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==LEMON Mnemonic==
*An airway assessment score based on criteria of the LEMON method is able to successfully stratify the risk of intubation difficulty in the emergency department.<ref>Reed, M. et al.  Can an airway assessment score predict difficulty at intubation in the emergency department? Emerg Med J. 2005 Feb; 22(2): 99–102. doi:  10.1136/emj.2003.008771</ref>

===LOOK===
*Look at the patient externally for characteristics that are known to cause difficult laryngoscopy, intubation or ventilation<ref> Rennie LM, Dunn MJG, et al. Is the ‘LEMON’ method an easily applied emergency airway assessment tool? European Journal of Emergency Medicine 2004;11:154–7</ref>

*Trauma
*Short neck
*Micrognathia
*Prior surgery
*May also be difficult to bag
**Body mass index
**Advanced age
**Beard
**No teeth
**Snoring
**Dentures

===Evaluate 3-3-2-1===
*3 - Ideally the distance between the patient's incisor teeth should be at least 3 finger breadths
*3 - Distance between the hyoid bone and the chin should be at least 3 finger breadths
*2 - Distance between the thyroid notch and the floor of the mouth should be at least 2 finger breadths 
*1 - Lower jaw should not sublux more than 1cm

===Mallampati===
*The patient sits upright, opens mouth and protrudes tongue
*Grades are based on visibility of the uvula, posterior pharynx, hard, and soft palate

===Obstruction===
*Assess for conditions leading to airway obstruction such as [[Peritonsillar Abscess (PTA)]], trauma, or [[Epiglottitis]].

===Neck Mobility===
*Patient places chin down onto their chest and extend their neck.
*Remove the hard collar and provide manual stabilization in trauma patients.
*Poor neck mobility impacts ability to have airway access alignment.

[[File:Mallampati Score.png|thumb|Mallampati Score]]
[[File:LEMON Score.png|thumb|3-3-2 ruleDistance between patient's incisor teeth of 3 finger breadths and distance between the thyroid notch and the floor of the mouth should be at least 2 finger widths]]

==ASA Difficult Airway Algorithm==
*Does not necessary apply to the ED since the patient can always be awakened and case cancelled
**[[Cricothyrotomy]] should always be the last step in patients with failure to oxygen and ventilate with BVM and inability to intubate
**Straight blade- Miller- may offer better manipulation of a large epiglottis in children or for micrognathia or "buck teeth"

==Improving Passive Oxygenation==
*Use in overweight, poor O2 reserve, hypoxia at baseline, concerns for rapid progression to hypoxia once apnea 
*Pre-oxygenate while sitting upright, only lay back once [[RSI]] drugs pushed. 
*30 degrees reverse trendelenburg position for intubation
*Nasal O2 while pre oxygenating and DURING intubation (after induction increase to 15L) 

==Airway Adjuncts==
===Endotracheal tube introducer (ETI)/Gum Elastic Bougie===
*Higher first pass success when used with direct laryngscope vs. styletted ET tube regardless of whether difficult airway was expected or not <ref>Driver, B. E., Prekker, M. E., Klein, L. R., Reardon, R. F., Miner, J. R., Fagerstrom, E. T., … Cole, J. B. (2018). Effect of Use of a Bougie vs Endotracheal Tube and Stylet on First-Attempt Intubation Success Among Patients With Difficult Airways Undergoing Emergency Intubation: A Randomized Clinical Trial. JAMA: The Journal of the American Medical Association, 319(21), 2179–2189.</ref>
*Blind orotracheal intubation

===Blind Naso Trach Intubation===
*Not as successful but still an option
*Higher complication rate - bleeding, emesis, and airway trauma
**'''Do not attempt in patients with posterior pharyngeal swelling such as in [[Angioedema (Upper Airway)]]'''

===Lighted Optical Stylets===
*High success rate - especially good for trauma, c-spine precautions
*Use for both reg and nasotrach
*Lower complication rate
*Limited by fogging, secretion, recognition of anatomy, cost, and rare provider experience

===[[LMA]]===
*Can use without muscle relaxants
*Better than face mask
*Can be used as bridge to fiberoptic intubation
*Limited by unreliable seal at peak insp pressure
*Aspiration risk
*Mucosal trauma
*LMA better than endotracheal for paramedics, especially in pediatric patients<ref>Zhu X-Y, Lin B-C, Zhang Q-S, Ye H-M, Yu R-J. A prospective evaluation of the efficacy of the laryngeal mask airway during neonatal resuscitation. Resuscitation. 2011;82(11):1405–1409. doi:10.1016/j.resuscitation.2011.06.010</ref><ref>Calkins MD, Robinson TD. Combat trauma airway management: endotracheal intubation versus laryngeal mask airway versus combitube use by Navy SEAL and Reconnaissance combat corpsmen. J Trauma. 1999;46(5):927–932</ref>

*Intubating LMA (LMA-Fastrach) provides the opportunity to convert to a definitive airway after rescue with the supraglottic device

===Combitube- esoph obturator===
*Good for nurses and paramedics with limited intubation skill
*Indicated if difficult airway predicted: cannot see glottis with laryngoscope
*Reduced risk for aspiration compared to  face mask or LMA
*Can maintain spinal immobilization
*Large size predisposes to esophogeal dilatation and laceration as a complication

===[[Percutaneous transtracheal ventilation]]===
*PTV
*Prefered over crithyrotomy in children up to age 10-12
*Needle, 16-18ga through cricoid membrane, connected to 50 psi 02<ref>Beck, E., Kharasch, M., Casey, J., Ochoa, P., Menon, S., Calabrese, N. and Wang, E. (2011) ‘Percutaneous Transtracheal jet ventilation’, Academic Emergency Medicine, 18(5), pp. e38–e38.</ref>
**Oxygenates well
**Ventilate through glottis and upper airway - can retain CO2
*Need adequate oxygen pressure
*1 sec insp and 2- 3 sec exp to avoid breath stacking
*Can use for 30-45 min
*May cause pneumothorax or barotrauma
*Contraindications
**Distorted anatomy
**Bleeding diathesis
**Complete airway obstruction

===Retrograde Intubation===
*Percutaneous guide wire through cricoid and retrograde intubation over wire
*Use guide catheter over wire and then ett
*Need time to set up
*Risk hematoma, pneumothorax
*Contraindicated
**Bleeding
**Distorted anatomy

===Fiberoptic Bronchoscopic Intubation===
*Takes time to set up
*Good for c-spine injury or awake patient with diff airway
*Go through nose
*Use for all ages, can give 02 during procedure thru fiberscope, immediate confirmation of position
*Limited by secretions, bleeding, poor suction,

===Rigid Fiberoptic Laryngoscopes===
*Use for diff airway or spinal immobolization
*Not as good and longer time to intubate than flex scope

==[[Surgical cricothyrotomy]]==
*Can get subglottic stenosis
*Rapid 4 step procedure faster but higher complication rate - cric cart fx
*Can also do wire guided
*Long term morbid, mortality similar to tracheostomy

==See Also==
{{Related Difficult Airway Pages}}

==Video==
{{#widget:YouTube|id=8y8QN1j_m4g}}

==References==
<references/>

[[Category:Procedures]]
[[Category:Critical Care]]