A scene from “Add It Up”

Meredith (voice-over): Anesthesiology is a lot more challenging than it looks because it's mostly math. A patient's weight, their estimated blood volume, their lung function - all these variables have to be accounted for. It takes careful calculation to suspend a person between life and death. And if one of those variables is off, you might wake up in the middle of your surgery, or never wake up at all.