Extra glottic airway devices maybe used as an alternative airway during general anaesthesia in elective cases and also a part of  difficult airway trolley as it can be used in both anticipated and unanticipated difficult airway to allow ventilation

Second-generation supraglottic airway devices with gastric access are recommended for daily clinical practice

 The ability to achieve high airway sealing pressures oropharyngeal leak pressure is important with SAD as it allows positive pressure ventilation at high pressures like laparoscopic surgeries and obesity

It also prevents pulmonary soiling in the event of regurgitation of gastric contents

This study is to compare the clinical performance of LMA protector LMA Proseal and BASKA in terms of OLP primary objective and insertion characteristics as secondary objective

AIM 

To compare the clinical performance of  LMA protector LMA pro seal and BASKA in terms of oropharyngeal leak pressure  OLP and insertion characteristics

PRIMARY OBJECTIVE

To compare the OLP of LMA Protector LMA ProSeal and BASKA in terms of OLP in neutral position and Lateral position 

 SECONDARY OBJECTIVE

To compare the insertion characteristics of LMA protector LMA proseal and BASKA in terms of 

Time taken for successful insertion

Ease of insertion

Number of attempts required for insertion

Ease of NG tube placement

Grading of fibre optic view of laryngeal structures

Blood stain present on removal of device

To look for any postoperative side effects like  sore throat dysphagia hoarseness of voice

Sample size is calculated for the two independent study group for continuous variables for randomised control trial

It was found in the previous study that the mean oropharyngeal leak pressure in LMA protector group was 32.24 ± 3.1 and LMA Proseal  group showed 29.74 ± 3.2 among anaesthetised and paralysed patients based on study conducted by Kerai S et al in 2023

Sample size

The aim of our study was to compare the leak pressure of LMA protector LMA Proseal and BASKA among the patients who are undergoing surgery under general anaesthesia in neutral and Lateral positions

Alpha error was taken as 0.05 beta 0.20

n1= 25 ,   n2 = 25 subjects for group 2

n3 = 25 subjects for group 3

Hence the total sample size will be 75

INCLUSION CRITERIA

  Patients aged 18 to 70 years, belonging to the American Society of Anesthesiologists ASA physical status I and II undergoing elective surgery of 1 to 3 hours duration under general anaesthesia will be included

EXCLUSION CRITERIA

Patients with known difficult airway edentulous body mass index more than 30 kg m2 upper airway pathology mouth opening less than 3.2 cm gastroesophageal reflux increased risk of aspiration recent upper respiratory tract infection and lack of consent to participate will be excluded from the study

Patients will undergo pre-anaesthetic evaluation as per our instituitional protocol

Written and informed consent will be obtained from eligible patients

On the day of surgery patients will be randomly allocated to three groups with codes as LP LMA Protector code  P LMA Proseal and code B  BASKA using computer generated random codes

The allocation of patients will be concealed in a white envelope which will be opened just before shifting to the operation theatre

The Size of the SAD will be selected according to manufacturers guidelines 

The insertion of SAD will be done by experienced anaesthetists who have done at least minimum of 25 LMA Proseal protector and  at least 10 BASKA insertions.

General anaesthesia will be induced using  IV fentanyl 1 to 2mcg kg IV propofol 2 to 2.5mg kg atracurium 0.5mg kg After three minutes of intermittent positive pressure ventilation with mixture of oxygen and nitrous mixture along with an inhalation agent isoflurane the SAD will be inserted as per the allocated code

In LP Group with patient in sniffing position LMA protector will be introduced pressing against the hard palate with a circular motion until resistance is felt in the hypopharynx The cuff will then be inflated to reach middle of the green zone of cuff pilot

 In  P Group LMA Proseal  will be mounted on an introducer and will be inserted gently pressing against the hard palate and should be distally advanced until resistance was felt in the hypopharynx The cuff will then be  inflated using a cuff manometer to 60 cm of H2O

Baska mask of appropriate size will be chosen as per manufacturer’s recommendation Before insertion the integrity of the device will be checked and the posterior surface of the mask will be lubricated with a water based lubricant before insertion Three attempts are allowed before declaring a failed insertion of a SAD In such cases endotracheal tube was inserted and patient will be excluded from the study

The insertion time is taken as the time from picking up the SAD until appearance of the first square of end tidal carbon dioxide this is taken as  0 minute 

Ease of insertion of SAD will be  evaluated according to manoeuvres required ie easy for no manoeuver and difficult for multiple manoeuvres. The ease of placement NG tube through drain channel will be  rated by the performer. The OLP is defined as the pressure in the anaesthesia breathing circuit at which gas leak will occurs around the SAD

The OLP is  determined by manometer leak test as described by  Keller et al

Simultaneously the insertion characteristics like time of insertion ease of insertion number of attempts   of insertion ease of NG tube insertion grading of fibreoptic blood stain presence on removal of SAD were also noted

After confirmation of correct positioning of the device anaesthesia was maintained with oxygen nitrous oxide gas mixture

To prevent lung barotrauma the expiratory valve should be opened as soon as the airway pressures reach 40cm H2O 

The position of SAD in relation to laryngeal inlet should be verified by passing a fibreoptic bronchoscope FOB to a position just proximal to the end of SAD

The view of laryngeal structures was scored as

Grade 1 clear view of the vocal cords

Grade 2 only arytenoids visible

Grade 3 only epiglottis visible

 Grade 4 no laryngeal structures visible

The grading of view of laryngeal structures will be recorded 

Following insertion the OLP should be  measured in neutral and lateral positions

For neutral position the external auditory canal and superior orbital margin of the patient should be aligned vertical to the OT table 

First the OLP will be measured in neutral position and after changing to lateral position the OLP should be recorded after 60seconds from position change

The surgery was allowed to proceed

The OLP was determined with the manometer leak test as described by Keller et al

Four different oropharyngeal leak pressure tests were performed in random order on each patient by two observers blinded to each other’s measurements

 test 1 involved detection of an audible noise

test 2 was detection of end tidal carbon dioxide in the oral cavity

 test 3 was observation of the aneroid manometer dial as the pressure increased to note the airway pressure at which the dial reached stability

 test 4 was detection of an audible noise by neck auscultation.

Haemodynamic parameters heart rate and systolic and diastolic blood pressure were recorded before induction baseline of anaesthesia after induction 0 minutes and 3mins 6mins and 9 minutes after the insertion of SAD

At the end of the surgery residual neuromuscular blockade was reversed SAD was removed and the presence of any blood staining was noted

 Patients were enquired about complaints of sore throat dysphagia and hoarseness of voice at 1 and 24 h after the removal of the device