Ambu®AuraGain™ Versus I-gel® in Obese Patients

Prospective Randomized Comparison Between a Fiber Optic Intubation Via the Ambu® AuraGain ™ or the i-Gel® Laryngeal Mask Until a Complete Airway Protection in Obese Patients

The aim of this study is the randomized comparison of two laryngeal mask (Intersurgical i-gel® and Ambu®AuraGain™) in obese patients

Since the incidence of a difficult intubation lies between 4.5% -7.5%, the search for alternative airway devices has been forced in the past. As an option, the laryngeal mask is suitable, which has been used as a universal airway with a high degree of safety in routine anesthesia. There are numbers of different laryngeal masks available which have the characteristic to insert an endotracheal tube through the ventilation lumen. The indications for these laryngeal masks can be extended due to continuous improvements in the laryngeal masks, these laryngeal masks can also be used in obese patients. Obese patients generally have a 4-fold increased risk of a difficult airway, and a BMI over 35 is a predictor of a difficult tracheal intubation. There are no studies comparing the Intersurgical i-gel® Laryngeal Mask and the Ambu®AuraGain ™ Laryngeal Mask in obese patients.

Measurement of a fiberoptic intubation with the laryngeal mask. Start: Insertion of the fiberoptic into the larynxmask until the intubation has been done and after the fiberoptic has been removed.

Detection of a successful Ventilation. There are two options: a tidal volume > 6mL/kg lean body mass or endtidal pCO2 < 6.7kPa

The maximum ventilation pressure is measured, which must be applied in order to adequately ventilate the patients. This is measured over 5 minutes

The resistance is measured with a score of 1- 4. 1: simple passage, no resistance, 2: little resistance for the passage, 3: significant resistance for the passage, 4: passage not possible

The position of the mask is determined by pushing the fiber optic to a maximum of 1cm over the LMA and then using the Brimacombe score.

The swallowing difficulties are questioned preoperatively and postoperatively (5 (± 1) h after anesthesia end).

The swallowing difficulties, the throat pain and the hoarseness are questioned preoperatively and postoperatively (5 (± 1) h after anesthesia end).

Inclusion Criteria: ASA 1-3 Shoulder-/Elbow-/Hip-/Knee- or Foot - Surgery Signed informed consent BMI > 35kg/m2 Exclusion Criteria: Non-sober patients (last meal <6 h) Symptomatic reflux disease Hiatus hernia Significant cardiovascular risk factors Severe COPD Gastric band or gastric bypass Disease which allows an accurate examination of the physicians (e.g. neuromuscular, mental, metabolic disease) Drug or drug abuse in the recent past Legal immaturity (incompetence) Acute disease, which calls into question the narcotic potential Patients with whom the use of a laryngeal mask is contraindicated or otherwise not possible

Moser B, Keller C, Audige L, Dave MH, Bruppacher HR. Fiberoptic intubation of severely obese patients through supraglottic airway: A prospective, randomized trial of the Ambu(R) AuraGain laryngeal mask vs the i-gel airway. Acta Anaesthesiol Scand. 2019 Feb;63(2):187-194. doi: 10.1111/aas.13242. Epub 2018 Aug 8.