**Question:** A 63-year-old man with multiple rib fractures and a pulmonary contusion requires prolonged intubation. He is unable to be weaned from the ventilator and is on a volume control mode. He has a tracheostomy and a percutaneous gastrotomy in place through which he is being fed. The surgeon orders a respiratory quotient (RQ), which is the ratio of the rate of carbon dioxide production over the rate of oxygen uptake. The RQ is 1. Based on this information, which of the following is the next step in his management?

A. Increase the level of sedation
B. Increase the PEEP
C. Decrease the ventilatory rate
D. Change the ventilatory mode to pressure control

**Correct Answer:** D. Change the ventilatory mode to pressure control

**Core Concept:** In patients with prolonged mechanical ventilation, adjusting the ventilatory mode can influence the patient's respiratory system workload and potentially improve weaning from the ventilator. The respiratory quotient (RQ) represents the ratio of carbon dioxide production to oxygen uptake. A respiratory quotient of 1 indicates a balanced respiratory system, where carbon dioxide and oxygen are produced and consumed at equal rates.

**Why the Correct Answer is Right:** The patient presents with pulmonary contusion and multiple rib fractures, which often leads to increased work of breathing and makes weaning challenging. By changing the ventilatory mode from volume control to pressure control, we can achieve better control over the pressure exerted on the lungs during inspiration and expiration, potentially reducing the respiratory workload. This may facilitate weaning from the ventilator and improve the patient's respiratory system efficiency.

**Why Other Options are Incorrect:**

A. Increasing the level of sedation (hypnosis): Although sedation is essential for patient comfort and ventilator synchrony, increasing the level of sedation doesn't directly address the patient's respiratory distress and weaning challenges.

B. Increasing PEEP (positive end-expiratory pressure): Although PEEP can improve oxygenation, it doesn't directly address the patient's weaning issues or the respiratory system workload.

C. Decreasing the ventilatory rate: Reducing the ventilatory rate might improve oxygenation and carbon dioxide elimination, but it doesn't specifically address the patient's weaning difficulties or improve the respiratory system workload.

**Clinical Pearl:** In cases of prolonged mechanical ventilation, transitioning to pressure control mode can be a beneficial intervention to address the patient's respiratory distress and facilitate weaning. This approach can improve the ventilatory workload and potentially expedite the patient's recovery. However, the choice of ventilatory mode should be based on the patient's individual condition, and consultation with a pulmonologist or respiratory therapist is often necessary to determine the most suitable ventilatory mode and weaning strategy.