|Year : 2013 | Volume
| Issue : 1 | Page : 94-99
To assess the efficacy of i-gel for ventilation, blind tracheal intubation and nasogastric tube insertion
Geeta Bhandari1, KS Shahi2, Mohd Asad1, Nitish Kumar Parmar1, Rajni Bhakuni1
1 Department of Anesthesiology, Govt. Medical College, Haldwani (Nainital), Uttarakhand, India
2 Department of Surgery, Govt. Medical College, Haldwani (Nainital), Uttarakhand, India
|Date of Web Publication||26-Jun-2013|
Associate Prof., Department of Anesthesiology, Govt Medical College, Haldwani (Nainital), Uttarakhand - 263 139
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: The i-gel is a novel supraglottic airway device with a soft and non-inflatable cuff. In our study we attempted to evaluate the performance of i-gel as a ventilatory device, as a conduit to blind tracheal intubation using conventional polyvinyl chloride tracheal tube and gastric tube insertion through it.
Materials and Methods: A total of 180 patients of American Society of Anesthesiologist (ASA) physical status I/II undergoing elective surgery under general anesthesia were included in this study. After induction of anesthesia, i-gel was inserted and the following parameters were recorded: Time taken for successful i-gel insertion, airway leak pressures, ease of gastric tube insertion and laryngeal view using fiberscope. Following this blind tracheal intubation was attempted. First attempt and overall success rate in blind tracheal intubation and gastric tube insertion were evaluated and tracheal intubation time was measured. Also presence of any side effects or complication following removal was recorded.
Results: We achieved a 100% success rate in insertion of i-gel and in 171 out of 180 patients; i-gel was inserted in the 1 st attempt itself. We also were able to achieve an overall success rate for blind endotracheal intubation via i-gel in 78.33% cases, and successful gastric tube placement was possible in 92.22%. In our study we also achieved a leak pressure of 25.52 (±2.33) cm of H 2 O.
Conclusion : I-gel may be effectively used for ventilation, nasogastric tube insertion and as a conduit to blind endotracheal intubation with minimal complication and acceptable airway sealing pressures.
Keywords: I-gel, nasogastric tube, seal pressure, tracheal intubation
|How to cite this article:|
Bhandari G, Shahi K S, Asad M, Parmar NK, Bhakuni R. To assess the efficacy of i-gel for ventilation, blind tracheal intubation and nasogastric tube insertion. Anesth Essays Res 2013;7:94-9
|How to cite this URL:|
Bhandari G, Shahi K S, Asad M, Parmar NK, Bhakuni R. To assess the efficacy of i-gel for ventilation, blind tracheal intubation and nasogastric tube insertion. Anesth Essays Res [serial online] 2013 [cited 2020 Nov 25];7:94-9. Available from: https://www.aeronline.org/text.asp?2013/7/1/94/114012
| Introduction|| |
Tracheal intubation with Macintosh laryngoscope is considered the "gold standard" in airway management, providing effective protection against aspiration.  However, laryngoscopy evokes a profound pressor response and also needs neuromuscular paralysis.  In the last couple of decades a plethora of supraglottic airway devices (SAD) have come into the anesthetic practice and these devices circumvent many of the problems associated with laryngoscopy and intubation. SADs can be easily inserted and with minimal hemodynamic perturbations, SADs can also be inserted without any neuromuscular paralysis and are well tolerated even under light plain of anesthesia.  The incidence to post-operative sore throat and hoarseness is also lower with supraglottic devices. , The search is on for supraglottic airway device which combines the advantages of supraglottic airway devices and also provide effective protection against aspiration. The i-gel (Intersurgical Ltd, Wokingham, UK) is a novel supraglottic airway device (SAD). It is a single use, latex free supraglottic device without any inflatable cuff and many other design innovations, which offer potential advantages over both classic (cLMA) and proseal LMA (PLMA).  Cadaver studies have shown that i-gel effectively conforms to the perilaryngeal anatomy and consistently achieves proper positioning for supraglottic ventilation. Studies performed on manikins and patients have shown that the insertion of the i-gel was significantly easier when compared with insertion of other SADs. Furthermore, there is evidence to suggest that it is easier to train non-anesthetists to correctly insert i-gel, compared with the conventional SADs, thus making it a potentially useful device for situations such as resuscitation. , SADs are helpful in difficult airways and in emergency life threatening scenarios. Some SADs like i-gel® allow for subsequent tracheal intubation using blind or a fibreoptic technique following establishment of airway. Several cases have been published reporting successful fibreoptic guided intubation through i-gel. ,, However, usage of fibreoptic endoscope for intubation is not always possible due to unavailability, especially in developing nations hence, we designed this study to evaluate the success rate i-gel in blind tracheal intubation.
| Materials and Methods|| |
This study was conducted on 180 patients undergoing elective surgery under general anesthesia after approval of Institutional ethics committee. Written informed consent was obtained from all the patients. Inclusion criteria were patients aged between 16-65 of either sex with ASA physical status I and II. Patients with head injury, psychiatric disorder, respiratory tract (oropharynx, larynx) pathology, endocrine disorder, predicted difficult airway (such as mouth opening <2 cm, modified Mallampati class 3 and 4, BMI > 35 kg/m2), gastroesophageal reflux disease, hiatus hernia, esophageal varices and pregnancy were excluded.
In the operation theatre after establishing an intravenous access, ringer lactate solution was started. All the patients received intravenous glycopyrrolate 0.2 mg, metoclopramide 10 mg, tramadol 2 mg/kg and midazolam 0.03 mg/kg 20 min prior to the induction of anesthesia. Standard monitors were attached. All the patients were preoxygenated with 100% oxygen for 3 min. Induction was done with propofol 2-2.5 mg/kg, and muscle relaxation was facilitated with succinylcholine 1.5 mg/kg and mask ventilation was continued for 1 min with mixture of oxygen, nitrous oxide and halothane. Then depending on body weight the following sizes of the i-gel and endotracheal tube (ETT) were chosen with little change in manufacturer's recommendations:
Size of SAD patients body weight (kg) ETT size (Internal diameter in mm)
Size 3 30-50 7.0
Size 4 50-90 7.5
Conventional PVC (Polyvinylchloride) Endotracheal tube (Portex® ) was used for blind tracheal intubation. Both i-gel and ETT were lubricated with 2% lignocaine jelly (LOX 2% Neon) prior to use. Size 7.0 mm ETT was chosen for patients weighing < 50 kg and 7.5 mm for patients weighing > 50 kg. The i-gel was inserted in extended neck position. Duration of successful insertion was defined as the time elapsed from insertion of i-gel between the dental arches until the confirmation of successful ventilation determined by, capnography, chest wall movement, auscultation of breath sounds, and absence of oropharyngeal leak with peak airway pressure ≥ 20 cm of H 2 O. The time was measured with the help of a stop watch. If successful ventilation was not established, accepted maneuvers were used as recommended by manufacturer. The number of attempts required for successful i-gel insertion was recorded. A failed attempt was defined as removal of the device from the mouth before reinsertion. If the device was not successfully inserted in second attempt this was recorded as failure of i-gel. After achieving successful ventilation with i-gel, leak pressure was measured in closed circle system by closing APL valve and continuing fixed flow rate at 6 l/min and allowing airway pressure to rise (maximum allowed 40 cm H 2 O). The pressure at which gas leak started was noted and was termed as leak pressure. Gas leak was checked at (1) Mouth, (audible) (2) Stomach, (epigastric auscultation) and (3) Proximal end of gastric channel, (bubbling of lubricant placed on proximal end).
Then a lubricated nasogastric tube was inserted and its position confirmed by aspiration of gastric content or by a stethoscope placed over epigastrium. A maximum of two attempts at nasogastric tube insertion was allowed. Following the insertion the positioning of the device in relation to the larynx was visualized using a fiberscope and graded as:
Following the laryngeal grading the fiberscope was withdrawn and patient was again ventilated for one minute. After ventilation blind tracheal intubation was attempted through i-gel. If resistance was felt during insertion, following maneuvers were tried: (1) twisting of the tracheal tube to align the bevel, and up and down movement of the tracheal tube gently within the i-gel, (2) Cricoid pressure was applied. Following intubation through the i-gel, correct placement of the endotracheal tube was confirmed via capnography and chest wall auscultation for breath sounds. Duration of successful blind tracheal intubation through i-gel was defined as the time elapsed from passing the ETT through i-gel untill the confirmation of successful ventilation which was determined by chest rise, auscultation of breath sounds and capnography. Then i-gel was removed using one size smaller tracheal tube. If tracheal intubation through the device was unsuccessful it was performed by direct laryngoscopy. Anesthesia was maintained with oxygen, nitrous and halothane and vecuronium and for analgesia paracetamol infusion (15 mg/kg) was given over 15 min and injection diclofenac sodium aqueous was given intravenously at a dose of 1 mg/kg body weight. At the end of surgery neuromuscular blockade was reversed using neostigmine and glycopyrrolate and patient's trachea extubated once patient had adequate neuromuscular recovery and was able to follow simple verbal commands.
- 1- Vocal cords entirely visible.
- 2- Vocal cords or arytenoid cartilage partially visible.
- 3- Epiglottis only visible.
- 4- No laryngeal structures visible.
After i-gel and ETT removal we observed for any lip trauma and dental injury and for blood mixed secretions. In post-operative period an investigator who was blinded to the study, asked to the patients about the signs of sore throat (throat pain, dysphonia) and for any change in voice (hoarseness) or dysphagia at 2 h, 8 h and after 24 h.
Throat pain at rest was assessed on a score of 0 to 3:
Dysphonia was assessed on a score of 0 to 1:
0. Dysphonia absent
1. Dysphonia present
Dysphagia was assessed on a score of 0 to 3:
0. Dysphagia absent
1. Mild dysphagia
2. Moderate dysphagia
3. Severe dysphagia
Hoarseness was assessed on a score of 0 to 1:
0. Hoarseness absent
1. Hoarseness present
Ease of i-gel insertion was assessed on a score of 1 to 3:
Ease of tracheal intubation score was assessed on a score of 1 to 3:
1. Easy-successful tracheal intubation without maneuvers.
2. Satisfactory -tracheal intubation with maneuvers.
3. Difficult -tracheal intubation not successful even with maneuvers.
Ease of removal of i-gel after successful tracheal intubation was assessed on score of 1to 3:
Bite block insertion depth score was assessed on a score of 0 to 4:
0. Bite block remained entirely outside the mouth
1. Bite block in lower third
2. Bite block in middle third
3. Bite block in upper third
4. Entire bite block inside mouth
Statistical analysis: All data were analyzed using IBM SPSS Statistics 20.0 software. The qualitative data was compared using Chi-square and for comparison of the continuous variable descriptive statistics was used.
| Results|| |
All the 180 patients enrolled in the study were used for the statistical analysis. There was no significant finding in the demographic data of the patients except for the fact that 71.66% (129 out of 180) of the patients enrolled in the study were females [Table 1]. The study population was evenly distributed in ASA physical status I and II [Table 1]. Hundred percent success rate was achieved in the i-gel insertion and in 95% (171 out of 180) patients i-gel was inserted in the first attempt itself [Table 2]. We achieved a success rate of 92.22% in the successful placement of nasogastric tube [Table 2]. The mean i-gel insertion time was 20.91 (±2.23) seconds and the mean ease of insertion score was 1.044 (±0.206) [Table 2]. Overall 78.33% (141 out of 180) patients could be successfully intubated through the i-gel with a first attempt success rate of 65.55% (118 out of 180) [Table 2]. It took a mean time of 21.20 (±4.39) seconds to successfully intubate a patients trachea via i-gel [Table 2]. The mean airway seal pressure was 25.52 (±2.33). There was no incidence of dysphonia, voice change, lip or dental trauma or presence of blood tinged secretions [Table 3].
| Discussion|| |
I-gel is a novel, single use latex free supraglottic airway device with various design innovations. It is made up of medical grade thermoplastic elastomer which is soft, gel like and designed to anatomically fit the perilaryngeal structures without an inflatable cuff.  Further design innovations include a rigid and a flattened stem to aid insertion and improve stabilization. It also includes a gastric channel which allows placement of a nasogastric tube, thus potentially reducing the incidence of aspiration. It is a highly versatile device and has been used as a primary ventilation device, as a rescue device for ventilation and also as a conduit for endotracheal intubation. ,,,
In a study conducted by Gatward et al., on 100 non-paralyzed patients, they reported insertion of i-gel as easy in the vast majority of the cases with a first time success rate of 86%.  In our study we achieved a first time success rate of 95% and a 100% overall success rate in i-gel placement. In the study conducted by Halwagi et al., the first attempt i-gel insertion success rate was 84% cases and overall successful rate was 96%.  In the study of M. Kleine Brueggeney et al., first attempt i-gel insertion success rate was in 93.7% and overall success rate was in 98.7%.  Successful i-gel insertion time from insertion till confirmation of successful ventilation was also very short, similar to the results of the studies conducted by Halwagi et al.  Halwagi et al., demonstrated first attempt successful i-gel insertion time at 19 (±8) seconds and overall successful i-gel insertion time was 26 (±24) seconds. M. Kleine Bruggeney et al., demonstrated that successful i-gel insertion time was 23 (±15) seconds. In our study, time for successful i-gel insertion in first attempt was 20.52 (±1.44) seconds and overall successful i-gel insertion time was 20.91 (±2.23) seconds. In the study conducted by Keijzer et al., i-gel insertion time was as short as 8.5 (±6.3) seconds.  These studies confirm the premise that i-gel is easy to insert and compares favorably to its competitors the cLMA and the PLMA. , In fact the first attempt success rate is superior to PLMA. Also in a study conducted by Wharton et al., on manikins and patients they reported that i-gel can be easily and correctly placed by novices with limited or no prior anesthetic experience.  The ease of insertion may be due to its flexible, soft non-metallic and more anatomical curvature.
In our study, we achieved a mean airway seal pressure of 25.52 (±2.33) cm of H 2 O, this is similar to study conducted by Keijzer et al., who reported leak pressure of 26.8 (±9.5) cm of H 2 O in i-gel group.  In a study conducted by Uppal et al., they obtained a median airway seal pressure of 28 cm of H 2 O.  These studies reflect that the airway seal achieved by the i-gel LMA is superior to that of cLMA (16-20 cm of H 2 O), however it falls marginally short of that achieved by PLMA (30 cm of H 2 O).  These studies also reflect the fact that though i-gel has a lower airway seal pressure, it provides adequate sealing pressures in most clinically relevant scenarios.
As a further protection against aspiration the i-gel contains an inbuilt channel for gastric drainage through which a nasogastric tube may be inserted. In our study nasogastric tube could be successfully inserted in 92.66% of the patients which is comparable to the other SADs which allow insertion of gastric tube; however the size of gastric tube which can be inserted through the i-gel is smaller than the PLMA.
Anatomic positioning following insertion of i-gel compares favorably with other supraglottic devices. On assessment of the laryngeal grading by fiberscope we observed that the laryngeal view was grade 1 in 78.33% of cases (141 patients) and grade 2 in 21.66% of cases (39 patients), similar to the study of Michalek P et al., who reported laryngeal view grade I (percentage of glottic opening 75-100%) in 70.22% cases.  Sastre et al., reported that laryngeal view (Brimacombe scale) was better in i-gel group as compared to intubating laryngeal mask airway, it was grade 1 in 77.78% cases.  M. Kleine Brueggeney et al., demonstrated that glottic view was grade 1 in 68.35% cases.  The i-gel has its epiglottis blocker on the outer surface of the bowl, and the fibreoptic view of larynx is usually straight and unobstructed. Also it does not have epiglottic aperture bar which further reduces the hindrance to the glottic view.
The intubating laryngeal mask airway (ILMA) over the years has become the standard among the supraglottic airway devices as a conduit for endotracheal intubation. Some studies have concluded high success rate for both fiber optic guided and blind intubation. [24-26] In a study conducted by Michalek et al., they found both i-gel and ILMA as highly effective modes for endotracheal intubation.  However, similar success could not be replicated by blind intubation through i-gel. The authors could attain a success rate of 51% using i-gel as compared to 88% with ILMA. In the study of Halwagi et al., first attempt successful tracheal intubation was 69% and overall successful tracheal intubation was 73%.  In Bruggeney et al., study fibreoptic guided first attempt successful tracheal intubation was 96%.  Sastre et al., demonstrated overall successful blind tracheal intubation in 40% cases.  We achieved similar results with our study with a first attempt success rate of 58.33% (106 patients) and an overall success rate of 78.33%. Though results in the previous studies do not support the superiority of i-gel over ILMA as a conduit for endotracheal intubation, however both our study and earlier studies do claim that it is effectively possible to intubate a large subset of population using i-gel particularly if fibre optic guidance is used.
Time required for tracheal intubation was 19.70 (±3.44) seconds in first attempt and 21.20 (±4.39) seconds in overall success rate. Similar results have been seen in some other studies.  The incidence of post-operative complications was low and mostly restricted to sore throat and dysphagia. These complications were self limiting and mild. The incidence of sore throat was similar to the cLMA, which has been reported between 12-28%. , The incidence of sore throat was lower in i-gel, similar to the results of the study conducted by Keijzer et al.  No Dysphonia and no change of voice was noticed in any patient. There was no incidence of lip trauma, dental trauma or blood tinged secretions over the i-gel or endotracheal tube in any case. There are many factors imposing limits on our study. First of all, the patients in our study are low risk patients with normal airway and without risk for regurgitation and aspiration. The patients with difficult airway were excluded from our study. Secondly i-gel was studied in isolation and no comparison was made with its most likely competitors, ILMA and PLMA. Also the lack of blinding may have induced some bias in our study. The anesthesiologist using i-gel in our setup has significant experience with the device and the results cannot be extrapolated to the entire anesthesiologist population.
Based on our study we conclude that i-gel may be effectively used for ventilation, nasogastric tube insertion and as a conduit to blind endotracheal intubation with minimal complication and acceptable airway sealing pressures.
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[Table 1], [Table 2], [Table 3]