Introduction
LMA is extremely useful in both elective and emergency situations. It can be used successfully difficult airway, The LMA-classic has been widely used in clinical practice. It provides a perilaryngeal seal with an inflatable cuff. Additional devices were added to the LMA family to satisfy specific needs, and a number of other devices were developed. Problems with use of Classic LMA(c-LMA) include: postoperative sorethroat (POST), aspiration risk, air leak due to inadequate seal, gastric distension and laryngospasm.
A relatively new supraglottic airway I-gel (lntersurgical Ltd., Wokingham, Berkshire, UK) has been introduced recently. Which has many additional features than the c- LMA. I-gel is made of thermoplastic elastomer. It has an anatomically designed mask that allows quick and easy insertion. It can be accurately positioned itself. It provides a reliable perilaryngeal seal without the need for an inflatable cuff. Its distinctive features like non-inflatable cuff, an integral bite block and buccal cavity stabilizer sets it apart from its other competitors. It also has a port for gastric tube placement.
In our study, objective is to compare the clinical performance of I-gel with classic LMA in relation to the ease of insertion, number of insertion attempts, time of insertion, airway leak pressure, hemodynamic changes, intra and Postoperative complications in anaesthetized, adult patients posted for elective surgeries under spontaneous ventilation.
Materials and Methods
This study was done as a observational study in a tertiary Hospital in south India. After getting the ethical committee approval 341/IEC/2012 and informed consent, 60 patients posted for elective surgery under GA with spontaneous ventilation, where assigned randomly into two groups. Patients inclusion in the study are American society of anaesthesiologists physical status I/II, aged18-60, weight between 60-90kgs Mallampati classification I and II and Elective procedures.
Obesity (bmi>35kg/m2), pregnancy, any full stomach patients, mouth opening <2.5cm, h/o GERD, asthma, pharyngeal or laryngel pathology, anticipated difficult intubation, emergencies, allergy to any of the study medications where excluded.
60 Patients were randomly allocated into two groups group 1 and group II.
All patients were kept nil orally for a minimum of 8 hours preceding the surgery. They received intravenous injection midazolam 1 mg, glycopyrrolate 0.2 mg and inj ondansetron 4 mg half an hour before surgery in the pre-anaesthetic room. On arrival in the operating room, after the placement of standard minimum monitoring devices, patients were preoxygenated for three minutes with I00% oxygen. All patients were induced with inj Propofol 2.5 mg/kg i/v and fentanyl 2μ/kg i/v.
LMA or I-gel was inserted according to the study group allotted by randomization. Depth of Anaesthesia was considered adequate for device insertion when the patient has lost eyelash reflex. The airway device size 3 or 4 according to the weight of patient was lubricated with 2% lignocaine gel, the device was inserted, bilateral air entry checked and device secured with tape. Anaesthesia was maintained with nitrous oxide and oxygen in a ratio 2: I along with sevoflurane to attain a MAC of 0.8 to 1.0.
Insertion time
Insertion time is calculated from the time in minutes taken from picking the airway in hand to the successful placement of airway as confirmed by auscultation and capnography.
If correct placement could not be achieved, the device will be removed and 2 more attempts will be permitted before failure of insertion were recorded. After 3 unsuccessful attempts, the trachea was intubated. Along with insertion time the number of insertion attempts was also recorded.
Ease of insertion
Ease of insertion was defined in terms of the need of airway manoeuvres as shown in Table 1.
Table 1
Showing easiness of insertion
|
Easy |
No airway manipulation required |
|
Satisfactory |
Required less than 2 manoeuvres |
|
Difficult |
Required more than 2 manoeuvres |
Maneuvers will be neck extension or flexion, chin lift, jaw thrust or gentle pushing or pulling of the device(1).
Airway leak pressure
Airway sealing pressure was determined by closing the expiratory valve of the circle system at a fixed fresh gas flow of 3L/min and recording the oropharyngeal leak pressure by detection of an audible noise using a stethoscope placed just lateral to the thyroid cartilage.
At the end of the surgical procedure, anaesthesia was discontinued and the device was removed while the patient was in a deeper plane of anaesthesia.
Hemodynamic parameters
The following parameters were monitored prior to insertion and at 0, 1,3,5,10,15 min after securing the airway.
Results
The prospective, randomized, comparative study compared the clinical performance between-gel and classical laryngel mask airway in anaesthetized spontaneously breathing patients in 60 adult patients. All date were collected, tabulated and expressed as Mean ± Standard deviation. Appropriate statistical analysis was consider using SSPC 21 version. To find association between two variable at 95% open epi software 2.2 version was used. All quantitative date were compared using unpaired student’s test. All qualitative date were compared using Chi square test P values were calculated for all testes. A p value < 0.05 was considered significant.
The summated result are presented below:
In group l (l-gel) out of 30 patient 21 patients were under ASA I & 9 by ASA II. In Group II (classic LMA) 18 were ASA I assessed under ASA I & 12 by ASAII.
Table 3
Showing age, gender, weight
The minimum and maximum age in c LMA were 19 years and 58 years respectively and that of I-gel group was 22 years and 57 years respectively. The mean age in group I and II were 38.4 and 36.63 years respectively. There was no significant difference in the age of the patients between Group I and Group II. X2 yates=6.033. df=4, P=0. 1967. Both the group are statistically comparable with respect to demographic variables likes age, sex and weight
The insertion of I-gel in group I patients was easy in 25(83%) patient satisfactory in 5(16.7%) patients. The insertion of c-LMA was easy in 15 (50%) patients. Satisfactory in 13 (43%) patients and difficult in 2(7%) patients.
Alph2 yates =8.056, df=. P=0.01781 *(significant)
I-gel insertion was successful in all cases (100%) in first attempt, classic LMA insertion was successful in 28/30(93.3%) in first attempt and 2/30 (7%) patients required additional second attempt. x2 yates =2.069, df =l, P=0.1504 (NS). The difference in successful placement in two groups, though appearing clinically relevant, on statistical analysis did not reveal any difference.
The mean duration of insertion of I-gel is 20.17 ±3.91 seconds and that of c-Lma is 26.80±7.24 seconds respectively the difference in duration is statistically significant P.000***(highly significant) t=4.42.
The mean airway leak pressure with I-gel is 20.40±5.68 (cmH20) and with c-LMA is 18.73±5.06(cmH20). The difference in the airway leak pressure not statistically significant. (P value equals 0.2349).
Table 4
Heart rate, systolic blood pressure, diastolic blood pressure
Heart rate systolic blood pressure, diastolic blood pressure were measured before insertion, then 1 min 3 min, 5 min 10 min 15 min after insertion the actual values are documented in the tabular column above statistical analysis by students t test reveals p value which is not significant hence there is no significant hemodynamic responses to insertion in both groups.
Intraoperative complications
Laryngospasm occurred in one patient in both groups. Both these patients were managed by deepening the plane of anesthesia. However results from both these patients are excluded from the study. Their postoperative period were uneventful.
Two cases in the classic-LMA group had blood stain on the device on removal while there was no blood staining in any case of I-gel group.
Only 1(3%) patient in group 1(I-gel) had developed sore throat post operatively compared to 4 (13.3%) patients in group 2 (c- LMA). They sore throat in all the 5 cases were mild requiring no treatment.
Dysphagia was observed in one patient of c-LMA while none had in I-gel group.
Cough was observed in 4(13.3%) patients in c- LMA while none of the patients experienced in I-gel group. Which was statically significant (p=0.04).
1(3%) patient experienced dysphonia in I-gel group while none of the patients had in Group 2.
Discussion
The laryngeal mask airway has been well-established for more than three decades and is often used when endotracheal intubation is not necessary.1, 2 Nevertheless, utility of the LMA is limited by the potential risk of aspiration.1, 3, 4
The I-gel supraglottic airway is a 2nd generation supraglottic airway device with a soft anatomically preformed non-inflatable stuff made of a gel like thermoplastic elastomer, containing a gastric port. The tensile properties of the I-gel bowl, along with its shape and the ridge at its proximal end, contribute to the stability of the device upon insertion. The main aim of this study was to compare the clinical performance of I-gel with the c -LMA in terms of the ease of insertion of the device, duration for insertion, leak pressure, and postoperative device related complications.
Demographic criteria
Both the groups were comparable and there was no statistically significant difference with regards to mean age, weight, sex.
Ease of insertion
In our study, insertion of I-gel was graded as easy in 25 (83.3%) patients and satisfactory in 5 (16.7%) patients and none of them were difficult insertion of c- LMA was easy in 15(50%) patients, satisfactory in 13 (43.3%) patients and were difficult in 2(7%) patients (X2 Yates=8.056, df=2) P=0.01781 *(significant).
Jee-Eun Chang, Hyerim Kim et al. in (2019),1 Smita R. Engineer, Digant B. Jansari, Saumya Saxena et al (2016).2 Vinuth Krishna Murthy, Krishna Prasad Patla et al. (2020)5 concluded that I-gel is effective airway which is easier to insert and provides a better airway maintenance even in the scene of a difficult airway. In many studies ease of insertion becomes an important factor when these devices are used by relatively untrained personnel.6 The firmness of the tubesection, having a non inflatable cuff and oropharyngel curvature allows easy insertion of I-gel.
Time need for insertion
I-gel requires less time for insertion with a preformed mask forming a good around the laryngeal inlet. We found that not only was the I-gel quicker to insert but it required fewer manipulations to facilitate insertion than the c-lma these findings widen the scope of I-gel as an emergency rescue airway devices especially in “cannot ventilate cannot intubate situations.7, 8, 9
Pratibha SD et al (2017),10 Balasaheb Tukaram Govadane et al (2018)2 also found that I-gel is an effective airway which is quicker to insert when compared to C-LMA
Number of attempts for successful placement
There is a100% success rate for I-gel when compared to c-LMA(93%) but it was not statically significant. In Janakiram et al11 study, the first attempt success rate with I-gel insertion was only 54% and with c-LMA it was 86%. Which was highly significant this was because during the use of I-gel in 14 patients a larger size had to be used due to the presence of an audible leak and hence required a second attempt. However, in our study we didn’t have such problem.
Successful airway management12 is the first priority in a variety of emergency care and pre hospital scenarios. Supraglotic airway s have provided to be relatively safe and easy to be used by operators with limited airway management experiences. The European Guidelines for resuscitation13, 14 reduced emphasis on early tracheal intubation in favour of supraglotic airway. Even though it is not statically significant, our study has proven a 100%success rate in first attempt for I-gel.
Oropharyngel leak pressure
In our study, the mean OPL is higher in I-gel (20.4mmHg) when compared to classic LMA (18.73) similar to the study conducted by Jeevan Sing, et al in 2012.15 Though our Leak pressure is not statistically significant, the airway sealing pressure of I-gel Group was very well within the normal limit to prevent aspiration. Thus proving the adequacy of ventilation Srinivas Rao et al in 2016,16 Gupta P, Kumar A 201517 had similar results.
Hemodynamic
There was no statistically significant difference in hemodynamic response in both groups, similar to studies done by Jee-Eun Chang, Hyerim Kim et al in (2019), 1 Gunaseelan Sivasamy et al. in (2018).18
Injuries observed
In our study, patients were inspected for any injury of the lips, teeth or tongue and the device for blood stain after its removal at the end of the surgery. None of the patients had blood stain in I-gel group and 2(7%) patients in classic LMA had blood on the device. No injuries to lip, teeth or tongue was noted in our study.
Vinuth Krishna Murthy et al. 20205 Syed Amir Raza et al., in 201219 in their study observed no blood stain on the device on removal of I-GEL.
Siddiqui AS et al. (2010)20 observed blood on device in18% patients in c-LMA group and none in the I-gel group.
Post operative complications
Because of the absence of an inflatable cuff, the authors hypothesized that use of the I-gel produced fewer postoperative throat and neck complaints compared with a c- LMA. In my study only I (3%) patient in I-gel group had developed sore throat post operatively compared to 4 (l 3.3%) patients in (c- LMA). The sore throat in all the 5 cases were mild requiring no treatment dysphagia was observed in one patient of c-LMA while none in I-gel group.
Cough was observed in 4(13,3%) patients in c-LMA while none of the patients experienced in I-gel group, which was statically significant (p=0.04).
1 (3%) patient experienced dysphonia in I-gel group while none of the patients had in c-LMA.
18-24 hours after surgery, patients were assessed for any postoperative complications like sore throat, dysphagia and hoarseness. Postoperative sore throat graded as nil, mild, moderate and severe.6, 21
Raajaram Mu, et al. 201622 in their study they observed no sore throat, Keijzer C et al. in 200923 in their study compared the post-operative throat and neck complications between c-LMA and I-gel. There was a higher incidence of sore throat and dysphagia at 1, 24, and 48 h in the LMA group compared with the I-gel group. Neck pain was also more common at 24 and 48 h in the c-LMA group.
Conclusion
Hence we conclude that I-gel is a better airway when compared to classic LMA with respect to ease of insertion with shorter duration for insertion. Adequate oropharyngeal seal with lesser pharyngolaryngeal morbidity and less incidence of airway trauma and no significant difference in number of attempts and oropharyngcal leak pressure.