Really fresh air known as oxygen is passed through the oxygen mask. Oxygen is good for the body, especially if we have to have an anaesthetic and undergo an operation. Before you go to sleep, we’d like you to help us to hold the oxygen mask in front of your nose and mouth, and take big, deep breaths so that your body is filled with lots of nice, fresh air. Oxygen masks come in different colours, shapes and sizes so we can be sure of finding one to fit you. Hospitals call these oxygen masks – but it’s not the kind of mask you’d wear for Halloween!