Abstract: Objective To assess the sedative efficacy of low-dose remimazolam combined with remifentanil during awake tracheal intubation under surface anesthesia in patients with a predicted difficult airway.Methods From May to November 2024,a prospective,randomized controlled study was conducted involving 60 adult patients scheduled for awake tracheal intubation under general anesthesia due to anticipated difficult airway management.Participants were randomly allocated into three parallel groups based on the anesthetic regimen employed:Group A (control),receiving surface airway anesthesia followed by video laryngoscope-guided oral tracheal intubation;Group B (remifentanil),receiving remifentanil infusion in conjunction with surface anesthesia;and Group C (remimazolam-remifentanil),receiving remifentanil infusion plus a single intravenous bolus of remimazolam prior to surface anesthesia.Hemodynamic parameters—including mean arterial pressure (MAP),heart rate (HR),and peripheral oxygen saturation (SpO²)—were recorded at six predefined time points:baseline (T0),immediately before surface anesthesia (T1),during oropharyngeal and supraglottic anesthesia (T2),during subglottic anesthesia (T3),immediately after tracheal intubation (T4),and one minute post-intubation (T5).Sedation depth was assessed using the modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scale.Patient and anesthesiologist satisfaction were quantified using a 5-point Likert scale.Secondary outcomes included total anesthesia duration,incidence of intraoperative coughing,frequency of bradycardia (HR<50 bpm) and apnea (SpO²<90% or respiratory pause>15 s),and occurrence of intubation-related adverse events (e.g.,laryngospasm,bronchospasm,hypoxemia,or airway trauma).Results The primary outcome:In group A (T4),SpO²,MAP and HR were (97.3±2.7) %,(118.4±28.2) mmHg and (111.6±18.7) beats per minute,respectively;In group B (T4),the data were (96.1±3.9) %,(105.3±26.1) mmHg and (102.8±22.5) beats per minute,respectively;In group C (T4),the data were (95.5±4.5) %,(96.2±24.5) mmHg and (95.3±15.3) beats per minute,respectively.Compared with group A,the levels of MAP and HR in groups B and C decreased after tracheal intubation,and the difference was statistically significant (P<0.05).Compared with group B,the MAP and HR levels in group C were lower,and the difference was statistically significant (P<0.05).SpO² values showed no statistically significant intergroup differences（P＞0.05）.Secondary outcomes:Compared with group A,groups B and C had higher MOAA/S sedation scores,higher patient satisfaction and anesthesiologist satisfaction,and the differences were statistically significant (P<0.05).The duration of anesthesia operation was shorter,and the incidence of choking cough in patients was lower,and the differences were statistically significant (P<0.05).Compared with group B,group C had a higher MOAA/S sedation score,higher patient satisfaction and anesthesiologist satisfaction,shorter duration of anesthesia operation,and lower incidence of choking cough in patients.The differences were statistically significant (P<0.05).None of the three groups of patients developed complications such as respiratory depression,bradycardia,hypoxemia,hypotension,or dental damage during anesthesia.Conclution Compared to simple surface anesthesia and surface anesthesia with remifentanil under awake sedation,a low-dose remimazolam and remifentanil combination for awake surface anesthesia during tracheal intubation provides superior sedation efficacy,attenuates stress responses associated with intubation,enhances patient satisfaction,and does not increase the incidence of anesthesia-related complications.

Key words: remimazolam, remifentanil, awake tracheal intubation, sedation, difficult airway