Positive pressure ventilation benefits left ventricular failure by which effect?

Positive pressure ventilation benefits left ventricular failure by which effect?

• A. Decreases preload to the heart
• B. Increases preload
• C. Increases afterload
• D. Increases systemic vascular resistance

Answer: (A)

Positive pressure ventilation raises intrathoracic pressure during inspiration, which reduces venous return to the heart. That lowers the left ventricular preload (end-diastolic volume and filling pressures). In left ventricular failure, reducing preload helps decrease pulmonary congestion and improves the heart’s efficiency. While intrathoracic pressure can influence afterload, the main beneficial effect in this context is decreased preload. Increasing preload, afterload, or systemic vascular resistance would worsen LV failure.

Positive pressure ventilation raises intrathoracic pressure during inspiration, which reduces venous return to the heart. That lowers the left ventricular preload (end-diastolic volume and filling pressures). In left ventricular failure, reducing preload helps decrease pulmonary congestion and improves the heart’s efficiency. While intrathoracic pressure can influence afterload, the main beneficial effect in this context is decreased preload. Increasing preload, afterload, or systemic vascular resistance would worsen LV failure.