A nurse in a critical care unit is caring for a client who is postoperative following a right pneumonectomy. After extubation from the ventilator, in which of the following positions should the client be placed?

The correct answer is A: On the nonoperative side. Placing the client on the nonoperative side after a right pneumonectomy helps promote optimal lung expansion and ventilation of the remaining lung. Placing the client on the operative side could compress the remaining lung, leading to decreased oxygenation and potential complications. The other choices are incorrect for various reasons: B (Sims) and D (Prone) positions are not suitable for a postoperative pneumonectomy patient as they may compromise respiratory function. C (Semi-Fowler's) position may not provide adequate support for the remaining lung.