Difficult Airway Flashcards
What is the most common cause of adverse respiratory events for patients undergoing anesthesia?
difficult tracheal intubation
Are difficult airway scenarios anticipated?
no, not usually; >75% of events are unanticipated
incidence of failed intubation
1 in 2000
incidence of failed intubation and ventilation
1 in 5000-10,000
what percentage of anesthesia related deaths does failed intubation/ventilation account for?
25%
what is the purpose of the difficult airway algorithm
- to facilitate management of the DA and reduce poor outcomes
- primary focus = tracheal intubation for patients undergoing general anesthesia
grade I view
full view of glottic opening
grade II view
posterior portion of glottic opening and arytenoid cartilage visible
grade III view
only tip of epiglottis visible
grade IV view
soft palate visible; no recognizable laryngeal structures
what is another name for a bougie
portex venn introducer
distinguishing features of a bougie
- long (60 cm)
- coude tip (35-40 degree bend)
- malleable yet firm
- no lumen for insufflation
ideal view to use bougie
grade III view
indications for bougie use
- unable to pass ETT
- grade III view
- ETT exchange
- digital intubation
- adjunct to invasive techniques
bougie insertion technique
- obtain the best view possible
- hold bougie like a pencil with coude tip anterior
- advance and hook epiglottis
- anticipate clicking (you can feel the tracheal rings)
- do NOT remove laryngoscope
- slide ETT over bougie (have an assistant)
pearls for using the bougie
- leave the laryngoscope in place during the procedure
- rotate ETT 90 degrees counter clockwise so the tip doesn’t get stuck
- use a flexible tip tube
- capnography
potential complications of bougie
- failed intubation
- perforation
- vocal cord trauma
airway exchange catheters
- commonly used when a secure airway should be changed or temporarily removed, but laryngoscopy is likely difficult
- intubating guides are different sizes, shapes, lengths, and materials
common features of airway exchange catheters include
- distance markings
- central lumen and/or side ports
- adapter for TTJV or 15mm connector
airway exchange catheter vs a bougie
- longer
- less flexible
- hollow lumen (so you can ventilate)
- straight tip, not coude like bougie
cook catheter
- type of airway exchange catheter
- radiopaque (lines)
- distal and side ports
- rapi-fit adaptor, luer lock 15mm attaches to vent
- distance markers
sheridan exchange catheter
- longer
- markings
- can ventilate
- standard = 81mm, 6.0-10.0 ETT
- extended (for DLT exchange) = 100 mm, 35-41 Fr. DLT
frova intubation introducer
- similar to bougie but with hollow lumen that allows for O2 delivery
- peds version available (3.0-5.0)
ETT introducer
- similar to bougie
- 10 cm longer and stiffer
parker flex-it directional stylet
-allows provider to elevate tip of ETT from proximal end
pearls for airway exchange catheters
- HIGH RISK procedure because you are manipulating a likely difficult airway (or else why would you be using the exchange catheter)
- have plan A, B, C and ALL EMERGENCY EQUIPMENT
- two anesthesia providers in the room at minimum
- review all previous airway and intubation notes/history
- perform a DVL first
lighted stylet
use the principle of transillumination of soft tissues like the anterior neck to guide the tip of the ETT into the trachea
indications for lighted stylet
- routine intubations (studies show high success rates and decreased airway trauma)
- patients with difficult airways
- can be used to locate tip of ETT when performing and percutaneous tracheotomy
- can be used with laryngoscope, LMA, Bullard, and during retrograde intubation
trachlight
- tip is bent to form a “field hockey stick” –> enhances movement through the glottic opening
- once the light passes through the glottis, the wire stylet is retracted 10 cm
- device inserted midline and advanced along sagittal plane
how to prepare the trachlight
- lubricate wire stylet
- lubricate the flexible wand
- attach ETT, clamp proximal end to handle
- bend tip 90 degrees like a field hockey stock
patient positioning for trachlight
- bed in low position
- head neutral to slightly extended
- DO NOT place patient in sniffing position
trachlight technique
- when illumination of the light is noted below the laryngeal prominence, retract the wire stylet 10 cm
- advance wand (without the wire stylet) until the glow disappears below the sternal notch (this is about 5 cm above the carina)
- unclamp the ETT from the handle and advance
trachlight pearls for use
- full muscle relaxation recommended
- jaw thrust or mandible lift
- insert device mid-line
- when a faint glow is seen above the larynx, lifting the jaw or tongue will raise the epiglottis and facilitate the wand toward the cords
- when wand enters the glottis opening, a well-defined light will be observed below the laryngeal prominence
- if resistance is met when attempting to advance ETT, rotate it 90 degrees
needle cricothyrotomy
- final option in ASA difficult airway algorithm
- provides rapid access to airway
- ability to oxygenate, but CO2 removal ineffective
- a 14-G needle with angio-catheter attached to a syringe partially saline filled
- can be performed using either landmark technique or with ultrasound guidance
needle cricothyrotomy landmark technique
- provider positioned on the same side as the patient’s dominant hand
- larynx stabilized with non-dominant hand; thumb and long finger
- index finger used to identify CTM
- needle inserted with dominant hand at a 45 degree angle caudally
- needle aspirated until presence of air noted
needle cricothyrotomy ultrasound guided TACA technique
- shown to be more effective
- begin at the superior Thyroid notch
- slide transducer caudally and identify CTM/Air tissue interface
- continue caudal to the hypoechoic Cricoid cartilage
- slide cephalad to CTM/air-tissue interface and mark the CTM membrane
retrograde intubation indications
- failed intubation
- urgent airway required but cords cannot be visualized
- elective based on patient condition
contraindications to retrograde intubation
- unfavorable anatomy
- laryngotracheal disease
- coagulopathy
- infection
retrograde intubation preparation
- positioning - sniffing with head hyper-extended
- skin prep - if possible should be sterilized
- anesthesia - should be anesthetized with airway nerve block (translaryngeal with superior laryngeal nerve block, translaryngeal with topicalization of the pharynx, glossopharyngeal nerve block and superior laryngeal nerve block with nebulized anesthetic)
- entry site - puncture can occur either above or below the cricoid cartilage (cricothyroid membrane, cricotracheal ligament)
retrograde intubation through cricothyroid membrane
- less bleeding because relatively avascular (cricothyroid artery becomes insignificant as it moves midline)
- greater chance of failed intubation
retrograde intubation through cricotracheal ligament
- higher success rate
- lower incidence of vocal cord trauma
- greater risk of bleeding
retrograde intubation guide-wire technique
- a needle with catheter is passed through the entry site until air is aspirated
- guide-wire is threaded through needle until it passes through the oropharynx or nasopharynx
- a hemostat clamps the guide-wire at the trachea insertion site
- ETT is passed over guide-wire until it meets resistance in larynx
retrograde intubation FOB technique
- guide-wire passed through the trachea in normal fashion
- guide-wire passed through a suction port of FOB allowing for straight path to vocal cords
- ETT can be passed over the FOB through vocal cords
- continuous O2 can be delivered
retrograde intubation pull through technique
- epidural catheter is passed as previously described
- silk suture tied to epidural catheter extending from pharynx
- catheter pulled through tracheal incision site with silk suture
- catheter removed
- ETT tied to cephalad end of suture
- hold slight pressure, ETT is passed until it abuts against the cricothyroid membrane
retrograde intubation pearls
- CTM associated with less bleeding, but lower success rate
- use a smaller ETT (6.5-7.0 mm)
- silk pull-through offers some benefits - less railroading, can perform multiple attempts with one puncture, ability to reintubate post-op
- J wire - less traumatic, easier to retrieve, less prone to kinking, can be used with FOB, takes less time to perform
retrograde intubation complications
- bleeding
- subcutaneous emphysema
- nerve injury
- broken wire
awake intubation
- gold standard for management of difficult airway
- spontaneous ventilation is maintained
- airway patency maintained
- larynx does not move into an anterior position
- awake patients can monitor own neurologic status
when do you use a FOB?
- routine induction/intubation sequence
- awake intubation with known, anticipated difficult airway
- as part of the ASA difficult airway algorithm
what is an endoscope?
- instrument composed of over 10,000 glass fibers that transmits light and allows for visulization of images
- all flexible endoscopes have three main parts - handle, insertion tube, flexible tip
FOB handle
- power source
- suction/valve
- working channel - inject meds like LA
- angulation control level - allows for manipulation of FOB tip
- lens with focus capability
FOB Lens
- all FOB have an eyepiece that can be focused
- a visible block notch in the eyepiece at the 12 o’clock position aids in orientation
- newer systems may also have - video output adapter, video screen, camera
FOB insertion tube four components
- light guide bundles
- transmit source
- angulation wires
- working channel
light guide bundles of FOB
- light is transmitted by one or two non-coherent glass fibers
- high-intensity light is focused at the proximal bundles
transmit source of FOB
- continuous glass fibers run the length of the insertion tube, transmitting images
- each fiber is approximately 20 times smaller in diameter than a human hair
- the fibers are VERY sensitive to damage
- damage to the fibers result in a black spot within the image
angulation wires of FOB
- two angulation wires course along the saggital plane
- these delicate wires move the flexible tip in opposite directions
- attempting to move the tip while still in the ETT can break the wires
working channel of FOB
- the working channel runs the length of the insertion tube
- it can be used to provide - oxygen, suction, meds, specimen collection
flexible tip of FOB
- contains the charged coupled device (CCD) chip and a second lens that allows viewing of structures
- the field of view is approximately 75-120 degrees
care of the endoscope/FOB
- valves and working channels are the most likely areas for ineffective FOB sterilization
- other sources of contamination include - sentinel patients, contaminated water, inadequate sterilization techniques, repeated use of brushes or cleaning fluid, FOBs with design errors or defects
- universal precautions = mandatory
disinfection of the FOB after use
- can take up to an hour
- inspect FOB for any damage
- disassemble moving parts, pass a cleaning brush through working port
- non-disposable parts placed in an appropriate cleaning solution
- after sterilization, bronchoscope washed and rinsed with water
- working port must be dried with 70% alcohol and compressed air
- ethylene oxide sterilization for 24 hours may be required after use in patients
airway anesthesia
prior to performing an awake fiberoptic intubation, anesthesia is needed to prevent discomfort, decrease psychological stress, minimize hemodynamic changes and increase pt cooperation
three components of successful airway anesthesia
- trigeminal nerve block (nasal intubation)
- glossopharyngeal nerve block (GPN)
- laryngeal nerve blocks
neural pathways involved in airway ansethesia
- trigeminal nerve (CN V)
- glossopharyngeal nerve (CN IX)
- vagus nerve (CN X)
trigeminal nerve
provides sensory innervation to the face
three divisions of trigeminal nerve
- opthalamic (V1)
- maxiallary (V2)
- mandibular (V3)
glossopharyngeal nerve
- provides sensory information to…
- posterior 1/3 of tongue
- oropharynx
- vallecula
- anterior epiglottis
- afferent limb of the gag reflex
superior laryngeal nerve
- branch of vagus nerve
- internal branch - sensory innervation to posterior epiglottis to vocal cord folds (SIS)
- external branch - motor innervation below the vocal cords (SEM)
recurrent laryngeal nerve
- sensory innervation below the vocal folds and trachea
- motor innervation to all intrinsic laryngeal muscles
RLN R branch
loops under subclavian artery
RLN L branch
loops under aorta, susceptible to injury
intubating oral airway
- patient either unconscious or anesthetized oropharynx
- advantages - protect bronchoscope, shield FOB from tongue + tissues, allows for passage of ETT up to 9mm
nasal paryngeal airway
- cut laterally along length of airway
- can serve as conduit for oxygen admin
swivel adapter
- used mostly for bronchoscopy
- allows for continuous ventilation without an airway leak
awake fiberoptic intubation indications
- anticipated difficult mask ventilation and intubation
- difficult airway with comorbidities likely to result in poor outcome if intubation not acheived
- failed asleep intubation
- small mouth
awake fiberoptic intubation equipment and monitoring
- IV access
- FOB cart and airway cart (test FOB for light and movement)
- oxygen delivery system
- two suctions
- monitors - pulse oximetry is mandatory
- medications
awake fiberoptic intubation psychological preparation
- explain and reassure the patient in a professional manner
- benefits of FOB
- probable amnesia
- local airway anesthetic administration
- patient assistance during procedure
awake fiberoptic intubation pre-mediation
- antisialogogue 15-20 min prior (glyco 0.2-0.4 mg), (atropine 0.4-0.6 mg)
- sedation (midaz 2mg PRN)
- nasal drops - phenyephrine 0.5% mixed with lido 2-4% spray
awake fiberoptic intubation local anesthesia
- drops
- injection
- nebulizer
- paste
- spray as you go
what does complete local airway anesthesia require?
- glossopharyngeal nerve block
- superior laryngeal nerve block
- transtracheal block
- nasal (both sides potentially)
GPN Block
- patient may be required to assist
- tongue moved medially
- LA is applied on inspiration to the tonsillar pillar
- injection of the area with local is NOT recommended
- common to apply local with long cotton swabs (lido lolly pop)
SLN block
- locate hyoid cornua
- with non-dominate hand, brace contralateral side
- advance needle until ipsilateral bone is contacted
- aspirate and inject
- repeat on other side
trans tracheal block
- straddle the trachea with the non-dominant hand
- locate the cricothyroid space, slowly advance the needle while aspirating
- stop when air is freely aspirated
- instruct the patient to take a small breath then max exhale
fiberoptic awake intubation procedure
- position patient
- assistant to help with special airways
- hold insertion tube so FOB remains straight
- blocks!
- FOB passed in a down up down motion (down - through oropharynx, up - toward anterior commissure, down - through vocal cords)
if there is a gag what needs to be blocked
GPN
if there is a cough what needs to be blocked
SLN
routine fiberoptic intubation preparation
- nasal drops
- antisialgogue pre-op
- standard induction
routine fiberoptic intubation unsuccessful
- reinstitute face-mask ventilation
- give more anesthetic prior to second attempt
FOB contraindications
- lack of skill by anesthesia provider
- lack of trained assistant or ready to use equipment
- wild, uncooperative patient
- near total upper airway obstruction
- another technique
things to consider with DAW and extubation
- have a strategy for safe extubation
- awake vs deep
- clinical symptoms that will impair ventilation
- management plan if unable to maintain adequate ventilation
- short-term use of airway exchanger
follow-up care of DAW
- differentiate between ventilation and intubation
- description of management techniques used
- provide patient with information for future care (dr note or medical alert bracelet)
