Comparison of the Effects of Propofol-Remifentanil and Thiopental-Remifentanil Administration on the Success of Classic Laryngeal Mask Airway (LMA) Placement, Hemodynamic Response, and Pharyngolaryngeal Morbidity: A Prospective Randomized Study

Study Protocol and Methods: This study was conducted after receiving approval from the Okmeydani Education and Research Hospital and Firat University Faculty of Medicine Drug Research Local Ethics Committee (decision number: 132). Informed consent was obtained from all participants. The study enrolled 80 patients classified as ASA I-II, aged 18–65 years, undergoing elective surgeries that did not require muscle relaxants, with a maximum duration of 2 hours and indications for laryngeal mask airway (LMA) insertion. Exclusion criteria included patients with neck or upper respiratory tract pathologies, a history or likelihood of difficult airway (Mallampati Class 3-4, sternomental distance <12 cm, thyromental distance <6 cm, head extension <90°, or mouth opening <1.5 cm), morbid obesity, history of pulmonary disease, allergies to study drugs, substance dependence, chronic sedative or opioid use, throat pain, dysphagia, or dysphonia. Monitoring and Randomization: Standard monitoring was conducted, including heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), electrocardiography (ECG), and peripheral oxygen saturation (SpO2). Depth of anesthesia was assessed using a BIS monitor (BIS-Vista™). Patients were randomized into two groups: Group P (Control Group): 2 µg/kg remifentanil followed by 2.5 mg/kg propofol. Group T (Thiopental Group): 2 µg/kg remifentanil followed by 5 mg/kg thiopental. Anesthetic Procedure: Preoxygenation was performed with 6 L/min oxygen for three minutes. Premedication included 0.03 mg/kg IV midazolam. Remifentanil (2 µg/kg) was infused over 60 seconds using an infusion pump. Propofol or thiopental was administered 30 seconds later over 30 seconds. The sequence was double-blinded; syringes were prepared by a nurse, and drug administration and LMA insertion were carried out by different personnel. Eyelash reflex was monitored to confirm loss of consciousness. Ninety seconds after thiopental administration, patients with BIS values <40 and sufficient jaw relaxation underwent LMA insertion. The LMA size was determined based on patient weight and inserted using a standardized technique. Cuff pressure was maintained at 60 cmH2O. Data Collection: The duration to loss of eyelash reflex and time to successful LMA insertion (from mouth opening to the first effective ventilation) were recorded. LMA insertion conditions were assessed using a 6-variable scale: mouth opening, ease of insertion, swallowing, coughing/gagging, laryngospasm, and movement. Conditions were rated as: Perfect: All variables rated as perfect. Good: A mix of moderate and perfect ratings. Poor: At least one variable rated as poor. Hemodynamic parameters (SAP, DAP, MAP, HR, SpO2) were recorded at baseline, 1 minute before LMA insertion, and 1, 2, 3, 4, and 5 minutes after insertion. Apnea duration was recorded from the last spontaneous breath after induction to the first spontaneous breath. Postoperative Evaluation: LMA removal was conducted under 100% oxygen, and cuff pressure was recorded. The presence of blood on the LMA was categorized as none, trace amounts, or significant. Patients were monitored for throat pain (0 = none, 1 = mild, 2 = moderate, 3 = severe) and dysphagia (present/absent) by a blinded researcher. Hypotension (MAP reduction >30%) was treated with 6 mg ephedrine, and bradycardia (HR <50 bpm) with 0.5 mg atropine.