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PHD Resident Airway Lecture Alan I. Frankfurt, MD Alan Frankfurt, M.D.; Gary Weinstein, M.D. Why Train? “…my life flashed before my eyes.” Meaning? Initial response to any stressful/life threatening experience… Mental rolodex scanning “Have I ever been in or seen a situation like this before?” What worked then?” What did not work? Why train? Populating your mental rolodex Making the unfamiliar, familiar in a controlled environment. Training: USAF Experience USAF Red Flag Training Exercise 90% of all fighter pilots who died in combat, did so in their first 10 missions. Learning curve: First ten missions. Flying those first ten missions in a training environment. Red Flag Training Exercise. Airway Class Objective Use this airway training as your own Red Flag Exercise Training Lecture Hands on lab Visualization Airway Topics Relevant airway anatomy Innervation of the airway Anesthesia of the airway PU<92% Concept Airway examination 6 D’s Airway Definitions and Concepts Jim Rich, CRNA Critical airway event: ability to rescue the airway. CICMV Intubation difficulty Definition: difficult airway SPO2<92% 100% Oxygen PPV Crash airway: early recognition for patient salvage. PU<92 IRS Intubation Rescue breathing Surgical airway Airway Evaluation: 6 D’s Difficulty airway options Intubation rescue options Law of insanity AB4C’S Overview of Upper Airway Anatomy: Structure and Function Nares: Nasal Turbinates Turbinate bones Superior Inferior Middle Function 10,000 L of ambient air pass through the nasal airway per day and 1 L of moisture is added to the air during this process. Inferior turbinate Highly vascular membrane Vasoconstriction prior to instrumentation Nasotracheal tube Nasopharyngeal airway Pharynx Location The pharynx situated between the nose and larynx. 3 Divisions Nasopharynx Oropharynx Hypopharynx (Laryngopharynx) The Pharyngeal Anatomic Divisions Nasopharynx Oropharynx Termination of the turbinates and nasal septum Soft palate. Soft palate Hyoid bone. Hypopharynx Hyoid bone First tracheal ring AKA Laryngopharynx Larynx Base of the tongue (hyoid bone) -> first ring of the trachea. Opposite C3-C6 Function Watchdog of the airway Swallowing Organ of phonation Bones Hyoid Cartilages Epiglottis Thyroid Cricoid Laryngeal Anatomy Cricoid Cartilage Anatomic lower limit of the larynx. Only complete cartilaginous ring in the upper airway. Attaches to the thyroid cartilage by the cricothyroid membrane. Laryngotracheal anesthesia Surgical airway Identification in the patient with poor anatomic landmarks. Cricothyroid artery The superior thyroid artery First anterior branch of the external carotid artery. The cricothyroid artery Branch of the superior thyroid artery Runs in the upper portion of the cricothyroid membrane. Surgical airway Tracheal hook placement Airway Innervation: 5-9-10 Innervation of the Nasal Passage and Nasopharynx: CN 5 Anterior 1/3 of the nares. Anterior ethmoidal nerve Posterior 2/3 of the nares. Greater and Lesser Palatine nerve Anesthesia for the Mouth and Oropharynx: CN 9 Anatomy Glossopharyngeal nerve (CN9) Anesthesia for the Mouth and Oropharynx: CN 9 Poster 1/3 tongue, Gag reflex Vallecula, Anterior surface of the epiglottis (lingual branch), Posterior and lateral walls of the pharynx (pharyngeal branch), and Tonsillar pillars (tonsillar branch). Laryngeal Innervation: CN 10 CN X (Vagus) Superior laryngeal nerve Internal laryngeal nerve. Posterior epiglottis to vocal cords. Penetrates at the thyrohyoid membrane. External laryngeal nerve. Cricothyroid muscle Innervation of Trachea and Vocal Cords Recurrent Laryngeal Nerve Sensory innervation of the tracheobroncheal tree up to and including the vocal cords. Intrinsic laryngeal musculature except cricothyroid muscle. Airway Anesthesia Airway manipulations issue without adequate anesthesia. Patient comfort Hemodynamic response Valsalva Airway anesthesia options “Spray and Pray”: Topicalization of the airway with local anesthesia Entire airway may be anesthetized using topical anesthesia Nerve block ? Glossophyngeal nerve Superior laryngeal nerve “Transtracheal nerve block” Airway Local Anesthesia Drug Absorption Topical anesthetic absorption Alveoli>Tracheobroncheal tree>Pharynx Airway Anesthesia Medications Cocaine 4% and 10% solutions 3 mg/kg (200 mg maximum dose) 5cc’s in a 70kg person. Benzocaine Rapid onset and short duration (10 minutes) Cetacaine Methemoglobinemia Bezocaine, Tetracaine Cyanosis, fatigue, weakness, headaches, dizziness and tachycardia Massimo pulse oximeter Lidocaine 1%, 2% and 4% solutions Rare to see toxic reactions within the context of airway anesthesia. 4% lidocaine/Afrin mixture Lidocaine 5% ointment Lidocaine 2% jelly Viscous lidocaine. Tetracaine Loaded in a syringe Swish and swallow Toxicity 100mg (40mg) Goal of Airway Anesthesia Airway Preparation for Awake Airway Manipulation First: Never sacrifice patient safety for patient comfort. What are the systemic effects of inadequate airway anesthesia? Coughing, straining, valsalva Hypertension and Tachycardia Myocardial oxygen consumption Increased ICP Increased IOP How to prepare for success prior to anesthetizing the airway. Maintain the ability to communicate with the patient. Dry the airway. Maximize effectiveness of the LA applied to the airway. Dilution of LA concentration by oral secretions Decreases LA effectiveness Comfortable patient is a cooperative patient: Sedation/analgesia/anesthesia Intravenous medications Transmembrane medication administration Patient Preparation for Anesthesia of the Airway Antisialogogues (Drying Agents) Vasoconstrictor Robinal 0.2-0.4 mg IV Atropine 0.5-1.0 mg IV Afrin spray Phenylephrine 1% spray Anxiolytics and Analgesia Versed Fentanyl Naloxone Monitors Flumazenil Pulse Oximetry Supplemental oxygen Key Airway Anesthesia Principles: Timing, Positioning and Lubrication Timing Give your preparation drugs time to work. Anticholinergic Vasoconstriction agents Positioning Position yourself to succeed. Go slow Monitor the patient Masimo pulse oximetry Don’t burn any airway bridges Reversible agents Lubrication The entire airway can be anesthetized topically with generous amounts of anesthetic jelly and ointment. Recurrent Laryngeal Nerve Block: AKA Transtracheal Block Indications Anesthesia for the laryngotracheal mucosa. Awake intubation, Retrograde intubation, Cricothyrotomy (surgical or percutaneous), Abolishment of gag reflex or hemodynamic response associated with intubation. Medications 4% Lidocaine 1-2% Lidocaine Recurrent Laryngeal Nerve Block: AKA Transtracheal Block Patient positioning Supine in the “sniffing” position Technique Cricothyroid membrane identification. Local anesthesia skin wheal: Conscious verse Unconscious Patient 2-3cc of 4% Lidocaine drawn into a 5cc syringe 20G Angiocath needle. Identification of the airway Loss of resistance Air bubbles signals entry into the larynx. How I Do It: Robinal Afrin/Afrin and 4% Lidocaine cocktail. Nasal manipulation. Sedation +/Nebulized 4% Lidocaine 2-3cc Prior to the application of gels or ointments. 4% Lidocaine in a syringe dribbled down the nares. (Viscous Lidocaine swish and swallow). Oral airway/Nasal trumpet with 5% Lidocaine gel. CN9 gag reflex: posterior tongue. Transtracheal block with 4% Lidocaine with 22G-25G needle or 20 G Angiocath. Above and below vocal cord anesthesia. PU-92 Concept Crash Airway Crash Airway Concept: Walls, R. Teaching Goal: To identify patients in extremis. Patients who are going to die unless you intervene quickly and decisively. Who are these patients? Altered mental status with airway compromise. Lethal combination: M/M increased 50-75% Unconscious Apneic or having agonal respirations. Arrested or near death. Anticipated to be unresponsive and tolerant to laryngoscopy. Getting Your Arms Around The Crash Airway: PU-92 Crash airway Meant to convey an unmistakable sense of urgency. Circling the drain! From conceptual idea to clinical action. PU-92 concept PU-92: Reflects the lethal combination of a cerebral insult (ischemic or traumatic) and hypoxia. Critical nature of early airway support in the face of brain injury. Airway compromise in a patient with compromised cerebral circulation may DOUBLE mortality. Provides a quick and reliable tool to recognize these patients early and intervene. PU-92 Parameters Level of consciousness SpO2 level PU-92 Parameters: LOC and SpO2 Level of consciousness using the AVPU system Alert, Voice response, Pain response only or Unresponsive McKay et al: P or U response corresponds to a GCS<9 GCS<9 immediate indication for intubation Patients SpO2 level SpO2<92%, despite: PPV manual airway opening techniques 100% oxygen ( if available). If SpO2 unavailable, use a RR <10 or > 30/breathes per minute. Use of SpO2 in the field environment. Masimo Movement algorithm Low perfusion algorithm Co and MetHg Maximum airway efforts utilizing: PU<92: Now What? The Crash Airway Response Patients require immediate improvement in Ventilation and Oxygenation Treatment options: IRS Intubation Rescue Ventilation Surgical airway Treatment options are decided upon after an Airway Evaluation Airway Evaluation reveals: No difficulty anticipated One attempt at direct laryngoscopy and Intubation (I). Failed intubation fall back to Rescue Ventilation (R) Class 2a agent Surgical airway (S) Difficulty anticipated Rescue Ventilation Surgical airway Rescue Ventilation Positive Pressure Ventilation with Class 2a adjunctive airway device. Class 2a: therapeutic option for which the weight of evidence is in favor of its usefulness and efficacy. ETC: Esophageal-tracheal Combitube LMA (King LT) Class 2a devices are supraglottic devices which do not address obstruction of the airway at the glottic or subglottic level. Endotracheal tube Cricothyrotomy Airway literature reveals that rescue ventilation is often effective in providing ventilation and oxygenation in the following conditions CMVCI Failed intubation ECT: Esophageal Combitube Tube ECT: Esophageal Combitube Tube ECT: Esophageal Combitube Tube LMA King LT Summary: Crash Airway Confirm a crash airway exist: Patient in extremis. PU-92. Call for help. Maximize airway support Manual maneuvers Airway devices: OA and NT PPV with 100% O2 as available Identify possible difficulty airway Pay the “IRS” Intubation attempt Only if airway appears easy to intubate Airway evaluation 6 D’s Rescue ventilation If intubation fails or airway appears difficult SpO2>92 Yes-monitor airway and reassess need for definitive airway No-> Surgical airway Airway Evaluation 6-D Method of Airway Assessment 6-D Method of Airway Assessment 6-D method of airway assessment is meant to assist health care providers in remembering the six signs that can be associated with a difficult intubation. Each sign begins with a D. The potential for airway difficulty is generally proportional to the number of signs observed. 6-D Method of Airway Assessment 1. Disproportion. 2. Distortion. 3. Decreased thyromental distance (3). 4. Decreased interincisor gap (2). 5. Decreased range of motion in any or all joints of the airway (1). 6. Dental overbite. 6-D Method of Airway Assessment Disproportion Size of tongue in relation to the oropharyngeal size. Obstructed laryngoscopic view of airway. Airway trauma (blunt or penetrating) with resultant swelling. Patient’s anatomy Assessment Mallampati Classification Predicting airway disproportion problems: Mallampati class 4 (3?) Swelling or protruding tongue Blunt or penetrating injury Receding mandible Mallampati Airway Classification System Class 1: soft palate, uvula, anterior and posterior pillars are visible. Class 2: soft palate and uvula are visible Class 3: only soft palate and base of uvula visible. Class 4: hard palate visible, but not the soft palate. 6-D Method of Airway Assessment Distortion Etiology: Neck mass, neck hematoma, neck abscess, previous surgery or trauma. Predicting airway distortion problems: Voice change Subcutaneous emphysema Laryngeal immobility Non palpable thyroid and/or cricoid cartilage. Neck asymmetry Tracheal deviation Subcutaneous emphysema 6-D Method of Airway Assessment Decreased thyromental distance Reflects an anterior larynx and decreased sub-mandibular space. Problem: Unable to displace the tongue into the submandibular space, out of the view of the laryngoscopist. Predicting airway difficult resulting from decreased thyromental distance: Thyromental distance <7 cm (<3 FB) Measured from the superior aspect of thyroid cartilage to the tip of the chin. Underdeveloped mandible 6-D Method of Airway Assessment Decreased interincisor gap Reduced mouth opening Reduced ability of the oral cavity to accommodate airway instrumentation. Predicting airway difficulty secondary to decreased incisor gap distance: Distance between the upper and lower incisors is <4 cm ( 2 FB ) Mandibular condyle fracture. Rigid cervical collar. TMJ dysfunction 6-D Method of Airway Assessment Decreased range of motion in any or all of the joints of the airway. Atlanto-occipital joint, cervical spine and TMJ. Sniffing position. Predicting airway difficulty secondary to decreased ROM of joints involved in assuming the sniffing position: Head extension < 35 degrees Neck flexion < 35 degrees Short, thick neck Cervical spine collar or C spine immobilization 6-D Method of Airway Assessment Dental overbite Large angled teeth disrupt the alignment of the airway axes and possibly result in decreased interincisor opening. Predicting airway difficulty secondary to dental overbite: Protruding maxillary incisors. Treatment of Airway Loss: Operator Skill and Equipment Requirements. Causes of Airway Obstruction: LIFT L-Level of consciousness Trauma or Medications. Loss of muscle tone Jaw lift Nasal trumpet I-Inflammation Burns Early intervention Advanced airway techniques Anaphylaxis F-Foreign body Blood clots, teeth, bone, food… Finger sweep, positioning T-Trauma If it was pushed in…pull it out. Treatment of Airway Obstruction: AIR A-Assess for airway obstruction Recognition Signs and symptoms Dysphonia, noisy breathing, RR<8 or >30, use of accessory muscles. I-Improve the airway Positioning Position of comfort Recovery position Cervical spine precautions. Mechanical Jaw thrust, Chin lift Nasal trumpet(s) R-Remove any debris Finger sweep Indications for Tracheal Intubation Airway protection and risk for aspiration. Need for a definitive airway. Patient will be going to OR and has an unstable airway. Respiratory failure/arrest and in need of mechanical ventilation PEEP administration GCS<9 or on AVPU scale a “P” or “U” ACLS drug administration Pulmonary toilet Hypoxemia refractory to oxygen therapy Uncontrolled seizure activity Depressed LOC in a trauma patient Combative patient with a compromised airway. Emergency Indications for Intubation Can’t protect airway Gag reflex absent in 37% population Ability to swallow and manage secretions Can’t maintain Ventilation/Oxygenation Inability to maintain SpO2>92% on oxygen, PaCO2>55 or 10 torr above baseline. RR <8 or >30/ minute Expected decline in clinical status. Deterioration/Impending Transport compromise Contraindication to RSI Evaluation of the patient’s airway reveals that laryngoscopy and intubation would not be successful Unfamiliarity with the technique Do what you do all the time. Lack of any rescue ventilation options 6 D’s Plan A, B, C. Other safer options Awake intubation under topical and nerve block anesthesia Cricothyrotomy under local anesthesia Local infiltration Transtracheal block Don’t burn an airway bridge. A lousy airway is better than no airway. Direct Laryngoscopy Checklist Variety of laryngoscopy blades Variety of Endotracheal tube (ETT) sizes Stylett the ETT Boogie Test balloon on ETT Class 2a rescue ventilation device Adequate muscle relaxation if indicated Head position Suction Test IV patency Pre-treatment Oxygen Vagolytic Non particulate antacid RSI indicated? Assistant present as available Look for the epiglottis first Don’t shotgun the laryngoscope Control the tongue Don’t lever the blade. Intubation confirmation device Techniques to Rescue a Difficult Intubation Avoid the Law of Insanity Law of Insanity Doing the same thing over and over again while expecting a different result. Techniques to Rescue a Difficult Intubation Access Visualization Passage of the ETT Techniques to Rescue a Difficult Intubation: Law of Insanity AB4C’S Axis Boogie BURP Blade: size and type Block Cricoid pressure: let up Stylet/Smaller ETT Techniques to Rescue a Difficult Intubation Sniffing Position Head extension Neck flexion Onto the shoulders 20-30 degree angle Aligning Axes of Upper Airway A Mouth A B B Pharynx C C Trachea Extend-the-head-on-neck (“look up”): aligns axis A relative to B Flex-the-neck-on-shoulders (“look down”): aligns axis B relative to C External Laryngeal manipulation (ELM): BURP BURP Laryngoscopist hand placed on top of assistant’s hand. Backward, Upward, Rearward Pressure. Thyroid cartilage Gum Elastic Bougie Gum Elastic Bougie Most beneficial with a Grade III larygoscopic view. Works synergistic with other airway maneuvers ELM: BURP airway manipulation Jaw thrust/chin lift. Indicators of successful tracheal placement of the bougie Tracheal clicking Hold up Leave the laryngoscope in place during ETT insertion with the bougie in place. Rotate the ETT counter clockwise 90 degree to prevent the tip of the ETT from hanging up on laryngeal structures during passage. BURP Maneuver Difficult intubation rescue option Improve visualization of the larynx by at least one grade. Knill RL; Can J Anesth 1993;40:279-82 BURP maneuver results in displacement of the larynx in three specific directions to place the vocal cords in view of the operator: Backward-Thyroid cartilage displacement dorsally (backward) as to abut the larynx against the bodies of the cervical vertebrae. Upward-Thyroid cartilage is moved cephlad about 2 cm until mild resistance is met. Rightward-laterally to the right approximately 0.5-2.0 cm. Pressure Employing the BURP maneuver, the assistant moves the larynx until mild resistance is met. BURP Maneuver Mechanism of Action As a result of the BURP maneuvers, the glottis is moved directly into the line of vision. Let’s examine why this is true: The laryngoscope enters the oral cavity from the right and displaces the tongue toward the left. Tongue attached to larynx. Hence the larynx is moved leftward as well. Resulting visual pathway is somewhat to the right side of the oral cavity midline. BURP maneuver may improve visualization of the glottis by moving the larynx more into the line of vision. Effect of BURP on Visualization Grade Initial After Inspection BURP Grade 1 0 231 Grade 2 181 38 Grade 3 80 4 Grade 4 12 0 Surgical Airway Cricothyrotomy Rapid Access to the Airway or Not. Indications for Surgical Airway Clinical Mid face trauma Blunt vs. Penetrating Airway obstruction above the level of the cricoid cartilage. Anaphylaxis/Anaphylactoid reaction Burn Failed intubation and failed rescue ventilation Cricothyrotomy: Rapid 4 Step Technique Instruments: Rapid 4 Step Technique Scalpel with a no.20 blade, tracheal hook, no. 6 Shiley tracheostomy tube. Instruments: Std Technique Scalpel with no.11 blade, Trousseau dilator, hemostats, tracheal hook, no. 6 Shiley tracheostomy tube. Cricothyrotomy: Standard Technique Steps Identification of the cricoid membrane Palpation Dissection 4 cm vertical skin incision over the cricoid membrane. Short horizontal stab wound over the lower portion of the cricoid membrane. Never remove scalpel blade until tracheal in place. Stabilization of the larynx with a tracheal hook at the inferior aspect of the thyroid cartilage. Dilation of the ostomy with a curved hemostat. Placement of the Shiley tube/Endotracheal tube. Sternal notch Cricothyrotomy: Rapid 4 Step Technique Steps Identification of the cricothyroid membrane by palpation. Horizontal stab wound through the skin and cricothyroid membrane with the scalpel. Non-palpable anatomy: skin incision Stabilization of the larynx with the tracheal hook at the inferior aspect of the ostomy (on the cricoid cartilage), providing caudal traction. Placement of the Shiley tube in the trachea. Cricothyrotomy: Modified Technique Identification of the cricoid cartilage. Easy Hard Anesthesia? Local infiltration Transtracheal block 2-4 cm vertical incision overlying the cricoid membrane. Non palpable and non visualized Sternal notch and work your way upward. Not a cosmetic procedure. Use the entire incision Define your anatomy No. 20 blade attached to a scalpel for cricoid membrane puncture. Puncture made at the superior aspect of the cricoid cartilage. Cricothyrotomy: Modified Technique Tracheal hook applied to the superior surface of the cricoid cartilage. The cricoid cartilage is delivered out of the wound. Stabilizes the larynx. Prevents blood from pooling in the wound. Not working in a deep hole. Kelly clamp used to dilate the ostomy. #5-6 ETT/#6 Shiley placed in the ostomy Bougie Confirmation of tracheal intubation CO2 detection Capnography Colorimetric SIB (Self inflating bulb) Questions?