Fentanyl and Propofol Versus Fentanyl and Etomidate for the Insertion Conditions of Laryngeal Mask Airway: A Prospective Observational Study

Abstract

Background:

Laryngeal mask airway (LMA) is often used in short surgeries for its easy insertion and minimal invasiveness but successful placement needs reflex suppression and stable vitals. This study compared Fentanyl-Propofol which gives better insertion but may cause hypotension with Fentanyl-Etomidate which maintains hemodynamics but causes more myoclonus.

Material and Methods:

60 American Society of Anesthesiologists I–II patients aged 18–60 years were included in this prospective study. Group A got Fentanyl + Propofol. Group B got Fentanyl + Etomidate. We compared attempts, time, ease, vitals, and side effects.

Results:

Group A had better insertion, first attempt success 90% versus 60%, time 23.27s versus 80.63s, and ease 96.67% versus 66.67%. Group B showed more myoclonus (43.33%), jaw tightness, and limb movements. Hemodynamics gets better with etomidate.

Conclusion:

Fentanyl-Propofol is better for smooth LMA insertion. Etomidate useful in unstable patients but may need caution due to insertion issues.

INTRODUCTION

Laryngeal mask airway (LMA) is commonly used in short and day-care surgeries due to easy insertion and less invasiveness. It allows airway control while patient breath on own. Introduced by Dr. Archie Brain in 1988, LMA sits in hypopharynx and covers supraglottic structures, partially isolating trachea.[1] Success of LMA depends on jaw relaxation and suppression of airway reflex. Propofol is widely used IV agent for this purpose. It gives sedation and reflex suppression but causes pain on injection, hypotension, and cardiac depression.[2] When combined with Fentanyl, it improves insertion and reduces Propofol need by better reflex blunting.[3] Etomidate is another agent, with fast onset and good cardiovascular stability, preferred in cardiac risk patients.[4] However, it lacks analgesia and may cause myoclonus, nausea, and adrenal suppression.[2,4] Adding Fentanyl improves jaw relaxation and reduces these issues.[5] As Propofol-Fentanyl may harm unstable patients,[6,7] we planned to compare Fentanyl-Propofol versus Fentanyl-Etomidate for LMA insertion.

MATERIALS AND METHODS

This prospective randomized observational study was conducted in Department of Anaesthesiology, MGM Medical College, and MY Hospital, Indore, from September 2023 to September 2024. Ethical clearance taken and trial registered (IEC No.: EC/MGM/Sept-23/73 and CTRI/2024/03/064653). Sample size calculated using G*Power v3.1.9.4 based on effect size from Uzun et al. Seventy-five patients were enrolled with 60 completing the analysis.[1] Patients randomized by odd-even method: Group A got Fentanyl 2 μg/kg + Propofol 1–2.5 mg/kg, Group B got Fentanyl 2 μg/kg + Etomidate 0.2–0.3 mg/kg. Inclusion: age 18–60 years, American Society of Anesthesiologists (ASA) I–II, Mallampati I–II, short elective surgery (<1.5 h). Exclusions were drug allergy, difficult airway, aspiration risk, BMI >35, epilepsy, steroid, or beta blocker use. All patients preloaded, preoxygenated, and induced per protocol. LMA inserted by experienced anaesthesiologist. We had monitored ECG, NIBP, SpO₂, and EtCO₂ Outcomes were based on number of attempts, insertion time, ease, vitals, and complications.

RESULTS

Table 1 presents that both groups were comparable in age, gender ratio, and weight, with no significant difference (P > 0.05). ASA I and Mallampati class I were more common in both groups, indicating similar baseline profiles.

Table 1.

Demographic and baseline characteristics of patients

Parameter	Group A (fentanyl + propofol)	Group B (fentanyl + etomidate)	P
Age (mean±SD)	39.13±12.4	42.2±10.71	0.310
Gender (female/male)	19/11	25/5	0.080
Weight (kg)	60.17±6.40	58.6±8.77	0.432
ASA Grade I/II	27/3	22/8	0.181
Mallampati Grade I/II	21/9	22/8	0.774

SD=Standard deviation, ASA=American Society of Anesthesiologists

Table 2 summarizes the comparative insertion parameters and complications between the two groups. Group A showed better LMA insertion outcomes with higher first attempt success (90% vs. 60%, P = 0.015), fewer attempts (1.1 vs. 1.4) and shorter insertion time (23.27s vs. 80.63s, P < 0.0001). Ease of insertion was better in Group A (96.67% vs. 66.67%, P = 0.006). Myoclonus (43.33% vs. 3.33%, P = 0.0004), jaw tightness (26.67% vs. 3.33%, P = 0.026), and limb movement (33.33% vs. 3.33%, P = 0.006) were significantly more in Group B. Gagging was higher in Group B (16.67%, P = 0.052), and hypotension and apnoea were slightly more in Group A but not significant. Additional drug requirement was similar in both groups (P = 0.791).

Table 2.

Comparison of laryngeal mask airway insertion parameters and complications

Parameter	Group A	Group B	P
First attempt success (%)	90	60	0.015
Mean number of attempts	1.1±0.31	1.4±0.50	0.007
Insertion time (s)	23.27±13.98	80.63±22.98	<0.0001
Ease of insertion (easy %)	96.67	66.67	0.006
Myoclonus (%)	3.33	43.33	0.0004
Inadequate jaw relaxation (%)	3.33	26.67	0.026
Limb movement (%)	3.33	33.33	0.006
Gagging (%)	0	16.67	0.052
Hypotension (%)	6.67	0	0.492
Apnoea (%)	10	3.33	0.612
Additional drug required (%)	36.67	40	0.791

DISCUSSION

LMA is widely used in short surgeries due to easier insertion and less airway trauma compared with intubation.[1] In our study, first-attempt insertion was higher with Fentanyl + Propofol (90%) than with Fentanyl + Etomidate (60%) (P = 0.015), consistent with Ghafoor et al., Uzun et al., and Alipour et al.[1,4,7] Propofol’s better reflex suppression and jaw relaxation likely explain smoother insertion. Insertion time was also significantly shorter with Propofol (23.27 ± 13.98 s) compared with Etomidate (80.63 ± 22.98 s) (P < 0.0001). Ease of insertion was better in the Propofol group (96.67% vs. 66.67%, P = 0.006). Myoclonus (43.33%) and poor jaw relaxation (26.67%) in the Etomidate group contributed to more difficult insertions. These findings are similar to those of Uzun et al. and Mohanty et al.[1,2] Although Fentanyl helped attenuate reflexes in both groups, it did not overcome the excitatory effects of Etomidate.

Group B (Etomidate) showed more stable mean arterial pressure (MAP) and heart rate (HR), while Propofol group had a greater MAP drop (74.47 ± 10.82 vs. 80 ± 9.4 mmHg, P = 0.039), especially at 3 min (P = 0.018), supporting earlier studies.[2,4,7,8,9] Etomidate had higher myoclonus (43.33% vs. 3.33%, P = 0.0004), more jaw tightness, and limb movement (P = 0.026, P = 0.006), consistent with previous reports.[1,2,10,11] Apnoea was slightly more in Propofol group (10% vs. 3.33%) but not significant, matching Alipour et al. and Liou et al.[7,11] Additional induction drug requirement was comparable (36.67% vs. 40%, P = 0.791), although the literature suggests that Etomidate may benefit from adjuncts to improve insertion.[1,10] Luan et al. showed that dexmedetomidine pretreatment significantly reduces Etomidate-induced myoclonus, supporting the need for such combinations in clinical practice.[12]

Fentanyl + Propofol gave faster and smoother LMA insertion while Fentanyl + Etomidate maintained better hemodynamics. However, Etomidate showed more motor issues such as myoclonus and jaw tightness, limiting its use without adjuncts. This was a single-centre study with small sample future trials should test Etomidate-Dexmedetomidine or Propofol-Butorphanol for better balance.

CONCLUSION

Fentanyl-Propofol gave better LMA insertion with higher success and ease, while Etomidate-Fentanyl maintained hemodynamics but caused more myoclonus and jaw stiffness. Etomidate may be useful in unstable patients, although adjuncts might be needed for smoother insertion.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.