The laryngeal mask airway (LMA) is a widely used supraglottic airway device for airway management during general anesthesia. Successful insertion requires adequate depth of anesthesia and suppression of airway reflexes to minimize coughing, gagging, laryngospasm, and patient movement. Propofol is commonly used for induction because of its favorable induction and recovery characteristics; however, achieving satisfactory conditions for LMA insertion may require doses that can contribute to respiratory and cardiovascular depression. [1] To improve LMA insertion conditions and reduce the requirement for propofol, various intravenous agents have been investigated as adjuvants. Dexmedetomidine, a selective α2-adrenergic receptor agonist, produces sedation and sympatholysis with relatively limited respiratory depression, whereas fentanyl provides analgesia and attenuates airway and hemodynamic responses to instrumentation. [2,3] Both agents have therefore been evaluated in combination with propofol for facilitating LMA insertion. Direct comparisons between dexmedetomidine-propofol and fentanyl-propofol have demonstrated generally comparable insertion conditions, although differences have been reported in respiratory and hemodynamic effects. Choudhary et al. reported comparable ProSeal LMA insertion conditions with both combinations, while dexmedetomidine was associated with a lower incidence of apnea and better postoperative analgesia. [1] Ramaswamy and Shaikh similarly reported comparable insertion conditions but observed more frequent and prolonged apnea with fentanyl. [2] A subsequent study evaluating LMA Supreme insertion also reported favorable insertion conditions with dexmedetomidine as an adjuvant to propofol. [3] More recent evidence has continued to examine this comparison. A randomized double-blind study published in 2025 evaluated dexmedetomidine-propofol and fentanyl-propofol for LMA insertion, further highlighting the potential differences between the two adjuvant strategies with respect to insertion conditions and adverse effects. [4] In addition, a network meta-analysis comparing anesthetic regimens for LMA insertion provided broader evidence regarding the relative performance of different drug combinations. [5] The effects of dexmedetomidine during airway management have also been evaluated in systematic reviews, with evidence suggesting that its sedative and sympatholytic properties may facilitate airway instrumentation while preserving spontaneous respiration. [6] Earlier work established the importance of adequate anesthetic depth for tolerance of LMA insertion and demonstrated that the anesthetic requirement differs between supraglottic airway and endotracheal airway management. [7] Fentanyl has also been used as a pretreatment agent to facilitate LMA insertion when propofol is used for induction. [8] Studies using different supraglottic airway devices have reported variable findings, including differences in insertion conditions, respiratory effects, hemodynamic responses, and propofol requirements. For example, dexmedetomidine-propofol has also been compared with fentanyl-propofol for i-gel insertion, demonstrating the importance of considering the specific airway device and anesthetic protocol when interpreting the results. [9] A randomized clinical study involving ProSeal LMA further compared dexmedetomidine and fentanyl as co-induction agents with propofol, adding to the evidence regarding their relative efficacy during supraglottic airway insertion. [10] Despite these studies, differences in drug doses, timing of administration, LMA type, induction technique, and outcome assessment make it difficult to establish a universally preferred adjuvant regimen. Therefore, the present study was undertaken to compare dexmedetomidine versus fentanyl as intravenous adjuvants to propofol for LMA insertion, with assessment of insertion conditions and relevant peri-induction clinical parameters.

Study Design and Setting This prospective, comparative study was conducted in the Department of Anaesthesiology at a tertiary-care teaching hospital. The study was designed to compare the efficacy and safety of dexmedetomidine and fentanyl when used as intravenous adjuvants to propofol for laryngeal mask airway (LMA) insertion. The study was conducted after approval from the Institutional Ethics Committee, and written informed consent was obtained from all participants before enrolment. Study Population The study included 60 adult patients aged 18–60 years who were scheduled for elective surgical procedures under general anesthesia requiring LMA insertion. Participants were divided into two equal groups of 30 patients each according to the intravenous adjuvant received: ● Group D (n = 30): dexmedetomidine with propofol ● Group F (n = 30): fentanyl with propofol Inclusion Criteria Patients were eligible if they were: 1. Aged 18–60 years; 2. Classified as American Society of Anesthesiologists (ASA) physical status I or II; 3. Scheduled for elective surgery under general anesthesia; 4. Considered suitable for LMA airway management; and 5. Willing to participate and provide written informed consent. Exclusion Criteria Patients were excluded if they had anticipated difficult airway, significant cardiovascular or respiratory disease, clinically significant hepatic or renal dysfunction, known allergy or hypersensitivity to any study medication, pregnancy, obesity with BMI ≥30 kg/m², history of upper-airway pathology or previous airway surgery, or were receiving medications likely to significantly influence cardiovascular or respiratory responses to anesthesia. Preoperative Assessment All patients underwent routine preoperative evaluation, including detailed medical history, physical examination, airway assessment, and review of relevant laboratory investigations. Baseline heart rate, systolic and diastolic blood pressure, mean arterial pressure, respiratory rate, and peripheral oxygen saturation (SpO₂) were recorded before induction of anesthesia. Anesthetic Technique Standard monitoring consisting of electrocardiography, noninvasive blood pressure, pulse oximetry, and respiratory rate was instituted before induction. Patients were preoxygenated with 100% oxygen for three minutes. Patients in Group D received dexmedetomidine 1 μg/kg intravenously over 10 minutes, whereas patients in Group F received fentanyl 1 μg/kg intravenously over 2 minutes. Following administration of the assigned adjuvant, anesthesia was induced with intravenous propofol at a dose of 2.5 mg/kg. Adequate depth of anesthesia was assessed clinically before LMA insertion. An appropriately sized LMA was inserted by an experienced anesthesiologist. Additional propofol was permitted when required to achieve adequate anesthetic depth, and the total dose administered was recorded. Assessment of LMA Insertion Conditions LMA insertion conditions were assessed using a standardized clinical scoring system based on patient response to insertion. Coughing, gagging, swallowing, limb or head movement, and jaw relaxation were assessed and recorded. The number of insertions attempts and the time required for successful insertion were also documented. Insertion conditions were categorized as excellent, satisfactory, or poor according to the predefined scoring criteria. Successful placement on the first attempt was recorded separately. Hemodynamic and Respiratory Assessment Heart rate and blood pressure were recorded at baseline, following administration of the study drug, immediately after induction, immediately after LMA insertion, and at 1, 3, 5, and 10 minutes after insertion. Respiratory parameters, including respiratory rate and SpO₂, were similarly monitored. The occurrence and duration of apnea, oxygen desaturation, bradycardia, hypotension, and other peri-induction adverse events were recorded. Propofol Requirement The total dose of propofol required to achieve adequate conditions for LMA insertion was recorded for each participant. The requirement was compared between the dexmedetomidine and fentanyl groups. Postoperative Assessment Following completion of surgery, patients were monitored in the postoperative recovery area. Recovery characteristics and postoperative adverse events, including nausea, vomiting, sore throat, and pain, were documented. Outcome Measures The primary outcome was the quality of LMA insertion conditions with dexmedetomidine-propofol compared with fentanyl-propofol. Secondary outcomes included: ● Number of attempts required for successful LMA insertion; ● Total propofol requirement; ● Heart rate and blood pressure changes; ● Incidence and duration of apnea; ● Oxygen desaturation; ● Recovery characteristics; and ● Postoperative adverse effects. Statistical Analysis Data were entered into Microsoft Excel and analyzed using appropriate statistical software. Continuous variables were expressed as mean ± standard deviation, while categorical variables were presented as frequencies and percentages. Continuous variables were compared between the two groups using the independent-samples t-test or Mann-Whitney U test, as appropriate. Categorical variables were compared using the chi-square test or Fisher's exact test. Repeated measurements of hemodynamic parameters were analyzed using an appropriate repeated-measures statistical approach. A p-value <0.05 was considered statistically significant.

A total of 60 patients were included in the study, with 30 patients in each group. The two groups were comparable with respect to baseline demographic characteristics, including age, sex, weight, and ASA physical status. No statistically significant differences were observed between the groups for these baseline variables (p > 0.05) (Table 1). Table 1. Baseline Demographic and Clinical Characteristics Variable Dexmedetomidine Group (n=30) Fentanyl Group (n=30) p-value Age (years), mean ± SD 39.2 ± 10.1 38.6 ± 9.7 0.82 Weight (kg), mean ± SD 61.8 ± 7.6 62.4 ± 8.1 0.77 Male, n (%) 17 (56.7) 18 (60.0) 0.79 Female, n (%) 13 (43.3) 12 (40.0) ASA I, n (%) 18 (60.0) 17 (56.7) 0.79 ASA II, n (%) 12 (40.0) 13 (43.3) Values are expressed as mean ± standard deviation or frequency (percentage), as appropriate. ASA: American Society of Anesthesiologists. The quality of LMA insertion was significantly better in the dexmedetomidine group. Excellent insertion conditions were observed in 23 (76.7%) patients receiving dexmedetomidine compared with 17 (56.7%) patients receiving fentanyl. First-attempt insertion was also more frequent in the dexmedetomidine group, although the difference did not reach statistical significance. The mean propofol requirement was significantly lower in the dexmedetomidine group than in the fentanyl group (Table 2). Table 2. LMA Insertion Conditions and Propofol Requirement Outcome Dexmedetomidine Group (n=30) Fentanyl Group (n=30) p-value Insertion condition, n (%) Excellent 23 (76.7) 17 (56.7) 0.04* Satisfactory 6 (20.0) 9 (30.0) Poor 1 (3.3) 4 (13.3) First-attempt insertion, n (%) 28 (93.3) 25 (83.3) 0.23 Insertion time (seconds), mean ± SD 18.4 ± 4.1 21.2 ± 5.3 0.02* Total propofol dose (mg), mean ± SD 148.6 ± 18.7 163.8 ± 21.4 0.005* LMA: laryngeal mask airway. p < 0.05 was considered statistically significant. Hemodynamic parameters remained within clinically acceptable ranges in both groups. However, patients receiving dexmedetomidine demonstrated a more stable heart rate and blood pressure following induction and LMA insertion. The magnitude of hemodynamic changes from baseline was significantly lower in the dexmedetomidine group at selected post-insertion time points (Table 3). Table 3. Peri-induction Hemodynamic Parameters Time point Dexmedetomidine Group Fentanyl Group p-value Heart rate (beats/min) Baseline 78.4 ± 8.6 79.1 ± 9.1 0.76 After induction 72.6 ± 7.9 76.8 ± 8.7 0.05 After LMA insertion 74.1 ± 8.2 81.3 ± 9.4 0.003* 5 min after insertion 75.8 ± 7.6 79.6 ± 8.5 0.07 Systolic BP (mmHg) Baseline 124.6 ± 11.8 125.8 ± 12.1 0.70 After induction 113.8 ± 10.7 108.2 ± 11.4 0.05 After LMA insertion 116.4 ± 10.3 109.6 ± 11.7 0.02* 5 min after insertion 119.2 ± 10.1 114.8 ± 11.2 0.11 SpO₂ (%) Baseline 99.1 ± 0.6 99.0 ± 0.7 0.56 After LMA insertion 98.7 ± 0.8 97.9 ± 1.2 0.004* BP: blood pressure; LMA: laryngeal mask airway; SpO₂: peripheral oxygen saturation. p < 0.05 was considered statistically significant. Respiratory adverse events were less frequent in the dexmedetomidine group. Apnea occurred in 3 (10.0%) patients in the dexmedetomidine group compared with 9 (30.0%) patients in the fentanyl group (p = 0.05). The mean duration of apnea was also shorter with dexmedetomidine. Postoperative adverse effects were generally comparable between groups, although sore throat and postoperative nausea were numerically more frequent in the fentanyl group (Table 4). Table 4. Respiratory and Postoperative Outcomes Outcome Dexmedetomidine Group (n=30) Fentanyl Group (n=30) p-value Apnea, n (%) 3 (10.0) 9 (30.0) 0.05 Duration of apnea (seconds), mean ± SD 18.3 ± 6.4 29.7 ± 10.2 0.001* Desaturation (SpO₂ <94%), n (%) 2 (6.7) 6 (20.0) 0.13 Bradycardia, n (%) 2 (6.7) 1 (3.3) 0.55 Hypotension, n (%) 3 (10.0) 5 (16.7) 0.45 Sore throat, n (%) 4 (13.3) 7 (23.3) 0.31 Postoperative nausea/vomiting, n (%) 3 (10.0) 6 (20.0) 0.27 SpO₂: peripheral oxygen saturation. p < 0.05 was considered statistically significant. Overall, dexmedetomidine used as an intravenous adjuvant to propofol was associated with better LMA insertion conditions, a lower propofol requirement, greater hemodynamic stability, and fewer respiratory adverse events than fentanyl, while both regimens provided acceptable conditions for LMA insertion.

The present comparative study evaluated dexmedetomidine and fentanyl as intravenous adjuvants to propofol for LMA insertion. The findings demonstrated that dexmedetomidine was associated with better insertion conditions, a lower propofol requirement, greater hemodynamic stability, and fewer respiratory adverse events than fentanyl. The significantly better insertion conditions observed with dexmedetomidine are consistent with previous comparative studies. Choudhary et al. reported comparable ProSeal LMA insertion conditions with dexmedetomidine-propofol and fentanyl-propofol, with optimal insertion achieved in 91.9% and 83.8% of patients, respectively. [1] Ramaswamy and Shaikh similarly reported satisfactory LMA insertion with both combinations, while dexmedetomidine demonstrated an advantage in preservation of spontaneous respiration. [2] Studies involving LMA Supreme and ProSeal LMA have also reported favorable insertion characteristics with dexmedetomidine as an adjuvant to propofol. [3,10] The lower propofol requirement observed with dexmedetomidine may be explained by its sedative and sympatholytic properties, which can reduce the depth of propofol required to achieve adequate conditions for airway instrumentation. Dexmedetomidine may therefore provide effective co-induction while avoiding excessive propofol administration. Similar advantages in propofol requirements and insertion quality have been reported in previous comparative studies. [3,10] The broader evidence from a network meta-analysis also supports the use of appropriate drug combinations to optimize LMA insertion conditions while limiting adverse effects. [5] An important finding was the lower incidence and shorter duration of apnea in the dexmedetomidine group. Ramaswamy and Shaikh reported more frequent and prolonged apnea with fentanyl compared with dexmedetomidine, despite comparable LMA insertion conditions. [2] Choudhary et al. likewise observed a significantly higher incidence of apnea with fentanyl. [1] This finding is clinically relevant because opioid-induced respiratory depression is an important consideration during induction, whereas dexmedetomidine generally produces sedation with relatively limited respiratory depression. Evidence from systematic review also supports the respiratory-sparing characteristics of dexmedetomidine during LMA-related anesthesia. [6] The present study also demonstrated greater hemodynamic stability with dexmedetomidine. The attenuation of heart rate and blood pressure responses following LMA insertion may be related to the sympatholytic action of dexmedetomidine. Similar hemodynamic advantages have been reported in studies comparing dexmedetomidine with fentanyl during supraglottic airway insertion. [1,3,10] Nevertheless, dexmedetomidine can produce bradycardia and hypotension, particularly at higher doses or with rapid administration, and therefore appropriate dosing and monitoring remain important. The findings should be interpreted in the context of differences among previous studies. Variations in the type of supraglottic airway device, the dose and administration time of the adjuvant, the propofol dose, and the scoring system used for insertion conditions may explain differences in reported results. The recent randomized study by Muthachen further demonstrates that dexmedetomidine-propofol and fentanyl-propofol can produce different peri-induction profiles despite both providing acceptable LMA insertion conditions. [4] The available evidence therefore suggests that the choice of adjuvant should consider not only insertion success but also respiratory and hemodynamic safety. The present study has several limitations. The sample size was relatively small, and the study was conducted in a single center, which may limit generalizability. The study included patients undergoing elective procedures and therefore the findings may not be applicable to patients with significant comorbidities or anticipated difficult airways. In addition, postoperative outcomes were assessed only over the immediate perioperative period, limiting conclusions regarding longer-term effects. Overall, dexmedetomidine appears to be a useful intravenous alternative to fentanyl when combined with propofol for LMA insertion. The present study provided favourable insertion conditions while requiring less propofol and producing fewer respiratory adverse events. These findings are broadly consistent with previous comparative evidence [1-6,10]. Further adequately powered comparative studies involving different LMA devices and standardized dosing protocols would help establish the optimal adjuvant regimen for supraglottic airway insertion.

Dexmedetomidine, when used as an intravenous adjuvant to propofol, provided favorable conditions for LMA insertion compared with fentanyl. It was associated with a lower propofol requirement, greater hemodynamic stability, and fewer respiratory adverse events, particularly apnea. Both regimens provided acceptable conditions for LMA insertion; however, dexmedetomidine may offer additional advantages during the peri-induction period. Further larger comparative studies are warranted to confirm these findings.

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