 Endpoint pain intensity In hospitalised children, pain assessment will be with the revised Faces Pain Scale FPS-r Hicks et al, 2001 and with the conventional 0-10 cm Visual Analogue Scale VAS. The FPS-r was adapted from the Faces Pain Scale Bieri et al, 1990 in order to make it possible to score on the widely accepted 0-10 point metric. It shows a close linear relationship with the visual analogue pain scale across the age range from 4 to 16 years. In the case that a younger child is not able to express adequately its pain with the FPS-r or with the VAS we will use the CHEOP Scale Children of Eastern Ontario Pain Scale; this is a behavioural observation scale McGrath et al,1985. Pain will be evaluated at arriving in the PACU, 1-hourly during the PACU stay, 4-hourly on the ward, and twice daily after discharge see questionnaire. Sleeping children will not be woken up. 