Application of Low-dose Muscle Relaxants in Bronchoscopic Interventional Procedures

Effects of Low-Dose Neuromuscular Blocking Agents on Perioperative Complications During Bronchoscopic Procedures

The purpose of this clinical trial is to observe the use of low-dose muscle relaxants in bronchoscopy intervention surgeries, compared with no muscle relaxants, in terms of the satisfaction of tracheal tube insertion after anesthesia induction, the incidence of laryngospasm, the grading of intraoperative cough and movement, and the recovery of patients after surgery. The main questions it aims to answer are:

• How safe and feasible is the use of low-dose muscle relaxants in bronchoscopy intervention surgeries?
• Is the muscle relaxant regimen better than the no-muscle-relaxant regimen?

Participants will:

• During anesthesia induction, the experimental group will use low-dose muscle relaxants for anesthesia, while the control group will not use muscle relaxants for anesthesia.
• Record the satisfaction of mask ventilation and the incidence of laryngospasm.

Objective: To investigate whether the prophylactic use of low-dose neuromuscular blocking agents, in addition to remimazolam combined with remifentanil for intravenous anesthesia, can reduce the incidence of difficult mask ventilation and laryngospasm during induction, and to systematically observe the effects of this regimen on intraoperative adverse reactions and the quality of postoperative recovery.

Methods: A total of 154 patients undergoing elective bronchoscopic procedures were randomly divided into two groups: a muscle relaxant group (n=77) and a no-muscle relaxant group (n=77). Anesthesia induction in the muscle relaxant group was achieved with intravenous lidocaine 0.5 mg/kg, remimazolam 0.2 mg/kg, remifentanil 3 μg/kg, and rocuronium 0.15 mg/kg. The no-muscle relaxant group received the same regimen, except rocuronium was replaced with an equal volume of normal saline. A suitably sized laryngeal mask airway was inserted using a standard technique in both groups. Anesthesia was maintained with a continuous infusion of remimazolam at 1 mg/kg/h and remifentanil at 0.25-0.5 μg/kg/min. The primary outcome measures were the grade of chest wall rigidity, the incidence of difficult mask ventilation, the incidence of SpO₂ <92% during mask ventilation, the incidence of laryngospasm, and the grade of coughing/body movement during bronchoscope insertion. Secondary outcome measures included the incidence of SpO₂ <92% during bronchoscope insertion, perioperative changes in blood pressure, heart rate, oxygen saturation, bispectral index, airway pressure, and end-tidal carbon dioxide partial pressure; laryngeal mask airway insertion parameters (time, number of attempts, and ease of insertion); intraoperative drug dosages; the incidence of intraoperative and postoperative adverse reactions; and the quality of postoperative recovery.

Inclusion Criteria:

1. Patients undergoing elective electronic bronchoscopic interventional surgery;
2. Age 18 years or older;
3. American Society of Anesthesiologists (ASA) I-III;
4. The duration of bronchoscopic surgery >=20min;
5. Through pre-anesthesia assessment, the patient/family member has informed consent and signed the consent form;
6. The general clinical information of the patient is complete.

Exclusion Criteria:

1. Patients with predictable difficult airway;
2. Small mouth opening (<2 transverse fingers);
3. Combined with severe cardiovascular disease, abnormal liver and kidney function;
4. Morbidly obese patients with body mass index (BMI) greater than 35kg/m^2;
5. Has a history of gastroesophageal reflux disease.
6. High risk of reflux aspiration;
7. Those who have a history of abnormal surgical anesthesia recovery in the past;
8. Patients with mental illness and previous allergies to conventional anesthetic drugs.