Jeffrey M. Elder, M.D. Deputy Medical Director New Orleans EMS Airway Lecture Series: Lecture 1 Predicting the Difficult Airway RSI Failure Rate 1% Jeffrey M. Elder, M.D. Deputy Medical Director

When To Intubate? Failure to maintain/protect the airway Required for successful oxygenation and ventilation Reflexes avoid aspiration Clear vocal communication is a good measure for airway protection/patency Absence of a gag reflex not sensitive or specific as indicator for the need of an airway (swallowing) Swallowing requires sensing the presence of pooled material and complex muscular actions to swallow Spontaneous respirations ≠ airway protection

When To Intubate? Failure of Ventilation or Oxygenation Supplemental oxygen not effective: ARDS Respiratory fatigue/failure: Asthma Can be reversible: Opioid overdose

When To Intubate? Anticipated Clinical Course Examples: Deterioration of the critically ill Patient is exposed to a period of increased risk: Long transport time, air evacuation, etc. Requires clinical gestalt Examples: Head injury/combative Expanding hematoma Expanding hematoma of the neck – prevertebral space hematoma may not be visible

Approach to Evaluating the Airway Ask a question: What is your name? Response can tell you about airway and neurological status Normal voice, ability to inhale and exhale in a manner required for speech, comprehending the question Only tells you about 1 moment in time If unable to phonate properly: perform a detailed assessment of the airway

Approach to Evaluating the Airway Examine Mouth and Oropharynx Bleeding Swelling of Mouth or Uvula Any abnormality that would interfere with the passage of air Examine Mandible and Central face integrity

Approach to Evaluating the Airway Examine the Anterior Neck, Larynx, and Trachea: Palpate for subcutaneous air Tracheal injury, pulmonary injury, esophageal rupture, gas forming infections Monitor the Respiratory Pattern Stridor = upper airway obstruction Subauditory stridor = needs stethoscope to hear

Approach to Evaluating the Airway Observe the chest through several respiratory cycles Look for symmetrical, concordant chest movement Paradoxical movement or flail chest Diaphragmatic breathing – spinal cord injury

Approach to Evaluating the Airway Auscultation of the chest Assess adequacy of air exchange Decreased breath sounds in hemothorax, pneumothorax, or other pulmonary process Monitor pulse oximetry, capnography, and mentation ABGs rarely helpful in the decision to intubate Anticipate clinical course!

Identification of the Difficult and Failed Airway

The Failed Airway Failure to maintain acceptable oxygen saturation during or after on or more failed laryngoscopic attempts (CICO) or Three failed attempts at orotracheal intubation by an experienced intubator, even when oxygen saturation can be maintained. *From Manual of Emergency Airway Management CICO= can’t intubate, can’t oxygenate

Clinical presentations of the Failed Airway There is not sufficient time to evaluate or attempt a series of rescue options, and the airway must be secured immediately because of an inability to maintain O2 sats via BVM. (CICO) There is time to evaluate and execute various options because the patient is in a “can’t intubate, can oxygenate situation”

Four Technical Operations of the Difficult Airway Difficult Bag Valve Mask Ventilation MOANS Difficult Laryngoscopy and Intubation LEMON Difficult Extra-Glottic Device RODS Difficulty Cricothyrotomy SHORT

Difficult Bag-Mask Ventilation: MOANS Mask Seal Obstruction/Obesity Age >55 No Teeth Stiff lungs M: can use KY on beard, but slimy mess O: resistance (chest wall, abd. Wall) redundant airway tissues A: loss of muscle and tissue tone N: face caves in.. Leave dentures or place gauze in cheeks S: high airway pressures: asthma, copd, pulm dz

Difficult Laryngoscopy and Intubation: LEMON Look Externally Evaluate 3-3-2 Mallampati Score Obstruction/Obesity Neck Mobility

Difficult Laryngoscopy and Intubation: LEMON Look Externally Gestalt Gut Feeling First Impression – “This looks bad!”

Difficult Laryngoscopy and Intubation: LEMON Evaluate 3-3-2 Rule: Relates the mouth opening to size of the mandible to the position of the larynx in terms of likelihood of successful visualization of the glottis by direct laryngoscopy

Difficult Laryngoscopy and Intubation: LEMON Mouth must open adequately to permit visualization past the tongue when both the blade and ET tube are within the oral cavity The mandible must be sufficient size to allow the tongue to be displaced fully into the submandibular space The glottis must be located a sufficient distance caudad from the base of the tongue so that a direct line of site can be created to look from mouth to vocal cords as the tongue is displaced inferiorly

Difficult Laryngoscopy and Intubation: LEMON First “3” Assesses for mouth opening 3 fingers between the upper and lower incisors

Difficult Laryngoscopy and Intubation: LEMON Second “3” Length of the Mandibular space Mentum to hyoid

Difficult Laryngoscopy and Intubation: LEMON “2” Position of the glottis in relation to the base of the tongue Space from Chin-neck junction (hyoid) to and thyroid notch

Difficult Laryngoscopy and Intubation: LEMON Mallampati Sitting Up Head in sniffing position Open mouth, protrude tongue without phonation Class I-IV Class I & II = low intubation failure rate Class III & IV = intubation failure may be > 10%

Difficult Laryngoscopy and Intubation: LEMON

Difficult Laryngoscopy and Intubation: LEMON Obstruction/Obesity Four Cardinal Signs of Upper Airway Obstruction: Muffled voice Difficulty swallowing secretions Stridor Sensation of dyspnea Dyspnea = critical obstruction

Difficult Laryngoscopy and Intubation: LEMON Stridor Occurs when airway circumference is less than 50% of normal (4.5mm or less) May quickly lead to total obstruction with administration of opiates or benzos Loose the stenting of open airways Prepare for double set up

Difficult Laryngoscopy and Intubation: LEMON Neck Mobility C spine immobilization may compound the effects of other difficult airway markers Trauma, RA, Ankylosing Spondylitis May require video laryngoscopy Video laryngoscopy – less neck movement

Difficult Extraglottic Device: RODS Restricted Mouth Opening Obstruction Disrupted or Distorted Airway Stiff Lungs or Cervical Spine

Difficult Extraglottic Device: RODS Restricted Mouth Opening Allowing for oral access to insert device

Difficult Extraglottic Device: RODS Obstruction Upper airway obstruction at larynx or below EGD will not bypass this obstruction

Difficult Extraglottic Device: RODS Disrupted or Distorted Airway Seat/Seal compromised of the device Flexion deformity of the neck

Difficult Extraglottic Device: RODS Stiff Lungs or Cervical Spine Increased airway resistance Severe Asthma Decreased pulmonary compliance Pulmonary Edema Decreased Cervical Movement

Difficult Cricothyrotomy: SHORT Surgery or Disrupted Airway Hematoma (infection/abscess) Obesity Radiation Tumor Cric. rate – 0.5% medical; 2.3% in trauma

Difficult Cricothyrotomy: SHORT Surgery or Airway Disruption Anatomy distortion Halo Device Old Tracheotomy, etc

Difficult Cricothyrotomy: SHORT Hematoma Infection Trauma or Postop Not a contraindication

Difficult Cricothyrotomy: SHORT Obesity Access Short neck Large pannus Subcutaneous Emphysema Careful palpation to overcome!

Difficult Cricothyrotomy: SHORT Radiation Distortion of Anatomy Scar Tissue Fixed Flexion Deformity of the Spine

Difficult Cricothyrotomy: SHORT Tumor Extrinsic Intrinsic Access and bleeding issues

Acknowledgement Manual of Emergency Airway Management, 3rd Edition. Walls, R. and Murphy, M. 2008.