A Comparison of Dexmedetomidine-Propofol and Fentanyl-Propofol for Laryngeal Mask Airway Insertion: A Randomized Double-Blind Study.

Introduction Successful laryngeal mask airway (LMA) insertion requires suppression of airway reflexes and adequate jaw relaxation. Although propofol is the preferred induction agent, higher doses may cause adverse hemodynamic and respiratory effects. Adjuvants such as opioids or dexmedetomidine can enhance insertion conditions while minimizing propofol requirements. This pilot study compared dexmedetomidine-propofol and fentanyl-propofol combinations in terms of LMA insertion conditions and hemodynamic responses. Materials and methods In this prospective, randomized, double-blind pilot study, 40 American Society of Anesthesiologists (ASA) I and II patients were randomized to receive either an intravenous infusion of 1 microgram per kilogram of dexmedetomidine (Group D, n=20) diluted to 20 ml, or normal saline 20 ml (Group F, n=20) administered over 10 minutes. Following this, Group F received 1 microgram per kilogram of fentanyl over two minutes, while Group D received an equivalent volume of normal saline. All patients were induced with 1.5 mg/kg of propofol. The primary outcome was the ease of LMA insertion, assessed by jaw mobility and the presence of adverse airway reflexes (coughing, gagging, or movement during insertion), which was noted and scored. Secondary outcomes included heart rate (HR), systolic and mean arterial pressure, respiratory rate, and oxygen saturation, measured at baseline, pre-insertion, and at one, three, five, 10, 15, and 20 minutes post-insertion. Both the anesthesiologist administering the drugs and the investigator performing the insertion were blinded to group allocation. Results All patients in Group D had favorable LMA insertion scores (<2), while 30% in Group F had unfavorable scores (>2) (p=0.020). Apnea occurred in two patients in Group D and six patients in Group F. A statistically significant reduction in HR was observed in group D compared to group F; however, the values remained within the clinically acceptable range, without evidence of hemodynamic instability (HR before insertion (p<0.001), HR at one minute (p<0.001), HR at three minutes (p=0.026), HR at five minutes (p=0.022), and HR at 10 minutes (p=0.038)). Respiratory rate was significantly higher in Group D at the time points of one minute (p=0.003), three minutes (p=0.002), five minutes (p=0.011), 10 minutes (p=0.024), 15 minutes (p=0.007), and 20 minutes (p =0.002) post insertion. Conclusion When compared to fentanyl with propofol, dexmedetomidine with propofol provided effective conditions for LMA insertion with preserved respiratory function and comparable hemodynamic stability. Larger randomized studies are needed to confirm these findings and optimize dosing.