None listed
Conditions
Brief summary
Commonly used airway devices during general anaesthesia include supraglottic airway devices, of which best practice involves minimising the number of attempts at airway insertion to reduce patient morbidity. The intervention of this study involves the use of two additional pieces of airway equipment, a laryngoscope and bougie, to guide supraglottic guide insertion. The hypothesis is that this insertion method will increase the first attempt insertion success rate.
Interventions
The drain tube of the i-gel (2nd generation supra-glottic airway device, made by Intersurgical) will be primed with a 14 French lubricated bougie (Frova Intubating Introducer, Cook Medical) with its straight end first, leaving the 5-cm bent portion protruding from the proximal end (for the airway assistant to grip), and the maximum length protruding from the distal end for the anaesthetist to manipulate. The posterior glottis will be identified under direct vision with a size 3 Macintosh laryngo
The drain tube of the i-gel (2nd generation supra-glottic airway device, made by Intersurgical) will be primed with a 14 French lubricated bougie (Frova Intubating Introducer, Cook Medical) with its straight end first, leaving the 5-cm bent portion protruding from the proximal end (for the airway assistant to grip), and the maximum length protruding from the distal end for the anaesthetist to manipulate. The posterior glottis will be identified under direct vision with a size 3 Macintosh laryngoscope (Koala Medical), with the distal portion of the bougie advanced in the midline, 5–10 cm into the oesophagus while the assistant holds the i-gel (Intersurgical) and the proximal portion. The laryngoscope will be removed with the i-gel inserted using a rotational insertion technique while the assistant stabilises the proximal end of the bougie, so it does not penetrate further into the oesophagus. The steps of rotational insertion will include: insertion of the entire cuff of the i-gel into the mouth in a midline approach without finger insertion; rotated 90° counter clockwise around the tongue; advanced until resistance is felt at the hypopharynx; then re-rotated clockwise to the standard orientation. The bougie will be removed while i-gel is held in position. If adequate ventilation does not occur, up to three minor airway interventions will be performed (adjusting head/neck position, jaw thrust, digital traction on the tongue, or changing depth of i-gel insertion). Adequacy of ventilation will be defined as: ability to ventilate with a tidal volume of at least 6 ml per kg of Ideal Body Weight with an end tidal-CO2 of < 45mmHg, with the following 3 criteria for sustained exhaled CO2 met: 1) Levels rising during exhalation and falling during inspiration 2) Consistent or increasing amplitude over seven breaths 3) End tidal -Co2 peak amplitude >7.5 mmHg above baseline A document outlining the steps and requirements of this intervention will be provided to the anaesthetist to guide their practice. An investigator will be present to clarify any queries.
Sponsors
The Canberra Hospital
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Elective non-head and neck surgery in the supine position 2. Body Mass Index greater than 30 kg/m2 3. Age greater than or equal to 18 years old At least 1 of the following: 1. Poor dentition, defined as partial dentures, loose, or broken teeth. 2. Reduced cervical spine range of motion, defined as less than 90° of flexion or less than 70° of extension. 3. Thyromental distance less than 6cm. 4. Limited mandibular protrusion or retrognathia: defined as ability to protrude upper incisors no further than being in line with the lower incisors.
Exclusion criteria
1. Procedures where paralysis is necessary to facilitate surgery. 2. Anticipated surgery duration of greater than 2 hours. 3. Patients at high risk of aspiration: 3a. Unfasted as per American Society of Anaesthesiologists: nil clear liquids for greater than 2 hours, toast greater than 6 hours, meat or fried/fatty foods greater than 8 hours. 3b. Active gastroesophageal reflux symptoms despite fasting and/or pharmacological treatment, defined as: belching, dyspepsia, or heartburn. 3c. Bowel obstruction or haematemesis 4. Known distorted airway anatomy (for example from imaging or a documented history) 5. Sore throat on day of surgery or known structural oesophageal disease. 6. Severe ventilatory disease confirmed by spirometry: Forced expiratory volume in one second of less than 50% of predicted 7. History of inability to bag mask ventilation (with or without oropharyngeal or nasopharyngeal device, and/or positive end expiratory pressure) 8. History of documented difficult intubation or a Cormack-Lehane laryngoscopy score of IIIa or above.
Outcome results
None listed