Pediatric Anesthesia ISSN 1155-5645
ORIGINAL ARTICLE
A comparative study of Laryngeal Mask Airway size 1 vs i-gel size 1 in infants undergoing daycare procedures Deepanjali Pant, Archna Koul, Bimla Sharma & Jayashree Sood Department of Anaesthesiology, Pain and Perioperative Medicine, Sir Ganga Ram Hospital, New Delhi, India
Keywords cLaryngeal Mask Airway size 1; i-gel size 1; oropharyngeal pressure Correspondence Deepanjali Pant, Department of Anaesthesiology, Pain and Perioperative Medicine, Sir Ganga Ram Hospital, Old Rajinder Nagar, New Delhi 110060, India Email: [email protected] Section Editor: Jerrold Lerman Accepted 15 September 2014 doi:10.1111/pan.12555
Summary Background: The i-gel size 1 is a relatively new, single use, second generation supraglottic airway device. This prospective, randomized, observational study compares the suitability of the i-gel size 1 with the classical Laryngeal Mask Airway (cLaryngeal Mask Airway) size 1 in pediatric patients undergoing elective daycare procedures. Methods: Forty ASA I and II children (2–5 kg body weight) were randomized to two groups of 20 each, to receive either the i-gel or the cLaryngeal Mask Airway as an airway device. The primary outcome variable was oropharyngeal seal pressure (OSP). We also assessed ease of insertion, number of insertion attempts, time taken for successful insertion and any intra-operative complications. Results: Demographic data did not differ between the two groups. The OSP with the i-gel was 22.30 4.72 cm H2O as compared to 18.05 1.95 cm H2O with the cLaryngeal Mask Airway and the difference was statistically significant (P = 0.001). Displacement of the airway device following change of position was reported less often with the i-gel as compared to the cLaryngeal Mask Airway [n = 1 (5%) vs n = 5 (35%), P = 0.04]. There were no major complications with either device and rest of all the variables were comparable with both the devices. Conclusions: The OSP of the i-gel size 1 was higher than that of the cLaryngeal Mask Airway. This was statistically significant, although may not be of clinical significance. The i-gel size 1 is less prone to displacement during position changes. However, being a preliminary study carried out on a small number of patients, further trials are warranted to come to any definite conclusion.
Introduction The introduction of a supraglottic device like the Laryngeal Mask Airway has revolutionized airway management in pediatric anesthesia practice. The classic Laryngeal Mask Airway (cLaryngeal Mask Airway, Intavent Orthofix Maidenhead, UK) was introduced into clinical anesthesia in 1988 (1). It is a cuffed supraglottic reusable device, made of silicone. Its use has expanded immensely and majority of anesthetic procedures in children are now facilitated with the use of the cLaryngeal Mask Airway as an airway device (2). However, several disadvantages of the cLaryngeal Mask Airway have lead 386
to development of alternative supraglottic devices. The i-gel size 1 (Intersurgical, Wokingham, UK) is an innovative second generation supraglottic airway device. It is a smaller model of the well known i-gel used in adult patients, made up of thermoplastic elastomer, styrene ethylene butadiene styrene (SEBS) with a unique soft, noninflatable cuff, bite block, epiglottic rest, and a buccal cavity stabilizer (3,4). The pediatric versions of i-gel airway are available in four different sizes (1, 1.5, 2, and 2.5) on the basis of body weight. However, both the i-gel size 1 and the cLaryngeal Mask Airway are without any esophageal port. The aim of this prospective randomized study was to evaluate and compare the suitability © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
D. Pant et al.
Laryngeal Mask Airway vs i-gel size 1
of the i-gel size 1 to the cLaryngeal Mask Airway size 1 as an airway device in pediatric daycare surgery. The primary outcome measured was the oropharyngeal seal pressure (OSP) in both the i-gel and the cLaryngeal Mask Airway groups. Assessing OSP is important to quantitate the efficacy of the seal. High OSP is important as it indicates airway protection, feasibility of positive pressure ventilation (PPV) and likelihood of successful placement of the supraglottic device (5). The secondary outcomes measured were the ease of insertion, number of insertion attempts, time taken for successful insertion, displacement of the device, and intra-operative and postoperative complications. Methods In this prospective randomized observational study, 40 pediatric patients were included after obtaining approval from the hospital ethics committee and an informed consent from the parents of the patients. The patients included in the study were neonates and infants between 2 and 5 kg body weight of ASA physical status I–II. They were scheduled to undergo daycare procedures like herniotomy, orchidopexy, cystoscopy with posterior urethral valve fulguration, rectal biopsy and umbilical granuloma excision with an estimated duration of anesthesia under one hour. The study was
registered with Clinical Trials Registry – India (CTRI) reference number CTRI 2013/02/003364. Children with sore throat or upper respiratory infection, potential for difficult airway and pulmonary aspiration and those requiring surgery in positions other than supine or lithotomy were excluded from the study. Randomization to one of the two airway devices (i-gel group size 1 or cLaryngeal Mask Airway group size 1) with twenty patients in each group was based on computer generated numbers kept in sequentially numbered opaque envelopes opened just before device insertion (Figure 1). We confirmed the fasting status and took preoperative history. The physical examination was completed and verbal and written informed consent from parents was obtained. No premedication was given. Anesthesia was induced with sevoflurane (4–8%) in 50% oxygen and 50% nitrous oxide through a face mask with standard monitors in place as per ASA guidelines, and the breathing circuit was connected to the anesthesia machine (Penlon, Abingdon, Made in UK, CE 0473). An intravenous access was secured followed by intravenous fentanyl 1 lgkg 1 and midazolam 0.02 mgkg 1 for analgesia and sedation, respectively. Ventilation was assisted with face mask to obtain adequate depth of anesthesia (loss of eyelash reflex, jaw relaxation, and absence of movement). This was followed by insertion of the i-gel or the cLaryngeal
Assessed for eligibility (n = 40)
Excluded (n = 0)
Randomized (n = 40)
Allocation Allocated to intervention (n = 20) • Received allocated intervention (n = 20) • Did not receive allocated intervention (n = 0)
Allocated to intervention (n = 20) • Received allocated intervention (n = 20) • Did not receive allocated intervention (n = 0)
Follow-up Lost to follow-up (n = 0) Discontinued intervention (n = 0)
Lost to follow-up (n = 0) Discontinued intervention (n = 0)
Analysis
Figure 1 CONSORT flow diagram. © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
Analysed (n = 20) • Excluded from analysis (n = 0)
Analysed (n = 20) • Excluded from analysis (n = 0)
387
D. Pant et al.
Laryngeal Mask Airway vs i-gel size 1
Mask Airway according to the manufacturer’s instructions after appropriate lubrication with a water based jelly using standard technique with partially inflated cuff (6). The device was connected to the breathing circuit (Jackson Rees modification of Ayre’s T-piece), the cLaryngeal Mask Airway cuff inflated to 40 cm H2O, with a Mallinckrodt aneroid cuff pressure monitor, followed by proper bimaxillary fixation with adhesive tape of the two devices (7,8). Correct placement of the device in both groups was assessed by observing for bilateral chest expansion, presence of square wave capnography, absence of audible leak at oral cavity, and lack of gastric insufflation recorded using a stethoscope placed over epigastrium. Initially manual ventilation was performed till the spontaneous effort returned; this was followed by assisted manual ventilation providing continuous positive airway pressure (CPAP). All the investigators were experienced users of cLaryngeal Mask Airway and had used i-gel on more than 10 occasions in pediatric patients. The device placement was followed by caudal epidural block with 0.25% bupivacaine in the lateral position, simultaneously observing for any displacement of the airway device during or after the block. The displacement of the device was defined by absence of capnographic trace on the monitor. The patient was placed supine following the block. Anesthesia was maintained with 1–2% sevoflurane in 66% N2O and 33% O2 with assisted manual ventilation with a fresh gas flow of 1–3 lmin 1. Ease of insertion was evaluated on the following scale: grade1 = easy insertion, grade 2 = at least one maneuver required for insertion, grade 3 = more than one maneuver required for insertion. Airway maneuvers used were chin lift, neck extension, or gentle manipulation of the device. The number of insertion attempts was recorded. Three attempts were allowed before the insertion was considered a failure. If adequate ventilation was not achieved using either of the supraglottic devices, tracheal intubation was performed and the participant was excluded from the study. The time taken for successful insertion of the device was measured as the time between picking up of the i-gel/the cLaryngeal Mask Airway and appearance of the first capnographic trace on the monitor. The OSP was measured as the airway pressure at which audible leak was heard near the mouth of the patient with the fresh gas flow set at 3 lmin 1 and the expiratory valve closed. The OSP was not allowed to exceed 30 cm of H2O to avoid barotrauma. All insertions were performed by one investigator, while measurement of OSP and other variables were recorded by a single observer who did not participate in the study. Intra-operative adverse events such as airway 388
obstruction, coughing, laryngospasm, desaturation (SpO2 < 92%), and regurgitation were also noted. After removal of the airway device, its cuff was inspected for blood or bile staining. Postoperatively, the patients were observed in the postoperative care unit and daycare unit for any burping, restlessness, or retching till the time of discharge. Statistics We based our sample size calculation on our primary outcome variable the OSP. No data about performance of the size 1 i-gel in neonates were available for a reliable sample size calculation. Based on the previous studies, a sample size of 20 patients per group was calculated to detect a difference in OSP of 3 cm of H2O between the i-gel and the cLaryngeal Mask Airway for a type I error of 0.05 with a power of 0.9 and population variance of 2 (9,10). The data were analyzed using SPSS software, (17.0 version; SPSS Inc., Chicago, IL, USA). Continuous variables were presented as mean SD, and categorical variables presented as absolute numbers and percentage. The comparison of normally distributed continuous variables between the groups was performed using Student’s t-test. Nominal categorical data between the groups were compared using Chi-square test or Fisher’s exact test as appropriate. For all statistical tests, a P < 0.05 was taken as statistically significant. Results The patients’ characteristics are shown in Table 1. The two groups were comparable with respect to age, sex, weight, and duration of surgery. Of 40 cases, 20 were operated for inguinal hernia repair, eight each for orchidopexy and cystoscopy with posterior urethral valve fulguration, three for rectal biopsy, and one for umbilical granuloma excision. Perioperative data and adverse events for the two devices are shown in Tables 2 and 3, respectively. The OSP was higher with the i-gel than with the cLaryngeal Mask Airway, 22.30 4.72 vs 18.05 1.95 cm H2O, respectively and was statistically significant (P = 0.001). Table 1 Patients characteristics
Age (week) Weight (kg) Sex (M/F) Duration of Surgery (min) Data are number (n), mean
i-gel (n = 20)
cLaryngeal Mask Airway (n = 20)
10.75 3.97 3.93 0.97 16/4 56.5 15.48
8.70 3.06 4.26 0.60 17/3 52.35 15.85
SD.
© 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
D. Pant et al.
Laryngeal Mask Airway vs i-gel size 1
Table 2 Comparison between the i-gel and the cLaryngeal Mask Airway (OSP, insertion data and device displacement)
OSP (cm H2O) Insertion Ease of insertion (n) Grade I Grade II Grade III Success rate 1st attempt: n (%) 2nd attempt: n (%) Insertion time (s) Device displacement after caudal
i-gel (n = 20)
cLaryngeal Mask Airway (n = 20)
95% CI of mean difference
P-value
22.3 4.72
18.05 1.95
1.938–6.562
0.001*
18 2 0
15 5 0
16 (80%) 04 (20%) 10.6 4.46 1 (5.0%)
12 (60%) 08 (40%) 9.9 4.12 7 (35%)
0.212 0.139 – 0.301 0.61 0.044*
Data are number (n), mean SD. *P-value < 0.05 is considered statistically significant.
Table 3 Perioperative complications
Airway obstruction Coughing Laryngospasm Desaturation Regurgitation Blood on airway device Bile on airway device Postop burping, retching and restlessness
i-gel (n = 20)
cLaryngeal Mask Airway (n = 20)
P-value
Nil Nil Nil 1 (5%) Nil Nil Nil 1 (5%)
Nil Nil Nil 7 (35%) 1 (5%) 2 (10%) 1 (5%) 5 (25%)
0.044* 1.0 0.49 1.0 0.17
Data are number (n), mean SD. *P-value < 0.05 is considered statistically significant.
There was no failure of insertion of airway device in any group. Insertion was graded easy for both the groups. There was no statistical difference in ease of insertion, insertion success rate, and time taken for insertion. There was less incidence of displacement of the device after caudal block with the i-gel as compared to the cLaryngeal Mask Airway (P = 0.04), which was statistically significant. The incidence of complications was low in both the groups except for desaturation (SpO2 < 92%), which was reported in seven cases (35%) in the cLaryngeal Mask Airway group. There was one case of pharyngeal regurgitation in the cLaryngeal Mask Airway group as was evidenced by presence of bile on the device. However, there was no clinical evidence of pulmonary aspiration. Discussion Our results demonstrate that the i-gel size 1 provides higher OSP than that provided by cLaryngeal Mask © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
Airway of the same size. After proper fixation, it is less prone to get displaced despite positional changes and may be used as an alternative to the cLaryngeal Mask Airway as an airway device in neonates and infants weighing 2–5 kg for short daycare procedures. The OSP determines the efficacy of a supraglottic device, the higher OSP may be an advantage in PPV, although our study patients were provided assisted mechanical ventilation. The OSP for the i-gel (22.30 4.72 cm H2O) was higher than for the cLaryngeal Mask Airway (18.05 1.95 cm H2O). Our results for OSP for the i-gel are in concurrence with previous work (11,12). The use of the i-gel in children has been reported in several studies. But there is paucity of data regarding the performance of the size 1 i-gel in children up to 5 kg of weight (11–17). The OSP reported for pediatric size cLaryngeal Mask Airway is between 15 and 19 cm H2O and comparable to our study (9,10,17). Although the OSP with i-gel was statistically significantly higher than that obtained with the cLaryngeal Mask Airway, this difference may not be clinically significant. However, the i-gel being cuffless eliminates the need for cuff inflation and the adverse effects associated with it (12). Accidental dislodgement is considered a minor complication if the patient’s airway is accessible, yet it can lead to rapid desaturation in children < 5 kg. In the cLaryngeal Mask Airway group, after giving caudal block in the lateral position and while turning the patient supine, there was displacement of the cLaryngeal Mask Airway despite proper fixation in 7 of 20 patients (35%) requiring repositioning. However, there was only one case of displacement of the i-gel, due to accidental stretch on anesthesia circuit in the study. Displacement of the i-gel has been reported in several studies where they noticed that the i-gel often slides out of mouth, 389
D. Pant et al.
Laryngeal Mask Airway vs i-gel size 1
especially in small children, requiring advancement and retaping (11,18,19). Our incidence of displacement was low because of proper bimaxillary fixation with an adhesive tape. The widened and flattened stem of the i-gel acts as a stabilizer within the buccal cavity, reducing the chances of axial rotation and thus malrolation (4). Also, the ridge at the proximal end of mask catches the base of tongue contributing to the positional stability, while the epiglottic rest prevents downfolding of epiglottis during insertion (3). Our study demonstrates that the i-gel size 1 has a similar performance in terms of ease of insertion, insertion success rate and time required for insertion when compared with the cLaryngeal Mask Airway size 1. Lee et al. (12) who compared the i-gel with the cLaryngeal Mask Airway in children (6–30 kg) reported easy insertion and shorter insertion time for the i-gel as compared to the cLaryngeal Mask Airway. On the contrary, Thieler et al. (18) while comparing the i-gel with the Ambu AuraOnce laryngeal mask in children (0–17 years), reported a longer insertion time with the i-gel, however, only three of their patients weighed between 5 and 9.9 kg. Perioperative complications were comparable in both the groups except for displacement of device leading to desaturation. Several complications like blood staining of the device, dislodgment, partial airway obstruction, neuropraxia, and regurgitation have been reported for the i-gel in pediatric patients, but we did not encounter such complications probably because the sample size and duration of surgery was too small to detect them (13,18–21). Limitations The i-gel and the cLaryngeal Mask Airway were used with assisted spontaneous ventilation with CPAP in patient with normal airways. The results cannot be extrapolated in patients with difficult airways and those requiring PPV.
Our sample size was too small to detect any significant differences in complications with the two devices. We also did not conduct the fiber optic assessment for airway patency. However, the ideal position of the Laryngeal Mask Airway is obtained only in 40–50% of patients on fiber optic assessment inspite of clinically adequate patency (22). Assessing correct placement on clinical ground is considered a normal practice for the Laryngeal Mask Airway insertion in children (23). The study could not be blinded because the anesthesia personnel were aware of the airway device used. However, the data were collected by an experienced anesthesiologists, not involved in the clinical trial. Another drawback of our study was that possibility of gastric insufflation during measurement of OSP was not assessed as both the devices were devoid of gastric channel. Conclusion The OSP of the i-gel size 1 is statistically significantly higher than that of the cLaryngeal Mask Airway size 1 and after the fixation, the i-gel is less prone to displacement on change of position as compared to the cLaryngeal Mask Airway in infants < 5 kg for short surgical procedures. However, being a preliminary study carried out on a small number of patients, further trials are warranted to come to any definite conclusion. Acknowledgments We thank our pediatric surgical colleagues for their cooperation and interest. We also thank Mr. Prakash Bisht for secretarial help and Mrs. Parul for the statistical analysis. This research was carried out without funding. Conflict of interest No conflicts of interest declared.
References 1 Brain AI. The development of the Laryngeal Mask–a brief history of the invention, early clinical studies and experimental work from which the Laryngeal Mask evolved. Eur J Anaesthesiol Suppl 1991; 4: 5–17. 2 White MC, Cook TM, Stoddart PA. A critique of elective pediatric supraglottic airway devices. Pediatr Anesth 2009; 19: 55–65. 3 Levitan RM, Kinkle WC. Initial anatomic investigations of the I-gel airway: a novel supraglottic airway without inflatable cuff. Anaesthesia 2005; 60: 1022–1026.
390
4 Wharton NM, Gibbison B, Gabbott DA et al. I-gel insertion by novices in manikins and patients. Anaesthesia 2008; 63: 991– 995. 5 Seet E1, Rajeev S, Firoz T et al. Safety and efficacy of laryngeal mask airway Supreme versus laryngeal mask airway ProSeal: a randomized controlled trial. Eur J Anaesthesiol 2010; 27: 602–607. 6 Ghai B, Makkar JK, Bhardwaj N et al. Laryngeal mask airway insertion in children: comparison between rotational, lateral and
standard technique. Pediatr Anesth 2008; 18: 308–312. 7 Wong JG, Heaney M, Chambers NA et al. Impact of laryngeal mask airway cuff pressures on the incidence of sore throat in children. Pediatr Anesth 2009; 19: 464–469. 8 von Ungern-Sternberg BS, Erb TO, Chambers NA et al. Laryngeal mask airways–to inflate or to deflate after insertion? Pediatr Anesth 2009; 19: 837–843. 9 Goldmann K, Jakob C. A randomized crossover comparison of the size 2 ½ laryngeal © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
D. Pant et al.
10
11
12
13
14
mask airway ProSealTM versus laryngeal mask airway-ClassicTM in pediatric patients. Anesth Analg 2005; 100: 1605–1610. Goldmann K, Jakob C. Size 2 ProSealTM laryngeal mask airway: a randomized, crossover investigation with the standard laryngeal mask airway in paediatric patients. Br J Anaesth 2005; 94: 385–389. Jagannathan N, Sommers K, Sohn LE et al. A randomized equivalence trial comparing the i-gel and laryngeal mask airway Supreme in children. Pediatr Anesth 2013; 23: 127–133. Lee JR, Kim MS, Kim JT et al. A randomised trial comparing the i-gel (TM) with the LMA Classic (TM) in children. Anaesthesia 2012; 67: 606–611. Lopez-Gil M, Brimacombe J, Alvarez M. Safety and efficacy of the laryngeal mask airway. A prospective survey of 1400 children. Anaesthesia 1996; 51: 969–972. Beringer RM, Kelly F, Cook TM et al. A cohort evaluation of the paediatric i-gelTM
© 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
Laryngeal Mask Airway vs i-gel size 1
15
16
17
18
airway during anaesthesia in 120 children. Anaesthesia 2011; 66: 1121–1126. Goyal R, Shukla RN, Kumar G. Comparison of size 2 i-gel supraglottic airway with LMA-ProSealTM and LMA-ClassicTM in spontaneously breathing children undergoing elective surgery. Pediatr Anesth 2012; 22: 355–359. Gasteiger L, Brimacombe J, Oswald E et al. LMA ProSeal(TM) vs. i-Gel(TM) in ventilated children: a randomised, crossover study using the size 2 mask. Acta Anaesthesiol Scand 2012; 56: 1321–1324. Beylacq L, Bordes M, Semjen F et al. The I-gelâ, a single-use supraglottic airway device with a non-inflatable cuff and an esophageal vent: an observational study in children. Acta Anaesthesiol Scand 2009; 53: 376–379. Theiler LG, Kleine-Brueggeney M, Luepold B et al. Performance of the pediatric-sized i-gel compared with the Ambu AuraOnce
19
20
21
22
23
laryngeal mask in anesthetized and ventilated children. Anesthesiology 2011; 115: 102–110. Hughes C, Place K, Berg S et al. A clinical evaluation of the I-gel TM supraglottic airway device in children. Pediatr Anesth 2012; 22: 765–771. Renes SH, Zwart R, Scheffer GJ et al. Lingual nerve injury following the use of an i-gel laryngeal mask. Anaesthesia 2011; 66: 226–227. Gibbison B, Cook TM, Seller C. Case series: Protection from aspiration and failure of protection from aspiration with the i-gel airway. Br J Anaesth 2008; 100: 415–417. Kundra P, Deepak R, Ravishankar M. Laryngeal mask insertion in children: a rational approach. Paediatr Anaesth 2003; 13: 685–690. Matta BF, Marsh DS, Nevin M. Laryngeal mask airway: a more successful method of insertion. J Clin Anesth 1995; 7: 132–135.
391
ORIGINAL ARTICLE
A comparative study of Laryngeal Mask Airway size 1 vs i-gel size 1 in infants undergoing daycare procedures Deepanjali Pant, Archna Koul, Bimla Sharma & Jayashree Sood Department of Anaesthesiology, Pain and Perioperative Medicine, Sir Ganga Ram Hospital, New Delhi, India
Keywords cLaryngeal Mask Airway size 1; i-gel size 1; oropharyngeal pressure Correspondence Deepanjali Pant, Department of Anaesthesiology, Pain and Perioperative Medicine, Sir Ganga Ram Hospital, Old Rajinder Nagar, New Delhi 110060, India Email: [email protected] Section Editor: Jerrold Lerman Accepted 15 September 2014 doi:10.1111/pan.12555
Summary Background: The i-gel size 1 is a relatively new, single use, second generation supraglottic airway device. This prospective, randomized, observational study compares the suitability of the i-gel size 1 with the classical Laryngeal Mask Airway (cLaryngeal Mask Airway) size 1 in pediatric patients undergoing elective daycare procedures. Methods: Forty ASA I and II children (2–5 kg body weight) were randomized to two groups of 20 each, to receive either the i-gel or the cLaryngeal Mask Airway as an airway device. The primary outcome variable was oropharyngeal seal pressure (OSP). We also assessed ease of insertion, number of insertion attempts, time taken for successful insertion and any intra-operative complications. Results: Demographic data did not differ between the two groups. The OSP with the i-gel was 22.30 4.72 cm H2O as compared to 18.05 1.95 cm H2O with the cLaryngeal Mask Airway and the difference was statistically significant (P = 0.001). Displacement of the airway device following change of position was reported less often with the i-gel as compared to the cLaryngeal Mask Airway [n = 1 (5%) vs n = 5 (35%), P = 0.04]. There were no major complications with either device and rest of all the variables were comparable with both the devices. Conclusions: The OSP of the i-gel size 1 was higher than that of the cLaryngeal Mask Airway. This was statistically significant, although may not be of clinical significance. The i-gel size 1 is less prone to displacement during position changes. However, being a preliminary study carried out on a small number of patients, further trials are warranted to come to any definite conclusion.
Introduction The introduction of a supraglottic device like the Laryngeal Mask Airway has revolutionized airway management in pediatric anesthesia practice. The classic Laryngeal Mask Airway (cLaryngeal Mask Airway, Intavent Orthofix Maidenhead, UK) was introduced into clinical anesthesia in 1988 (1). It is a cuffed supraglottic reusable device, made of silicone. Its use has expanded immensely and majority of anesthetic procedures in children are now facilitated with the use of the cLaryngeal Mask Airway as an airway device (2). However, several disadvantages of the cLaryngeal Mask Airway have lead 386
to development of alternative supraglottic devices. The i-gel size 1 (Intersurgical, Wokingham, UK) is an innovative second generation supraglottic airway device. It is a smaller model of the well known i-gel used in adult patients, made up of thermoplastic elastomer, styrene ethylene butadiene styrene (SEBS) with a unique soft, noninflatable cuff, bite block, epiglottic rest, and a buccal cavity stabilizer (3,4). The pediatric versions of i-gel airway are available in four different sizes (1, 1.5, 2, and 2.5) on the basis of body weight. However, both the i-gel size 1 and the cLaryngeal Mask Airway are without any esophageal port. The aim of this prospective randomized study was to evaluate and compare the suitability © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
D. Pant et al.
Laryngeal Mask Airway vs i-gel size 1
of the i-gel size 1 to the cLaryngeal Mask Airway size 1 as an airway device in pediatric daycare surgery. The primary outcome measured was the oropharyngeal seal pressure (OSP) in both the i-gel and the cLaryngeal Mask Airway groups. Assessing OSP is important to quantitate the efficacy of the seal. High OSP is important as it indicates airway protection, feasibility of positive pressure ventilation (PPV) and likelihood of successful placement of the supraglottic device (5). The secondary outcomes measured were the ease of insertion, number of insertion attempts, time taken for successful insertion, displacement of the device, and intra-operative and postoperative complications. Methods In this prospective randomized observational study, 40 pediatric patients were included after obtaining approval from the hospital ethics committee and an informed consent from the parents of the patients. The patients included in the study were neonates and infants between 2 and 5 kg body weight of ASA physical status I–II. They were scheduled to undergo daycare procedures like herniotomy, orchidopexy, cystoscopy with posterior urethral valve fulguration, rectal biopsy and umbilical granuloma excision with an estimated duration of anesthesia under one hour. The study was
registered with Clinical Trials Registry – India (CTRI) reference number CTRI 2013/02/003364. Children with sore throat or upper respiratory infection, potential for difficult airway and pulmonary aspiration and those requiring surgery in positions other than supine or lithotomy were excluded from the study. Randomization to one of the two airway devices (i-gel group size 1 or cLaryngeal Mask Airway group size 1) with twenty patients in each group was based on computer generated numbers kept in sequentially numbered opaque envelopes opened just before device insertion (Figure 1). We confirmed the fasting status and took preoperative history. The physical examination was completed and verbal and written informed consent from parents was obtained. No premedication was given. Anesthesia was induced with sevoflurane (4–8%) in 50% oxygen and 50% nitrous oxide through a face mask with standard monitors in place as per ASA guidelines, and the breathing circuit was connected to the anesthesia machine (Penlon, Abingdon, Made in UK, CE 0473). An intravenous access was secured followed by intravenous fentanyl 1 lgkg 1 and midazolam 0.02 mgkg 1 for analgesia and sedation, respectively. Ventilation was assisted with face mask to obtain adequate depth of anesthesia (loss of eyelash reflex, jaw relaxation, and absence of movement). This was followed by insertion of the i-gel or the cLaryngeal
Assessed for eligibility (n = 40)
Excluded (n = 0)
Randomized (n = 40)
Allocation Allocated to intervention (n = 20) • Received allocated intervention (n = 20) • Did not receive allocated intervention (n = 0)
Allocated to intervention (n = 20) • Received allocated intervention (n = 20) • Did not receive allocated intervention (n = 0)
Follow-up Lost to follow-up (n = 0) Discontinued intervention (n = 0)
Lost to follow-up (n = 0) Discontinued intervention (n = 0)
Analysis
Figure 1 CONSORT flow diagram. © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
Analysed (n = 20) • Excluded from analysis (n = 0)
Analysed (n = 20) • Excluded from analysis (n = 0)
387
D. Pant et al.
Laryngeal Mask Airway vs i-gel size 1
Mask Airway according to the manufacturer’s instructions after appropriate lubrication with a water based jelly using standard technique with partially inflated cuff (6). The device was connected to the breathing circuit (Jackson Rees modification of Ayre’s T-piece), the cLaryngeal Mask Airway cuff inflated to 40 cm H2O, with a Mallinckrodt aneroid cuff pressure monitor, followed by proper bimaxillary fixation with adhesive tape of the two devices (7,8). Correct placement of the device in both groups was assessed by observing for bilateral chest expansion, presence of square wave capnography, absence of audible leak at oral cavity, and lack of gastric insufflation recorded using a stethoscope placed over epigastrium. Initially manual ventilation was performed till the spontaneous effort returned; this was followed by assisted manual ventilation providing continuous positive airway pressure (CPAP). All the investigators were experienced users of cLaryngeal Mask Airway and had used i-gel on more than 10 occasions in pediatric patients. The device placement was followed by caudal epidural block with 0.25% bupivacaine in the lateral position, simultaneously observing for any displacement of the airway device during or after the block. The displacement of the device was defined by absence of capnographic trace on the monitor. The patient was placed supine following the block. Anesthesia was maintained with 1–2% sevoflurane in 66% N2O and 33% O2 with assisted manual ventilation with a fresh gas flow of 1–3 lmin 1. Ease of insertion was evaluated on the following scale: grade1 = easy insertion, grade 2 = at least one maneuver required for insertion, grade 3 = more than one maneuver required for insertion. Airway maneuvers used were chin lift, neck extension, or gentle manipulation of the device. The number of insertion attempts was recorded. Three attempts were allowed before the insertion was considered a failure. If adequate ventilation was not achieved using either of the supraglottic devices, tracheal intubation was performed and the participant was excluded from the study. The time taken for successful insertion of the device was measured as the time between picking up of the i-gel/the cLaryngeal Mask Airway and appearance of the first capnographic trace on the monitor. The OSP was measured as the airway pressure at which audible leak was heard near the mouth of the patient with the fresh gas flow set at 3 lmin 1 and the expiratory valve closed. The OSP was not allowed to exceed 30 cm of H2O to avoid barotrauma. All insertions were performed by one investigator, while measurement of OSP and other variables were recorded by a single observer who did not participate in the study. Intra-operative adverse events such as airway 388
obstruction, coughing, laryngospasm, desaturation (SpO2 < 92%), and regurgitation were also noted. After removal of the airway device, its cuff was inspected for blood or bile staining. Postoperatively, the patients were observed in the postoperative care unit and daycare unit for any burping, restlessness, or retching till the time of discharge. Statistics We based our sample size calculation on our primary outcome variable the OSP. No data about performance of the size 1 i-gel in neonates were available for a reliable sample size calculation. Based on the previous studies, a sample size of 20 patients per group was calculated to detect a difference in OSP of 3 cm of H2O between the i-gel and the cLaryngeal Mask Airway for a type I error of 0.05 with a power of 0.9 and population variance of 2 (9,10). The data were analyzed using SPSS software, (17.0 version; SPSS Inc., Chicago, IL, USA). Continuous variables were presented as mean SD, and categorical variables presented as absolute numbers and percentage. The comparison of normally distributed continuous variables between the groups was performed using Student’s t-test. Nominal categorical data between the groups were compared using Chi-square test or Fisher’s exact test as appropriate. For all statistical tests, a P < 0.05 was taken as statistically significant. Results The patients’ characteristics are shown in Table 1. The two groups were comparable with respect to age, sex, weight, and duration of surgery. Of 40 cases, 20 were operated for inguinal hernia repair, eight each for orchidopexy and cystoscopy with posterior urethral valve fulguration, three for rectal biopsy, and one for umbilical granuloma excision. Perioperative data and adverse events for the two devices are shown in Tables 2 and 3, respectively. The OSP was higher with the i-gel than with the cLaryngeal Mask Airway, 22.30 4.72 vs 18.05 1.95 cm H2O, respectively and was statistically significant (P = 0.001). Table 1 Patients characteristics
Age (week) Weight (kg) Sex (M/F) Duration of Surgery (min) Data are number (n), mean
i-gel (n = 20)
cLaryngeal Mask Airway (n = 20)
10.75 3.97 3.93 0.97 16/4 56.5 15.48
8.70 3.06 4.26 0.60 17/3 52.35 15.85
SD.
© 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
D. Pant et al.
Laryngeal Mask Airway vs i-gel size 1
Table 2 Comparison between the i-gel and the cLaryngeal Mask Airway (OSP, insertion data and device displacement)
OSP (cm H2O) Insertion Ease of insertion (n) Grade I Grade II Grade III Success rate 1st attempt: n (%) 2nd attempt: n (%) Insertion time (s) Device displacement after caudal
i-gel (n = 20)
cLaryngeal Mask Airway (n = 20)
95% CI of mean difference
P-value
22.3 4.72
18.05 1.95
1.938–6.562
0.001*
18 2 0
15 5 0
16 (80%) 04 (20%) 10.6 4.46 1 (5.0%)
12 (60%) 08 (40%) 9.9 4.12 7 (35%)
0.212 0.139 – 0.301 0.61 0.044*
Data are number (n), mean SD. *P-value < 0.05 is considered statistically significant.
Table 3 Perioperative complications
Airway obstruction Coughing Laryngospasm Desaturation Regurgitation Blood on airway device Bile on airway device Postop burping, retching and restlessness
i-gel (n = 20)
cLaryngeal Mask Airway (n = 20)
P-value
Nil Nil Nil 1 (5%) Nil Nil Nil 1 (5%)
Nil Nil Nil 7 (35%) 1 (5%) 2 (10%) 1 (5%) 5 (25%)
0.044* 1.0 0.49 1.0 0.17
Data are number (n), mean SD. *P-value < 0.05 is considered statistically significant.
There was no failure of insertion of airway device in any group. Insertion was graded easy for both the groups. There was no statistical difference in ease of insertion, insertion success rate, and time taken for insertion. There was less incidence of displacement of the device after caudal block with the i-gel as compared to the cLaryngeal Mask Airway (P = 0.04), which was statistically significant. The incidence of complications was low in both the groups except for desaturation (SpO2 < 92%), which was reported in seven cases (35%) in the cLaryngeal Mask Airway group. There was one case of pharyngeal regurgitation in the cLaryngeal Mask Airway group as was evidenced by presence of bile on the device. However, there was no clinical evidence of pulmonary aspiration. Discussion Our results demonstrate that the i-gel size 1 provides higher OSP than that provided by cLaryngeal Mask © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
Airway of the same size. After proper fixation, it is less prone to get displaced despite positional changes and may be used as an alternative to the cLaryngeal Mask Airway as an airway device in neonates and infants weighing 2–5 kg for short daycare procedures. The OSP determines the efficacy of a supraglottic device, the higher OSP may be an advantage in PPV, although our study patients were provided assisted mechanical ventilation. The OSP for the i-gel (22.30 4.72 cm H2O) was higher than for the cLaryngeal Mask Airway (18.05 1.95 cm H2O). Our results for OSP for the i-gel are in concurrence with previous work (11,12). The use of the i-gel in children has been reported in several studies. But there is paucity of data regarding the performance of the size 1 i-gel in children up to 5 kg of weight (11–17). The OSP reported for pediatric size cLaryngeal Mask Airway is between 15 and 19 cm H2O and comparable to our study (9,10,17). Although the OSP with i-gel was statistically significantly higher than that obtained with the cLaryngeal Mask Airway, this difference may not be clinically significant. However, the i-gel being cuffless eliminates the need for cuff inflation and the adverse effects associated with it (12). Accidental dislodgement is considered a minor complication if the patient’s airway is accessible, yet it can lead to rapid desaturation in children < 5 kg. In the cLaryngeal Mask Airway group, after giving caudal block in the lateral position and while turning the patient supine, there was displacement of the cLaryngeal Mask Airway despite proper fixation in 7 of 20 patients (35%) requiring repositioning. However, there was only one case of displacement of the i-gel, due to accidental stretch on anesthesia circuit in the study. Displacement of the i-gel has been reported in several studies where they noticed that the i-gel often slides out of mouth, 389
D. Pant et al.
Laryngeal Mask Airway vs i-gel size 1
especially in small children, requiring advancement and retaping (11,18,19). Our incidence of displacement was low because of proper bimaxillary fixation with an adhesive tape. The widened and flattened stem of the i-gel acts as a stabilizer within the buccal cavity, reducing the chances of axial rotation and thus malrolation (4). Also, the ridge at the proximal end of mask catches the base of tongue contributing to the positional stability, while the epiglottic rest prevents downfolding of epiglottis during insertion (3). Our study demonstrates that the i-gel size 1 has a similar performance in terms of ease of insertion, insertion success rate and time required for insertion when compared with the cLaryngeal Mask Airway size 1. Lee et al. (12) who compared the i-gel with the cLaryngeal Mask Airway in children (6–30 kg) reported easy insertion and shorter insertion time for the i-gel as compared to the cLaryngeal Mask Airway. On the contrary, Thieler et al. (18) while comparing the i-gel with the Ambu AuraOnce laryngeal mask in children (0–17 years), reported a longer insertion time with the i-gel, however, only three of their patients weighed between 5 and 9.9 kg. Perioperative complications were comparable in both the groups except for displacement of device leading to desaturation. Several complications like blood staining of the device, dislodgment, partial airway obstruction, neuropraxia, and regurgitation have been reported for the i-gel in pediatric patients, but we did not encounter such complications probably because the sample size and duration of surgery was too small to detect them (13,18–21). Limitations The i-gel and the cLaryngeal Mask Airway were used with assisted spontaneous ventilation with CPAP in patient with normal airways. The results cannot be extrapolated in patients with difficult airways and those requiring PPV.
Our sample size was too small to detect any significant differences in complications with the two devices. We also did not conduct the fiber optic assessment for airway patency. However, the ideal position of the Laryngeal Mask Airway is obtained only in 40–50% of patients on fiber optic assessment inspite of clinically adequate patency (22). Assessing correct placement on clinical ground is considered a normal practice for the Laryngeal Mask Airway insertion in children (23). The study could not be blinded because the anesthesia personnel were aware of the airway device used. However, the data were collected by an experienced anesthesiologists, not involved in the clinical trial. Another drawback of our study was that possibility of gastric insufflation during measurement of OSP was not assessed as both the devices were devoid of gastric channel. Conclusion The OSP of the i-gel size 1 is statistically significantly higher than that of the cLaryngeal Mask Airway size 1 and after the fixation, the i-gel is less prone to displacement on change of position as compared to the cLaryngeal Mask Airway in infants < 5 kg for short surgical procedures. However, being a preliminary study carried out on a small number of patients, further trials are warranted to come to any definite conclusion. Acknowledgments We thank our pediatric surgical colleagues for their cooperation and interest. We also thank Mr. Prakash Bisht for secretarial help and Mrs. Parul for the statistical analysis. This research was carried out without funding. Conflict of interest No conflicts of interest declared.
References 1 Brain AI. The development of the Laryngeal Mask–a brief history of the invention, early clinical studies and experimental work from which the Laryngeal Mask evolved. Eur J Anaesthesiol Suppl 1991; 4: 5–17. 2 White MC, Cook TM, Stoddart PA. A critique of elective pediatric supraglottic airway devices. Pediatr Anesth 2009; 19: 55–65. 3 Levitan RM, Kinkle WC. Initial anatomic investigations of the I-gel airway: a novel supraglottic airway without inflatable cuff. Anaesthesia 2005; 60: 1022–1026.
390
4 Wharton NM, Gibbison B, Gabbott DA et al. I-gel insertion by novices in manikins and patients. Anaesthesia 2008; 63: 991– 995. 5 Seet E1, Rajeev S, Firoz T et al. Safety and efficacy of laryngeal mask airway Supreme versus laryngeal mask airway ProSeal: a randomized controlled trial. Eur J Anaesthesiol 2010; 27: 602–607. 6 Ghai B, Makkar JK, Bhardwaj N et al. Laryngeal mask airway insertion in children: comparison between rotational, lateral and
standard technique. Pediatr Anesth 2008; 18: 308–312. 7 Wong JG, Heaney M, Chambers NA et al. Impact of laryngeal mask airway cuff pressures on the incidence of sore throat in children. Pediatr Anesth 2009; 19: 464–469. 8 von Ungern-Sternberg BS, Erb TO, Chambers NA et al. Laryngeal mask airways–to inflate or to deflate after insertion? Pediatr Anesth 2009; 19: 837–843. 9 Goldmann K, Jakob C. A randomized crossover comparison of the size 2 ½ laryngeal © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
D. Pant et al.
10
11
12
13
14
mask airway ProSealTM versus laryngeal mask airway-ClassicTM in pediatric patients. Anesth Analg 2005; 100: 1605–1610. Goldmann K, Jakob C. Size 2 ProSealTM laryngeal mask airway: a randomized, crossover investigation with the standard laryngeal mask airway in paediatric patients. Br J Anaesth 2005; 94: 385–389. Jagannathan N, Sommers K, Sohn LE et al. A randomized equivalence trial comparing the i-gel and laryngeal mask airway Supreme in children. Pediatr Anesth 2013; 23: 127–133. Lee JR, Kim MS, Kim JT et al. A randomised trial comparing the i-gel (TM) with the LMA Classic (TM) in children. Anaesthesia 2012; 67: 606–611. Lopez-Gil M, Brimacombe J, Alvarez M. Safety and efficacy of the laryngeal mask airway. A prospective survey of 1400 children. Anaesthesia 1996; 51: 969–972. Beringer RM, Kelly F, Cook TM et al. A cohort evaluation of the paediatric i-gelTM
© 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 386–391
Laryngeal Mask Airway vs i-gel size 1
15
16
17
18
airway during anaesthesia in 120 children. Anaesthesia 2011; 66: 1121–1126. Goyal R, Shukla RN, Kumar G. Comparison of size 2 i-gel supraglottic airway with LMA-ProSealTM and LMA-ClassicTM in spontaneously breathing children undergoing elective surgery. Pediatr Anesth 2012; 22: 355–359. Gasteiger L, Brimacombe J, Oswald E et al. LMA ProSeal(TM) vs. i-Gel(TM) in ventilated children: a randomised, crossover study using the size 2 mask. Acta Anaesthesiol Scand 2012; 56: 1321–1324. Beylacq L, Bordes M, Semjen F et al. The I-gelâ, a single-use supraglottic airway device with a non-inflatable cuff and an esophageal vent: an observational study in children. Acta Anaesthesiol Scand 2009; 53: 376–379. Theiler LG, Kleine-Brueggeney M, Luepold B et al. Performance of the pediatric-sized i-gel compared with the Ambu AuraOnce
19
20
21
22
23
laryngeal mask in anesthetized and ventilated children. Anesthesiology 2011; 115: 102–110. Hughes C, Place K, Berg S et al. A clinical evaluation of the I-gel TM supraglottic airway device in children. Pediatr Anesth 2012; 22: 765–771. Renes SH, Zwart R, Scheffer GJ et al. Lingual nerve injury following the use of an i-gel laryngeal mask. Anaesthesia 2011; 66: 226–227. Gibbison B, Cook TM, Seller C. Case series: Protection from aspiration and failure of protection from aspiration with the i-gel airway. Br J Anaesth 2008; 100: 415–417. Kundra P, Deepak R, Ravishankar M. Laryngeal mask insertion in children: a rational approach. Paediatr Anaesth 2003; 13: 685–690. Matta BF, Marsh DS, Nevin M. Laryngeal mask airway: a more successful method of insertion. J Clin Anesth 1995; 7: 132–135.
391
