The effect of topical airway anesthesia on hemodynamic profiles during the induction period in patients undergoing cardiac surgery: Study protocol for a randomized controlled trial

BACKGROUND: Patients scheduled for cardiac surgery are often accompanied by cardiac dysfunction and hemodynamic instability. However, the conventional induction strategy for anesthesia using high-dose intravenous anesthetics is often associated with persistent and recurrent hypotension after tracheal intubation. The purpose of this study is to investigate the effects of topical airway anesthesia on the hemodynamic profile of patients undergoing cardiac surgery during the induction period. METHODS: This is a superiority, single-blind, randomized controlled study with two parallel groups. Participants scheduled to undergo elective cardiac surgery will be allocated into two blocks according to the New York Heart Association (NYHA) classification and then randomly assigned to the following two groups at a 1:1 ratio: the conventional induction group and the combined topical airway anesthesia induction group. The combined topical airway anesthesia induction strategy includes aerosol inhalation airway anesthesia, subglottic airway anesthesia, and general anesthesia induction using low-dose intravenous anesthetics. The primary outcome is the area under the curve (AUC) of blood pressure below baseline mean arterial pressure (MAP) from 3 to 15 min after endotracheal intubation. Secondary outcomes include the AUC above baseline MAP and below baseline MAP at other time points, the highest and lowest arterial blood pressure values during the induction period, type and dose of vasoactive drugs, incidence of arrhythmias, cardiac function, and the incidence of postoperative hoarseness and sore throat. DISCUSSION: The study will explore whether aerosol inhalation airway anesthesia and subglottic airway anesthesia could reduce the incidence and duration of hypotension during the induction period in patients undergoing cardiac surgery. CLINICAL TRIAL REGISTRATION: This trial was registered on www.ClinicalTrials.gov (NCT05323786).