FCA1-0322

A 5-year-old child is scheduled for squint surgery requiring general anaesthesia. To begin, she is given sevoflurane for the inhalation induction, then intravenous access is established along with the insertion of a supraglottic airway. Anaesthesia is maintained with fentanyl 1 mcg/kg, with an air/oxygen/sevoflurane mix with spontaneous respirations. Once the surgery begins, her pulse rate drastically reduces from 120 beats/min to 8 beats/min. What is the most appropriate next step for this patient?