Fibre-optic Guided Tracheal Intubation Through SADs

Tracheal intubation through a supraglottic airway device (SAD) is a well-established technique in the management of patients with a difficult airway. The technique can be used in patients in whom difficult intubation is expected, or in situations when tracheal intubation using another method was not possible. It is now recommended that tracheal intubation through the SAD should be performed using a fibreoptic scope (a camera device) to minimise the risk of trauma to the airway, and that second generation SADs are used to minimise the risk of aspiration of gastric contents.

There are two second generation SADs currently available which allow tracheal intubation: the I-gel and the LMA protector.

The I-gel is a second generation supraglottic airway device widely used in anaesthesia and resuscitation. Fibreoptic intubation through the I-gel has been evaluated in a recent prospective study (1), with the first attempt success rate of 91.4%. In another study (2) of patients with predicted difficult airway, the success rate of the procedure at first attempt was 96%.

LMA Protector is a recently introduced, improved version the LMA supreme - another second generation SAD. LMA supreme has been used in clinical practice for more than 10 years, however, tracheal intubation through the device was extremely difficult because of the small size of the breathing channel. The LMA Protector, has a larger breathing channel allowing the passage of an endotracheal tube. Compared to the I-gel, is has also got a larger gastric drainage tube. This allows easy suction in the event of regurgitation. Therefore, it appears to be superior to the I-gel in preventing the aspiration. But there are no studies comparing the ease of intubation through I-gel and LMA Protector

The aim of this study is to compare the ease of performing the fibreoptic guided tracheal intubation through these two devices. Our hypothesis is that intubation through the I-gel is easier and quicker.

Inclusion criteria

• All patients aged above 18, presenting for elective surgical procedure, where a supraglottic airway device can be used and left in place throughout the duration of surgery and requiring tracheal intubation

Exclusion criteria

• Patients who are do not wish to take part
• Patients with class II obesity (BMI >40)
• Patients below 18 years of age
• American Society of Anaesthesiologists (ASA 3, 4 and 5)
• Patients with mouth opening of less than 3 cm
• Patients deemed to require awake intubation
• Surgery involving head and neck region
• Surgery requiring prone position