Anaesthetist's trolley, in an operating theatre, prior to open heart surgery. Anaesthetic liquids and gases, such as enflurane (centre), are administered from this trolley to maintain the patient's unconscious state during surgery. There are various pieces of equipment including needles, drips and swabs on the trolley. There are also dials and gauges to ensure the correct amount and mixture of drugs. Screens show the patient's vital signs (cardiovascular and respiratory functions), which the anaesthetist is responsible for monitoring during the operation.