The Airway and Intubation

The Airway and Intubation David N. Schrier, MD But first… a few pointers • • • • • Work hard… “opportunities to learn” The pt comes first… always Know when to call for help Never stop reading Try new techniques • Airway management • Medications • Know who your friends are • Go on a MedRete with Dr Horlbeck Airway Overview • • • • • It’s the A in “ABC” for a reason You will become the airway expert in the hospital You will still be surprised by difficult intubations You must always have a backup plan (2-3 tiers) When in doubt, Nunquam exuro vestri pontus! Lecture Topics • • • • • • • • • Airway examination Direct laryngoscopy Mask ventilation Confirming ETT placement Airway anatomy and neuroanatomy Alternatives to direct laryngoscopy Difficult airway algorithm Extubation criteria Pediatric airways Reasons to Intubate • Control the airway • • • • Render the pt unconscious or apneic Surgical position/site/duration makes mask vent difficult Upper airway involved in disease process Potential for aspiration or copious secretions • Control the lungs • Deficiency of oxygenation or ventilation • Provide positive pressure ventilation • Diagnostic or therapeutic procedures Airway Evaluation • Modified Mallampati Classification System I - Uvula, soft palate, tonsillar pillars II - Soft palate, uvula III - Base of uvula IV - Hard palate only • • • • Mouth opening Thyromental distance Neck extension Dentition Difficult Mask Ventilation • • • • • • Edentulous status Beard Obesity OSA Large tongue/tonsils Abnormal facial anatomy Mask Ventilation Aids • Proper “E-C” maneuver • Chin lift • Not if cervical spine unstable • Jaw thrust • Oral airway • Stimulates gag reflex/laryngospasm • Bleeding and dental trauma possible • Nasal airway • Not in basilar skull fx, nasal deformities Predictors of Difficult Intubation * History of Difficult Intubation * • • • • • • • • • • Mallampati class III or IV Limited neck mobility (<80° ROM) Limited mouth opening (2 FB or 3-4cm) Limited thyromental distance (2 FB or 3-4cm) Large tongue (relative to oral cavity) Prominent incisors (“buck teeth”) Short and/or thick neck Large overbite or inability to prognath mandible Arched or narrow palate Altered submandibular space: stiff, indurated, mass effect Predictors of Difficult Intubation: The Short Version (4 D’s) • Distortion (trauma, infection, neoplasm, edema, hemorrhage, vomitus) • Disproportion (tongue/pharynx, thyromentaldisplacement space) • Dysmobility (atlanto-occipital joint, neck mobility, TMJ) • Dentition (prominent incisors) Airway Positioning OA PA OA PA LA LA Airway Anatomy Confirmation of Intubation • Subjective indicators: • • • • Directly visualizing the ETT passing the vocal cords Palpation of ETT during cricoid pressure Compliance of breathing bag “Fog” in ETT Confirmation of Intubation • Objective indicators: • • • • • • End-tidal CO2 on 3-5 successive breaths Color change with plug-in CO2 detector Bilateral chest rise and auscultation Re-inflation of esophageal bulb Visualizing tracheal rings via bronchoscope Air flow through ETT with spontaneous ventilations Confirmation of Intubation • Negative Indicators • • • • Gastric contents from ETT Pt able to phonate Pt breathing around ETT Gastric insufflation with positive pressure Airway Neuroanatomy Trigeminal n. Glossopharyngeal n. (afferent branch of gag reflex) Superior laryngeal n. Recurrent laryngeal n. (efferent branch of gag) Numbing the Airway • • • • Keep toxic dose of LA in mind Require pt cooperation Provide adequate sedation, but not too much Prepare airway by region or by nerve • Nares and nasopharynx (if applicable) • Pharynx and base of tongue • Larynx and trachea Other Airway Methods • Adjunct to DL • Eschmann stylet or gum elastic bougie • External cricoid pressure • “Ramp” or shoulder roll • No cuffed ETT • • • • LMA COPA LTD Combi-tube Other Airway Methods • Ways to see or get around a corner • • • • • • • • • • Fiberoptic bronchoscope Intubating LMA Lightwand Bullard Retrograde wire Digital intubation Seeing stylet Air-trach Retrograde wire Blind nasal intubation Other Airway Methods • When you’re desperate • • • • Cricothyrotomy Tracheostomy Transtracheal jet ventilation Apneic oxygenation Difficult Airway Algorithm • Answer these three questions: • Spontaneously ventilating or not? • Surgical airway or non-surgical airway? • Before or after induction of general anesthesia? Difficult Airway Algorithm Extubation Criteria • Spontaneous and adequate ventilations • RSBI or f/VT < 105 • Adequate muscular strength • Reversal of neuromuscular blockade • 5s tetany, head lift, hand grip • Hemodynamically and metabolically stable • Able to control airway • Follow commands, gag reflex • Out of stage II of anesthetic Pediatric Airways • Large occiput • Often require shoulder roll rather than head pillow • Large tongue relative to rest of oropharynx • Elongated, stiff epiglottis • Straight blade most commonly used • Narrowest portion of larynx • Level of cricoid cartilage in children • Vocal cords in adults • Vocal cords more cephalad • Vocal cords oriented in transverse plane Pediatric Airways • • • • • • Most kids are easy airways High VO2  more rapid desaturation Beware of vagal response to DL ID ETT = Age/4 + 4 (variable) Check for leak (<25cm H2O) Easy to mainstem kids • Or convert properly placed ETT into mainstem Conclusions • Airway comes first for a reason • Approach even the “easy” airway with respect • Approach the anticipated difficult airway with respect, forethought, and planning • Practice airway adjuncts on elective cases • Confirm your ETT placement • Do your own airway exam on every patient • Can’t intubate, can ventilate… you’ve got time • Can’t intubate OR ventilate… get help fast