Laryngeal mask airway (LMA) was invented by Dr. Archie Brain in 1981 in the United Kingdom and has been in clinical use since 1988 [1]. It represents a novel concept in airway management. It is an alternative to more invasive endotracheal intubation by allowing air exchange through a specially designed supraglottic mask, which can fit over the laryngeal inlet and form a seal around the glottis without entry into the trachea [2]. The device is gaining popularity for both adult and pediatric anesthesia because of its simplicity, reduced airway trauma, and decrease in physiological stress associated with insertion. In pediatric anesthesia, the LMA plays an important role, particularly in elective surgeries, management of the difficult pediatric airway, and diagnostic airway procedures [3, 4]. Pediatric-sized LMAs are essentially scaled-down versions of their adult counterparts. However, due to anatomical differences in the airway of neonates and infants, such as a relatively larger tongue, higher glottic position, and more anterior larynx, achieving optimal conditions for LMA insertion can be more challenging in this population.

Insertion of LMA stimulates multiple structures such as the soft palate, the hard palate, the posterior pharyngeal wall, as well as the hypopharynx.  Although the depth of anesthesia needed for inserting a laryngeal mask airway (LMA) is generally less than what is required for endotracheal intubation, it is important to ensure the patient is adequately anesthetized. This helps prevent adverse responses such as coughing, gagging, laryngospasm, or movement during the procedure. One of the main advantages of using an LMA instead of endotracheal intubation is that it usually does not require neuromuscular blocking drugs. As a result, there is less impact on the cardiovascular system, and patients tend to recover more quickly after surgery [5]. To achieve the best conditions for insertion of a laryngeal mask airway (LMA), various induction agents are used. Propofol is a popular choice because of its rapid onset, short duration, and ability to help suppress reflexes in the upper airway that can interfere with the procedure. Midazolam, a fast-acting benzodiazepine, is often added for its anxiolytic and amnestic effects. Fentanyl, a potent opioid analgesic, is also commonly used; it reduces the amount of other inducting agents and blunts airway reflexes [6-8].  Fentanyl, in moderate to low doses, can improve insertion conditions of LMA and does not require skeletal muscle relaxants. However, its ideal dosage is a topic of debate and investigation, especially in pediatric age groups, because it requires balancing efficacy and safety.  High doses may enhance insertion conditions but risk respiratory depression and bradycardia, whereas lower doses may not adequately suppress airway reflexes. This prospective randomized clinical study was undertaken to evaluate and compare the effectiveness of two different doses of fentanyl (1 µ/kg and 2 µ/kg), in combination with a standard dose of propofol (2.0 mg/kg) and midazolam (0.05 mg/kg), in facilitating LMA insertion in children undergoing elective surgeries under general anesthesia. The primary objective of this study is to assess the quality of LMA insertion conditions and ease of insertion, patients' response, and hemodynamic stability, with an additional objective to include the appropriate dose of fentanyl that balances optimal conditions and produces minimal side effects.

This prospective randomized controlled study was conducted in the Department of Anesthesiology, Gandhi Medical College and Hospital, Secunderabad, Telangana. Institutional Ethical approval was obtained for the study after explaining the nature of the study in the vernacular language. Written consent was obtained from parents/guardians of all participants of the study.

Inclusion criteria

1. Children aged 3 to 9 years.
2. ASA Grade I and II
3. Males and Females
4. Undergoing elective surgical procedures under General Anesthesia

Exclusion criteria

1. History of bronchial asthma
2. Difficult intubations
3. Obesity
4. Known allergy or hypersensitivity to fentanyl, propofol, midazolam, or any components of these drugs.
5. Patients with raised intracranial pressure or neurological disorders affecting respiratory drive.

After approval by the ethics committee, n=60 cases were included in the study based on the inclusion and exclusion criteria. All children received Injection atropine in the dose 0f 20µ/kg intramuscularly 45 minutes before induction. On arrival in the operating theatre room, continuous recording of oxygen saturation and pulse by pulse oximeter was done. Intravenous access was established. Blood pressure was recorded manually. After recording the baseline values, patients were pre-oxygenated with 100% oxygen for 3minutes. Midazolam injection in the dose of 0.05 mg/kg was given intravenously.

Group A: These children received Injection fentanyl 1µ/kg IV, one minute later, Inj propofol 2.0 mg/kg IV as an induction agent.

Group B: These children received Injection fentanyl 2µ/kg IV, one minute later followed by Injection propofol 2.0 mg/kg IV as an induction agent.

After 90 seconds of giving an Injection of propofol, an LMA of appropriate size (2-wt.10-20 kg, 2.5-wt. 20-30 kg) was inserted by a theatre anaesthesiologist who was unaware of the doses of drugs given. The LMA was inserted using the standard partial inflation technique. The anaesthetist who inserts the LMA will assess the ease of LMA insertion. Adverse responses were monitored, such as inadequate jaw relaxation, gagging, coughing, limb or head movement, hiccoughs, or laryngospasm. The response was graded in the following way: mild if the reaction was transient and minimal, moderate if the reaction lasted for more than a few seconds but resolved in 20 seconds, and severe if the reaction was sustained for more than 20 seconds and required additional inducting agent to allow insertion. The overall ease of insertion of LMA was graded as excellent, satisfactory, or poor. If additional doses were required, Injection of propofol in a dose of 0.5 mg/kg was given in incremental doses. After inserting the LMA, the cuff was inflated with the prescribed volume of air (10ml- 2 size, up to 14ml- -2.5 size). Sizes 2 and 2.5 were used in the study. After confirming bilateral air entry, the LMA was secured with adhesive plasters. Anaesthesia was controlled by using a non-depolarizing muscle relaxant, Injection of atracurium 0.5 mg/kg IV, and maintained with oxygen and nitrous oxide 50 % each.

Parameters observed were the number of attempts in inserting the LMA.  Overall ease of LMA insertion. Pulse rate, Blood pressure, and requirement of propofol top-up doses. Pulse rate and blood pressure were noted before LMA insertion, at 1 minute, and 5 Minutes. Any movement of the patient and application of the surgical draping was avoided up to 5 minutes after inserting the LMA. After the end of the surgery, all anaesthetics were cut off, and recovery time was assessed with the modified Aldrete score [9]. The time required to attain a score >9 is recorded. If the total score is >9, the patient can be discharged from the recovery room. And recovery was assessed.

A total of n=60 cases, equally divided into two groups based on the inclusion and exclusion criteria, were used in the study. Table 1 depicts the baseline demographic characteristics of group A (fentanyl 1µ/kg) and group B (fentanyl 2µ/kg). The mean age in Group A was 5.46 ± 1.94 years, and in Group B, it was 5.63 ± 1.71 years (p = 0.725), showing no significant differences. Similarly, the mean weight was 15.83 ± 4.54 kg in Group A versus 17.00 ± 4.02 kg in Group B (p = 0.296). Gender distribution was identical in both groups (M: F = 22:8), indicating balanced and comparable cohorts for assessing the effect of fentanyl dosing on LMA insertion and related outcomes.

Table 2 presents the success and ease of LMA insertion in both groups. A critical analysis of the table shows that Group B showed a significantly higher first-attempt success rate (93.3%) than Group A (66.7%) with a p-value of 0.042. Additionally, only 6.7% in Group B required an additional dose versus 33.3% in Group A, indicating better initial insertion conditions. Ease of insertion was rated as “Excellent” in 86.7% of Group B compared to 50% in Group A (p = 0.003). Poor insertion conditions were significantly more frequent in Group A (33.3%) than in Group B (6.7%) (p = 0.01), reflecting greater procedural efficacy with the higher fentanyl dose.

            *Significant

Table 3 compares hemodynamic parameters, including heart rate and mean arterial pressure (MAP), at different time points. Baseline heart rates were similar across groups (p = 0.191), but post-insertion measurements showed significantly lower heart rates in Group B at 1 minute (85.96 ± 6.76 bpm vs. 89.67 ± 5.69 bpm and p = 0.013) and 5 minutes (86.40 ± 6.92 bpm vs. 90.00 ± 5.02 bpm and p = 0.012). MAP values also decreased more in Group B at 1 minute (62.10 ± 2.52 mmHg vs. 63.50 ± 2.53 mmHg and p = 0.018) and 5 minutes (63.80 ± 1.84 mmHg vs. 65.07 ± 2.72 mmHg and p = 0.019), indicating better hemodynamic stability with the higher fentanyl dose.

                            *Significant

Table 4 shows the oxygen saturation during various stages of the procedure. A critical analysis of the table shows that oxygen saturation levels remained consistently high in both groups across all time points, with no statistically significant differences at any interval. At 0, 1, and 5 minutes, mean SpO₂ values in Group A were 98.90%, 98.86%, and 98.90% respectively, while in Group B, they were 98.80%, 98.80%, and 98.90%. All p-values exceeded 0.99, suggesting that neither fentanyl dose adversely affected oxygenation during the procedure. These findings affirm the respiratory safety of both dosing regimens during LMA insertion.

Table 5 shows the recovery characteristics of both groups. Analysis of the table shows that the mean recovery times were similar between Group A (5.70 ± 1.84 minutes) and Group B (6.00 ± 1.78 minutes and p = 0.261, indicating no delay due to the higher fentanyl dose. However, the time to first rescue analgesia was significantly shorter in Group B (32.07 ± 3.55 minutes) compared to Group A (49.20 ± 4.02 minutes) with a highly significant p-value (<0.001). This shows that while both groups recovered similarly, children in Group B experienced earlier onset of postoperative discomfort, possibly due to higher opioid metabolism or redistribution.

                             *Significant

Since its inception, the laryngeal mask airway (LMA) has transformed the airway management system. It is less invasive compared to endotracheal intubation. In pediatric anesthesia, a simpler and less traumatizing airway (less trauma to the airway) is always needed [1, 10]. Its application, however, is contraindicated in cases with increased risk of aspiration and with poor lung compliance [1]. Its successful insertion requires proper technique and the proper depth of anesthesia. Difficulties negotiating the posterior pharynx, poor anesthesia, and incorrect size of LMA are common issues. Its insertion is made easy by effective suppression of the upper airway reflexes like coughing, gagging, and movements of limbs. It requires the use of agents that adequately blunt airway reflexes without impairing cardio-respiratory stability [11]. One of the most common drugs is propofol, which has significant airway reflex depressant potentials; however, it does not produce analgesia, and in larger doses, may lead to hypotension and respiratory depression [12, 13].

To overcome these limitations, propofol dose-reducing agents or even adjuvants such as opioids and benzodiazepines are administered. Fentanyl, more specifically, lowers the EC50 of propofol, thus reducing the required concentration for LMA insertion and causing minimal adverse effects [14, 15]. Kodaka et al. [12] have established that fentanyl doses of 0.5-2 µg/kg strongly affected the EC50 value of propofol 3.25 µg /mL in controls to 1.50 µg/mL with a 2µg/kg fentanyl dose. A study by Martlew et al. [16] confirmed that premedication with midazolam decreased propofol dosing needs by a third. Nevertheless, higher doses of propofol (5 mg/kg) may cause undesirable hemodynamic effects in children [17, 18]. Therefore, the combination of midazolam and fentanyl allows for dose-sparing and stable conditions. In this study, we found that group B patients who received fentanyl 2 µg/kg along with propofol (2 mg/kg) and midazolam (0.05 mg/kg) had better conditions for LMA insertion. A success rate of 93.3% in first-attempt was achieved within the above group with minimal adverse responses such as gagging or limb movement, which proves that this combination provides optimal depth of anesthesia. In this study, we followed a partially inflated cuff technique, which is known to enhance insertion success. Kundra et al. [19] in a similar study observed that lateral insertion with a partially inflated cuff reduced insertion time and number of attempts. The use of lidocaine to nullify propofol pain and the 3-minute interval after fentanyl and midazolam administration allows peak drug effects and insertion conditions. The current study also found that group B had better hemodynamic stability. There was no significant increase in pulse rates or mean arterial pressure during LMA insertion, showing adequate depth of anesthesia. More importantly, we did not find the development of hypotension, which requires the use of vasopressors. These results are consistent with earlier studies showing the hemodynamic benefit of combining fentanyl with propofol [20]. In a larger study series, Brimacombe et al. [21] and Mason et al. [22] have confirmed the safety of LMA in children with successful use in over 90% of cases, making it a reliable airway device when used in appropriate conditions.

Within the limitations of the current study, we found that the combination of fentanyl 2 µg/kg with propofol 2 mg/kg and midazolam 0.05 mg/kg provides optimal conditions for LMA insertion in pediatric patients. This combination also ensures higher first-attempt success rates, minimal adverse airway responses, and stable hemodynamics. This regimen effectively suppresses airway reflexes without causing significant respiratory or cardiovascular depression. It offers a safe, reliable, and efficient technique for airway management in children undergoing elective surgeries. Therefore, it can be recommended as a preferred induction strategy in this population.

1. Brain AIJ. The laryngeal mask—a new concept in airway management. Br J Anaesth. 1983;55(8):801–05.
2. Jones JR. Laryngeal mask airway: an alternative for the difficult airway. AANA J. 1995 Oct;63(5):444-49.
3. Jamil SN, Alam M, Usmani H, Khan MM. A Study of the Use of Laryngeal Mask Airway (LMA) in Children and Its Comparison with Endotracheal Intubation. Indian J Anaesth. 2009 Apr;53(2):174-78.
4. Jagannathan N, Sohn LE, Chang E, Sawardekar A, Langen KE, Anderson K. A randomized trial comparing the laryngeal mask airway Supreme™ and the LMA ProSeal™ in children. Anaesthesia. 2012;67(6):632–39.
5. Jannu A, Shekar A, Balakrishna R, Sudarshan H, Veena GC, Bhuvaneshwari S. Advantages, Disadvantages, Indications, Contraindications and Surgical Technique of Laryngeal Airway Mask. Arch Craniofac Surg. 2017 Dec;18(4):223-229.
6. Lingamchetty TN, Hosseini SA, Saadabadi A. Midazolam. [Updated 2023 Jun 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537321/ [Accessed on Jan 20th 2025]
7. Bhardwaj N, Yaddanapudi S, Ghai B, Panda NB. Airway management in children: Current concepts. Indian J Anaesth. 2011;55(5):448–53.
8. Darlong V, Kunhabdulla NP, Punj J, Garg R, Pandey RK. Comparison of propofol and sevoflurane for insertion of classic laryngeal mask airway in children undergoing elective ophthalmological surgeries. Saudi J Anaesth. 2011;5(2):133–37.
9. White PF, Song D. New criteria for fast-tracking after outpatient anesthesia: A comparison with the modified Aldrete’s scoring system. Anesth Analg. 1999; 88:1069–72.
10. Pavlin DJ, Rapp SE, Polissar NL, Malmgren JA, Koerschgen ME, Keyes H. Factors affecting discharge time in adult outpatients. Anesth Analg. 1998;87(4):816–26.
11. O’Neil J, Morton NS. The laryngeal mask airway in paediatric anaesthesia. Anaesthesia. 1992;47(8):607–9.
12. Kodaka M, Johansen JW, Wada T, Asai T, Miyabe M. The influence of fentanyl on the EC50 of propofol for laryngeal mask airway insertion and bispectral index. Br J Anaesth. 2004;93(3):384–9.
13. Hohlrieder M, Brimacombe J, Eschertzhuber S, Ulmer H, Keller C. The effect of fentanyl and remifentanil on propofol EC50 for insertion of the laryngeal mask airway. Anaesthesia. 2007;62(4):336–41.
14. Brimacombe J. Insertion of laryngeal mask –an indication of propofol. Anaesthesia Intensive Care.1992,40(2):394-95
15. Dutt A, Joad AK, Sharma M. Induction for classic laryngeal mask airway insertion: Does low-dose fentanyl work? J Anaesthesiol Clin Pharmacol. 2012 Apr-Jun;28(2):210-13.
16. Martlew RA, Meakin GH, Glover R, Ingram GS. The dose of propofol required to insert a laryngeal mask airway in children: effect of premedication with midazolam. Br J Anaesth. 1996;76(4):484–85.
17. Blake DW, Dawson P, Donnan G, Bjorksten A. Propofol induction for laryngeal mask airway insertion: dose requirement and cardiorespiratory effects. Anaesth Intensive Care. 1992 Nov;20(4):479-83.
18. GW Brown. Comparison of propofol and thiopentone for laryngeal mask insertion. Anesthesia 1991,46(9):771-72.
19. Kundra P, Deepak R, Ravishankar M. Laryngeal mask insertion in children: comparison of two techniques with and without cuff inflation. Anaesthesia. 2003;58(9):846–49.
20. Dwivedi MB, Nagrale M, Dwivedi S, Singh H. What happens to the hemodynamic responses for laryngeal mask airway insertion when we supplement propofol with butorphanol or fentanyl for induction of anesthesia: A comparative assessment and critical review. Int J Crit Illn Inj Sci. 2016 Jan-Mar;6(1):40-44.
21. Brimacombe J, Berry A. The laryngeal mask airway: preoperative assessment and an overview of 1,400 uses in infants and children. Paediatr Anaesth. 1995;5(5):293–99.
22. Mason DG, Bingham RM. The laryngeal mask airway in children. Anaesthesia. 1990 Sep; 45(9):760-73.