Comparison of I-gel to the Laryngeal Mask Airway

Not Applicable

Completed

Conditions: Endotracheal Intubation
Supraglottic Airway

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

Registration Number: NCT00706823

Lead Sponsor: The University of Texas Health Science Center, Houston

Brief Summary: 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.

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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 50

Inclusion Criteria

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.
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:

obesity, (BMI > 35 kg/m2)
pregnancy
history of gastric regurgitation, heart burn, ileus or "full stomach"
history of low pulmonary compliance or high pulmonary resistance
known history of difficult endotracheal intubation or signs suggesting the possibility of difficult intubation
pharyngeal pathology
upper airway obstruction due to laryngeal pathology

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
LMA-Unique	Laryngeal Mask Airway-Unique	Patients who received the Laryngeal Mask Airway-Unique (uLMA) for intubation
i-gel-SGA	i-gel airway (Intersurgical Ltd., Wokingham, England)	Patients who received i-gel supraglottic device (i-gel airway) for intubation

Primary Outcome Measures

Name	Time	Method
Time Required for Intubation	duration of intubation	The total time to intubation was measured from the beginning of supraglottic airway device (SGA) insertion to successful endotracheal tube intubation, verified by detection of CO2 on the capnogram (anesthesia machine).
Leak Pressure	duration of intubation	After successful placement, airway leak pressure was assessed by closing the circuit to atmosphere and allowing fresh gas flow to build airway pressure. The pressure at which an audible leak was heard was recorded; airway pressure was not permitted to exceed 40 cm H2O.

Secondary Outcome Measures

Name	Time	Method
Number of Participants With Successful Gastric Drainage Tube Placement as Assessed by Fiberoptic Scope Visualization	after intubation	When the fiberoptic scope was placed in the gastirc drain tube of the i-gel, if the esophageal mucosa was visible and the stomach was readily accessible, then placement was considered succussful.
Number of Attempts	Before intubation	The number of attempts taken to place the device
Level of Difficulty for Intubation	duration of intubation	Ease of SGA insertion and intubation was subjectively assessed by the operator on a scale from 1 to 5 (1 = very easy, 2 = easy, 3 = neutral, 4 = difficult, 5 = very difficult).
Number of Participants With Oropharyngeal Discomfort	post operative, immediately and 24 hrs after intubation	Oropharyngeal discomfort was assessed. including sore throat, hoarseness, and dysphagia.