Transcript The Difficult or Failed Airway

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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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
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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
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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-MaskVentilate the patient
• The first response to failure of bag-maskventilation is always better bag-maskventilation
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
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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
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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
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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
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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
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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
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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”.