The pump rhythmically tightens different parts of the boot to help push the blood back up to the heart and keep clots from forming. Do not sleep on the ice pack. Treatment with ice is most effective when started right after surgery and used for 24 to 48 hours. After the first 24 to 48 hours you may use heat for pain or swelling. Do not sleep on the heating pad or hot water bottle.
Heat brings blood to the area of the surgery and helps it heal faster.
You may need to rest in bed for a while. But even if you are confined to bed, it's important to exercise your legs in order to stop blood clots from forming. Lift one leg off the bed and draw big circles with your toes, then repeat with the other leg. You can also try lying on your side and pretending to pedal a bike. When you're told it's OK to get out of bed, make sure someone is with you the first time you try.