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ORIGINAL ARTICLE
Year : 2022 | Volume
: 23
| Issue : 2 | Page : 111-117
A Randomized comparative study to observe the safety and efficacy of I gel and blockbuster laryngeal mask airway used in patients undergoing short surgical procedure under general anesthesia
Arvind Khare, Poonam Awana, Beena Thada, Veena Mathur, Pradeep Kumar
Department of Anaesthesiology, J.L.N. Medical College, Ajmer, Rajasthan, India
Correspondence Address:
Dr. Beena Thada
IW/3/7, Behind Isolation Ward, J.L.N. Hospital Campus, Ajmer - 305 001, Rajasthan
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/TheIAForum.TheIAForum_39_22
Background and Aims: Blockbuster laryngeal mask airway (LMA), a newer supraglottic airway device, provides a quick and reliable seal of the airway, making it useful for positive pressure ventilation. This randomized comparative study was undertaken to compare the safety and efficacy of I-gel and Blockbuster LMA used in short surgical procedures under general anesthesia.
Materials and Methods: Hundred patients of either sex aged between 18 and 60 years belonging to the American Society of Anesthesiologist physical Status I and II undergoing general anesthesia were randomized into two groups of 50 patients each, using either I-gel (Group IG) or Blockbuster LMA (Group BB). After standard monitoring and induction of anesthesia, LMA was inserted according to their randomized groups and adequate ventilation was achieved. The primary objectives were grading of ease of insertion and time taken for successful insertion of device, while number of attempts for insertion, oropharyngeal seal pressure (OSP), hemodynamic changes, and adverse effects such as blood staining of device, injury of lips, tongue and teeth, postoperative hoarseness of voice and sore throat were secondary objectives. Data were analyzed using SPSS version 3.0.0.34.
Results: The ease of insertion was graded as very easy in 46 patients in Group BB and 26 patients in Group IG (P < 0.001). The mean time for insertion was less with Group BB (24.30 ± 3.91 s) as compared to Group IG (29.50 ± 12.5 s) (P < 0.0001). 48 patients in Group BB while 37 patients in Group IG (P = 0.008) were required one attempt for insertion. The average OSP was 22.59 ± 1.44 cmH2O in Group BB as compared to 20.88 ± 2.22 cmH2O in Group IG (P < 0.0001). Hemodynamic changes were comparable at different time intervals. Complications such as blood stain of device and sore throat were more with I-gel.
Conclusions: The Blockbuster LMA is an effective alternative to I-gel with faster, easier insertion, required a smaller number of attempts, high airway sealing pressure with stable hemodynamic, and less incidence of blood staining and postoperative sore throat.
Keywords: Blockbuster laryngeal mask airway, I-gel, supraglottic airway device
Securing airway is the most essential skill that anesthesiologists have to acquire. The most definite way of securing an airway is by endotracheal intubation. Supraglottic airway device (SAD) is a bridge between endotracheal intubation and bag and mask ventilation. Compared with the face mask, the SAD allows for a more “hands-free approach” to airway management.[1] SAD has emerged as a formidable choice over endotracheal intubation since its invention in 1981 by Brain.[2]
With progress of time, SADs with advanced features such as anatomical similarity, intubation facility, increased cuff volume to have good airway sealing pressure and many more have been introduced. The current guidelines on cardiopulmonary resuscitation also recommend SADs as an alternative to tracheal intubation.[3],[4] These devices are also a part of difficult airway cart.[5]
I-gel is a second-generation novel SAD with anatomically designed, noninflatable mask, which is made of soft gel-like transparent medical-grade thermoplastic elastomer called styrene ethylene butadiene styrene. The soft noninflatable cuff fits snugly onto the peri laryngeal framework and its tip lies in the proximal opening of the esophagus, thus isolating oropharyngeal opening from the laryngeal opening. It has a buccal cavity stabilizer which has a property to take its shape of oropharyngeal curvature of the patient. This buccal cavity stabilizer is a part of airway tubing.[6] It has a separate gastric channel and can be used in daycare short surgical procedures without the use of the neuromuscular blockade, in order to reduce the postoperative hospital stay and the postoperative complaints of sore throat.[7]
A newer, Blockbuster laryngeal mask airway (LMA) has been invented by Prof. Ming Tian. It has been gaining popularity in airway management. It is advantageous in providing ventilation and is being increasingly used for cases of difficult intubation.[8] The Blockbuster LMA has some unique features like its 95° angulated airway that makes ventilation and intubation easier through it. It also has a gastric port for suction. The Blockbuster LMA provides a better airway sealing pressures at lower volumes. Equipped with Blockbuster endotracheal tube, it can be used as a rescue device for unanticipated difficult intubation and may also be used for both blind and fiberoptic-guided intubation.[9],[10]
The safety and efficacy of Blockbuster LMA are yet to be explored. Hence, we undertook this study to compare the I-gel with Blockbuster LMA with regards to ease of insertion and time taken for successful insertion of device as primary objectives while secondary objectives were the number of attempts for successful insertion, oropharyngeal seal pressure (OSP), hemodynamic changes (heart rate [HR], systolic blood pressure [SBP] and diastolic blood pressure [DBP]) and adverse effects (blood staining of device, injury of lips, teeth, and tongue, postoperative hoarseness of voice and sore throat) in patients undergoing short surgical procedures of <45 min under general anesthesia.
Materials and MethodsThis study was registered with the Clinical Trials Registry– India (CTRI/2021/12/038753) and was conducted according to Good Clinical Practice standards and the Helsinki Declaration. After obtaining Institutional Ethical Committee approval (JLNMC/49/Acad-III/MCA/2021 on 08/01/2021), written informed consent was taken from all the 100 patients of the American Society of Anesthesiologists (ASA) physical status I-II, Mallampati classification I and II, aged between 18 and 60 years undergoing elective short surgical procedure lasting for 45 min under general anesthesia. Exclusion criteria included mouth opening <2 cm, Mallampati Grade III and IV, oral pathology, patients with loose dentures, patients with increased risk of aspirations (Gastroesophageal reflux disease (GERD), full stomach, hiatus hernia, emergency surgeries), procedures like head and neck surgeries and in pregnant female.
This was a hospital-based prospective randomized comparative study. A total of 100 patients were randomly divided into two groups - Group IG (I-gel) and Group BB (Blockbuster LMA) with 50 patients in each group (n = 50) using a computer-generated random number table. Concealment of SADs has been done using opaque sealed envelopes, containing the name of the group and name of patient, the patients were asked to pick up one envelope each. The envelope selected by the patient was opened by a senior anesthesiologist who was not involved in the study.
A routine preanesthetic examination was conducted on the evening before surgery. Investigations such as complete blood count, blood sugar, blood urea, serum creatinine, chest X-ray, and electrocardiogram (ECG) were done in all patients. Thorough preoperative evaluation was done according to standard protocol and relevant demographic data were collected from all the patients before surgery. All patients included in the study were kept nil per oral up to 8 h before induction and written and informed consent taken. The study protocol was explained that each one was followed up for a minimum of 24 h after surgery. Injection ranitidine 50 mg and injection metoclopramide 10 mg were administered intravenously 30 min before the operation. Patients were safely transferred to the operating room.
After taken for procedure in the operating room, an 18-gauge intravenous cannula was secured and an infusion of ringer lactate was started. The patient's head was placed on a soft pillow of 10 cm thickness before induction of anesthesia with the neck flexed and head extended. The patient was connected to multi-parameter monitor, which recorded pulse rate, noninvasive measurements of SBP, DBP, continuous ECG monitoring, and oxygen saturation. The baseline systolic, DBP and HR were recorded. Pre-oxygenation was done with 100% oxygen for 5 min through a facemask. I gel was inserted in patients belonging to Group IG and vice versa. Proper-sized device was taken by anesthesiologist based on patient's body weight and manufacturer's recommendation. Both devices were checked for any damage and leaks and were lubricated using water-soluble jelly on the tip and posterior surface as recommended by the manufacturer and the Blockbuster LMA fully deflated before insertion.
The patient's head was kept in a neutral position and was premedicated with intravenous injection midazolam 0.02 mg/kg, injection glycopyrrolate 0.004 mg/kg, and injection tramadol 2 mg/kg body weight as standard. Intravenous lignocaine (2%) 2 ml was given to prevent pain on injection of propofol. Anesthesia was induced with intravenous injection propofol 2 mg/kg body weight in slow incremental dose until the loss of eye reflex and adequate jaw relaxation achieved. Once an adequate depth of anesthesia was achieved, the patient was paralyzed by giving intravenous succinylcholine 1.5 mg/kg body weight. The patient was mask ventilated with 100% oxygen for 1 min. SAD was inserted by a qualified anesthesiologist with an experience of 25 successful insertions with both the devices and also performed blind tracheal intubation using either of the SADs. For both the groups, the device was successfully inserted then connected to the breathing circuit and effective airway was confirmed by bilaterally symmetrical chest movements, and air entry on chest examination with stethoscope, square-wave form capnograph trace on manual ventilation, normal EtCO2 and stable SPO2 (>95%) for both devices. After ensured placement of the device, then it was secured with adhesive tape. After successful placement of the SAD, anesthesia was maintained using 66% of nitrous oxide and 33% of oxygen with sevoflurane 1%–2% w/v. Neuromuscular blockade was maintained with injection atracurium loading 0.5 mg/kg followed by 0.1 mg/kg body weight as required. At the end of the procedure, all the patients were ventilated with 100% oxygen during emergence from anesthesia. The patient was reversed with injection neostigmine 0.05 mg/kg body weight and injection glycopyrrolate 0.01 mg/kg body weight. The patient remained in the supine position and the device removed after the patient was fully awaked and met all the reliable signs of recovery from neuromuscular blockade. All the patients were observed for 24 h in postoperative period. The ease of insertion was graded using a subjective scale on from 1 to 3 (1 - very easy [when assistant help was not required], 2 - easy [when jaw thrust is needed and given by assistance], 3 - difficult [when jaw thrust and deep rotation or second attempt was used for proper device insertion]).[11]
The time taken for insertion of the device, i.e., the time taken from the removal of the facemask to the confirmation of effective ventilation by bilateral chest movement, square wave pattern capnography and normal end-tidal CO2 and number of attempts taken for insertion were also noted. The successful placement was confirmed with the ability to achieve tidal volume of at least 7 ml/kg with a square wave capnogram.
The number of attempts required for successful insertion to secure the effective airway was also noted. For failed first attempt of LMA, second attempt was done by increasing the depth of insertion, applied jaw thrust, chin lift, and change of device. A maximum of three insertion attempts were allowed, after that the device was considered a failure, and the procedure was abandoned. Then, the patient was given a muscle relaxant and tracheal intubation was performed under direct laryngoscopy and this participant was excluded from the study.
Oropharyngeal seal pressure of the device was measured by closing the expiratory valve of the circle system with a fresh gas flow of 3 L/m. The aneroid manometer dial was observed as the pressure increased, and when the dial reached stability, the airway pressure was recorded as OSP of the device (not allowed to exceed 30 cm H2O).[11]
Adverse effects such as blood staining of device, injury of lips, teeth and tongue, postoperative hoarseness of voice, and sore throat were also noted. Hoarseness is defined as change in volume and pitch of voice which mostly clears up on its own without any medical intervention. Sore throat is defined as pain or irritation of throat that often worsens on swallowing and was treated with warm saline gargles in the postoperative period.
Statistical analysis
Based on a previous study by Jadhav et al.,[12] a total sample size of 100 patients (n = 50 in each group) was calculated using power and sample size calculator (Statistical Package for Social Sciences software version 20.0 (IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp., NY,USA)), with power of 80% and 95% confidence level with ∝ error of 0.05% test. Continuous data were presented as mean and standard deviation, whereas categorical data were presented as number of patients and percentage. Standard qualitative and quantitative tests were used to compare the data (e.g., unpaired Student's t-test, Chi-square test). Data were considered statistically significant with P < 0.05.
ResultsA total of 100 patients were included in the study and assessed for different parameters. Our study adheres to CONSORT guidelines [Figure 1].
The demographic variables such as age, weight, gender, and ASA physical status I and II were comparable among the groups [Table 1].
The difference in grading of ease of insertion, the mean time taken for the insertion of device and number of attempts taken for insertion were found statistically significant among the groups (P < 0.05) [Table 2].
Table 2: Comparison of grading of ease of insertion, number of attempts for successful insertion and mean time taken for insertion of device between both groupsThere was a statistically significant difference in the OSP between the groups (P < 0.05) [Figure 2].
Figure 2: OSP between both groups (P = 0.0001) significant. OSP: Oropharyngeal seal pressureThe mean HR and the mean arterial blood pressure were comparable among both groups at various time intervals (P > 0.05) [Figure 3] and [Figure 4].
Figure 3: Line diagram showing mean heart rate changes between both groups
Figure 4: Line diagram of mean arterial blood pressure changes between both groups at various time intervalsAdverse effects such as blood staining of device and postoperative sore throat were statistically less in Group BB than Group IG (P < 0.05) and injury of lip, tongue, teeth, and postoperative hoarseness of voice were comparable among groups (P > 0.05) [Table 3].
Table 3: Comparison of adverse and postoperative complications between both the groups Discussion The airway management is assessment, planning, and series of medical procedures required to maintain or restore an individual's ventilation or breathing. The present study was undertaken to compare I-gel and Blockbuster LMA in anesthetized patients with respect to ease of insertion, time taken for insertion, number of attempts for successful insertion, OSP, hemodynamic changes and side effects in terms of blood staining of the device, postoperative sore throat.
Our primary objective was to compare the ease of insertion between two devices. In our study, ease of insertion of Blockbuster LMA was graded as very easy in 46 (92%) patients and easy in 3 (3%) patients, and difficult in only 1 (2%) patient. On the other hand, the insertion of I-gel was graded very easy in 26 (52%) patients, easy in 15 (30%) patients, and difficult in 9 (18%) patients. Hence, the insertion of Blockbuster LMA was found easier and required less skill as compared to I-gel and the results were found statistically significant (P < 0.001).
Our study supported by Endigeri et al.[13] with 60 patients, who concluded that the overall success rate of insertion of the devices in both groups (Fastrach LMA and Blockbuster LMA) was 100%. Both the devices were easy to insert and the difference in terms of ease of insertion was found statistically nonsignificant (P > 0.05).
Our results were comparable with study done by Jadhav et al.[12] who found that there was difference in ease of insertion for both groups and concluded that the insertion of I-gel was easier and faster as compared to LMA-Proseal. In 29 out of 30 patients, I-gel was easier to insert as compared to 24 out of 30 patients with LMA-Proseal (P < 0.05).
In our study, the mean time of insertion of I-gel in Group IG patients and Blockbuster LMA in Group BB patients were 29.50 ± 12.75 and 24.30 ± 3.91 s, respectively, and the difference of mean duration of insertion of device was found statistically significant (P < 0.0001). The I-gel is made up of thermoplastic elastomer and has noninflatable cuff which takes time to expand and take the shape of the perilaryngeal inlet. Hence, there could be a delay in achieving adequate ventilation with I gel. Blockbuster LMA has an inflatable cuff and has a buccal cavity stabilizer, which provides good stability and facilitates LMA insertion without even using finger to guide the device into the mouth of patient.
In the study by Endigeri et al.,[13] the mean duration of insertion of device was 12.2 ± 1.5 s with Blockbuster LMA and 12.1 ± 1.5 s with Fastrach LMA, respectively. The difference in time taken for insertion of device was found statistically nonsignificant (P > 0.05). Similar results were demonstrated in study of Sachidananda et al.,[14] who compared the Baska mask with I-gel for minor surgical procedures under general anesthesia, where they found that the insertion time of Baska mask (14.9 ± 6.2 s) was marginally higher compared with that of the I-gel (14.7 ± 4.4 s). However, the mean duration of insertion between both devices was found statistically nonsignificant (P > 0.05). Our results were consistent with the study done by Jadhav et al.,[12] who also found a significant difference in mean insertion time. Insertion of I-gel was easier as compared to LMA-Proseal. The mean duration of insertion for I-gel was 29.53 ± 08.23 s as compared to 41.00 ± 09.41 s in LMA-Proseal.
In our study, 37 (74%) patients out of 50 in Group IG were required one attempt for insertion of I-gel and 12 patients were required second attempt for insertion. While 48 (96%) patients out of 50 in Group BB were required only one attempt for insertion of Blockbuster LMA and only 2 patients were required second attempt for insertion. The third attempt required for only one patient in Group IG and there was no third attempt required in Group BB. The difference in number of attempts for both devices was found statistically significant (P = 0.008).
Our result was comparable with study done by Jadhav et al.[12] In the study conducted by Sachidananda et al.,[14] where they found that the first-time success rate of the Baska mask was 21/24 (87.5%) as compared to that of I-gel, which was 23/25 (92%). The difference in number of attempts between both groups was found statistically nonsignificant (>0.05). And they concluded that the lower success rate achieved for Baska mask may be attributed to the morphology of the device and unique expertise needed to insert the device. Endigeri et al.[13] compared overall success rate of intubation between Blockbuster LMA versus Fastrach LMA, they found that in Group B intubation was successful using Blockbuster LMA was 96.6% while in Group F intubation was successful using Fastrach LMA was 89.9%. The difference in terms of number of attempts was found nonsignificant (P > 0.3).
The average OSP was 20.88 ± 2.22 cmH2O in Group IG as compared to 22.59 ± 1.44 cmH2O in Group BB (P < 0.0001). The difference in OSP between both the devices was found statistically significant (P < 0.05). Our study was comparable with the study of Endigeri et al.[13] and they demonstrated oropharyngeal sealing pressure higher with Blockbuster LMA (33.7 ± 1.8 cmH2O) as compared to Fastrach LMA (22.7 ± 1.5 cmH2O). Their results were found statistically significant (P < 0.05).
The mean HR rises from baseline for both devices just after insertion and at 15 min of insertion. This change in HR did not require any intervention as change was <20% of baseline. At 5 min and 10 min, the mean HR increased more in Group IG as compared to Group BB (P = 0.040) and (P = 0.047).
The mean arterial blood pressure rises just after insertion and at the time of removal of device in both groups and did not require any intervention because changes were <20% of baseline. At different time intervals, the mean arterial blood pressure for both groups was found statistically nonsignificant (P > 0.05). Our result of mean arterial pressure changes was comparable with the study of Agarwal et al.,[15] they observed that the comparative changes in hemodynamic were nonsignificant after insertion of SAD.
In our study, 15 patients in Group IG had blood staining of device while in Group BB, six patients had blood staining of device, and this difference was found statistically significant (P = 0.049). Twelve patients in Group IG developed postoperative sore throat as compared to three patients in Group BB and the incidence was found statistically significant (P = 0.025). Five patients in Group IG developed postoperative hoarseness as compared to two patients in Group BB, but this incidence was found statistically nonsignificant (P = 0.433). Four patients had developed injury of lips/teeth/oral cavity in each group equally hence this comparison was found statistically nonsignificant (P = 0.712). The sore throat in all patients required no treatment. During the insertion of SADs, the deflated leading edge of the mask can catch the epiglottis edge and cause it to downfold or improper placement beneath the tongue and cause pharyngeal injury. An inflatable mask also has potential to cause tissue distortion, venous compression, and nerve injury.
Our results were similar to Endigeri et al.[13] study where they found incidence of blood staining in Group B and Group F as 3.3% (1/30) and 20% (6/30) with P = 0.04 respectively, which was significant. Ekinci et al.'s[16] study noticed only sore throat as postoperative complication in 3 (7.5%) patients in Group I (I-gel) and in 7 (17.5%) patients in Group P (Proseal) which was statistically significant (P = 0.001).
The significance of our study lies in the fact that we have taken higher sample size which was must need for accuracy of study, there was no incidence of device change and intubation was found.
The limitations of our study were that we compared newly launched Blockbuster LMA with I-gel for which no Indian studies are available, so more studies need to be done in future to compare various intubation devices. We included only ASA I and II patients in our study which cannot be extrapolated for higher ASA grades and pediatric age groups.
ConclusionsBlockbuster LMA is an effective alternative to I-gel with faster, easier insertion, required a smaller number of attempts, high airway sealing pressure with high hemodynamic stability, and less incidence of blood staining and postoperative sore throat.
Financial support and sponsorship
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Conflicts of interest
There are no conflicts of interest.
References
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