European Journal of Cardiovascular Medicine

Laparoscopic cholecystectomy is the gold standard for the surgery of gall stone disease. General anaesthesia with intubation is routinely done for securing airway in these surgeries with pneumoperitoneum, but it causes increased catecholamine release, hypertension, tachycardia, myocardial ischaemia, depressed myocardial contractility, ventricular arrhythmias and intracranial hypertension.¹

Use of LMA obviates these haemodynamic changes and advantages of using LMAs over Endotracheal Tube (ETT) include ease of insertion, avoidance of neuromuscular blocking agents, hence facilitating spontaneous breathing and avoiding translaryngeal placement with its attendant cardiovascular impact andintimate vocal cord contact.² The most common SADs used in laparoscopic cholecystectomies are second generation LMAs. The advantages of these second generation LMAs are that they could accommodate suction or nasogastric tubes for the aspiration of gastric contents, have inbuilt bite blocks and maintain a seal pressure of 25-28 cm H₂O.

Since the advent of the first such  second generationSAD, the proseal LMA, many second generation SAD’s have been manufactured to improvise the functions with a good seal and a wide nasogastric tube for aspiration of gastric contents. Baska mask, LMA supreme, Igel, Ambu Aura gain are few such second generation devices, each with its unique features and advantages. 

Though, there were many studies that compared the clinical performance of LMA Proseal with these 3 supraglottic devices separately, there are not many studies in the literature which compare the clinical performance of Baska mask, Ambu AuraGain and LMA Supreme. Because of the very similar design of Ambu AuraGain and LMA Supreme and self-sealing, membranous, non-inflatable cuff of the Baska mask, we hypothesised that Baska mask would have higher sealing pressures (oropharyngeal leak pressures) than LMA Supreme and Ambu AuraGain. Hence, we planned a study to compare these three supraglottic devices in patients undergoing Laparoscopic Cholecystectomy.

Aims and objectives

We planned a study to compare the efficacy and safety of Baska mask, Ambu AuraGain and LMA Supreme in the airway management of the laparoscopic cholecystectomy patients in terms of the oropharyngeal leak pressure, ease and accuracy of insertion and difference in time taken for the insertion.Ease and size of gastric tube insertion, difference in the incidence of postoperative complications and Laryngopharyngeal morbidities associated with these three supraglottic devices was also noted.

A randomized controlled, open label study was done in patients undergoing elective laparoscopic cholecystectomy under general anaesthesia in Department of Anaesthesia at a tertiary care centre for a period of one year w e.f . october 2020 to september 2021.

One hundred and fifty patients of either sex undergoing laparoscopic cholecystectomy were enrolled after the approval of the Institutional Ethical committee and the study was registered with Clinical Trial Registry of India with CTRI/2021/07/034811. Patients were randomly allocated to one of the following three groups, i.e. Group I(Baska mask), Group II( Ambu Aura Gain) and Group III(LMA Supreme) consisting of 50 patients each. Informed written consent was taken from all the patients. All the cases were performed by the same team of Anaesthesiologists who were experienced in the use of all the three types of SADs.

The sample size of our study was taken as 150 with the significance level of 5%. The confidence level was taken as 95% and the sample size was calculated with the help of G-power software.

Patients of either sex in the age group of 20 t0 70 years who belonged to ASA physical status I and II and were to undergo elective laparoscopic cholecystectomy were included in the study. Patients with difficult airway, Mouth opening <2.5 cms, any pathology of neck or upper respiratory tract and obese patients(BMI > 30 kg/m² were excluded. Patients with increased risk of aspiration, for example, pregnancy, trauma, full stomach patients (<8 hours fasting), or any intra-abdominal pathology like intestinal obstruction, peritonitis, gastric paresiswere also excluded. Surgery of more than 2 hours duration was excluded

The patients were randomly allocated to one of the three groups comprising of 50 patients using a computer generated permuted block table.

The pre anaesthetic visit of the patient was done by an anaesthetist who was not participating in the study and patient was evaluated one day before the surgery.

All patients were premedicated with tablet alprazolam 0.5 mg and tablet ranitidine 150 mg at bed time before the day of the surgery and also at 6 a.m. in the morning prior to surgery. Patient was kept fasting overnight.

On the day of the surgery, patient was shifted to the operation theatre and an intravenous line was secured with 18 Gauge cannula in the left hand. All the patients were monitored using routine parameters like EtCO2, SPO2, ECG, NIBP, HR. Preoxygenation with 100% oxygen for 3 minutes was done. The patients were then induced with intravenous injection of fentanyl 2 μg/kg and propofol 1.5-2 mg/kg and atracurium 0.5 mg/kg. The end point was considered when the patient did not respond to verbal commands and there was no response of the patient to the jaw thrust, the anaesthesia was considered acceptable for device insertion. The device was selected according to the random table no. just before the start of the case.

The Baska mask, Ambu AuraGain and LMA Supreme were thoroughly checked for their function and integrity. These three supraglottic devices were inserted by a senior anaesthesiologist in 25 pilot cases before this study. The size of the mask was selected according to the body weight as recommended by the manufacturer.

Size 3, 4 and size 5 was used for the patients with weight between 30-50 kg, 50-70 kg and 70-100 kg respectively for all the three devices.

Group I (Baska mask)

The patient was placed in sniffing position to secure the airway. The Baska mask was lubricated and then introduced in the mouth towards the hard palate and advanced downwards till resistance was felt. Whenever necessary, the “tab” was manipulated to negotiate the palatopharyngeal curve. Then the mask was attached to the anaesthetic circuit and ventilation was checked.

Group II (Ambu AuraGain)-

The cuff of Ambu aura gain was deflated properly and the posterior surface was lubricated with a water based jelly. Head was placed in sniffing position. By using pencil insertion technique, the mask was inserted and the deflated cuff was pressed against the patient’s posterior pharyngeal wall and the mask was advanced further into the mouth.When the mask was in place, a resistance was felt. Then the cuff was inflated with the volume of air in millilitres according to the size of Ambu AuraGain. The mask was connected to the anaesthetic circuit and checked for the ventilation.

Group III (LMA Supreme)

LMA Supreme of appropriate size was selected and the cuff was deflated thoroughly and a water soluble jelly was applied to its posterior surface before its insertion. Then head was placed in sniffing position and the mask was inserted, pressing the tip of the mask against the hard palate. Then the hand was rotated inwards in the circular motion so that the device followed the curvature behind the tongue. Then the cuff was inflated with the volume of air in millilitres according to the size of LMA Supreme. Then the mask was attached to the anaesthetic circuit and we checked the ventilation.

Figure 1- Flow Chart of patients recruited and analyzed in three groups-

During the insertion of device, manipulations like adjusting insertion depth, jaw thrust, head flexion or extension beyond sniffing position was done. Three attempts were allowed and each attempt was proceeded for 60 seconds. When the insertion failed even after three attempts, then tracheal intubation was performed using a direct laryngoscope and it was recorded as failure.

The correct insertion of the device was assessed by adequate bilateral chest rise and B/L equal air entry. A lubricated gastric tube of appropriate size was inserted through gastric channel. The correct placement of gastric tube was confirmed through injecting air by auscultation of epigastrium and aspiration of gastric contents. Ease of gastric tube placement was graded as follows: 1- first attempt, 2- second attempt, 3- impossible. The size of the gastric tube was also noted. OLP and the leak fraction were also noted. If leak was >8%, then the LMA was removed and the patient was intubated.

Anaesthesia was maintained with isoflurane 1%-2.5% in 35% oxygen in nitrous oxide. A clear airway was defined as end tidal CO2<50 mm Hg, tidal volume >6 ml/kg, SPO2>95%. Injection ondansetron 0.15 mg/kg intravenously was given prophylactically for prevention of postoperative nausea and vomiting. Intravenous injection diclofenac sodium 1.5 mg/kg and injection paracetamol 15 mg/kg was given to reduce postoperative pain. At the end of surgery, the residual neuromuscular blockade was reversed by intravenous injection of neostigmine 0.05 mg/kg and glycopyrrolate 0.01 mg/kg.

The Baska mask, Ambu AuraGain and LMA Supreme were removed and checked for any blood or bile stains after achieving adequate spontaneous breathing, adequate neuromuscular reversal and adequate response to verbal commands.

Data Collection was done for-Time taken for the insertion, ease of insertion, no. of attempts taken to secure, ease of gastric tube placement and size of gastric tube inserted, Oropharyngeal Leak Pressure,(OLP),Leak fraction, Ease of removal, postoperative morbidity and laryngopharyngeal morbidity.

The insertion time was noted for all the  three devices and defined as time in seconds from device touching the teeth to the first recorded bilateral equal air entry. A stopwatch was started when the SAD touched the teeth and was stopped when there was bilateral equal air entry. Three attempts were allowed and 60 seconds were given for each attempt. Only the successful attempt was counted.

Ease of insertion was also be noted and evaluated according to the required manipulations during insertion i.e. easy for no manipulation, fair for one manipulation, difficult for more than one type of manipulation. Number of attempts needed for the placement were also noted.

The ease of placement of gastric tube was noted and the size of gastric tube was also noted.

OLP (Oropharyngeal Leak Pressure) test was performed after the loss of spontaneous respiration. The OLP was defined as anaesthesia circuit pressure at which a gas leak occurs around SAD. The OLP test was done with the adjustment valve set at 70 cm of H2O and oxygen flow at 6 litres/min.

Device stability and function was assessed by calculating the leak fraction which was defined as tidal volume inspired -tidal volume expired/tidal volume inspired (Vinsp-V exp/Vinsp) multiplied by 100.

Ease of removal of device was also noted and device was thoroughly checked for its integrity and shape at the time of its removal.

The postoperative morbidity was evaluated in the form of any trauma to lips, teeth, tongue, any coughing, ease to put gastric tube, any blood stain on the device and adequate clearance of the sump.

Laryngopharyngeal morbidity(LPM) in the form of sore throat, dysphagia, dysphonia(hoarseness) was evaluated at extubation and 2 hours after the extubation and LPM score was given as follows: 0- no morbidity is present, 1- minimal sore throat, dysphagia, dysphonia, 2- moderate sore throat, dysphagia, dysphonia, 3- severe sore throat, dysphagia and dysphonia.

Statistical analyses were performed using IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp. Results on continuous measurements were presented on Mean ± SD (Min-Max) & categorical as Frequency (Percentage). Normality of the data was assessed using Shapiro Wilk test/ Kolmogorov-Smirnov test. Inferential statistics like Chi-square test/Fischer Exact test, Analysis of Variance (ANOVA). The significance of level adopted was 5%. The total sample size of our study was 150, in which 50 patients were in Baska mask group, 50 patients in AAG group and 50 patients in LMA Supreme group.

We analyzed the data from 150 ASA I & II physical status patients over a period of one year after a randomized control trial.(Figure 1). All the three groups were comparable for age, weight, height, BMI, Mallampatti grade and mouth opening between the groups while there was significant difference for gender distribution i.e. females > males[p=0.001](Table1) which can be due to more incidence of cholelithiasis in females. Statistically significant difference was observed for ASA physical status between the groups [ASA II > ASA I](p= 0.006).

Successful placement of Baska mask in first attempt(88%)  was comparable to AAG (90%) and LMA Supreme(72%).(figure 2) After failed first attempt, Baska mask was inserted in 2 patients with successful second attempt(4%) and LMA Supreme was inserted successfully in 4 patients in second attempt(8%). Overall success rate of all the three groups was comparable. In 4 patients (8%), Baska mask could not be inserted. AAG and LMA Supreme could not be inserted in 5(10%) and 8(16%) patients respectively.

 Based on subjective judgement, AAG(100%) was rated as “easy” to insert as compared to Baska mask(95.6%) and LMA Supreme(85.8%){p= 0.02}. Further additional manoeuvres were applied to insert the AAG in 2/50 patients and LMA Supreme in 4/50 patients, hence rated as slightly difficult. In 2 patients, LMA Supreme was inserted with difficulty. (Table 2)

The time required for successful insertion was least for AAG with median 7.8 sec followed by Baska mask (8.15sec - median) and LMA Supreme (9.45 sec). But the time required from the successful insertion to the adequate ventilation was least for Baska mask followed by AAG and LMA Supreme(p=0.003).(Figure 3)

Figure No.2: No. of Attempts in insertion of SAD

Figure No.3: Time Required for insertion

Figure No. 4: oropharyngeal Leak Pressure and fraction

 Figure No. 5:  Changes in Heart Rate at different time  points between three SAD

Table No.1: Demographics data

Table 2: LPS Score (02 Hours)

The oropharyngeal leak pressure(OLP) is significantly higher in Baska mask group (32.39 ± 1.65) than AAG group(28.33 ±1.17) and LMA Supreme(25.91 ±1.44). OLP of Baska mask was significantly higher than that of AAG and LMA There was no significant difference in the leak fraction between the three groups(p=0.569)(figure 4).

No statistically significant difference was observed between the groups for ease of insertion{p=0.06}of gastric tube, as gastric tube was easily inserted in 100% patients of Baska mask group, 97.8% patients of AAG group and 95.2% patients of LMA Supreme group. Gastric tube passed with difficulty in 1 patient of AAG group whereas in 2 patients of LMA Supreme group, gastric tube could not pass. Statistically significant difference was observed between the three groups for size of insertion(p=0.001) of gastric tubes with sizes 10,12 and 14. Size 10 was inserted in 40/50 patients(95.2%) of LMA Supreme group, 4/50(8.7%) patients of Baska mask group and 3/50 patients(6.7%) patients of AAG group. Size 12 was inserted in 22/50(47.8%) patients of Baska mask group, 16/50 patients(35.6%) of AAG group and 2/50 patients(4.8%) of LMA Supreme group. Size 14 was inserted in 26/50(57.8%) patients of AAG group, 20/50(43.5%) patients of Baska mask group. But size 14 gastric tube could not pass in any of the patients of LMA Supreme group.  The time required for successful insertion was least for AAG with median 7.8 sec followed by Baska mask (8.15sec - median) and LMA Supreme (9.45 sec). But the time required from the successful insertion to the adequate ventilation was least for Baska mask followed by AAG and LMA Supreme(p=0.003).

There was no statistically significant difference observed between the three groups in the incidence of postoperative complications like lip trauma and throat pain.(Table 2)

No statistically significant difference was observed in the incidence of postoperative laryngopharyngeal morbidity both in the immediate period postoperatively and after 2 hrs of the surgery in all the three groups.

The mean arteial pressure ,heart rate and SpO2 was maintained and comparable in all three groupos throughout the surgery.(figure 5)

Laparoscopic surgeries require creation of the CO₂ pneumoperitoneum leading to increase in the intraabdominal pressure. Also the surgeon has to manuplate the position, hence there is increase in the airway pressures, decreased thoracic compliance and reduced FRC. Hence the second generation SAD’S are used  more commonly in laparoscopic surgeries.

The primary objective of our study was to compare these three SADs in terms of oropharyngeal leak pressure, ease of insertion and difference in the time taken to insert these devices. The secondary objective of our study was to compare these three SADs in terms of incidence of postoperative morbidities associated with them All the three groups had significant difference for gender distribution i.e. females > males [p=0.001] as females have higher prevalence of cholelithiasis. Statistically significant difference was observed for ASA status between the groups with ASA II > ASA I physical status (p=0.006). This difference was observed as many patients were having Diabetes Mellitus, systemic hypertension, hypothyroidism, chronic smoker or chronic alcoholics. The results of our study are in accordance with the previous studies.^3,4,5. SAD of size 3 was used in 62% patients in Baska mask group, 100% patients in AAG group and not used in LMA Supreme group (p=0.001). Whereas size 4 was used in 38% patients of Baska mask group, not used in AAG group and 100% patients of LMA Supreme group. This difference was observed due to the patients’ characteristics especially gender as in our study. In other studies, Size 4 of LMA Supreme was inserted in maximum patients which was similar to our study.^6,7 Another study used Size 3 of Baska mask in 26 of 48 patients as more patients were females in their study. Baska mask and AAG had higher success rates of insertion in first attempt than LMA Supreme(88% vs 90% vs 72%). These findings are concurrent with the similar study, in which Ambu AuraGain was inserted in 100% patients in first attempt.⁸ Another previous study showed that Baska mask was successfully inserted in 100% patients in first attempt.⁵ The best first attempt insertion rate in AAG was due to its compact size, deflated cuff and preformed shape which helped in easy insertion. Baska mask was also inserted successfully due to its cuffless, membranous flap seal that increases with IPPV and decreases with expiration. Whereas in LMA Supreme, the insertion was difficult due to the bulkier size of its double airway tube. The time required for successful insertion was least for AAG with median 7.8 sec followed by Baska mask (8.15sec) and LMA Supreme (9.45 sec) (p=0.019). The time required for successful insertion of Baska mask was comparable with AAG and LMA Supreme (p=0.824, p=0.823 respectively). The more time taken for adequate insertion in LMA Supreme can be due to the bigger size of the double airway tube of LMA Supreme which makes it difficult to perform maneuvers and bigger inflatable cuff.  Similarly, Baska mask is also bulky which makes it difficult for the insertion. Based on subjective judgement, AAG (100%) was rated as “easy” to insert as compared to Baska mask (95.6%) and LMA Supreme (85.8%) {p= 0.02}. It was because the airway tube of AAG was preformed according to the oropharyngeal curve and Baska mask and LMA Supreme required further manipulations like chin lift or jaw thrust to insert. In our study, Baska mask provides a significantly higher OLP as compared to AAG and LMA Supreme, hence it results in greater airway protection during laparoscopic cholecystectomy. The OLP was higher in Baska mask group (32.39±1.65 cm H₂O) as compared to AAG group and LMA Supreme group (28.33±1.17 cm H₂O and 25.91± 1.44 cm H₂O){p=0.001}. There was no significant difference in the leak fraction between the three groups (p=0.569). Hence, all the three SADs are efficient in maintaining adequate ventilation during laparoscopic cholecystectomy and there was no need for the conversion into ETT intubation for ventilation. The higher OLP of Baska mask is attributed to the fact that it has self recoiling, membranous, non inflatable cuff which provides variable pressure ventilation. This is in accordance with the previous studies.^9,4,10,11 A similar study³, showed that the OLP of AAG was higher than that of LMA Proseal. In another study, the OLP of LMA Supreme was significantly higher than that of i-gel (28 vs 24). In our study, gastric tube was easily inserted in 100% patients of Baska mask group, 97.8% patients of AAG group and 95.2% patients of LMA Supreme group.  But there was a significant difference in the size of gastric tube which was passed through these three devices (p=0.001) as the size 10 Fr was inserted in maximum patients of LMA Supreme group when compared to Baska mask and AAG groups (p=0.001). Whereas size 12 Fr and 14 Fr of gastric tube were inserted easily in both Baska mask and AAG groups (p=0.394). It is due to the fact that the Baska mask has a wider sump cavity and bigger fish mouthed gastric opening which allows gastric tube of bigger size to pass easily. Even the AAG has a bigger gastric drainage channel than LMA Supreme. The findings are in accordance with previous studies.^4,3which showed better gastric clearance in Baska mask and AAG. The postoperative morbidity in the form of trauma to lips, teeth, tongue, any coughing, LPM at 0 hr and 2 hrs post extubation, blood stain on the device post removal was comparable in all the three groups. These findings were in accordance with the previous studies.^4,9,8,5,6,11The lower incidence of postoperative complications after removal of all the three SADs suggest that these SADs can be used effectively in the airway management of patients undergoing laparoscopic cholecystectomy. MAP, HR and SpO₂ were maintained throughout the surgery.

All the three SADs are comparable and efficient in maintaining the hemodynamic stability throughout the laparoscopic surgery. These findings are in accordance with our study.^5,10,11 The higher first attempt success rate, less time required for adequate insertion and ventilation of the patients, ease of insertion, ease of gastric drainage, less intubation response of Baska mask, AAG and LMA Supreme make them an ideal choice for airway management of patients undergoing laparoscopic cholecystecomy.

Our study had some limitations. It was a single centre study, and maximum patients had normal airway, insertion by expert anaesthesiologists and the inclusion of cost effectiveness of these SADs.

List of Abbreviations

ASA               American Society of Anaesthesiology

AAG              AmbuAuraGain

BMI                Body Mass Index

ECG                Electrocardiography

ETCO2            End Tidal concentration of Carbon dioxide

ETTEndotracheal Tube

FRC                Functional Residual Capacity

HR                  Heart Rate

LMA               Laryngeal Mask Airway

LPM                Laryngopharyngeal Morbidity

NIBP               Non-Invasive Blood Pressure

OLP                Oropharyngeal Leak Pressure

SADs              Supraglottic Airway Device

SPO2              Saturation of oxygen in peripheral blood

1. Helmy AM, Atef HM, El-Taher EM, et al. Comparative study between I-gel, a new supraglottic airway device, and classical laryngeal mask airway in anesthetized spontaneously ventilated patients. Saudi journal of anaesthesia. 2010 Sep;4(3):131
2. Seung HY, Beirne OR. Laryngeal mask airways have a lower risk of airway complications compared with endotracheal intubation: a systematic review. Journal of oral and maxillofacial surgery. 2010 Oct;68(10):2359-76.
3. Singh K, Gurha P. Comparative evaluation of Ambu AuraGain with ProSeal laryngeal mask airway in patients undergoing laparoscopic cholecystectomy. Indian J Anaesth. 2017 Jun;61(6):469-474.
4. Chaudhary UK, Mahajan SR, Mahajan M et al. A comparative analysis of the baska mask versus I-gel for general anesthesia in surgical patients undergoing laparoscopic cholecystectomy. Acta Medica International. 2018;5:69.
5. Choi SR, Lee TY, Kim SW, et al. Comparison of clinical performance of i-gel and Baska Mask during laparoscopic cholecystectomy. Korean J Anesthesiol. 2019 Dec;72(6):576-582.
6. Kriege M, Piepho T, Zanker S, et al. LMA Supreme and Ambu AuraGain in anesthetized adult patients: a prospective observational study. Minerva Anestesiol. 2017 Feb;83(2):165-174.
7. Teoh WH, Lee KM, Suhitharan T, et al. Comparison of the LMA Supreme vs the i-gel in paralysed patients undergoing gynaecological laparoscopic surgery with controlled ventilation. Anaesthesia. 2010 Dec;65(12):1173-9.
8. Lopez AM, Agusti M, Gambus P, et al. A randomized comparison of the Ambu AuraGain versus the LMA supreme in patients undergoing gynaecologic laparoscopic surgery. J Clin Monit Comput. 2017 Dec;31(6):1255-1262..
9. Sreedevi Jayalekshmi CP, Thomas MK. Efficacy of Baska mask and Laryngeal mask airway supreme during positive pressure ventilation–A comparative study. Journal of anaesthesiology, clinical pharmacology. 2020 Jan;36(1):31.
10. Sreedevi Jayalekshmi CP, Thomas MK. Efficacy of Baska mask and Laryngeal mask airway supreme during positive pressure ventilation–A comparative study. Journal of anaesthesiology, clinical pharmacology. 2020 Jan;36(1):31.
11. Sachidananda R, Shaikh SI, Mitragotri MV, et al. Comparison between the Baska Mask® and i-gel for minor surgical procedures under general anaesthesia. Turkish journal of anaesthesiology and reanimation. 2019 Feb;47(1):24.