Throughout the operation your anaesthetist will be keeping a watchful eye on your breathing and the action on your heart using the monitors. He or she will see that the level of anaesthesia is kept just as deep as is necessary, that you are not feeling pain and that you are sufficiently relaxed for the surgeon to perform his task.
He will also be mindful of the shifts of your internal body fluids that occur during surgery and will ensure that you receive the correct amount of intravenous fluids. Should there be blood loss sufficient for you to be in danger of undue anaemia, blood may be administered. Your anaesthetist will remain with you throughout and will not leave the theatre.