The Difficult Airway The Difficult Airway Robert J. Vissers, MD FACEP Department of Emergency Medicine Legacy, Emanuel Hospital Defining ng the problem Defining ng the difficult d airway a Identifying ng the difficult d airway a Managing ng the difficult d airway a Difficult Airway Algorithms: ASA Cancel Case Fig 1 ASA DIFFICULT A AIRWAY ALGORITHM Anesthesiology 1996;84:686 Awaken Ectopic Anesthesia Problem: Urgency Cost of failure Formula for error 1
Emergency Airway Management Solution: Preparation Anticipate difficulties Simple, consistent, reproducible approach Difficult Airway Algorithms Common principles Assessment of ventilation difficulty Assessment of intubation difficulty Awake vs. induction and paralysis Calling for help Surgical airway is a potential endpoint Decision to intubate Approach to the Emergency Airway Decision to intubate Decision to Intubate Near death? Unresponsive? Difficult Airway? Rapid Sequence Intubation Crash Airway Difficult Airway Techniques Failed Airway Airway maintenance Oxygenation Ventilation Facilitate therapy Expected course Adapted from: Walls RM, Ed. The Manual of Emergency Airway Management Philadelphia, Lippincott, 2000. 2
Decision to Intubate: Modifiers Operator experience Setting Potential for a difficult airway Never take away what you cannot replace National Emergency Airway Registry (NEAR) Prospective airway registry n = 12,000 <1% fail rate with RSI Cricothyrotomy rate 0.6% No cases of cannot intubate, cannot ventilate with death The Difficult Airway DIFFICULT BAG AND MASK VENTILATION DIFFICULT LARYNGOSCOPY AND INTUBATION DIFFICULT CRICOTHYROTOMY SAKLES TRIANGLE 3
The Difficult Airway Assessment of Difficult BVM DIFFICULT BAG AND MASK VENTILATION DIFFICULT LARYNGOSCOPY AND INTUBATION DIFFICULT CRICOTHYROTOMY SAKLES TRIANGLE Assessment of Difficult BVM Consider potential difficulty of BVM ventilation before RSI Beware the full stomach Equipment out and ready Five predictors of difficult BVM: facial hair, obesity, adentulous,, elderly, snoring * *Langeron O, et al. Anesthesiology, 2000. Assessment of Difficult BVM: Bones M ask seal O besity/obstruction A ge > 55 N o teeth S tiff lungs 4
The Difficult Airway DIFFICULT BAG AND MASK VENTILATION DIFFICULT LARYNGOSCOPY AND INTUBATION DIFFICULT CRICOTHYROTOMY SAKLES TRIANGLE Assessment of Difficult Intubation Laryngoscopic view (Cormack-Lehane) too late Systems too complex, impractical Need simple, fast approach 5
Difficult Airway? LEMON Law L ook externally E xamine (3-3-2) M allampati grade O bstruction N eck mobility Adapted from: Walls RM, Ed. The Manual of Emergency Airway Management Philadelphia, Lippincott, 2000. Cognitive forcing strategies in clinical decisionmaking. P Croskerry. Ann Emerg Med Jan, 2003. LEMON: Look Simple visual inspection often reveals obvious potential difficulties 6
LEMON: Examine 3-3-2 Assess oral opening - 3 fingers Measure the mandible - 3 fingers Position of larynx - 2 fingers LEMON: Examine 3-3-2 Assess oral opening should be able to accommodate 3 fingers LEMON: Examine 3-3-2 Measure the mandible - should be able to fit 3 fingers between the mentum and the hyoid bone 7
LEMON: Examine 3-3-2 Assess position of larynx should get 2 fingers between the thyroid cartilage and the mandible 8
LEMON: Mallampati Class I Class II Class III Class IV LEMON: Obstruction? 1) Location? 2) Fixed or mobile? 3) Speed of progression? 9
LEMON: Neck Mobility Can the patient flex and extend the neck? Actively assess in the non-trauma obtunded patient. Cervical spine immobilization - remove anterior collar while c-spine c is immobilized. 10
LEMON Law L ook externally E xamine (3-3-2) M allampati grade O bstruction N eck mobility LEMON: Predictive? 156 ED patients requiring intubation Scored using LEMON Simple point system used (0 to 10) Compared to laryngoscopic view (Cormack Lehane) Felt to be predictive, P<0.05 Reed MJ et al. Can an airway assessment score predict difficulty at intubation in the emergency department? Emerg Med J 2005 Feb; 22:99-102. 11
LEMON: Predictive? Reed MJ et al. Can an airway assessment score predict difficulty at intubation in the emergency department? Emerg Med J 2005 Feb; 22:99-102. Airway alternatives Nasal Supraglottic: Infraglottic: ZIST BNTI Fiberoptics BVM Intubating LMA Lightwand Glidescope Fiberoptics Bougie Combitube King-LT TTJV Cricothyrotomy Zone of Increasing Sphincter Tone 12
Rescue Devices Combitube Most require oral access Most are designed to deal with high anterior cords I-LMA, King-LT, Combitube Intubating stylet (bougie, frova,, etc.) Video - glidescope King-LT I-LMA 13
Video Laryngoscopy LMA CTrach Glidescope 14
Pediatric Asthmatic Preoxygenation: Desaturation Beginning to fatigue Sats dropping Needs to be intubated 6 ml/kg/min 3.4 ml/kg/min From: Benumof JL: Anesthesiology 87:979-982, 1997. Preoxygenation: Desaturation 15
Awake look/scopes Antisyalogogue atropine or glycopyrrolate Anesthesia lidocaine (2-4%), benzocaine Decongestant oxymetazoline (afrin) Nebulize,, atomize (MADgic ), viscous Sedation ketamine,, versed Agitated Burn Case 42-year-old woman set herself on fire in her car. Uncooperative, yelling let me die. 70-80% burns, mostly 3, 3, to face, trunk, anterior arms and thighs. Unable to get a BP or O2 sat. 16
Intubating Stylet/Bougie Clinical Issues: Agitated Patient Assessment of the difficult airway beware ego, fear, urgency The agitated or violent trauma patient Haldol, Droperidol, Midazolam, Ketamine 5 yo girl, choked on peanuts last night Unable to sleep, trouble breathing Looks tired, resp distress, tripod Oh, nuts 17
Airway alternatives Nasal Supraglottic: Infraglottic: ZIST BNTI Fiberoptics BVM Intubating LMA Lightwand Glidescope Fiberoptics Bougie Combitube King-LT TTJV Cricothyrotomy Zone of Increasing Sphincter Tone 18
No landmarks? Cricothyroid membrane under the 4 th finger The tongue is your friend find it and follow it to the glottis Suction,, suction, suction 4-finger rule for the cricothyroid membrane 19
Consider surgical airway early Summary Organized, rapid, simple approach Assess for difficult ventilation BONES Assess for difficult intubation LEMON 20
Obese asthmatic 21