactive oxygen species that injure the alveolar-capillary membranes. The resulting inflammation and edema irrit the airways, producing a nonproductive cough and substernal chest pain, while crackles reflect alveolar involvement as fluid leaks into the interstitium and small airways begin to fill. Recognizing this pattern is important because the fix is to reduce FiO2 to the lowest level that maintains adequate oxygenation while monitoring the patient closely.

Pneumothorax would typically present with sudden sharp chest pain, dyspnea, and decreased or absent breath sounds on the affected side, not the described cough and crackles. Pulmonary edema would involve significant dyspnea and often pink-tinged frothy sputum with widespread crackles from fluid overload. Atelectasis tends to show decreased breath sounds and dullness to percussion rather than the combination of chest pain and crackles seen with oxygen toxicity.