Why should rescuers avoid over-ventilating during CPR?

Why should rescuers avoid over-ventilating during CPR?

• A. It wastes oxygen.
• B. It increases intrathoracic pressure and reduces venous return, decreasing CPR effectiveness.
• C. It slows chest compressions.
• D. It causes lung injury.

Answer: (B)

Ventilation during CPR should be controlled because too much air inflates the chest and raises intrathoracic pressure. When the chest is pressurized during breaths, blood has a harder time returning to the heart between compressions, so the amount of blood being circulated to the heart and brain drops. This reduces the effectiveness of CPR. Keeping breaths at a safe volume and rate helps maintain good venous return and perfusion. While over-ventilation can also increase the risk of gastric distension and lung injury, the main issue is the decreased venous return that lowers overall CPR effectiveness.

Ventilation during CPR should be controlled because too much air inflates the chest and raises intrathoracic pressure. When the chest is pressurized during breaths, blood has a harder time returning to the heart between compressions, so the amount of blood being circulated to the heart and brain drops. This reduces the effectiveness of CPR. Keeping breaths at a safe volume and rate helps maintain good venous return and perfusion. While over-ventilation can also increase the risk of gastric distension and lung injury, the main issue is the decreased venous return that lowers overall CPR effectiveness.