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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
50
supra-glottic airway device
supra-glottic airway device
Memorial Hermann Hospital
Houston, Texas, United States
Time Required for 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).
Time frame: duration of intubation
Leak Pressure
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.
Time frame: duration of intubation
Level of Difficulty for 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).
Time frame: duration of intubation
Number of Participants With Oropharyngeal Discomfort
Oropharyngeal discomfort was assessed. including sore throat, hoarseness, and dysphagia.
Time frame: post operative, immediately and 24 hrs after intubation
Number of Participants With Successful Gastric Drainage Tube Placement as Assessed by Fiberoptic Scope Visualization
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.
Time frame: after intubation
Number of Attempts
The number of attempts taken to place the device
Time frame: Before intubation
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