Comparison of Two Supraglottic Airway Devices: I-gel Airway and ProSeal Laryngeal Mask Airway Following Digital Insertion in Nonparalyzed Anesthetized Patients

Abstract

Aims:
The study is aimed to compare the efficacy of I-gel and ProSeal laryngeal mask airway (PLMA) in nonparalysed anesthetized individuals following manufacturer-recommended digital insertion.

Materials and methods:
In this prospective randomized observational study, 40 American Society of Anesthesiologists I and II patients, aged 18-65 years scheduled for elective surgical procedures were allocated either to PLMA group (Group P, n = 20) or the I-gel group (Group I, n = 20). Following digital insertion of PLMA or I-gel, the following parameters were compared: insertion time, ease of insertion, number of attempts, failed insertion, airway reaction during insertion, oropharyngeal leak (OPL) pressure, and gastric insufflation on auscultation. Fiberoptic view of both the channels of the airway devices and ease of insertion of 12 F Ryle's tube through gastric drain channel were graded. Postoperative complications were also noted.

Results:
First attempt and overall insertion success were similar (PLMA, 85% and 100%; I-gel 80% and 100%, respectively). Mean (standard deviation) insertion times were similar (PLMA, 27.40 [11.51] s; I-gel 25.45 [9.03] s). Mean OPL pressure was 3.5 cm H2O higher with PLMA (P < 0.012). The passage of Ryle's tube was easier through I-gel than PLMA. Grade I glottic view (full view of the vocal cords) was visible in 17 (85%) patients who were managed with I-gel whereas only 9 (45%) patients had Grade I view in the PLMA group.

Conclusion:
The time required for digital insertion of PLMA and I-gel in nonparalyzed anesthetized patients is similar but PLMA forms a better oropharyngeal seal. I-gel is better positioned over the laryngeal framework and esophagus. I-gel allows easier passage of Ryle's tube through its drain channel than PLMA. The incidence and severity of postoperative sore throat and hoarseness was higher with PLMA.

Full text

Abstract
Original Article
IntroductIon
The ProSeal™ laryngeal mask airway (PLMA; Laryngeal
Mask Company North America, San Diego, CA, USA) is
a laryngeal mask device with a modied cuff and a drain
tube.[1] The manufacturer recommends inserting the PLMA
using digital manipulation, like the LMA-Classic™, or with
an introducer tool, like the Intubating™ LMA (Laryngeal
Mask Company North America).[2] When inated, its modied
cuff presses the bowl of the device forwards and improves
the seal with the larynx. However, PLMA still possesses few
disadvantages of inatable cuff, which can negatively impact
its insertion, positioning and performance.[3] Gum-elastic
bougie-guided insertion of PLMA is recommended by a few
researchers to overcome these problems.[4]
I-gel is the single use supraglottic airway from Intersurgical,
UK (Intersurgical Ltd., Wokingham, Berkshire, UK) with
overall insertion success rate is as high as 100%.[5] It possesses
an anatomically designed, noninatable mask made of a
gel-like thermoplastic elastomer. It has a widened, attened
stem with a rigid bite block that acts as a buccal stabilizer
to reduce axial rotation and malpositioning, and a port for
Aims: The study is aimed to compare the efcacy of I-gel and ProSeal laryngeal mask airway (PLMA) in nonparalysed anesthetized individuals
following manufacturer-recommended digital insertion. Materials and Methods: In this prospective randomized observational study, 40
American Society of Anesthesiologists I and II patients, aged 18–65 years scheduled for elective surgical procedures were allocated either to
PLMA group (Group P, n = 20) or the I-gel group (Group I, n = 20). Following digital insertion of PLMA or I-gel, the following parameters
were compared: insertion time, ease of insertion, number of attempts, failed insertion, airway reaction during insertion, oropharyngeal
leak (OPL) pressure, and gastric insufation on auscultation. Fiberoptic view of both the channels of the airway devices and ease of insertion
of 12 F Ryle’s tube through gastric drain channel were graded. Postoperative complications were also noted. Results: First attempt and overall
insertion success were similar (PLMA, 85% and 100%; I-gel 80% and 100%, respectively). Mean (standard deviation) insertion times were
similar (PLMA, 27.40 [11.51] s; I-gel 25.45 [9.03] s). Mean OPL pressure was 3.5 cm H2O higher with PLMA (P < 0.012). The passage of
Ryle’s tube was easier through I-gel than PLMA. Grade I glottic view (full view of the vocal cords) was visible in 17 (85%) patients who were
managed with I-gel whereas only 9 (45%) patients had Grade I view in the PLMA group. Conclusion: The time required for digital insertion
of PLMA and I-gel in nonparalyzed anesthetized patients is similar but PLMA forms a better oropharyngeal seal. I-gel is better positioned
over the laryngeal framework and esophagus. I-gel allows easier passage of Ryle’s tube through its drain channel than PLMA. The incidence
and severity of postoperative sore throat and hoarseness was higher with PLMA.
Keywords: I-gel, oropharyngeal seal pressure, ProSeal laryngeal mask airway
Address for correspondence: Dr. Ankur Luthra,
Department of Anaesthesia and Intensive Care, Postgraduate
Institute of Medical Education and Research, Chandigarh, India.
E‑mail: zazzydude979@gmail.com
This is an open access journal, and arcles are distributed under the terms of the Creave
Commons Aribuon‑NonCommercial‑ShareAlike 4.0 License, which allows others to
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is given and the new creaons are licensed under the idencal terms.
For reprints contact: reprints@medknow.com
How to cite this article: Luthra A, Chauhan R, Jain A, Bhukal I, Mahajan S,
Bala I. Comparison of two supraglottic airway devices: I-gel airway and
ProSeal laryngeal mask airway following digital insertion in nonparalyzed
anesthetized patients. Anesth Essays Res 2019;13:669-75.
Comparison of Two Supraglottic Airway Devices: I‑gel Airway
and ProSeal Laryngeal Mask Airway Following Digital Insertion
in Nonparalyzed Anesthetized Patients
Ankur Luthra, Rajeev Chauhan, Amit Jain1, Ishwar Bhukal, Shalvi Mahajan, Indu Bala
Department of Anaesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research, Chandigarh, India, 1Department of Anesthesiology,
Anesthesiology Institute, Cleveland Clinic Abu Dhabi, Al Maryah Island, Abu Dhabi, United Arab of Emirates
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DOI:
10.4103/aer.AER_132_19
Submitted: 31-Oct-2019 Revised: 11-Nov-2019
Accepted: 19-Nov-2019 Published: 16-Dec-2019
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Luthra, et al.: I‑gel versus ProSeal digital insertion in nonparalyzed anaesthetized patients
gastric tube insertion.[5] The manufacturer recommends
digital insertion technique for I-gel. However, gum-elastic
bouige-guided insertion has also been described.[6]
Several studies have compared the safety and efficacy
of the I-gel and the PLMA. However, most studies used
neuromuscular blocking drugs and insertion was performed
using either introducer tool or gum-elastic bougie for PLMA
and digital technique or gum-elastic bougie-guided insertion
for I-gel.[6-8]
In the current study, we test the hypothesis that the ease of
insertion using manufacturer recommended digital technique
and efcacy of seal as measured by oropharyngeal leak (OPL)
pressure differ between I-gel and PLMA in nonparalyzed
anesthetized patients. The intraoperative orogastric tube
insertion success rate, view of the glottis using beroptic
laryngoscopy, airway reactions during insertion, and
postoperative complications associated with the two devices
were also compared.
MaterIals and Methods
With institutional ethical committee approval (Reference:
7821/PG-2Trg/2008) and written informed consent, this
prospective randomized noncross observational study of
two supraglottic airway devices, namely the PLMA and the
I-gel airway was performed. Forty patients in the age group
18–65 years of both sexes belonging to American Society of
Anesthesiologists (ASA) physical status I and II scheduled
for elective surgical procedures of <1 h duration were studied.
Computer generated random numbers were used to allocate
patients to either of the two study groups: PLMA group (Group P,
n = 20) or the I-gel group (Group I, n = 20). Exclusion criteria
included pregnant patients, gastro-esophageal reux disease,
morbid obesity (body mass index >35 kg/m2), coagulation
abnormalities, anticipated difcult airway (Mallampati Grade
III/IV and mouth opening <3 cm) or oropharyngeal pathology.
Size 3 and 4 PLMA used for patients weighing 30–50 kg and
50–70 kg, respectively and size 3 and 4 I-gel for patients
weighing 30–60 kg and 60–90 kg, respectively. All patients
underwent detailed preanesthetic evaluation, including
airway examination. Patients were kept fasted according to
the standard nil per oral guidelines. After shifting the patients
to the operation theatre, standard 5-lead electrocardiography,
noninvasive blood pressure, pulse oximetry and bi-spectral
index monitors were attached and baseline parameters were
noted. Intravenous access was secured with 18 G cannula
and all patients received 2 μg.kg-1 fentanyl. Patients were
preoxygenated with 3 min of tidal volume ventilation.
Anesthesia was induced with propofol 2 mg.kg-1. Ventilation
was assisted using a face mask with 100% oxygen. After the
bispectral index (BIS) value of 40 was obtained, the anesthesia
provider checked for apnea and the lack of motor response to
a jaw thrust.[9]
Additional 0.5 mg.kg-1 propofol was given for ensuring
adequate depth if patient was breathing spontaneously, moved
or showed motor response to jaw thrust. Either PLMA or I-gel
airway was inserted according to the group allocation by the
same anesthetist with substantial experience of both devices
using manufacturer recommended digital techniques (>75
uses). I-gel was inserted using the rotational technique,
whereas PLMA was inserted using the index nger. The
cuff was inated according to the size of PLMA and cuff
pressure of PLMA was set at 60 cm H2O using a digital
manometer (Mallinckrodt Medical, Athlone, Ireland). The
patients’ lungs were then ventilated at an inspired tidal volume
of 10 ml.kg-1, a respiratory rate of 10 min−1 and an Inspiratory:
Expiratory ratio of 1:2. Maintenance anesthesia was given by
intravenous propofol in a dose of 75–150 μg.kg-1.min-1 with
33% oxygen in nitrous oxide to maintain BIS value between
40 and 60.
The parameters noted were (1) insertion time (time to
successful insertion of the device measured from picking
the device to obtaining the rst breath). (2) Ease of insertion
(easy or no resistance, moderate or minimal resistance, difcult
or signicant resistance, and impossible). (3) Number of
attempts (maximum of three attempts were allowed before
considering the device a failure). Failed insertion was dened
by any of the following criteria: (1) failed passage of the
airway device into the pharynx; (2) malposition (air leaks);
(3) ineffective ventilation (maximum expired tidal volume
<6 mL.kg-1 or end-expiratory carbon dioxide >6 kPa if correctly
positioned), or (4) drainage tube leaks. The etiology of failed
insertion was documented. Failed cases were managed with
the endotracheal tube. (4) Airway reaction (laryngospasm,
bronchospasm, coughing, gagging). (5) OPL pressure (leak
detected by audible noise heard on keeping the stethoscope
on lateral aspect of thyroid cartilage): With fresh gas ows at
3 L.min-1 and adjustable pressure limit valve set to 40 cm of
H2O, ventilation was stopped temporarily and a stethoscope
was placed over the neck just lateral to thyroid cartilage to
measure the minimal airway pressure at which an audible gas
leak occurred.[10] (6) Fiberoptic view of both the channels of
the airway devices by a beroptic bronchoscope (PENTAX
FB 15P) and noted as Grade I – Full view of the vocal cords,
Grade II – Posterior cords and arytenoids only, Grade III – Only
epiglottis seen, or Grade IV – No laryngeal structures seen.
The view via drain tube was scored as: mucosa; closed upper
esophagus; open upper esophagus; drain tube occluded;
and whether the berscope could be/could not be passed.[11]
(7) Ability to pass a lubricated 12 F Ryle’s tube through
gastric drain channel (easy/difcult/impossible); maximum
of two attempts were allowed. (8) Any gastric insufations
(by auscultation over the patient’s epigastric area).
On completion of the procedure, the duration of the surgery
and total propofol administered was recorded. The device was
removed when the BIS value reached 75–80 and patient became
responsive to oral commands. The following parameters
were then noted-ease of removal (easy, moderate, difcult),
airway reaction (laryngospasm, bronchospasm, coughing and
gagging), visible blood on the airway device and evidence of
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Luthra, et al.: I‑gel versus ProSeal digital insertion in nonparalyzed anaesthetized patients
of propofol used or the duration of surgery between the
groups [P > 0.05, Tab le 3]. Data about intraoperative
hemodynamics, arterial saturation, end-tidal CO2 and BIS
values were also comparable (P < 0.05).
Data related to the ease of insertion, number of insertion attempts
and insertion time were also statistically similar [Table 4]. The
rst attempt success rate was 85% and 80% with PLMA and
I-gel, respectively. The second attempt success rate was 100%
in both the groups.
Mean OPL was 3.5 cm H2O higher with the PLMA [P = 0.012,
Table 5]. The incidence of gastric insufation was more with
PLMA (10% as compared to 0% in I-gel group), but the
difference was not signicant [P = 0.147, Table 5]. Ryle’s
tube placement was successful and easy in all 20 patients with
I-gel. In the PLMA group, the placement was not possible in
3 (15%) patients and was easy only in 60% of the patients. The
passage of Ryle’s tube was analyzed using Chi-square test and
the difference was statistically signicant [P = 0.007, Table 5].
The laryngeal views on beroptic examination through
the shaft of the device were compared in Table 6. Grade I
view (full view of the vocal cords) was visible in 17 (85%)
patients who were managed with I-gel whereas 9 (45%)
patients had Grade I view in the PLMA group. Posterior
cords and arytenoids (Grade II) were visible in 10 (50%)
Group P patients and 3 (15%) Group I patients and only
epiglottis seen (Grade III) in only one patient of the P Group,
but none in I Group.
The beroptic view through the drain tube could only be
obtained in the PLMA group because only adult berscope
with external diameter 4.8 mm was available which could not
be negotiated through the drain tube of size 4 I-gel. Six (30%)
patients in the PLMA group had a Grade II view (closed upper
regurgitation of yellowish gastric uid.
Postoperatively, patients were queried for sore throat,
dysphagia, dysphonia, nausea, neck/jaw/ear pain and
hoarseness of voice immediately after the procedure (at 0 h)
and after 24 h. Soreness was quantified on a 101-point
numerical rating score where 0 was no soreness at all and 101
point referred to maximum soreness.[12]
Statistical analysis
The number of individuals was based on preliminary
experimental data on I-gel. The mean airway pressure at
which gas leaks around the PLMA has been reported to be
29 ± 6[13] and the OPL pressure obtained with I-gel in our pilot
study with 10 patients was 25.1 ± 4. To detect a projected
difference of 10% (with estimated standard deviation [SD] of
4) between the groups with respect to the primary variable-OPL
pressure, a Type I error of 0.05 and a power of 0.8, a total of
18 patients were required in each group, but 20 were included
to compensate for possible dropouts.
Parametric data was expressed as mean ± SD and analyzed using
the student’s t-test. Nonparametric data was expressed as median
and interquartile range was analyzed using the Mann–Whitney
U-test. Count data was compared using the Chi-square test.
P < 0.05 was considered as statistically signicant.
results
The patients’ characteristics were similar between the
two groups and most of the patients in both the groups
were ASA I [P > 0.05, Table 1]. On preoperative airway
assessment, the patients in both the groups were not
signicantly different [Table 2]. The number of patients
based on the sizes of I-gel and PLMA used are shown in
Table 3. There was no signicant difference in the dose
Table 1: Patient characteristics (n=20)
Group P (PLMA) Group I (I‑gel) P
Age (years), mean (SD) (range) 40.75 (13.26) (19-62) 41.90 (10.23) (24-59) 0.761
Height (cm), mean (SD) (range) 161.95 (7.66) (146-179) 162.73 (7.55) (154-178) 0.749
Weight (kg), mean (SD) (range) 62.85 (11.86) (42-90) 67.15 (10.96) (50-90) 0.241
BMI (kg/m2), mean (SD) (range) 23.91 (3.96) (17.15-32.25) 25.23 (2.82) (21.08-32.79) 0.233
ASA I:II 19:1 15:5 0.077
Sex ratio (male:female) 9:11 10:10 0.875
P<0.05 is statistically signicant. All values are expressed as mean (SD) (range) except ASA status and male:female ratios. ASA=American society of
Anesthesiologists, BMI=Body mass index, SD=Standard deviation, PLMA=Proseal laryngeal mask airway
Table 2: Preoperative airway assessment (n=20)
Group P (PLMA) Group I (I‑gel) P
MMP, n (%)
I 3 (15) 5 (25) 0.429
II 17 (85) 15 (75)
MO (cm), mean (SD) (range) 4.17 (0.29) (3.8-4.8) 4.03 (0.27) (3.7-4.6) 0.119
TMD (cm), mean (SD) (range) 6.82 (0.22) (6.4-7.3) 6.82 (0.27) (6.5-7.5) 0.949
P<0.05 is statistically signicant. MO and TMD are expressed as mean (SD) (range). MMP=Mallampati grading, MO=Mouth opening, TMD=Thyromental
distance, SD=Standard deviation, PLMA=Proseal laryngeal mask airway
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Luthra, et al.: I‑gel versus ProSeal digital insertion in nonparalyzed anaesthetized patients
esophagus) while open upper esophagus was seen in 13 (65%)
patients of PLMA group [Table 6]. In one patient, drain tube
was occluded.
The data related to the postoperative complication are
shown in Table 7. There were no airway reactions during
placement of the PLMA in any of the patients; whereas
2 patients had bronchospasm during the placement of
I-gel LMA. On removal of the airway device, we observed
blood on the PLMA in one patient whereas blood was
visible on the I-gel in 3 patients. There was significantly
higher incidence of sore throat (both at extubation and
at 24 h postoperatively) with PLMA (P = 0.005). The
sore throat was also more severe in patients in the PLMA
group (P = 0.004). Hoarseness was present in 80% and 10%
of the patients with PLMA and I-gel, respectively (P < 0.05).
No patient had dysphagia, dysphonia, ear, neck, or jaw pain
in either groups.
dIscussIon
The present study compared the efcacy of I-gel with PLMA
following their digital insertion in nonparalyzed anaesthetized
adult patients. No device is superior to the other in terms of
success and ease of insertion. Nonguided digital-aided rst
attempt insertion of the PLMA was successful in 85% patients.
First attempt success rate of insertion with I-gel was 80%. The
difference was not signicant (P = 0.799). The second attempt
success rate was 100% with both the devices. Our ndings are
consistent with the observations of Bosley et al.,[14] who compared
the PLMA and I-gel in nonparalyzed anaesthetized European
patients following insertion using manufacturer recommended
standard technique. The authors reported 1st time insertion
success rate as PLMA 86% and I-gel 78% (P = 0.61). Also, the
data from individual studies on PLMA and I-gel are similar to
our observations. First attempt and second attempt success rates
with the PLMA as observed by Lu et al. were 82.5% and 100%,
respectively.[15] Similarly, rst attempt success rate in a study
where I-gel was inserted by novices in manikins and patients
was 82.5%, but reached 100% after three attempts.[16] Gatward
et al.[17] evaluated size 4 I-gel and found similar success rates.
Jadhav et al.[18] and Das et al.[19] also reported similar rst and
second attempt success rates with both I-gel and PLMA.
The mean insertion time for PLMA and I-gel in the present
study was 27.40 ± 11.51 s (range 14-54 s) as compared to
Table 3: Laryngeal mask airway size, propofol used and duration of surgery (n=20)
Group P (PLMA) Group I (I‑gel) P
LMA size, n (%)
3 4 (20) 0 0.035*
4 16 (80) 20 (100)
Total dose of propofol (mg), mean (SD) (range) 323.75 (104.46) (155-550) 324.25 (125.51) (170-600) 0.989
Total surgical duration (min), mean (SD) (range) 24.65 (12.01) (8-50) 24.90 (12.75) (8-60) 0.949
*P<0.05 is statistically signicant. Total dose of propofol and surgical duration are expressed as mean (SD) (range). LMA=Laryngeal mask airway,
SD=Standard deviation, PLMA=Proseal LMA
Table 4: Insertion characteristics and time taken for placement of laryngeal mask airway’s (n=20)
Group P (PLMA) Group I (I‑gel) P
Number of insertion attempts, n (%)
1 17 (85) 16 (80) 0.799
2 3 (15) 4 (20)
Fail 0 0
Ease of insertion, n (%)
Easy 9 (45) 8 (40) 0.799
Moderate 10 (50) 11 (55)
Difcult 1 (5) 1 (5)
Impossible 0 0
Time for device placement (s), mean (SD) (range) 27.40 (11.51) (14-54) 25.45 (9.03) (12-44) 0.758
P<0.05 is statistically signicant. Time taken for placement of LMA is expressed as mean (SD) (range). LMA=Laryngeal mask airway, SD=Standard
deviation, PLMA=Proseal LMA
Table 5: Oropharyngeal leak pressures, gastric insufflation,
passage of ryle’s tube and fibreoptic view through drain
tube n (%) (n=20)
Group P
(PLMA)
Group I
(I‑gel)
P
Oropharyngeal leak pressures
(cm of H2O), mean (SD) (range)
30.55 (4.02)
(24-38)
27.05 (4.40)
(18-35)
0.012*
Gastric insufation, n (%) 2 (10) 0 0.147
Passage of ryle’s tube, n (%)
Easy 12 (60) 20 (100) 0.007*
Moderate 5 (25) 0
Impossible 3 (15) 0
*P<0.05 is statistically signicant. PLMA=Proseal laryngeal mask airway,
SD=Standard deviation
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Luthra, et al.: I‑gel versus ProSeal digital insertion in nonparalyzed anaesthetized patients
OLP of PLMA was 30.55 cm H2O and was 3.5 cm H2O higher
than that with I-gel. This small difference may be important in
obese patients, patients with poor lung compliance, or during
laparoscopy surgeries. Cook et al.[21] and Lu et al.[15] observed
mean OPL pressure of 29 cm of H2O for PLMA. Bosely
et al.[14] compared PLMA and I-gel in 100 European patients
using standard insertion techniques. Airway leak pressure was
higher in the PLMA group (LMA ProSeal® 28 cm. H2O, I-gel®
22 cm. H2O, difference 6.0 cm. H2O, 95% condence interval
3.0-9.0 cmH2O, P = 0.002). Curpod and Basavalingaiah[25] also
observed higher OPL with PLMA (29 ± 0.75) as compared to
I-gel airway (23.9 ± 0.7), ndings quite comparable to our study.
On the contrary, but similar to the ndings of Uppal et al.[26]
(mean seal pressure of 28 cm H2O for I-gel), we observed mean
OLP of 27.05 ± 4.4 s in patients with I-gel. Whether different
outcomes in OPL pressure with the use of I-gel in these studies
was due to digital insertion over guided-insertion or due to
difference in patient characteristics is uncertain. In either case,
the inatable cuff of PLMA with a ventral and dorsal cuff could
have resulted in better seal than I-gel with a noninatable cuff.
In the present study, all the patients in the two groups had
adequate ventilation without any sign of obstruction. However,
on beroptic examination of upper airway, only 45% patients
in the PLMA group had Grade I laryngeal view (full view of
vocal cords). Poor laryngeal visualization with PLMA was
also seen in previous investigations. Only 54% patients had
optimum positioning of PLMA in a study by Brain et al.[1]
One plausible reason for these observations was the broader
proximal cuff of PLMA catching the epiglottis during insertion,
resulting in greater epiglottic downfolding. It seems that down
folded epiglottis does not signicantly impede air ow with
PLMA, perhaps, because of accessory vent. Possibly that is
why, the respiratory variables of PLMA were similar to the
LMA even though the full view of the vocal cords was seen
only in 13% patients by Brimacombe et al.[20]
In contrast, we observed Grade I view (full view of vocal
cords) in 85% patients in I-gel group. Similarly, full view of
the vocal cords was seen in 91% of the patients with I-gel in a
study by Gatward et al.[17] and Janakiraman et al.[27] could see
vocal cords plus other parts of larynx in all 42 patients (100%)
with I-gel. The I-gel group provided a better fiberoptic
25.45 s ± 9.03 s (range 12–44 s). The difference was not
clinically signicant (P = 0.758). Insertion time reported in
the present study was higher than that reported in the previous
studies;[16,17,20,21] however, probably this absolute time difference
is of negligible clinical importance in day-to-day anesthetic
practice. Bosley et al.[14] reported lesser insertion time for both
PLMA and I-gel (mean time LMA ProSeal® 12 s, I-gel® 17 s).
However, similar to our study, the difference was not clinically
signicant (P = 0.06). On the contrary, according to Kini
et al.[22] and Hayashi et al.,[23] I-gel provides signicantly
faster insertion time. Kini et al. found that mean time required
for successful insertion of I-gel was 21.98 s and PLMA was
30.60 s (P = 0.001).[22] Hayashi et al. reported insertion time
for I-gel 4.4 s as compared to PLMA 16 s, P < 0.01.[23] Jadhav
et al.[18] observed even higher mean insertion times with
PLMA (41 ± 9.4 s) as compared to I-gel airway (29.5 ± 8 s).
However, Singh et al.[24] could achieve faster insertion with
both PLMA (23 ± 2.5 s) and I-gel airway (13.5 ± 4.4 s). The
denition of “insertion time” varies from studies to studies and
that may also explain difference in the result of these studies.
One of the statistically significant differences between
performances of the two devices was that the PLMA achieved a
signicantly higher airway leak pressure than the I-gel®. Mean
Table 6: Fibreoptic view through airway channel and
drain tube (n=20)
Group P
(PLMA),
n (%)
Group I
(I‑gel),
n (%)
P
Fiberoptic view (airway channel)
Full view of vocal cords 9 (45) 17 (85) 0.027*
Posterior cords and arytenoids 10 (50) 3 (15)
Only epiglottis seen 1 (5) 0
Fiberoptic view (drain tube)
Mucosa 0 0 NA
Closed upper esophagus 6 (30) 0
Open upper esophagus 13 (65) 0
Drain tube occluded 1 (5) 0
Fiberscope not passed 0 20 (100)
*P<0.05 is statistically signicant. NA=Not analyzed, PLMA=Proseal
laryngeal mask airway
Table 7: Postoperative complications (n=20)
Group P (PLMA) Group I (I‑gel) P
Sore throat at 0 h, n (%) 16 (80) 8 (40) 0.005*
Sore throat at 24 h, n (%) 8 (40) 1 (5) 0.004*
NRS at 0 h, mean (SD) (range) 24.75 (20.86) (0-60) 5.50 (8.256) (0-30) 0.002*
NRS at 24 h, mean (SD) (range) 8.00 (11.96) (0-40) 0.50 (2.236) (0-10) 0.007*
Dysphagia at 0 h, n (%) 0 0 NS
Dysphagia at 24 h, n (%) 0 0 NS
Hoarseness of voice at 0 h, n (%) 12 (60) 2 (10) 0.001*
Hoarseness of voice at 24 h, n (%) 4 (20) 0 0.035*
Ear/neck/jaw pain, n (%) 0 0 NS
*P<0.05 is statistically signicant. NRS is expressed as mean (SD) (range). NS=Not signicant, SD=Standard deviation, NRS=Numerical rating score,
PLMA=Proseal laryngeal mask airway
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Luthra, et al.: I‑gel versus ProSeal digital insertion in nonparalyzed anaesthetized patients
view of glottis than PLMA in another study by Curpod and
Basavalingaiah[25] similar to our study. They observed that
37 (92.5%) and 3 (7.5%) patients in I-gel group and 30 (75%)
and 10 (25%) patients in the ProSeal group had beroptic
score of 1 and 2 respectively (P = 0.034). These ndings were
consistent with our study.
Thus, in our study, I-gel was better positioned over laryngeal
framework. However, PLMA group had higher leak pressure
of 30.55 cm of H2O as compared to 27.05 cm of H2O for I-gel.
The data show that there is no relation between beroptic
view and the seal provided by supraglottic airway device.
Earlier studies also demonstrated lack of correlation between
beroptic views and clinical consequences.[28,29]
The drainage tube aligns the orogastric tube with the upper
esophageal sphincter and is designed to reduce gastric ination
and risk of regurgitation. This has been widely investigated in
PLMA; however, efcacy of drain tube in I-gel is still doubtful.
A recent study by Singh et al.[24] observed prolonged insertion
times for orogastric tube in the I-gel group (12.21 ± 3.82 s)
and attributed it to the smaller aperture of the gastric port in
the device which may increase the time to insert the leading
edge of the tube into the gastric port aperture. Interestingly,
in the present study, placement of 12 F orogastric tube was
successful and easy in all patients with I-gel, but only in 85%
in PLMA group (P = 0.007).
Incidence of postoperative sore throat and hoarseness of voice
was signicantly higher in PLMA group as compared to the
I-gel (P < 0.05). Our ndings were similar to those observed by
Jadhav et al.[18] They demonstrated 16.7% patients in the PLMA
group to have sore throat as compared to only 3.3% in the I-gel
airway group. Postoperative sore throat is probably caused by
a combination of trauma on insertion, intracuff pressure being
maintained at 60 cm H2O, and a large cuff of PLMA exerting
pressure against the pharyngeal mucosa. There was no evidence
of any aspiration or regurgitation in either of the groups.
There has been ample literature on supraglottic airway
devices and many of the studies have compared PLMA and
I-gel, in adult patients undergoing general anesthesia with
neuromuscular blocking drugs.[7,13,19,24,25,30-36] The parameters
like time to insertion, ease of insertion, overall success rate,
OLP and complications such as hoarseness and sore-throat
may be affected by the use of muscle relaxants.
Few studies have directly compared PLMA and I-gel in
nonparalyzed anaesthetized patients; two of these used
gum-elastic bougie-guided insertion technique. Gasteiger
et al. studied 151 patients in a combination of European and
Australian settings and compared insertion characteristics when
LMA ProSeal® and I-gel® were inserted using a laryngoscope
and gastric tube guided technique.[6] They reported very high
rst attempt insertion success rates (LMA ProSeal® 99%,
I-gel® 97%) and observed a mean OLP of 30 ± 7 s with
PLMA. However, the mean OLP with I-gel was 23 ± 7 s only.
Van Zundert et al., studied 150 patients in a European setting
(50 each LMA ProSeal®, I-gel® and Supreme LMA) using
the same insertion technique.[37] LMA ProSeal® and I-gel®
performance were entirely equivalent during insertion and
spontaneous breathing anaesthesia.
Few studies utilized manufacturer recommended standard
insertion techniques for PLMA and I-gel in nonparalyzed
anaesthetized patients.[14,18,22,23,25,38]
But, three of these RCTs did not specify whether the
index nger or the thumb-insertion technique was used for
PLMA.[14,22,23] Hence, the result of these studies could not be
compared to the present study where both the devices were
introduced by the nonguided digital techniques, specically
index nger technique for PLMA and rotational technique
for I-gel. Moreover, one of these studies was performed on
Japanese population and one on European population.
The studies that used the similar insertion technique in
nonparalyzed anaesthetized patients was by Liew et al.,[38] and
Jadhav et al.[18] Liew et al. studied 150 patients in an Asian
setting (50 each LMA ProSeal®, I-gel® and Supreme LMA).
In similarity to our ndings, the mean insertion time and rst
attempt success rate was not signicantly different between
PLMA and I-gel. However, contrary to our study, airway
leak pressure was found to be higher for the I-gel than the
PLMA (mean ± standard error of the mean: 27.31 ± 0.92 cm
H2O and 24.44 ± 0.70 cm H2O, respectively; P = 0.003).
According to the authors, one possible reason for the I-gel’s
higher leak pressure was the modification applied to its
weight-based size selection criteria to account for the 10-kg
overlap between sizes 3 and 4. Nevertheless, there was a
higher incidence of signicant air leakage in the I-gel group,
with three cases of the size 3 I-gel as opposed to none in the
other devices (0.047); two patients had tracheal intubations,
and another patient was changed to ProSeal.
The present study has few limitations. First, the investigators had
more experience with PLMA than I-gel LMA. However, there
is evidence showing similar success rates of the I-gel insertion
by novices and more experienced individuals.[16] Secondly,
our data only applied to use of the size 4 I-gel device as none
of the patient in the I-gel Group weighed <50 kg or more than
90 kg; hence, size 3 I-gel or size 5 I-gel was not used in any
patient, according to manufacturer’s recommendation. Thirdly,
the study was unblinded, which can be a possible source of
bias. The devices were used in nonobese patients with normal
airways and no underlying respiratory disorder; hence, the results
cannot be extrapolated to other groups of patients. Lastly, due to
nonavailability of the pediatric berscope, we could not grade
the drain tube beroptic view as the adult berscope could not be
negotiated through the narrow drain tube of the size 4 I-gel airway.
conclusIon
Both PLMA and I-gel can be inserted easily and rapidly using
nonguided digital technique: index nger method for PLMA
and rotational technique for I-gel. The time required for
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674
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Luthra, et al.: I‑gel versus ProSeal digital insertion in nonparalyzed anaesthetized patients
insertion is similar but the PLMA forms a better oropharyngeal
seal. However, I-gel is better positioned over the laryngeal
framework and the esophagus and it allows easier passage
of orogastric tube through its drain channel than the PLMA.
The incidence of intraoperative complications is similar,
however, incidence and severity of postoperative sore throat
and hoarseness of voice is higher with the PLMA.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conicts of interest.
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