1 The Anaesthetic Department, Pediatric Anesthesia and Pain Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond St, WC1 3JH, London, Großbritannien. glyn.williams@gosh.nhs.uk.
2 The Anaesthetic Department, Pediatric Anesthesia and Pain Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond St, WC1 3JH, London, Großbritannien.
3 Pediatric Psychology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, Großbritannien.
4 Pediatric Psychology, University of Southampton, Southampton, Großbritannien.