Which of the following would be most helpful at increasing a patient's functional residual capacity after surgery?

Increasing a patient's functional residual capacity (FRC) after surgery is crucial for enhancing pulmonary function and promoting better gas exchange. The correct choice, maximal exhalation exercises, directly contribute to this goal by actively engaging the respiratory muscles and helping to clear secretions from the airways. These exercises encourage deeper breathing, which can help expand the lungs and improve FRC, thus aiding recovery post-surgery.

In contrast, prone positioning, while beneficial in certain respiratory conditions, mainly serves to improve oxygenation rather than directly increase FRC. Sedative medications can depress the respiratory system, potentially leading to reduced lung volumes and decreased FRC, which is counterproductive following surgery. Cough coaching can encourage effective coughing but does not specifically target the enhancement of FRC and may not be as helpful as maximal exhalation exercises in promoting lung expansion and overall respiratory function after surgery.