4- Correct A patient with a medical condition involving only one lung requires focused intervention. A lateral or side-lying position is used for patients whose condition involves only one lung, because it allows for improved ventilation to perfusion that matches with the affected lung. This position also optimizes pulmonary blood flow and ventilation to the dependent lung areas. When a patient is in the prone position, air-filled, non-atelectatic alveoli in the ventral (anterior) portion of the lung become dependent, and perfusion may be better matched to ventilation. However, not all patients respond well to prone positioning and there is no reliable way of predicting who will respond. Tripod positioning helps to increase chest and lung expansion and decrease the effort needed to breathe for patients with chronic obstructive pulmonary disease, not patients with conditions affecting only one lung. The supine position changes the pleural pressure and predisposes the patient to atelectasis. Text Reference – p. 1662 More test answers on https://studyhippo.com/n123-aq-chp-68-acute-respiratory-failure/