Correlation of Nasopharyngeal (NP) and Lower Oesophageal (LO) Temperatures in Ventilated Children

Children lose heat under general anaesthesia, thus temperature is routinely monitored during anaesthesia for all but the shortest cases, and active warming can be used to prevent hypothermia and its resulting complications. Temperature can be measured at several sites dependent on the type of surgery and patient factors. Previously a temperature probe has been sited in the lower third of the oesophagus (swallowing tube) but it is difficult to accurately place this without an X-Ray. Consequently it is more common to use a temperature probe placed in the nasopharynx (where the nose and throat meet), when the child is anaesthetised. However the investigators do not know if the temperature in the nasopharynx correlates well with the real core temperature or not.This prospective, unblinded, agreement study will seek to find an agreement of 2 methods to measure temperature in children undergoing general anaesthesia with a breathing tube that has a leak.