It is normal to admit a patient who is having an operation under general anaesthetic to hospital 6 to 24 hours before the operation is scheduled. During this time routine tests and checks are performed and the anaesthetist will check the heart, lungs and other vital systems. If the operation is an emergency, these checks will be performed in the theatre to save time. If the surgeon is concerned about the patient, s/he may arrange for the patient to be seen in the anaesthetist’s rooms several days before the operation so that any complications can be sorted out well in advance.
About an hour before an operation the patient is changed into an easily removable gown and given an injection to dry up the saliva and induce relaxation. Shortly before the operation, s/he is put onto a trolley and wheeled into the theatre suite. In many hospitals the normal bed is wheeled all the way.
In the theatre the patient is transferred to the operating table under a battery of powerful lights. While breathing oxygen through a mask a needle is placed in a vein and a medication is injected to induce sleep and relax the muscles (e.g. vecuronium). This is not at all frightening and is just like going to sleep naturally.
The drugs used last only a short time, and the anaesthesia is maintained by gases that are given through a mask or by a tube down the throat (endotracheal tube). The anaesthetist regularly checks the pulse, blood pressure, breathing and heart during the operation to ensure there is no variation from the normal. When the operation is finished the anaesthetist turns off the gases and gives another injection to wake up the patient.
The first memory after the operation is of the recovery room where the patient stays under the care of specially trained nurses and the anaesthetist until fully awake.
Side effects of a general anaesthetic can include:
- a sore throat (from the tube that was placed down the throat),
- excessive drowsiness (all side effects of the medication).
A very rare complication of a general anaesthetic is malignant hyperthermia.
General anaesthetics are now extremely safe and the risk of dying from the effects of a general anaesthetic are now no greater than one in 250,000.