Comparison of the Effects of Propofol-Dexmedetomidine and Propofol-Remifentanil Combinations on the Success of Classical LMA (Laryngeal Mask Airway) Placement, Haemodynamic Response and Pharyngolaryngeal Morbidity in ASA I-II Patients

Intervention Description:Group D (Dexmedetomidine Group) This study was completed after receiving permission from Okmeydani Education and Research and Firat University Faculty of Medicine Drug Research Local Ethics Committee (date 5/11/2013 and decision number 134) and with informed consent from patients. The study included 80 patients classified as ASA I-II according to the ASA physiological classification, aged 18-65 years, undergoing elective surgery without requiring muscle relaxants, with operation duration not exceeding 2 hours and with indications for LMA insertion. Cases with any neck and upper respiratory tract pathology, history or possibility of difficult airway (Mallampati class 3-4, sternomental distance less than 12 cm, thyromental distance less than 6 cm, head extension less than 90 degrees, mouth opening less than 1.5 cm), morbid obesity, history of pulmonary disease, history of allergy to the study drugs, history of alcohol and substance dependence, history of chronic sedative and opioid analgesic use, throat pain, dysphagia, and dysphonia were excluded from the study. Group D (Dexmedetomidine Group) - Drug Administered: Patients in Group D received 1 µg/kg dexmedetomidine. Test syringes contained 20 mL of dexmedetomidine solution, diluted with 0.9% saline to a total of 50 mL. An independent anaesthesia expert prepared these syringes. - Monitoring: Anaesthesia depth was monitored using the BIS-Vista™ system (Aspect Medical Systems; Newton, MA, USA). - Blinding: The anaesthesiologist responsible for LMA insertion and monitoring parameters was blinded to the administered drug. Before anaesthesia, patients were taken to the operating room, where standard monitoring was performed, including heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), electrocardiography (ECG; lead II), and peripheral oxygen saturation (SpO2). Patients had venous access in the back of the hand with a 20 G cannula and were administered 7 mL/kg saline infusion before induction. Patients in Group D were given 1 µg/kg dexmedetomidine in a 50 mL injector completed to 50 mL with 0.9% NaCl (Precedex®, 100 µg/mL, Hospira, USA), infused over 10 minutes with an infusion pump (Braun Infusomat®; Braun Melsungen Ko, Germany). Thirty seconds after the dexmedetomidine infusion, 2.5 mg/kg propofol was administered over 30 seconds for anaesthesia induction. During the perioperative period, if hypotension occurred (defined as a reduction in MAP of >30% compared to baseline values), 6 mg ephedrine (Efedrin, Haver, Istanbul, Türkiye) was administered. Bradycardia, defined as HR less than 50 beats/min, was treated with 0.5 mg IV atropine (atropine sulphate, Haver, Istanbul, Türkiye). With eyelash reflex checks after induction, patients were ventilated with 100% O2 using a face mask. The time from the start of induction agent administration until the loss of the eyelash reflex was recorded. Ninety seconds after propofol administration, when BIS values were below 40 and sufficient chin relaxation was achieved, the LMA size was selected according to the patient’s body weight, as recommended in the manufacturer’s guidelines. The LMA was lubricated with a water-soluble gel on the side facing the oropharynx, the cuffs were fully deflated, and it was inserted using the standard method described by Brain by a single researcher with more than 3 years of experience. After insertion, cuff pressure monitoring (cuff pressure manometer, Rüsch, Germany) was performed to standardize postoperative pharyngeal morbidity. The laryngeal mask cuff was inflated until the cuff pressure reached 60 cmH2O, which was maintained throughout the operation. The duration until successful insertion (time from mouth opening to first successful ventilation) was recorded. Criteria for successful insertion included observing square waveforms on the capnogram, easy ventilation with a respiratory balloon, visible chest movements, and no air leak with 20 cmH2O positive pressure ventilation. Anaesthesia maintenance ensured BIS values between 40 and 60 and was achieved using 1.5-2% sevoflurane in a 40% O2/60% N2O mixture. If sufficient induction was not achieved, and no movement was observed during the first attempt, an additional dose of 1 mg/kg propofol was administered to keep BIS values below 40, and a second LMA insertion attempt was made. The number of attempts was recorded, but insertion conditions were assessed only during the first attempt. Postoperative Monitoring SAP, DAP, MAP, HR, BIS, and SpO2 values were recorded at baseline, immediately before LMA insertion, and at the 1st, 2nd, 3rd, 4th, and 5th minutes after insertion. Apnoea duration (the time from the last spontaneous respiration before induction to the first spontaneous respiration) was recorded. Five minutes before the end of the operation, 100% O2 was administered. Before removing the LMA, intracuff pressure was measured again and recorded. In the presence of sufficient ventilation, the LMA was removed, and the duration of LMA use (time between insertion and removal) was recorded. After removing the laryngeal mask, the presence of blood was assessed on a scale: 1 (no blood seen), 2 (trace amounts), and 3 (significant amount of blood). Postoperative Complications Waking patients were sent to the recovery unit with 100% oxygen. To determine the frequency and severity of pharyngolaryngeal complications, a single researcher, blind to group assignment and not involved in the anaesthesia process, evaluated all patients upon discharge from the recovery unit and again 24 hours later for throat pain (constant pain, independent of swallowing) and dysphagia (difficulty swallowing, provoked by drinking). Patients were asked about the presence or absence of these symptoms. Throat pain was assessed as follows: - 0 points: No complaint, - 1 point: Mild throat pain, - 2 points: Moderate throat pain, - 3 points: Severe throat pain.