1. Specialist Registrar, The Royal Hospitals NHS Trust, Queen Elizabeth Hospital for Children, and National Hospital for Neurology and Neurosurgery, The Royal London Hospital, Whitechapel, London E1 1BB, UK,
2. Consultant Anaesthetist, The Royal Hospitals NHS Trust, Queen Elizabeth Hospital for Children, and National Hospital for Neurology and Neurosurgery, The Royal London Hospital, Whitechapel, London E1 1BB, UK