General anaesthesia is used in surgery to induce unconsciousness and thereby to prevent pain. First, a rapidly acting drug is injected through a catheter into a vein in the back of your hand or in your arm. A drug given at the same time relaxes the muscles. Once unconscious, you are given a mixture of gases, including oxygen, through a tube inserted into your trachea (windpipe).
A fast-acting general anaesthetic is injected through a catheter into a vein in the back of your hand. You become unconscious within seconds.
A mixture of oxygen and anaesthetic gases is given to keep you unconscious. These gases are delivered directly into the lungs through an endotracheal tube, which is inserted down the throat into the trachea.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.