Question

How does pressure control ventilation improve oxygenation in morbidly obese patients during mechanical ventilation?

a) Reduces intrapulmonary shunting
b) Enhances lung compliance
c) Decreases airway resistance
d) Improves chest wall compliance

Answer 1

Pressure control ventilation improves oxygenation in morbidly obese patients during mechanical ventilation through reducing intrapulmonary shunting, enhancing lung compliance, decreasing airway resistance, and improving chest wall compliance.

Step-by-step explanation:

Pressure control ventilation can improve oxygenation in morbidly obese patients during mechanical ventilation through a combination of factors.

1. Reduces intrapulmonary shunting: Pressure control ventilation helps improve oxygenation by minimizing intrapulmonary shunting. Intrapulmonary shunting occurs when blood bypasses the alveoli where gas exchange takes place. By maintaining positive pressure in the airways during the entire respiratory cycle, pressure control ventilation helps prevent collapse of alveoli and keeps the airways open, thereby reducing intrapulmonary shunting.
2. Enhances lung compliance: Obesity can lead to reduced lung compliance, which makes it harder for the lungs to expand and contract during breathing. Pressure control ventilation can improve oxygenation by increasing lung compliance. By delivering breaths with a constant pressure and maintaining positive pressure during the entire respiratory cycle, pressure control ventilation helps the lungs inflate more easily, improving oxygenation.
3. Decreases airway resistance: Pressure control ventilation can help reduce airway resistance, which can be increased in morbidly obese patients due to factors such as excess adipose tissue in the airway walls. By delivering breaths with a constant pressure, pressure control ventilation helps maintain airway patency and reduces resistance to airflow, improving oxygenation.
4. Improves chest wall compliance: Morbidly obese patients often have reduced chest wall compliance, which can negatively affect ventilation and oxygenation. Pressure control ventilation can help improve oxygenation by enhancing the compliance of the chest wall. By maintaining positive pressure in the airways during the entire respiratory cycle, pressure control ventilation helps expand the chest wall more easily, facilitating better ventilation.