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The Difficult or Failed Airway. Pat Melanson, MD. The Difficult Airway. Must be able to assess or anticipate the degree of difficulty Then select method most likely to succeed If properly assessed and felt to be intubatable without significant difficulty
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The Difficult or Failed Airway Pat Melanson, MD
The Difficult Airway • Must be able to assess or anticipate the degree of difficulty • Then select method most likely to succeed • If properly assessed and felt to be intubatable without significant difficulty • 1-4 /1000 will be impossible intubations (O.R.) • 1 / 280 obstetrical patients • 1 /10,000 impossible to intubate or ventilate(O.R.) • 1-2 % cricothyroidotomy rate in ED
Definitions • Failed intubation • inability to place an ETT • Difficult intubation • requires more than 3 attempts or 10 minutes • Difficult laryngosopy • Cormack and Lehane grade III (epiglottis only) or grade IV view (soft palate only) • Difficult mask ventilation • Failed airway • can’t intubate, can’t ventilate
The Difficult Airway: Necessary Skills • Clinical Airway Assessment • ability to recognize/ predict Difficult Airway • Facility with array of airway equipment • knowledge of indications and advantages • ability to choose most appropriate technique for the particular situation • manual skills • Detailed knowledge of intubation medications
The Difficult Airway • Not all airway management failures are avoidable or predictable • Attempt to minimize failures • Have several definite back-up plans ready for the “Failed Airway”
Prediction of the Difficult Airway • Historical features ( prior AW difficulty) • Anesthesia record in old chart • Medic alert bracelet • Cric or tracheotomy scar • Anatomic features
Prediction of the Difficult Airway • C-spine mobility • External dimensions ( 3-3-2 rule) • Mouth opening 3 fingers (TMJ) • Mandible large enough to accommodate tongue - 3 fingers from tip of chin to hyoid • Length of neck/position of larynx - 2 fingers between top of thyroid and floor of jaw
Prediction of the Difficult Airway (con’t) • Teeth • large or protruding incisors obstruct vision • jagged teeth can lacerate balloon • Oral dimensions • narrow facial features and high arched palates (decreased lateral space) • Mallimpadi classification
Mallimpadi Classification (Tongue to Pharyngeal Size) • I - soft palate, uvula, tonsillar pillars visible • 99 % have grade I laryngoscopic view • II - soft palate, uvula visible • III - soft palate, base of uvula • IV - soft palate not visible • 100% grade III or grade IV views • *** this exam is seldom possible in an emergency situation
Predictors of Difficult Laryngoscopy • Short,thick, muscular neck • Receding mandible • Protruding maxillary incisors • “Buck teeth” • Poor TMJ mobility/ limited jaw opening • Limited head and neck movement • ( including trauma ) • High, arched palate
Difficult Airway : Laryngoscopy • Tumor, abscess or hematoma • Burns • Angioneurotic edema • Blunt or penetrating trauma • Rheumatoid arthritis, ankylosing spondylitis • Congenital syndromes • Neck surgery or radiation
Plan B : Response to Unanticipated Difficulty • Difficult laryngoscopy and intubation • Can’t intubate but Can ventilate • Can’t intubate and Can’t ventilate • Difficult Mask Ventilation
Unsuccessful Intubation : Plan B • Bag the patient • Maximize neck flex/ head ex • Move tongue out of line of site • Maximize mouth opening • ID landmarks and adjust blade • BURP maneuver • (Backwards Upwards Rightwards Pressure on Thyroid Cartilage) • Increasing lifting force • Consider Miller blade • Bag the patient
Unsuccessful Intubation : Plan B • An optimal or best attempt at difficult laryngoscopy should consist of : • use of optimal sniffing position • no significant muscle tone • use of optimum external laryngeal manipulation (BURP) • one change in length of blade • one change in type of blade • a reasonably experienced laryngoscopist
Unsuccessful Intubation : Plan B • Remember, the first response to failure to intubate should always be to Bag-Mask-Ventilate the patient • The first response to failure of bag-mask-ventilation is always better bag-mask-ventilation
Algorithm for Difficulty “Bagging” • Remove FB - Magill forceps • Triple maneuver if c-spine clear • Head tilt, jaw lift, mouth opening • Nasal or oropharyngeal airways • two-person, four-hand technique • Do not abandon bagging unless it is impossible with two people and both an OP and NP airway
The Failed Intubation: Definition • Three failed attempts to intubate • by an experienced intubator • Inability to ventilate with BVM • Inability to oxygenate
The Failed Intubation • If can’t intubate but can ventilate with BVM have time to consider options • Light guided technique (Lighted stylet) • Combitube • LMA • Fiberoptic techniques • Retrograde intubation • Cricothyrotomy
The Failed Intubation • If can’t intubate, can’t ventilate , must act immediately • Cricothyrotomy • Percutaneous Transtracheal Jet Ventilation • Combitube • LMA • The last three are temporizing measures and not definitive airway management
Clinical Approach to the Difficult Airway • Is a difficult airway predicted? • “nothing should be taken away from the patient that the airway manager can’t replace” • Bag-Mask predicted to be successful? • Intubation deemed reasonably likely ? • Do I have the ability to rescue the airway if “can’t intubate, can’t ventilate”?
Awake Oral Intubation • Consider for anticipated can’t intubate, can’t ventilate situation • distorted upper airway anatomy • (i.e., penetrating neck trauma) • Avoids ‘burning bridges” • maintains ventilation • maintains patient’s ability to protect airway • May use to take quick look to assure that you can see enough for RSI
Awake Oral Intubation • Prepare patient psychologically • Pre-oxygenate • Topical anesthesia if time permits • Titrated sedation - avoid obtundation • Reassure patient throughout procedure
Difficult Airway Kit • Multiple blades and ETTs • ETT guides (stylets, bougé, light wand) • Emergency nonsurgical ventilation ( LMA, Combitube, TTJV ) • Emergency surgical airway access ( cricothyroidotomy kit, cricotomes ) • ETT placement verification • Fiberoptic and retrograde intubation
Techniques for Difficult Intubation • Alternative laryngoscope blades • Awake intubation • Blind oral or nasal intubation • Fiberoptic intubation • Gum Elastic Bougé • Light wand • Retrograde intubation • Surgical airway
Techniques for Difficult Ventilation • Combitube • Laryngeal Mask Airway • Oral and nasopharyngeal airways • Two person mask ventilation • Transtracheal jet ventilation • Surgical airway
Difficult Airway Maxims • The first response to failure of Bag-Mask Ventilation is always better BVM • optimize airway position • place both OP and NP airways • two-handed, two-person technique • try lifting head off pillow to open airway • Generate as much positive pressure as possible without inflating the stomach
Difficult Airway Maxims • Use judicious sedation and topical airway anesthesia to have a quick look in doubtful cases • In certain situations a paralytic agent and RSI may still be the best choice
Difficult Airway Maxims • “It is preferable to use superior judgement -- to avoid having to use superior skill”.