Compare 15:2 with 30:2 ratios
Here we compare 15:2 and 30:2 ventilation ratios. Both measurements are over a period of 30 compression.
Normal Ventilation
Normal Respiration
With Normal Respirations, the pressure in the chest becomes negative when the diaphragm contracts and pulls down.
The negative pressure in the chest now does 2 things:
1. Draws air into the lungs.
2. Draws venous blood into the inferior and superior vena cava increasing the priming pressure for the heart.
So what?
The priming effect is lost with artificial Positive Ventilation. This loss of venous priming changes we deliver CPR.