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Comparison of I-gel to the Laryngeal Mask Airway

This study has been completed.
Information provided by:
The University of Texas Health Science Center, Houston Identifier:
First received: June 24, 2008
Last updated: March 8, 2011
Last verified: March 2011

The purpose of this study is to evaluate a new disposable supra-glottic airway device, the i-gel airway (Intersurgical Ltd., Wokingham, England). We propose to test its ease of insertion, position within the airway, drain tube patency and anatomic sealing properties during mechanical ventilation in non-obese anesthetized patients undergoing elective general surgery. The study device will be compared to the current standard in the industry, the LMA Unique.

Condition Intervention
Device: i-gel airway (Intersurgical Ltd., Wokingham, England)
Device: Laryngeal Mask Airway-Unique

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Subject)
Primary Purpose: Treatment
Official Title: A Randomized Clinical Comparison of the Intersurgical I-gel and the Laryngeal Mask Airway Unique in Non-Obese Adult Patients During General Surgery

Further study details as provided by The University of Texas Health Science Center, Houston:

Primary Outcome Measures:
  • Time Required for Intubation [ Time Frame: duration of intubation ] [ Designated as safety issue: No ]
  • Level of Difficulty for Intubation [ Time Frame: duration of intubation ] [ Designated as safety issue: No ]
  • Degree of Throat Irritation [ Time Frame: post operative, immediately and 24 hrs after intubation ] [ Designated as safety issue: Yes ]
  • Number of Attempts [ Time Frame: Before intubation ] [ Designated as safety issue: No ]
    The number of attempts taken to place the device

Secondary Outcome Measures:
  • Leak Pressure [ Time Frame: duration of intubation ] [ Designated as safety issue: No ]

Enrollment: 50
Study Start Date: February 2008
Study Completion Date: August 2008
Primary Completion Date: August 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: i-gel
Patients who received i-gel supraglottic device for intubation
Device: i-gel airway (Intersurgical Ltd., Wokingham, England)
supra-glottic airway device
Active Comparator: uLMA
Patients who received uLMA for intubation
Device: Laryngeal Mask Airway-Unique
supra-glottic airway device

Detailed Description:

During the past decade, several pharyngeal airways have been introduced for airway management, such as the Laryngeal Mask Airway (LMA), the Cobra perilaryngeal airway, the Esophageal Tracheal Combitube (ETC), the EasyTube, the Laryngeal Tube6, and the Streamlined Liner of the Pharyngeal Airway (SLIPA). These airway devices have become very popular because of their ability to maintain an airway without perturbing the trachea and can be used in patients without muscle relaxation who are only lightly anesthetized.

The LMA Classic (cLMA) generally provides an adequate airway, but certain problems remain:

  1. In 8-33% of LMA placements, more than one attempt is required.
  2. It is sometimes difficult to advance the LMA without extending the neck (which is contraindicated in some patients).
  3. The device does not protect the airway from aspiration of gastric contents.
  4. It does not provide an airtight seal around the larynx (the usual pressures causing leakage of gas being 15-20 cm H20). Consequently, the device may function poorly during positive-pressure ventilation.
  5. The esophagus is included within the rim of the LMA in 10-15% of patients, directly exposing the esophagus to positive airway pressures. This often results in insufflation of the stomach and postoperative discomfort.

The LMA Unique (uLMA) is a disposable, inflatable supraglottic airway device that is based on the LMA Classic design which has been used as the "model" in the industry. It has been listed as a commonly accepted device for routine and rescue airway management and is now listed in the American Society of Anesthesiologists (ASA) Difficult Airway Management Algorithm as an airway conduit for tracheal intubation.

The i-gel (Intersurgical Ltd., Wokingham, England) is a cuffless, single-use supraglottic airway device designed to provide a more effective seal than the uLMA, thus eliminating problems 3-5 described above with the addition of a gastric drain. Made of a gel-like thermoplastic elastomer, the i-gel has an anatomically-designed mask that allows quick, easy insertion and can accurately position itself over the laryngeal framework to provide a reliable perilaryngeal seal without the need for an inflatable cuff. In a preliminary study, the peak airway pressures were found to be above 30 cm H2O with a sustained leak pressure of 24 cm H2O versus an average of 18-21 cm H2O seen with the cLMA. According to the 100 patient trial, the i-gel is easier to insert, it has better sealing properties and there is no cuffed inflates.

This clinical study has been designed to compare the i-gel and the uLMA, as to ease of placement, ventilation during mechanical ventilation, proper positioning, seal pressures, the patency of the drain tube, and finally, any complications with their use. Fiberoptic observations through each device will provide information in relation to the epiglottis and the distal opening of the device.


Ages Eligible for Study:   18 Years to 80 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  1. The subjects will be adult surgical candidates aged 18-80, ASA I-II, Mallampati I or II, presenting for elective surgery who require general anesthesia in whom tracheal intubation is not necessary.
  2. Both male and female patients will be included.

Exclusion Criteria:

Patients will be excluded from the study if they present as Mallampati III or IV, ASA III-V or emergency status. Additionally, they will be excluded if they meet one of the contraindication criteria of the LMA including:

  1. obesity, (BMI > 35 kg/m2)
  2. pregnancy
  3. history of gastric regurgitation, heart burn, ileus or "full stomach"
  4. history of low pulmonary compliance or high pulmonary resistance
  5. known history of difficult endotracheal intubation or signs suggesting the possibility of difficult intubation
  6. pharyngeal pathology
  7. upper airway obstruction due to laryngeal pathology
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00706823

United States, Texas
Memorial Hermann Hospital
Houston, Texas, United States, 77030
Sponsors and Collaborators
The University of Texas Health Science Center, Houston
Principal Investigator: Carin A Hagberg, M.D. The University of Texas Medical School at Houston
  More Information

No publications provided

Responsible Party: Carin Hagberg, M.D./ Professor and Interim Chair, The University of Texas Health Science Center, Houston Identifier: NCT00706823     History of Changes
Other Study ID Numbers: HSC-MS-08-0004
Study First Received: June 24, 2008
Results First Received: March 8, 2011
Last Updated: March 8, 2011
Health Authority: United States: Institutional Review Board

Keywords provided by The University of Texas Health Science Center, Houston:
Endotracheal Intubation
Supraglottic Airway processed this record on November 25, 2014