Hospital procedures and policies vary, but there are a number of things you probably can expect to have happen when you check in for surgery.
You will probably be admitted the afternoon before your operation so that some routine tests, such as blood and urine tests and a chest x-ray, can be performed. Shortly before the operation, the surgical area (breast and underarm) will be shaved, and you may be given some medicine to help you relax.
When it is time for surgery, you will be taken to the operating room and an anesthesiologist will put you to sleep. Electrocardiogram sensors will be attached to your arms and legs with adhesive pads to check your heart rate during surgery. The surgical area will be cleaned and sterile sheets will be draped over your body, except for the area around the operation. Depending on the procedure, surgery will take between 2 and 4 hours.