Supraglottic Airway Devices for Elective Pediatric Anesthesia: I-gel versus Air-Q, Which is the Best?

OBJECTIVES: The objectives of the study were to compare the insertion facility, the effect on hemodynamic parameters, and effective ventilation using I-gel versus Air-Q supraglottic airway devices (SADs) for pediatric patients undergoing short-duration surgical procedures. PATIENTS AND METHODS: One hundred and fifty children aged 3-10 years were randomly divided into two equal groups: Group I received I-gel and Group Q received Air-Q SAD. All patients were anesthetized by sevoflurane inhalation using a face mask without neuromuscular blockade. Study outcomes included SAD insertion success rate (SR), insertion time, anatomic alignment of the SAD to the larynx as judged using fiberoptic bronchoscope (FOB) inserted through the SAD, and tidal volume leak, and incidence of postoperative complications.
RESULTS: Total and first attempt SRs were 97.3% and 85.3% for I-gel and 94.7% and 82.7% respectively, for Air-Q with nonsignificant differences. However, I-gel insertion time (12.3 ± 3.6 s.) was significantly (P = 0.034) shorter than Air-Q (13.7 ± 4.2 s). FOB grading of laryngeal view through SAD was better with I-gel but without significant difference for patients who had view Grades 1-2. Percentage of tidal volume loss was significantly decreased at 5 min after insertion than immediately after insertion, in all patients, with a nonsignificant difference in favor of I-gel. Intraoperative hemodynamic changes and postoperative complications showed a nonsignificant difference between both the groups.
CONCLUSION: Both Air-Q and I-gel SAD provided advantages for pediatric anesthesia during short-duration surgical procedure with nonsignificant differences. However, I-gel SAD required a shorter insertion time and provided a high SR which is satisfactory for trainees and during an emergency. I-gel SAD allowed minimization of tidal volume leak and gastric inflation and is associated with infrequent complications. Copyright:

INTRODUCTION

Artificial airway establishment is crucial to provide lung mechanical ventilation during surgical procedures under general anesthesia,[1] for management of critically ill patients,[2] and for patients requiring maintenance of patent airway in emergency situations.[3]

Laryngeal masks are supraglottic airway devices (SADs) developed in the early 1980s[4] to be inserted into the pharynx for ventilation.[5] SADs are advantageous than endotracheal tubes for providing smooth induction of anesthesia without hemodynamic instability[6] with easier and faster insertion, especially for professionals with limited experience in securing airways via conventional endotracheal intubation.[7]

Following the overwhelming success of the laryngeal mask airway (LMA), SADs are developed with increasing frequency[8] and nowadays are frequently used in clinical routine to provide airway access for mechanical ventilation in patients undergoing surgery with a short duration.[4]

The first generation of SAD, the classic LMA, and the laryngeal tube is lacking protection against aspiration,[9] while the second generation such as the laryngeal mask ProSeal and the laryngeal tube S offered an esophageal drainage tube and/or an improved oropharyngeal leak pressure (OLP) during positive pressure ventilation.[10]

The I-gel is one of the second generations of SAD that allows proper fitting to the perilaryngeal structure secondary to its manufacturing characteristics using a thermoplastic elastomer[11] allowing proper prevention of air leak and with a bite block and lumen for the gastric tube to provide effective airway management.[12] Moreover, I-gel allows less epiglottic downfolding and better fiberoptic view than the first generation of SAD.[13] Small-sized I-gel provided satisfactory airway management during general anesthesia for pediatric patients.[14]

Air-Q LMA is another member of the second-generation SAD that was used successfully as a conduit for tracheal intubation in the pediatric difficult airway.[15] The Air-Q is an excellent device for intubation because of its larger internal diameter and removable 9 mm adapter.[16] Moreover, Air-Q LMA provides adequate airway control despite the unfavorable airway anatomy in children.[17]

Objectives

This study targets to compare insertion facility, effect on hemodynamic parameters, and effective ventilation using I-gel versus Air-Q LMA for pediatric patients undergoing short-duration surgical procedures.

PATIENTS AND METHODS

This prospective comparative clinical trial was started in October 2018 after approval of the study protocol by the Local Ethical Committee. All children between 3 and 10 years old and assigned for short-duration surgical procedure of <60 min operative time were eligible for evaluation for inclusion and exclusion criteria. Informed consent was obtained from parents of the children. This study is registered in Clinical Trials. gov Number NCT04458064.

All eligible children were clinically evaluated for demographic data including age, sex, and weight and to determine their American Society of Anesthesiologist (ASA) grade, baseline heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), and peripheral oxygen saturation. Inclusion criteria included age range of 3–10 years, ASA Grade 2—2, assigned for surgical procedures requiring supine positioning, and with an expected operative time of <60 min. Exclusion criteria included age >10 years, ASA Grade >2, current or recently resolved upper respiratory tract infection, presence of oropharynx or laryngeal pathologies or congenital anomalies, pathologies inducing reflux or increasing the possibility of aspiration, allergy to anesthetic or drugs to be used, renal, cardiac or hepatic diseases, or bronchial asthma. In addition, patients who underwent surgical procedures that accidentally required prolonged operative time for >60 min for any cause were also excluded from the study.

Parents of children fulfilling the inclusion criteria were asked to choose a sealed dark envelope containing a card carrying the group label. These envelopes were previously prepared by an assistant who was blinded about the significance of the labels. One-hundred and seventy-four children were eligible for evaluation; 24 children were excluded for not fulfilling the inclusion criteria; 12 had upper respiratory infection, four patients had acute gastroenteritis, 3 had Type-I diabetes mellitus and were uncontrolled, 2 had congenital heart conditions, and 3 had a history of hepatitis and 150 patients were randomly divided into two equal groups according to the type of SAD to be inserted: Group I included patients who will receive I-gel SAD (i-gel® Intersurgical, Wokingham, Berkshire, UK) and Group Q (Air-Q®, Cook gas LLC, USA) included patients who will receive Air-Q SAD [Figure 1]. Patients’ enrolment data showed nonsignificant (P > 0.05) difference between both the groups [Table 1].

Figure 1

Consort flow sheet

Table 1

At enrolment clinical characteristics of thestudied patients

Parameters	Group		P
	Group I (n=75)	Group Q (n=75)
Age	5.8±1.7	6±1.5	0.453
Sex; male: female	53:22	46:29	0.228
Weight (kg)	24±4.5	24.4±5.6	0.741
ASA Grade; I: II	66:9	63:12	0.481

Data are shown as mean, SD, ratios, I: I-gel SAD, Q: Air-Q SAD; P value indicates significance of difference between both groups; P<0.05 indicates significant difference; P>0.05 indicates nonsignificant difference. SAD=Supraglottic airway device, ASA=American Society of Anesthesiologist, SD=Standard deviation

All patients were premedicated using 0.15 mg.kg−1 intramuscular injection of midazolam at 10 min before induction of anesthesia. Preoperative monitoring included noninvasive monitoring of HR, MAP, and SpO2. Patients were preoxygenated with 100% oxygen and anesthesia was induced using propofol intravenous injection in a dose of 2 mg.kg−1, then after disappearance of eyelash reflex, lungs were ventilated with 8 vol% of sevoflurane in 100% oxygen for 3 min using a face mask. No neuromuscular blocking agent was given. On arrival to the adequate depth of anesthesia, as judged by the absence of motor and cardiovascular response to stimulation, SAD was inserted by a senior anesthetist with pediatric anesthesia experience. Anesthesia was maintained with 2%–3% sevoflurane in 50% oxygen through the inserted device with mechanical ventilation to provide a tidal volume of 8 mg.kg, fresh gas flow of 3 L/min and RR of 14–20 breaths/min, and end-tidal CO2 of 30–40 mmHg. At the end of the surgery, sevoflurane was stopped, and the lungs were ventilated with 100% oxygen and after the recovery of self-respiration, the device was removed.

Both SADs were lubricated with lidocaine gel before insertion. The SAD size was chosen according to the manufacturer guidelines adjusted to the patient's weight. For I-gel SAD, size 1 was applied for patients weighing 2–5 kg, 1.5 for patients weighing >5–12 kg, size 2 for patients weighing >12–25 kg, size 2.5 for patients weighing >25–35 kg, and size 3 for patients weighing >35–60 kg. For Air-Q SAD, size 1 was used for patients weighing <7 kg, size 1.5 was used for patients weighing 7–17 kg, size 2 for patients weighing >17–30 kg, and size 2.5 for patients weighing >30–50 kg. After insertion of Air-Q, its cuff was inflated with 0.5 ml and 1 ml for sizes 1.5 and 2, respectively, to achieve cuff pressure of 20–30 cmH2O.[18] Finally, the breathing circuit of the anesthesia machine was attached to the proximal end of the SAD.

Study outcomes

Primary outcome was considered as the SAD success rate (SR); SAD failure was defined as three failed insertion attempts of a device considering failed insertion attempt as the inability to insert the assigned device or insufficient ventilation (<6 ml.kg) or requirement of high airway pressure (peak airway pressure >30 cmH2O) to achieve sufficient ventilation despite device manipulation including adjustment of the head/neck position and changing the insertion depth.[19] After an event of device failure, the device was removed from the mouth and endotracheal intubation was performed with 0.6 mg.kg of rocuronium bromide.

Secondary outcomes:

Insertion time as defined by time passed since removal of the face mask till stable capnography was traced on the monitor with the presence of sufficient ventilation determined as no audible leakage with manual ventilation of 20 cmH2O and bilateral symmetric chest movements

Anatomic alignment of the SAD to the larynx was judged using fiberoptic bronchoscope (FOB) inserted through the SAD and the best view observed at 1 cm above the tip of the ventilating orifice was graded according to Jagannathan et al.[20] scoring system for FOB grading of laryngeal view through SAD as follows: Grade 1 if only vocal cords were seen, Grade 2 if vocal cords and posterior surface of epiglottis were seen, Grade 3 if the vocal cords and tip of the anterior surface of the epiglottis were seen and indicates <50% obstruction to vocal cords by the epiglottis, Grade 4 if epiglottis was down-folded with its anterior surface was seen and indicates >50% obstruction to vocal cords is by the epiglottis, and Grade 5 if the epiglottis was down-folded and vocal cords cannot be directly seen. FOB Grades 1 and 2 indicate that the SAD position can be considered optimal, while FOB Grades 3–5 indicated a suboptimal position

OLP was determined by the application of slow increments of airway pressure with a constant fresh gas flow into the circuit in the closed manual mode until audible leak sound was detected either from the mouth and/or by auscultation over the larynx.[21] Tidal volume loss was estimated as the percentage of the difference between the inspiratory and expiratory volumes in relation to the inspiratory volume ([inspiratory − expiratory]/[inspiratory] multiplied by 100) and was recorded just after insertion and 5 min thereafter

Impact of SAD insertion and removal on HR, MAP, and SpO2 measures that were recorded immediately before insertion, immediately, 1 and 5 min after insertion, and before device removal

Incidence of postoperative complications including cough, nausea, vomiting, sore throat, and blood staining of the device.

Sample size calculation

Henlin et al.[22] and Kleine-Brueggeney et al.[23] studied 80 and 101 pediatric patients per group and detected a nonsignificantly higher first attempt insertion SR between Supreme LMA and both of I-gel and Air-Q, respectively. A sample size of 75 patients per group would achieve a power of 80% with α value of 0.05 and β value of 0.2 and fulfill the study target to get nonsignificant difference in the first attempt SR.

Statistical analysis

Obtained data were presented as mean ± standard deviation, ratios, numbers, and percentages. The results were analyzed using one-way ANOVA test and Chi-square test. Repeated measurements (HR, MAP, and tidal volume losses %) were analyzed using paired t-test. Statistical analysis was conducted using the IBM SPSS (Version 23, 2015; IBM, South Wacker Drive, Chicago, USA) for Windows statistical package. P < 0.05 was considered statistically significant.

RESULTS

The current trial reported a total SR, irrespective of the device used, of 96% with a nonsignificantly higher SR for I-gel (97.3%) than for Air-Q (94.7%). SR at the first attempt of insertion was 85.3% and 82.7% for I-gel and Air-Q, respectively, with nonsignificantly higher frequency with I-gel SAD. Similarly, the SR for patients required second and third attempts nonsignificantly (P = 0.785 and 0.56, respectively) higher SR with I-gel [Figures 1 and 2].

Figure 2

Patients’ distribution according to times of attempts for device insertion

On the contrary, SAD insertion time was significantly (P = 0.034) shorter with I-gel (12.3 ± 3.6 s.) than with Air-Q (13.7 ± 4.2 s) device [Figures 1 and 3].

Figure 3

Mean (±standard deviation) of device insertion time [significant differnces]

FOB grading of laryngeal view through SAD was better on using I-gel without significant difference (P = 0.411) for patients who had view Grades 1–2 than on using Air-Q and the frequency of patients who had view of Grade 1 was nonsignificantly (P = 0.169) higher with I-gel than Air-Q [Figure 4].

Figure 4

Distribution of patients had successful insertion according to fiberoptic bronchoscope grading of laryngeal view through the device

The percentage of tidal volume loss significantly decreased at 5 min after insertion in comparison to immediately after insertion with nonsignificantly lower levels with I-gel than with Air-Q at both the times [Figure 5].

Figure 5

Mean tidal volume loss immediately and 5 min after insertion study outcomes included

Operative time and intraoperative hemodynamic changes showed nonsignificant differences between both the groups throughout the operative time till removal of the device. Thirty patients developed PO complications; 9 had cough, 11 had sore throat, 3 had nausea and vomiting, and SAD was blood stained in seven patients with nonsignificantly higher incidence of PO complications with I-gel than Air-Q [Table 2].

Table 2

Intraoperative and postoperative data of studied patients

Parameters	Group		P
	Group I (n=75)	Group Q (n=75)
Operative time (min)	5.8±1.7	6±1.5	0.453
Heart rate (beats/min)
Preinsertion	86.8±7.4	88.8±7.3	0.089
Immediate after insertion	101.3±7.3	103.4±8.4	0.093
1 min after insertion	96.2±8	97.7±7.9	0.249
5 min after insertion	90.9±8.5	93.4±7.9	0.059
After removal	85.2±8.3	86.8±8.1	0.251
Mean arterial pressure (mmHg)
Preinsertion	58.8±6.3	58.2±8.1	0.589
Immediate after insertion	62.6±6.5	63±7.2	0.704
1 min after insertion	59.8±6.1	60±7.2	0.869
5 min after insertion	57.1±6.2	57.4±7	0.814
After removal	57.7±6	55.8±6.5	0.064
Complications (%)
Cough	5 (6.7)	4 (5.3)	0.745
Sore throat	6 (8)	5 (6.7)
Nausea and vomiting	1 (1.3)	2 (2.7)
Blood staining	4 (5.3)	3 (4)
Total	16 (21.3)	14 (18.7)	0.683

Data are shown as mean, SD, ratios, I: I-gel SAD, Q: Air-Q SAD; P value indicates significance of difference between both groups; P<0.05 indicates significant difference; P value>0.05 indicates nonsignificant difference. SAD=Supraglottic airway device, SD=Standard deviation

DISCUSSION

The present study reported divergent results indicating that no type of SAD is absolutely superior to others; the feasibility and safety of insertion of I-gel and Air-Q SAD were comparable where the total insertion SR and first attempt SR were nonsignificantly different between both the types. However, I-gel superceded Air-Q for its significantly shorter insertion time; these findings had been attributed to the manufacturing characteristics of I-gel which has a gel-like cuff composed of thermoplastic elastomer that did not require cuff inflation[2425] and this may shorten insertion time;[24] moreover, insertion of I-gel does not need laryngoscope;[26] thus, I-gel can be a useful tool in emergency situations requiring prompt airway care and for pediatric anesthesia, especially for trainee and junior anesthetists.

These findings go in hand with Siddiqui et al.[26] who in noncomparative study reported that I-gel is simple and easy to use with an SR for insertion in the first attempt of 92% within short insertion time and with Kim et al.[27] who in the comparative study versus Air-Q SAD found that I-gel SAD insertion was significantly easier for pediatric anesthesia.

On contrary to the obtained results, concerning insertion variables, An et al.[24] in a comprehensive meta-analysis found that I-gel can be inserted more quickly than other SAD except Air-Q and LMA Supreme devices, Raza and Khan[28] reported higher SR of blind tracheal intubation with Air-Q than I-gel, and Massoudi et al.[29] showed that the mean insertion time and number of insertion attempts were significantly lower with Air-Q than I-gel in general anesthesia with muscle relaxation. However, these trials included adult patients with varied constitutional factors[2829] and the meta-analysis conducted by An et al.[24] included studies comparing SAD insertion in manikins for adults and by volunteer physicians, not anesthetists. Moreover, the effect of the use of muscle relaxants may be an attribute of the differences between these studies and the current study.

In support of the results of the current study and against this controversy, recently, Lee et al.[30] found no statistically significant differences in insertion variables of either of I-gel or Air-Q SAD to get patent airway for geriatric patients during general anesthesia; a fragile patients’ category as pediatrics. In addition, Mihara et al.[31] and Hur et al.[32] in comparison of the clinical performance of I-gel versus AuraGain found that the time to successful device insertion was significantly shorter[3132] and device insertion was significantly easier with I-gel group than AuraGain SAD.[32]

However, the controversy of the results concerning FOB grading of laryngeal view and tidal volume loss measures was also evident in literature where the current study detected nonsignificant difference between I-gel and Air-Q concerning these two points of evaluation and Mihara et al.[31] and Hur et al.[32] reported nonsignificant differences between I-gel and AuraGain regarding FOB view and OLP. Furthermore, Kohli et al.[33] found that I-gel is comparable to endotracheal intubation in terms of adequacy of ventilation, but the increase in peak airway pressures is less with I-gel. In a similar comparative study, Abdel-Ghaffar et al.[34] compared the performance of LMA classic, Air-Q, and I-gel at different head and neck positions and found that in comparison to neutral position, maximum neck flexion significantly increased OLP and compromised the ventilation, but the extension and left lateral rotation decreased OLP mildly with mild effect on ventilation parameters, and I-gel SAD at different positions and throughout operative period exhibited the best ventilation parameters and FOB view grade. On contrary, Kim et al.[5] found that FOB view was better with AuraGain, but OLP was higher with I-gel, but Lee et al.[30] found that FOB view grading was nonsignificantly different between I-gel and Air-Q, while OLP was significantly higher with I-gel.

Furthermore, intraoperative hemodynamic and oxygen saturation changes showed nonsignificant difference between both the devices in favor of I-gel, while PO complications showed nonsignificant differences in favor of Air-Q. Also,in comparison between I-gel and endotracheal intubation,[33] LMA,[35] LMA Classic[36] and LMA Supreme™[37] found nonsignificant differences in hemodynamic variables and PO complications were not significantly different[3336] except nausea and vomiting that was significant higher with LMA[36] and gastric insufflations was significantly less frequent with I-gel than with both LMA[36] and LMA Supreme TM.[37] Furthermore, Mihara et al.[31] reported significantly lower incidence of device blood staining with I-gel than with AuraGain SAD, and Massoudi et al.[29] reported a significantly higher incidence of sore throat but nonsignificant difference regarding other PO complications with I-gel than with Air-Q.

CONCLUSION

No SAD is immune against defaults; both Air-Q and I-gel SAD provided advantages for pediatric anesthesia during short-duration surgical procedure with nonsignificant differences. However, I-gel SAD required a shorter insertion time and provided a high SR which is satisfactory for trainees and during an emergency. Secondary to its inherent manufacture character, it allowed minimization of tidal volume leak and gastric inflation, so it spares the need for insertion of the gastric tube. Moreover, I-gel insertion is associated with infrequent postinsertion complications and so its application is to great extent safe.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.