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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Evaluation of the clinical performance of laryngeal mask airway (LMA) Protector in the moderately obese patients
Scientific title
Evaluation of the clinical performance of LMA Protector in the moderately obese patients
Secondary ID [1] 292139 0
Universal Trial Number (UTN)
Trial acronym
LMA-laryngeal mask airway
Linked study record

Health condition
Health condition(s) or problem(s) studied:
obesity 303844 0
Condition category
Condition code
Diet and Nutrition 303209 303209 0 0
Anaesthesiology 303539 303539 0 0
Other anaesthesiology

Study type
Description of intervention(s) / exposure
After approval from the hospital’s Institutional Review Board, we will recruit a total of 30 patients scheduled for elective surgical procedures under general anaesthesia that are amenable to supraglottic airway management in our tertiary hospital.
Patients are not premedicated. They are positioned supine on the operating table, with the head resting on a head ring. Standard monitoring will be instituted before induction of anaesthesia, for example, pulse oximetry, electrocardiograph and non-invasive blood pressure. Pre-oxygenation is carried out with high flow oxygen for three minutes prior to induction of anaesthesia.

The LMA Protector cuff is completely deflated and a water-based lubricant is applied to the posterior part of cuff and airway tube. The LMA protector size 4 is utilized for all subjects. After pre-oxygenation, anaesthesia will be induced with fentanyl 1.5 to 2 mcg/kg, propofol 2 to 3 mg/kg and anaesthesia maintained with sevoflurane (end tidal concentration of 2 to 3%) in oxygen until the jaw is considered relaxed at the discretion of the investigators. Neuromuscular blockade is used if indicated. Under direct vision, the tip of the device is pressed flat against the hard palate and the LMA Protector is inserted until definite resistance is felt. The cuff is then inflated with air until the marker of the pilot balloon sits within the green zone (indicative of 40-60cmH20) with an upper limit of clear zone pressures of not more than 70cmH20). The amount of air to achieve this will be recorded, and the intra-cuffpressure is doubly confirmed with a handheld aneroid manometer (Portex® Pressure Gauge; Smiths Medical Intl Ltd, Kent, UK) to achieve an intra-cuff pressure of 60cmH2O.
The appearance of the first square end-tidal carbon dioxide (ETCO2) trace denotes successful establishment of effective ventilation. Otherwise, the device is completely removed for another insertion attempt. Three insertion attempts are allowed. Each “attempt” is defined as re-insertion of the airway device into the mouth. We define “insertion failure” of the device as one comprising more than 3 unsuccessful attempts or if the entire process of insertion exceeds 120 seconds. This includes the time the airway device is removed from the mouth and any bag-mask ventilation in between. In case of failure to insert the LMA Protector, the airway will be secured according to the decision of the attending anaesthesiologist.

Once the airway device is in place, the tube is fixed by taping over the patient’s cheek. A gel plug is placed in the proximal one centimeter of the male gastric drain outlet whilst closing the female port of the gastric drain and the suprasternal notch test is done to confirm placement (gently tapping the suprasternal notch causes the gel to pulsate, confirming the tip location behind the cricoid cartilage). Then, a 14 French gauge gastric tube is inserted through the female port gastric drain. These gastric tubes are pre-lubricated with a water-soluble lubricant. Ease of insertion was graded 1 to 3 (1-easy, 2-difficult, 3-impossible). Time to insertion of the gastric catheter will also be noted. Confirmation of correct placement of the gastric catheter is through detection of injected air by auscultation of epigastrium, and aspiration of gastric contents. Gastric decompression is done and the amount of gastric fluid aspirated is noted, and will be checked against fasting duration.
The anatomical airway position of the LMA Protector is then assessed by fiberoptic examination via the airway channel and scored as follows: Grade 1, clear view of the vocal cords; Grade 2, view of the arytenoids only; Grade 3, view of the epiglottis only; Grade 4, no laryngeal structures visible.
The oropharyngeal leak pressure (OLP) is measured after closing the adjustable pressure-limiting (APL) valve with a fresh gas flow of 3 L min-1, noting the airway pressure at equilibrium or when there is an audible air leak from the throat. Maximum pressure allowed is 40 cm H20. The epigastrium is also auscultated when measuring the OLP to detect any air entrainment in the stomach.
We record the number of insertion attempts and time to establish effective ventilation (interval from when the LMA Protector enters the mouth to first ETCO2 trace), the ease of insertion of airway, subjectively assessed on a 5 point scale (1= easy, 2 = not so easy, 3 = difficult, 4= very difficult, 5= impossible), blood pressure and heart rate every minute for the first five minutes from induction of anaesthesia, manoeuvers required to optimize positioning or ventilation with the airway devices: adjusting head and neck position, depth of insertion, applying jaw lift, and changing device size. Maintenance of anaesthesia is achieved with an oxygen: air mixture in sevoflurane 1-2 MAC. The airway device is removed upon return of spontaneous breathing and eye opening of the patient. The airway device is then inspected for presence of visible blood. Forty five minutes later, an independent observer will assess patients for post-operative sore throat, dysphonia or dysphagia.

All airway insertions were performed by experienced staff anaesthesiologists with >10 year experience with supraglottic airway management, who had perfomed at least 10 insertions LMA protector prior to trial commencement. Contemporaneous data collection of airway insertion times, ventilatory parameters and complications of placement (desaturation < 95%, gross regurgitation or aspiration [defined as fluid in the ventilation tube], bronchospasm, mucosal, lip, tongue or dental injury) were done by the same investigator.
Intervention code [1] 298477 0
Treatment: Devices
Comparator / control treatment
no control group
Control group

Primary outcome [1] 302583 0
ease of insertion (1.easy, 2.fair, 3.difficult, 4.very difficult, 5.impossible).
Timepoint [1] 302583 0
during scheduled treatment period
Primary outcome [2] 302979 0
Time to effective ventilation (mean time for first appearance end tidal carbon dioxide achievable by all successful LMA insertions)
Timepoint [2] 302979 0
During scheduled treatment period
Secondary outcome [1] 336428 0
high oral leak pressure (once device is inserted, the oxygen flow from the ventilator will be set to 3 litre/minute and the adjustable pressure limiting valve will be closed. the achievable airway pressure will be recorded with maximum set at 40cmh2o
Timepoint [1] 336428 0
during scheduled treatment period
Secondary outcome [2] 336429 0
vocal cord view (using fibreoptic view and the view is graded as such:
1 = clear view of vocal cords
2 = view of arytenoids only
3 = view of epiglottis only
4 = no laryngeal structures visible
Timepoint [2] 336429 0
during scheduled treatment period
Secondary outcome [3] 336431 0
complications due to LMA such as desaturation < 95%, bronchospasm, gross regurgitation/aspiration (fluid in ventilation tube), intra-op gastric distension, dental injury, lip/tongue injury, mucosal injury
(blood on laryngeal mask device post removal) intraoperatively and 30 minutes after admission to perianaesthesia care unit, again patients will be asked if they have post operative sore throat, dysphonia or dysphagia.
Timepoint [3] 336431 0
during scheduled treatment period
Secondary outcome [4] 337618 0
Cardiovascular response to LMA insertion (number of patients with significant change in blood pressure and/or heart rate more than 20 percent from preinduction readings)
Timepoint [4] 337618 0
Upto 5 minutes after LMA insertion.

Key inclusion criteria
30 patients scheduled for elective surgical procedures under general anaesthesia that are amenable to supraglottic airway management in our tertiary hospital. We will include patients who are moderately obese (BMI between 30 to 35 kg/m2).
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
patients of ASA physical status IV, at high risk of regurgitation or aspiration for example those with symptomatic gastro-esophageal reflux, hiatus hernia, respiratory tract pathology eg. preoperative sore throat, patients with previous head and neck surgery with deformity or radiotherapy to the neck with hypopharyngeal involvement, and patients with inadequate mouth opening to permit insertion of device.

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
not applicable
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
not applicable
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
a total of 30 patients scheduled for elective surgical procedures under general anaesthesia that are amenable to supraglottic airway management in our tertiary hospital by convenience sampling therefore sample size calculation not required. Once they fulfilled the inclusion and exclusion criterias, the investigators will approach the potential participants for recruitment. A patient information sheet will be given to them with all the necessary contact informations. Once they agree to participate, the consent which is available in bilingual will be obtained.
Data will be analysed by using SPSS xxx TM (SPSS Inc., Chicago, IL, USA). We used means and standard deviation to describe continuous data; median, interquartile ranges (IQR) and ranges for non-parametric data; and percent- ages for categorical data

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 9024 0
State/province [1] 9024 0
kuala lumpur

Funding & Sponsors
Funding source category [1] 296677 0
Name [1] 296677 0
University of Malaya Medical Center
Address [1] 296677 0
University of Malaya Medical Center, jalan university 59100 kuala lumpur
Country [1] 296677 0
Primary sponsor type
University of Malaya Medical Center
University of Malaya Medical Center,
jalan university 59100 kuala lumpur
Secondary sponsor category [1] 295637 0
Name [1] 295637 0
Address [1] 295637 0
Country [1] 295637 0

Ethics approval
Ethics application status
Ethics committee name [1] 297905 0
UMMC Medical Research Ethics Committee
Ethics committee address [1] 297905 0
University Malaya Medical Centre
Lembah Pantai,59100
Kuala Lumpur, Malaysia.
Ethics committee country [1] 297905 0
Date submitted for ethics approval [1] 297905 0
Approval date [1] 297905 0
Ethics approval number [1] 297905 0

Brief summary
Study Title
Evaluation of the clinical performance of LMA Protector in the moderately obese patients.

The LMA protector are supraglottic airway devices used to maintain the airway and breathing in a person undergoing general anaesthesia. The device is inserted into the mouth and correctly placed in the throat where breathing will take place. It is available in sizes 3, 4 and 5. It helps prevent the need of introduction of an endotracheal tube into the trachea; which is invasive and uncomfortable. It is currently widely used abroad during general anaesthesia.

What is the purpose of this study?
This study will help to ascertain the performance of LMA protector in moderately obese patients undergoing general anaesthesia.

What are the procedures to be followed?
All that is required from you as the patient is that you come well fasted for at least 6 hours.

Who should not enter this study?
1. If you are obese with a body mass index of more than 40kg/m2 - body weight (kg) divided by height2 (m2)
2. If you have medical problem(s) which are life-threatening such as symptomatic heart conditions/failure, uncontrolled symptomatic high blood pressure, severe bronchial asthma and airway related problems.
3. If you are not well fasted.
4. If you have an upper respiratory tract infection.
5. If you at high risk of regurgitation or aspiration e.g.: symptomatic gastro-oesophageal reflux, 2nd to 3rd trimester of pregnancy.

What will be the benefits of this study?
To you as a subject:
-None. However it will benefit the patients undergoing general anaesthesia in the future.
To the investigator.
-None. It will help the doctors in the future to choose which device will suit their patients best.

What are the possible drawbacks?
You may have slight discomfort of your throat upon waking up from anaesthesia. There may also be some injury to your lips, teeth and tongue; which is the similar risk carried for any other patient undergoing general anaesthesia with an airway device.

Can I refuse to take part in this study?
Absolutely. Your decision to refuse will not affect your medical care.
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 1838 1838 0 0
Attachments [2] 1839 1839 0 0
/AnzctrAttachments/373090-Patient Info Sheet 1(English).docx (Participant information/consent)
Attachments [3] 1840 1840 0 0
/AnzctrAttachments/373090-Consent Form 1(English).docx (Participant information/consent)
Attachments [4] 1841 1841 0 0

Principal investigator
Name 75418 0
Address 75418 0
University Malaya Medical Centre
Lembah Pantai,59100
Kuala Lumpur, Malaysia.
Country 75418 0
Phone 75418 0
Fax 75418 0
Email 75418 0
Contact person for public queries
Name 75419 0
Address 75419 0
University Malaya Medical Centre
Lembah Pantai,59100
Kuala Lumpur, Malaysia.
Country 75419 0
Phone 75419 0
Fax 75419 0
Email 75419 0
Contact person for scientific queries
Name 75420 0
Address 75420 0
University Malaya Medical Centre
Lembah Pantai,59100
Kuala Lumpur, Malaysia.
Country 75420 0
Phone 75420 0
Fax 75420 0
Email 75420 0

No information has been provided regarding IPD availability
Summary results
No Results