Effect of Midazolam Premedication on Opioid-induced Mask Ventilation Difficulty

Effect of Midazolam Premedication on Opioid-induced Mask Ventilation Difficulty During General Anesthesia Induction: A Randomized Clinical Trial

Mask ventilation has great importance during anesthesia induction because it is the only way to oxygenate patients who have lost consciousness and spontaneous breathing. Opioid-derived drugs used in anesthesia induction may cause difficulty in mask ventilation due to their chest wall rigidity and respiratory depressant effects. Adequate muscle relaxation and depth of anesthesia may assist with mask ventilation. It is known that premedication reduces anxiety and has a relaxing effect on airway muscles. Midazolam is frequently used in premedication because it has a rapid onset of action and does not cause hemodynamic changes. In addition, midazolam may relax the airway by acting directly on the airway smooth muscle and thus facilitate mask ventilation during anesthesia induction. In this study, the investigators will evaluate the effect of midazolam premedication on the mask ventilation after induction with remifentanil.

American Society of Anesthesiologists (ASA) class I and II patients who are admitted to undergoing elective surgery under general anesthesia will be enrolled. Patients in midazolam group (Group M) will be treated with midazolam premedication (3 cc mixture of 0.035 mg/kg midazolam and normal saline; maximum midazolam dose, 3 mg) intravenously in a waiting area 3 minutes before transportation to an operating room, while 3 cc normal saline will be administered to control group (Group S) patients. The difficulty of mask ventilation will be evaluated before the injection of neuromuscular blocking during general anesthetic induction. The anxiety and sedation levels of patients will be estimated before the intervention and before anesthetic induction in an operating room. Remifentanil will be used as an opioid in the induction of the patients. In anesthesia induction, propofol 1.5 mg/kg will be given after remifentanil is infused at a dose of 0.30 µg/kg/min for three minutes. Before the patients were given muscle relaxants, the patients were evaluated with the Warter scale

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) class I and II patients
• Patients who are scheduled for any elective surgery under general anesthesia

Exclusion Criteria:

• age <18 or >60 years
• current cervical spine disease or history of cervical spine surgery;
• morbid obesity (body mass index, ≥35 kg/m2);
• sleep apnea;
• craniofacial anomaly;
• allergic reaction to midazolam and remifentanil
• chronic use of opioid, benzodiazepine, antipsychotic medications
• pregnancy
• presence of muscle weakness or dyspnea