3 Purpose of this Module Review Airway Anatomy Learn Advanced Airway Assessment Techniques3-3-2Laryngoscope View GradingMallampati ClassificationsBURPDuring this module the student will review the airway anatomy.The student will learn advanced airway assessment techniques not limited to Mallampati classification, Laryngosopic view grading, and the “3-3-2” airway grading method.
4 IF Endotracheal Intubation fails, you must have a back-up plan... King-LTDLMABVMCombi-TubeCricothyrotomy
5 Upper Airway Upper Airway The face and the facial skeleton and are considered components of upper the airway. The upper airway heats, humidifies and conducts air into the lower airways. Problems can arise from obstructions, fractures and soft tissue injuries.
7 Middle Airway Middle Airway The middle airway consists primarily of the larynx. It is fairly well protected but is susceptible to injury. The larynx is comprised of cartilage and contains the vocal cords. Because it is narrow, edema, secretions, or foreign bodies can quickly cause problems.The rigid laryngeal structures are the hyoid bone, thyroid cartilage, cricoid cartilage and arytenoid cartilage. Inferior to the cricoid cartilage are tracheal cartilages. The cricoid cartilage is a complete ring and can be used to prevent passive reflux of stomach using cricoesophageal pressure (Sellick’s Maneuver)Laryngeal CartilagesThe Cricothyroid artery is a small branch of the superior thyroid artery. It travels along the inferior border of the thyroid cartilage and becomes smaller as it reaches the midline. Cricothyroid puncture in the midline, inferior part of the membrane above the cricoid cartilage is least likely to produce bleeding.The large superior and inferior thyroid arteries supply the thyroid gland. The gland is highly vascular. A pyramidal lobe may extend to the hyoid bone. Puncture below the cricoid cartilage has increased risk of bleeding. Palpate the puncture site carefully and avoid any masses (Engel et al, 2001).
8 Thyroid versus Cricothyroid Cartilage Thyroid cartilage used in “BURP” maneuver. Does not form a complete ring around the trachea.Cricothyroid Cartilage used in CricoidPressure, does form a full ring around the trachea allowing for the compression of the esophagus.
14 Difficult Airways - Assess the Risks “The difficult airway is something one anticipates; the failed airway is something one experiences.”-Walls 2002
15 How do you know if your patient is going to be difficult to intubate… …and does it really matter??In most pre-hospital cases the airway needs managing regardless of the level of difficulty, and the provider is expected to do that, regardless of difficulty ….so what is the benefit of knowing a fancy system?
16 Some Predictors of a Difficult Airway DenturesLimited jaw openingLimited cervical mobilityUpper airway conditionsFace, neck, or oral traumaLaryngeal traumaAirway edema or obstructionMorbidly obeseC-spine immobilized trauma patientProtruding tongueShort, thick neckProminent upper incisors (“buckteeth”)Receding mandibleHigh, arched palateBeard or facial hairTrauma: immobilized – cannot align axisPeds: anterior and cephalad airway, large tongue, large occiput, small mouth, stiff/floppy epiglottis (more horizontal)Obesity or very smallShort Muscular neckLarge breastsProminent Upper Incisors (Buck Teeth)Receding Jaw (Dentures)BurnsFacial TraumaS/S of AnaphylaxisStridorFBAOBloodVomitusEpiglottisDenturesTumorsImpaled ObjectsSpinal PrecautionsLack of adequate access
17 Additional Predictors: Medical History Joint diseaseAcromegalyThyroid or major neck surgeriesTumors, known abnormal structuresGenetic anomaliesEpiglottitisPrevious problems in surgeryDiabetesPregnancyObesityPain issuesRheumatoid ArthritisAnkylosing Spondylitis: Painful Stiffening of the jointCervical Fixation DevicesKlippel-Fiel Syndrome: Short wide neck, reduction in number of cervical vertebrae, and possible fusion of vertebrae.Thyroid or major neck surgeriesPierre Robin Syndrome: Small Jaw, cleft Palate, No Gag reflex, downward displacement of tongueAcromegaly: Thickening of Jaw, Soft tissue structures of the face, associated with middle age
18 Assess the RiskIdentifying a potentially difficult airway is essential to preparing and developing a strategy for successful ETI and also preparing an alternate plan in the event of a failed ETI.The American Society of Anesthesiology (AMA) has noted:“… there is strong agreement among consultants that preparatory efforts enhance success and minimize risk.”And “…the literature provides strong evidence that specific strategies facilitate the management of the difficult airway “Well, many Anesthesiologists have the option to “Abort” induction, or to work through a problem with as much assistance as needed.In the REAL WORLD of EMS that is seldom the case.However many of the BASIC principles are valid in the clinical evaluation of patients, and thus valuable in our education as medics.Knowing these principles will improve our decision making process and Patient Care;.
19 Objectives Identify 4 areas of airway difficulty Predict a difficult airway using the following mnemonics:MOANSLEMONSDOA
20 Airway Difficulties Difficult to ventilate with a BVM Difficult laryngoscopyDifficult to intubateDifficult to perform cricothyrotomyThe four dimensions of difficult airways.
21 Difficult to Bag (MOANS) Mask SealObesity or ObstructionAge > 55No TeethStiff
22 MOANS Mask Seal Small Hands Wrong Mask Size Oddly Shaped Face Bushy BeardBlood/VomitFacial Trauma
23 Obesity or Obstruction MOANSObesity or ObstructionObesityHeavy chestAbdominal contents inhibit movement of the diaphragmIncreased supraglottic airway resistanceBillowing cheeksDifficult mask sealQuicker desaturationMore dead space in cheeksLower residual volumes
24 Obesity or Obstruction MOANSObesity or Obstruction3rd Trimester PregnancyIncreased body massQuick desaturationIncreased Mallampati ScoreGravid uterus inhibits movement of the diaphragm
25 Obesity or Obstruction MOANSObesity or ObstructionObstructionsForeign BodyAngioedemaAbscessesEpiglottitisCancerTraumatic Disruption/Hematoma/Burns
26 MOANSAge > 55Associated with BVM difficulty, possibly due to loss of tone in the upper airway
27 MOANS No Teeth Face tends to “cave in” Consider leaving dentures in for BVM and remove for intubation
28 MOANS Stiff Refers to Poor Compliance Reactive Airway Disease COPD Pulmonary Edema/Advance PneumoniaHistory of Snoring/Sleep ApneaAlso predicts a higher Mallampati score
30 LOOK Externally LEMONS Beards or facial hair Short, fat neck Morbidly obese patientsFacial or neck traumaBroken teeth (can lacerate balloons)Dentures (should be removed)Large teethProtruding tongueA narrow or abnormally shaped face
31 Any single indicator has poor specificity LEMONSEVALUATE 3-3-2Bottom of Jaw/Chin to Neck > 3 fingersJaw/Palate > 3 fingers wideMouth opens > 2 fingers wideThyromental DistanceMeasure from upper edge of thyroid cartilage to chin with the head fully extended.A short thyromental distance equates with an anterior larynx that is at a more acute angle and also results in less space for the tongue to be compressed into by the laryngoscope blade.> 7 cm is usually a sign of an easy intubation< 6 cm is an indicator of a difficult airwayRelatively unreliable unless combined with other testsAny single indicator has poor specificity
32 LEMONS EVALUATE 3-3-2 Mouth Opens at least 3 finger widths. Three finger widths thyromental distance.Two finger widths mandibulohyoid distance.
33 LEMONSEVALUATE 3-3-2Will patients mouth open wide enough to accommodate 3 fingers?Will 3 fingers fit between the mentum and hyoid bone?Will 2 fingers fit between the hyoid and thyroid notch?If not, expect a difficult intubation
34 Mouth opens at least 3 fingers width? LEMONSMouth opens at least 3 fingers width?
35 LEMONS Thyromental Distance Distance from the mentum to the thyroid notch.Ideally done with the neck fully extended. Can be done in-lineHelps determine how readily the laryngeal axis will fall in line with the pharyngeal axis.
36 LEMONS Thyromental Distance If the thyromental distance is short, <3 finger widths, the laryngeal axis makes a more acute angle with the pharyngeal axis and it will be difficult to achieve alignment.Less space to displace the tongue.
38 Mandibulohyoid Distance- 2 fingers? LEMONSMandibulohyoid Distance- 2 fingers?Measured from the mentum to the top of the hyoid bone.The epiglottis arises from the thyroid and remains dorsal to the hyoid bone.Therefore, the position of the hyoid bone marks the entrance to the larynx.
40 Mandibulohyoid Distance LEMONSMandibulohyoid DistanceWhen the position of the hyoid bone is caudal or relatively caudal, a large portion of the tongue is situated in the hypopharynx instead of the mouth.During laryngoscopy, this large hypopharyngeal tongue mass further compromises the compliance needed for its displacement
41 Mandibulohyoid Distance LEMONSMandibulohyoid DistancePatients who have a longer mandibulohyoid distance, greater then 2 finger widths, tend to be more difficult to intubate.A more caudal hyoid bone thus indicates a relatively caudal larynx.
42 LEMONS Upper & Lower Face Measure the size of the upper face as compared to the lower face.Should be roughly the same.If the lower face is longer than the upper face then you should anticipate some degree of difficulty lining up the structures.
43 Upper and lower face equal? LEMONSUpper and lower face equal?
44 Upper and lower face equal? LEMONSUpper and lower face equal?
46 LEMONS Mallampati Score Have patient sit up, and stick out tongue without phonatingMay be unable to properly assess this in an emergent field situationModified version is to use a laryngoscope blade like a tongue blade to visualize the oropharynx – (not as sensitive or specific)
47 Mallampati Classification LEMONSMallampati ClassificationRelates to tongue size to pharyngeal size.Performed with patient in a sitting position, head neutral, mouth open wide and tongue protruding to the maximum.The Subsequent Classification is assigned based upon the pharyngeal structures visible.
48 Mallampati Classification LEMONSMallampati ClassificationClass I: Visualization of the soft palate, fauces, uvula, and anterior & posterior pillars
49 Mallampati Classification LEMONSMallampati ClassificationClass II: Visualization of the Soft palate, fauces and uvula.
50 Mallampati Classification LEMONSMallampati ClassificationGrade III: Visualization of the soft palate and the base of the uvula.
51 Mallampati Classification LEMONSMallampati ClassificationGrade IV: The soft palate is not visible at all.
52 LEMONSPt should be sitting, head in neutral position, mouth wide open, and tongue extended out as far as possible. The number classification is based on the structures that are visible.A Class I view is a Grade I Intubation 99% of the timeA Class IV view is a Grade III or IV intubation 99% of the timeClass IV: <1% prevalence (hard palate only visible) Severe Difficulty IntubatingClass III: <13% prevalance (soft palate, base of uvula visible) Moderate Difficulty IntubatingClass II: 40% prevalence (soft palate, uvula, fauces visible) No Difficulty IntubatingClass I: 46% prevalence (soft palate, uvula, fauces, pillars visible) No Difficulty Intubating
54 LEMONSObstructionLaryngoscopy or intubation may be more difficult in the presence of an obstructionAnatomyTraumaForeign body obstructionEdema (burns)
55 Obstructions Laryngoscopic View Grades LEMONSObstructions Laryngoscopic View GradesGrade 1: Full aperture visibleGrade 2: Lower part of cords visibleGrade 3: Only epiglottis visibleGrade 4: Epiglottis not visible
56 Obstructions Laryngoscopic View Grades LEMONSObstructions Laryngoscopic View GradesGraded in order from the best view to worst.Grade 1: Visualization of the entire laryngeal apeture
57 Obstructions Laryngoscopic View Grades LEMONSObstructions Laryngoscopic View GradesGrade 2: Visualization of just the posterior portion of the laryngeal aperture.Grade 3: Visualization of only the epiglottisGrade 4: Visualization of the soft palate only.
58 Obstructions Laryngoscopic View Grades LEMONSObstructions Laryngoscopic View GradesA severe grade III or IV view with failed endotracheal intubation occurs in % of patients
60 Cormack & Lehane Grading LEMONSCormack & Lehane GradingGrade I = success & ease of intubation10-30%Grade I: full aperture is visibleGrade II: Lower portion of cords visibleGrade III: Epiglottis only visibleGrade IV: Epiglottis not visibleGrades III & IV are rare. So, if you frequently see Grade III or IV – consider revisiting your technique.<5%<1%% listed = incidence
61 LEMONSNeck MobilityIdeally the neck should be able to extend back approximately 35°Problems:Cervical Spine ImmobilizationAnkylosing SpondylitisRheumatoid ArthritisHalo fixation
62 Scene and Situation (SEE) LEMONSScene and Situation (SEE)Scene safetyEnvironmentDo you have a reasonable chance to get the tube?Space, positioning, accessEgressWill you be able to ventilate during egress?A respiratory rate of 4 is better than a rate of 0!Enough meds for a long extrication?
63 Difficult Cricothyrotomy DOADifficult CricothyrotomyDOADisruption or DistortionObstructionAccess ProblemsIf you can’t bag and can’t cric, they’re DOA
66 DOA Obstructions Hematoma Abscess Tumor Tumors can also create distortions & extra bleeding
67 DOA Access Issues Obesity Halo Short neck SC Emphysema Bushy beard Flexion deformity of the spine
68 “BURP” – a.k.a. “External Laryngeal Manipulation” Backward, Upward, Rightward Pressure: manipulation of the trachea90% of the time the best view will be obtained by pressing over the thyroid cartilage90% of the time the best view will be obtained by pressing over the thyroid cartilage – because, anatomically, the vocal cords are connected here.“BURP”-backwards, upwards, right, pressureMay help with difficult intubationDiffers from the Sellick Maneuver
69 To Summarize Airway assessment is a critical part of the RSI process The difficult airway assessment must be performed prior to ALL RSI attempts.While this criteria helps identify difficult airways, it does not guarantee an easy intubation—Be Prepared!