Inclusion Criteria:  • All children from 1 month to 18 years of age undergoing elective or urgent inhalational induction of anaesthesia at Nottingham University Hospitals NHS Trust over a six month study period (August 2020 to January 2021)  Exclusion Criteria:  Children receiving an attempted awake venous cannula insertion Children receiving an a failed intravenous induction of anaesthesia prior to an inhalational induction of anaesthesia Child or family history of malignant hyperthermia Congenital or idiopathic methaemoglobinaemia Glucose-6-phosphate dehydrogenase deficiency (G6PD) Known sensitivity to topical analgesia Use of analgesics within the preceding 24 hours