Addition of topical airway anaesthesia to conventional induction techniques to reduce haemodynamic instability during the induction period in patients undergoing cardiac surgery: protocol for a randomised controlled study

INTRODUCTION: The aim of this prospective study is to evaluate the effects of combining topical airway anaesthesia with intravenous induction on haemodynamic variables during the induction period in patients undergoing cardiac surgery. METHODS AND ANALYSIS: This randomised, double-blind, controlled, parallel-group, superiority study from 1 March 2021 to 31 December 2021 will include 96 participants scheduled for cardiac surgery. Participants will be screened into three blocks (ASA II, ASA III, ASA IV) according to the American Society of Anesthesiologists (ASA) grade and then randomly allocated into two groups within the block in a 1:1 ratio. Concealment of allocation will be maintained using opaque, sealed envelopes generated by a nurse according to a computer-generated randomisation schedule. In addition to general intravenous anaesthetics, participants will receive supraglottic and subglottic topical anaesthesia. Changes in arterial blood pressure and heart rate in both groups will be recorded by an independent investigator at the start of anaesthesia induction until the skin incision. If vasopressors are used during this period, the frequency, dosage and types of vasopressors will be recorded. The incidence and severity of participants’ postoperative hoarseness and sore throat will also be assessed. ETHICS AND DISSEMINATION: This study was approved by the Ethics Committee of Qianfoshan Hospital of Shandong Province (registration number: YXLL-KY-2021(003)). The results will be disseminated through a peer-reviewed publication and in conferences or congresses. TRIAL REGISTRATION NUMBER: NCT04744480.