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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
Pilot study evaluating the efficacy and safety of second generation supraglottic airway devices in adult surgical patients.
Scientific title
Efficacy and safety of second generation supraglottic airway devices in adult surgical patients: a prospective pilot study.
Secondary ID [1] 290803 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Malpositioned airway device 301452 0
Condition category
Condition code
Anaesthesiology 301173 301173 0 0

Study type
Description of intervention(s) / exposure
The following interventions placed by the consultant anaesthetist, the supraglottic airway devices the LMA-Supreme 'Registered Trademark', LMA-Protector 'Registered Trademark' and i-gel 'Registered Trademark' devices inserted with blind or video-guided methods will be sequentially allocated to each study participant for use as airway management during anaesthesia. Blind or video-guided insertion will be at the clinical discretion of the treating anaesthetist based on skills and preference. Maximum of three attempts will be allowed for each intervention insertion, at which time standard care device is used. Anatomical details will be recorded during insertion for each device using both the blind and video-guided insertion methods. Postoperative incidence of sore throat, dysphagia and dysphonia will also be assessed. Characteristics of each of these supraglottic airway devices (SADs), also termed laryngeal mask airways (LMAs), are as follows:

The LMA-Supreme 'Registered Trademark' (The Laryngeal Mask Company, Le Rocher, Victoria, Mahe,Seychelles) combines features of earlier devices, such as the LMA-ProSeal 'Registered Trademark' (high oropharyngeal seal cuff, gastric access and bite block – to facilitate ventilation, airway protection and airway obstruction, respectively), the LMA-Fastrach 'Registered Trademark' (fixed curve tube and guiding handle – to facilitate insertion and fixation) and the LMA-Unique 'Registered Trademark' (single use – prevention of disease transmission). Furthermore, the LMA-Supreme 'Registered Trademark' incorporates additional features: the anatomically shaped airway tube incorporates a drain tube within its lumen to separate the ventilation and digestive tracts; an elongated cuff at the distal drainage orifice and a 10 degree slant to fit better in the oesophageal tube; an oval-shaped tube to match better the shape of the mouth and to reduce rotation in the pharynx; a strengthened inner cuff to prevent airway obstruction from infolding; and epiglottic fins to prevent airway obstruction from epiglottic downfolding.

The LMA-Protector 'Registered Trademark' (Teleflex Medical, Athlone, Westmead, Ireland) is a later single-use CE-marked and TGA (Therapeutic Goods Administration, Australia) approved laryngeal mask that has similar features to the LMA-Supreme 'Registered Trademark', but has similarities to the LMA-Classic 'Registered Trademark' and LMA-ProSeal 'Registered Trademark', as this device is made entirely from medical-grade silicone. This makes it more flexible and potentially less traumatic than the rigid LMA-Supreme 'Registered Trademark' which is made of polyvinyl chloride. The LMA-Protector 'Registered Trademark' provides access to, and functional separation of the ventilation and digestive tracts. The anatomically shaped airway tube is elliptical in cross-section and ends distally at the laryngeal mask, with the cuff is designed to conform to the contours of the hypopharynx. The LMA-Protector 'Registered Trademark' contains two drainage channels, which emerge as separate ports proximally and enter a chamber, located behind the cuff bowl, which is a new feature. The chamber communicates distally with the upper oesophageal sphincter. Removal of gastric fluid through the upper oesophageal sphincter can be realized by attaching a suction tube to the male suction port or by insertion of a gastric tube through the female drainage port to the stomach.

The i-gel 'Registered Trademark' is an innovative second generation SAD, designed to create a non-inflatable, anatomical seal of the pharyngeal, laryngeal and perilaryngeal structures while avoiding compression trauma. The shape, softness and contours accurately mirror the perilaryngeal anatomy, requiring no cuff inflation.

Intervention code [1] 296720 0
Treatment: Devices
Comparator / control treatment
LMA-Classic 'Registered Trademark' with a blind insertion technique will be the control. The LMA-Classic 'Registered Trademark' (The Laryngeal Mask Company, Le Rocher, Victoria, Mahe, Seychelles) was the original LMA released into the market, and as a first generation device is versatile and re-usable. It is made with soft, silicone and aperture bars, designed to prevent blockage of the airway by the epiglottis. As the standard care device, a maximum of three insertion attempts are allowed.
Control group

Primary outcome [1] 300593 0
The oropharyngeal leak pressure (OPLP) which is a measure of patency of the supraglottic airway will be assessed using a cuff pressure manometer.
Timepoint [1] 300593 0
After successful insertion.
Secondary outcome [1] 330364 0
Incidence of different malpositions of the supraglottic airways observed with the videolaryngoscope.
Timepoint [1] 330364 0
After supraglottic airway insertion.
Secondary outcome [2] 330365 0
Intracuff pressures measured with a manometer.
Timepoint [2] 330365 0
On insertion.
Secondary outcome [3] 330366 0
Capnography assessed by measurement of PaCO2 and waveform interpretation.
Timepoint [3] 330366 0
After insertion.
Secondary outcome [4] 330367 0
Incidence of air leak, assessed by the presence of audible escaping air.
Timepoint [4] 330367 0
After insertion.
Secondary outcome [5] 330368 0
Incidence of airway obstruction assessed by low pulse oximetry readings of SpO2.
Timepoint [5] 330368 0
After insertion.
Secondary outcome [6] 330724 0
Sore throat assessed from patients' telephone feedback using a 10 point Visual Analogue Scale.
Timepoint [6] 330724 0
Postoperatively on day one following surgery.
Secondary outcome [7] 330725 0
Dysphonia assessed from patients' telephone feedback using a 10 point Visual Analogue Scale.
Timepoint [7] 330725 0
Postoperatively on day one following surgery.
Secondary outcome [8] 330726 0
Dysphagia assessed from patients' telephone feedback using a 10 point Visual Analogue Scale.
Timepoint [8] 330726 0
Postoperatively on day one following surgery.

Key inclusion criteria
Patients aged > 18 years;
Planned general anaesthesia;
ASA (American Society of Anesthesiologists) Score 1-3;
Informed written consent.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Requiring endotracheal intubation with a high risk of aspiration;
Surgery requiring non-supine positioning;
Head and neck surgery;
Potentially difficult airway.

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

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Descriptive statistics will be used in the form of frequency (percent) for categorical variables, mean (standard deviation) for parametric continuous variables and median (interquartile range) for non-parametric variables to describe the sample and characteristics across groups. Groups will be analysed as intention-to-treat. A two-way ANOVA will be used to assess the differences across treatment groups. Test will be declared statistically significant at a<0.05. Predictive Analytics Software (IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0 Armonk. NY:IBM Corp.) will be used for analysis.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date

Funding & Sponsors
Funding source category [1] 295229 0
Name [1] 295229 0
Royal Brisbane and Women's Hospital
Address [1] 295229 0
Butterfield Street, Herston. Queensland. 4029.
Country [1] 295229 0
Primary sponsor type
Royal Brisbane and Womens Hospital
Butterfield Street, Herston. Queensland. 4029.
Secondary sponsor category [1] 294057 0
Name [1] 294057 0
The University of Queensland.
Address [1] 294057 0
St Lucia. Queensland. Australia. 4072.
Country [1] 294057 0

Ethics approval
Ethics application status
Ethics committee name [1] 296571 0
Royal Brisbane and Women's Hospital Human Research Ethics Committee
Ethics committee address [1] 296571 0
Butterfield Street. Herston. Queensland. 4029.
Ethics committee country [1] 296571 0
Date submitted for ethics approval [1] 296571 0
Approval date [1] 296571 0
Ethics approval number [1] 296571 0

Brief summary
We will investigate the occurrence of incorrect positioning in four commonly used supraglottic airway devices in anaesthesia using both blind and videolaryngoscopic techniques, including examination of the importance of such information to anaesthetists. The proposed pilot study is in preparation for a larger investigation. It is anticipated that
it will provide a rich perspective on the occurrence of incorrectly positioned supraglottic airway devices which may potentially cause complications including patient pain and discomfort. Valuable insights and information will guide future research to improve clinical anaesthesia practice. Supraglottic airway devices (SADs) are the most commonly selected airway management device for general anaesthesia, and have a prominent role in the difficult airway algorithm of American Society of Anesthesiology. Although generally effective, the oropharyngeal airway seal in these devices is not airtight and there is the possibility of subsequent failure due to the added effects of inappropriate size, insertion technique, dislodgement following malpositioning and impact on anatomical structures. Imaging studies of SADs have revealed that a variety of malpositioning occurs in up to 70% of all ‘blind’ insertions, with the epiglottis posteriorly deflected. This results in partial epiglottic downfolding in the bowl of the airway device (70-80%) producing air leaks, airway obstruction, trauma (oedema, ischemia), and sore throat. Ideally, the SAD tube
opening opposes the glottic opening and the entrance to the trachea, allowing for spontaneous breathing and mechanical ventilation. 1st generation SADs are simple airway devices with a single airway tube connected to a bowl and cuff with low oropharyngeal leak pressures (<20 cm H20). 2nd generation SADs have specifically designed features to reduce the risk of aspiration. Assessment of malpositioning provides a baseline to improve
placement and better understand positioning for cuffed and uncuffed devices . Oropharyngeal leak pressure is a function of the cuff pressure of airway devices with inflatable cuffs, and determination of this pressure is defined as the airway pressure at which leakage is first detected as escaped air. This pressure indicates when the airway
device is patent and positioned correctly. This primary end point has been previously used in clinical and fiberoptic assessments of SADs. The SADs LMA Classic 'Registered Trademark', LMA Supreme 'Registered Trademark' and igel 'Registered Trademark' have been evaluated alone or in pairwise comparisons but differing study designs make it difficult for comparison of results. The LMA Protector 'Registered Trademark' has not been clinically assessed. The aims of the study are to provide information about malpositioning indicated by the oropharyngeal leak pressure (OPLP) in the four different SADs,
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 71334 0
Prof Andre Van Zundert
Address 71334 0
Royal Brisbane and Women's Hospital,
Butterfield Street,
Herston. Qld. 4029
Country 71334 0
Phone 71334 0
+617 3646 5673
Fax 71334 0
Email 71334 0
Contact person for public queries
Name 71335 0
Prof Andre Van Zundert
Address 71335 0
Royal Brisbane and Women's Hospital,
Butterfield Street,
Herston. Qld. 4029
Country 71335 0
Phone 71335 0
+617 3646 5673
Fax 71335 0
Email 71335 0
Contact person for scientific queries
Name 71336 0
Prof Andre Van Zundert
Address 71336 0
Royal Brisbane and Women's Hospital,
Butterfield Street,
Herston. Qld. 4029
Country 71336 0
Phone 71336 0
+617 3646 5673
Fax 71336 0
Email 71336 0

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