“How long do you stay in the hospital after bypass surgery?”

About 4-12 days.

Cardiac Bypass Surgery requires a patient be placed on a machine to pump blood while the heart undergoes surgery. If this is your loved one they are likely at a cardiac center. After surgery they will stay in intensive care for 2-3 days. During this time they are often maintained on sedation. After intensive care they will be in the hospital from 3 to 10 days. The variation in time depends how physically fit they are before surgery.
Best doc G