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 Difficult 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

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”.