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anaesthesia.Airway evaluation and management.(dr.ameer)


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anaesthesia.Airway evaluation and management.(dr.ameer)

  1. 1. Airway Evaluation and Management <ul><li>Key Learning Objectives </li></ul><ul><li>Review the anatomy relevant to airway management </li></ul><ul><li>Understand the components of an airway examination </li></ul><ul><li>Learn the principles of mask ventilation and intubation </li></ul>
  2. 2. Introduction <ul><li>Despite the site of surgery or the anesthetic technique chosen, every patient receiving anesthetic care is exposed to a varying degree of risk of airway compromise. That is, all levels of sedation, general anesthesia, and regional anesthesia carry with them at least a small risk of airway obstruction and apnea. </li></ul><ul><li>Therefore, every anesthesia provider must examine each patient in anticipation of a need to mechanically ventilate and intubate, regardless of whether or not such interventions were part of the primary anesthetic plan. A thorough airway examination and history, combined with expert airway management, guard against the life-threatening risks of airway obstruction and apnea. </li></ul>
  3. 3. Airway Anatomy <ul><li>The human airway is a dynamic structure that extends from the nares to the alveoli. </li></ul><ul><li>Obstruction can occur at any point because of anatomic collapse or a foreign body </li></ul><ul><li>which includes liquids such as mucous, blood, and gastric contents </li></ul>
  4. 6. Pharynx <ul><li>The pharynx is basically a wide muscular </li></ul><ul><li>tube forming the common upper pathway of alimentary </li></ul><ul><li>and respiratory tracts. It extends from the base of the skull </li></ul><ul><li>to the level of C6. </li></ul><ul><li>The pharynx lies posterior to, and communicates with, </li></ul><ul><li>the nose, mouth and larynx. This relationship </li></ul><ul><li>divides the pharynx into three sections: naso-, oro and </li></ul><ul><li>Laryngo pharynx. The posterior surface of the pharynx </li></ul><ul><li>lies on the prevertebral fascia and cervical vertebrae. </li></ul>
  5. 7. Larynx <ul><li>The larynx is a functional sphincter at the beginning of the respiratory tree to protect the trachea from foreign bodies. It is lined by ciliated columnar epithelium and consists of a framework of cartilages </li></ul><ul><li>linked together by ligaments which are moved by a series of muscles. </li></ul>
  6. 8. Cartilages of the larynx <ul><li>The thyroid cartilage is said to be shaped like a </li></ul><ul><li>shield. It consists of two plates that join in the </li></ul><ul><li>midline inferiorly to form the thyroid notch (Adam’s </li></ul><ul><li>apple). Each plate has a superior and inferior horn or cornua at the upper and lower limit of its posterior border, respectively. The inferior horn articulates with the cricoid cartilage. </li></ul>
  7. 9. <ul><li>The cricoid cartilage is shaped like a signet ring, with the large laminal portion being posterior. </li></ul><ul><li>Each lateral surface features a facet that articulates with the inferior horn of the thyroid cartilage. The upper border of the lamina has an articular facet for the </li></ul><ul><li>arytenoid cartilage. </li></ul>
  8. 10. <ul><li>There is a pair of arytenoid cartilages , each shaped like a triple-sided pyramid possessing medial, posterior and anterolateral surfaces. </li></ul><ul><li>Each arytenoid cartilage projects anteriorly as the vocal process and in a similar fashion laterally as the muscular process. </li></ul><ul><li>The posterior and lateral cricoarytenoid muscles are inserted into the muscular process. </li></ul>
  9. 11. <ul><li>The epiglottis is a leaf-shaped cartilage. It has a lower tapered end which is joined to the thyroid cartilage by the thyroepiglottic ligament. </li></ul><ul><li>The free upper end is broader and projects superiorly behind the tongue. </li></ul><ul><li>The lowest part of the anterior surface of the </li></ul><ul><li>epiglottis is attached to the hyoid by the hyoepiglottic ligament. </li></ul><ul><li>Two other minor cartilages are the corniculate and the cuneiform. </li></ul>
  10. 12. Ligaments of the larynx <ul><li>Extrinsic ligaments are the: </li></ul><ul><li>thyrohyoid membrane, cricotracheal, cricothyroid, and hyoepiglottic ligaments. </li></ul><ul><li>The intrinsic ligaments of the larynx are of minor importance, being the capsules of the small synovial joints </li></ul>
  11. 13. Muscles of the larynx <ul><li>Extrinsic group: </li></ul><ul><li>Sternothyroid, thyrohyoid and inferior constrictor is a constrictor of the pharynx </li></ul><ul><li>Intrinsic group: These are paired, with the exception of the ( transverse arytenoid). </li></ul><ul><li>Cricothyroid, posterior cricoarytenoid, lateral cricoarytenoid, aryepiglottic, thyroarytenoid </li></ul>
  12. 14. Nerve supply <ul><li>The mucous membrane of the larynx above the vocal cords is supplied by the internal laryngeal nerve, that below by the recurrent laryngeal nerve. </li></ul><ul><li>All muscles of the larynx are supplied by the recurrent laryngeal nerve except for the cricothyroid, which is supplied by the superior (also known as external) laryngeal nerve. </li></ul>
  13. 19. Trachea <ul><li>The trachea descends from the lower border of the cricoid </li></ul><ul><li>cartilage (C6) to terminate at its bifurcation into the two </li></ul><ul><li>main bronchi at the sternal angle (T4). The length of the </li></ul><ul><li>adult trachea varies between 10 and 15 cm. The walls of </li></ul><ul><li>the trachea are formed of fibrous tissue reinforced by 15– </li></ul><ul><li>20 incomplete cartilaginous rings. Internally the trachea </li></ul><ul><li>is lined by respiratory epithelium. The trachea may be </li></ul><ul><li>divided into two portions, that in the neck and that in the </li></ul><ul><li>thorax. </li></ul>
  14. 20. Bronchial tree <ul><li>Extrapulmonary bronchi </li></ul><ul><li>At the carina, the two main bronchi arise. The right </li></ul><ul><li>main bronchus is shorter, wider and more upright than </li></ul><ul><li>the left. The right pulmonary artery and azygos vein are </li></ul><ul><li>intimately related to the right main bronchus. The left </li></ul><ul><li>main bronchus passes under the aortic arch anterior to </li></ul><ul><li>the oesophagus, thoracic duct and descending aorta. The </li></ul><ul><li>structure of the extrapulmonary bronchi is very similar to </li></ul><ul><li>that of the trachea. </li></ul><ul><li>Intrapulmonary bronchi </li></ul><ul><li>Branching of the intrapulmonary bronchi gives rise to </li></ul><ul><li>functional units – the bronchopleural segments. </li></ul>
  15. 27. Airway assessment <ul><li>History </li></ul><ul><li>Adverse events related to prior airway management </li></ul><ul><li>Radiation/surgical history </li></ul><ul><li>Burns /swelling/ tumor /masses </li></ul><ul><li>Obstructive sleep apnea (snoring) </li></ul><ul><li>Temporomandibular joint dysfunction </li></ul><ul><li>Problems with phonation </li></ul><ul><li>C-spine disease (disc dz, osteoarthritis, rheumatoid arthritis, Down’s syndrome) </li></ul>
  16. 28. <ul><li>Examination of the upper airway: </li></ul><ul><li>Cervical spine mobility </li></ul><ul><li>Temporomandibular mobility </li></ul><ul><li>Prominent central incisors </li></ul><ul><li>Diseased or artificial teeth </li></ul><ul><li>Ability to visualize uvula </li></ul><ul><li>Thyromental distance </li></ul>
  17. 29. Malampatti/ Samson–Young classification of the oropharyngeal view <ul><li>Class I: uvula, faucial pillars, soft palate visible; </li></ul><ul><li>Class II: faucial pillars, soft palate visible; </li></ul><ul><li>Class III: soft and hard palate visible; </li></ul><ul><li>Class IV: hard palate visible only </li></ul>
  18. 32. Components of the preoperative airway physical examination <ul><li>Component </li></ul><ul><li>Length of upper incisors------------------------- </li></ul><ul><li>Relation of maxillary and mandibular-------- incisors during normal jaw closure </li></ul><ul><li>Relation of maxillary and mandibular-------- incisors during voluntary protrusion of the jaw </li></ul><ul><li>Inter-incisor distance (mouth opening)------- </li></ul><ul><li>Visibility of uvula------------------------------------ </li></ul><ul><li>Shape of palate------------------------------------- </li></ul><ul><li>Compliance of submandibular space—------ </li></ul><ul><li>Thyromental distance------------------------------ </li></ul><ul><li>Length of neck--------------------------------------- </li></ul><ul><li>Thickness of neck----------------------------------- </li></ul><ul><li>Range of motion of head and neck------------- </li></ul><ul><li>Non reassuring finding </li></ul><ul><li>Relatively long </li></ul><ul><li>Prominent “overbite” (maxillary incisors anterior to mandibular incisors) </li></ul><ul><li>Patient’s mandibular incisors anterior to (in front of) maxillary incisor </li></ul><ul><li><3 cm </li></ul><ul><li>Not visible when tongue is protruded with patient in sitting position (e.g., Malampatti class > II ) </li></ul><ul><li>Highly arched or narrow </li></ul><ul><li>Stiff, indurated, occupied by mass, or non-resilient </li></ul><ul><li><3 fingerbreadths or 6–7 cm </li></ul><ul><li>Short </li></ul><ul><li>Thick neck (size > 17 inches) </li></ul><ul><li>Patient cannot touch tip of chin to chest or cannot extend neck </li></ul>
  19. 33. Airway Devices <ul><li>Oral and nasal airways: </li></ul><ul><li>Typically inserted secondary to loss of upper airway muscle tone in anesthetized patient </li></ul><ul><li>Airway obstruction caused by tongue falling against posterior pharyngeal wall. </li></ul><ul><li>Length of nasal airway estimated by measuring from the nares to meatus of ear, use caution when used with patients on anticoagulants or has basal skull fractures </li></ul>
  20. 37. Mask
  21. 42. Laryngeal mask airway (LMA)
  22. 45. Tracheal intubation <ul><li>usually simply referred to as intubation , is the placement of a flexible plastic or rubber tube into the trachea to maintain an open airway or to serve as a conduit through which to administer certain drugs. </li></ul>
  23. 46. Endotracheal tubes <ul><li>Modified for variety of specialized applications: </li></ul><ul><li>Flexible, wired-reinforced (armored), rubber, </li></ul><ul><li>Microlaryngeal, oral/nasal RAE, double lumen, cuffed non cuffed. </li></ul><ul><li>All endotracheal tubes has a radio-opaque line. </li></ul><ul><li>Airflow resistance depends on tube diameter, curvature and length. </li></ul>
  24. 52. Indications for orotracheal intubation <ul><li>Provide patent airway </li></ul><ul><li>Prevent inhalation (aspiration of gastric content) </li></ul><ul><li>Need for frequent suctioning </li></ul><ul><li>Facilitate Positive pressure ventilation </li></ul><ul><li>Operative position other than supine </li></ul><ul><li>Operative site near or involved the upper airway </li></ul><ul><li>Airway maintenance by mask difficult </li></ul><ul><li>Disease involving the upper airway </li></ul>
  25. 58. Complications of tracheal intubation <ul><li>During direct laryngoscopy and intubation of the trachea: </li></ul><ul><li>Dental and oral soft tissue trauma </li></ul><ul><li>Hypertension and tachycardia </li></ul><ul><li>Cardiac dysrhythmias </li></ul><ul><li>Myocardial ischemia </li></ul><ul><li>Inhalation (aspiration) of gastric contents </li></ul>
  26. 59. <ul><li>While the tracheal tube is in place </li></ul><ul><li>Tracheal tube obstruction </li></ul><ul><li>Endobrochial intubation </li></ul><ul><li>Esophageal intubation </li></ul><ul><li>Tracheal tube cough leak </li></ul><ul><li>Barotrauma </li></ul><ul><li>Nasogastric distention </li></ul><ul><li>Accidental disconnection from breathing system </li></ul><ul><li>Tracheal mucosa ischemia </li></ul><ul><li>Accidental extubation </li></ul>
  27. 60. <ul><li>Immediate and delayed complications after extubation of the trachea </li></ul><ul><li>Laryngospasm </li></ul><ul><li>Inhalation of gastric content </li></ul><ul><li>Pharyngitis (sore throat) </li></ul><ul><li>Laryngitis </li></ul><ul><li>Laryngeal or subglottic edema </li></ul><ul><li>Laryngeal ulceration with or without granuloma formation </li></ul><ul><li>Tracheitis </li></ul><ul><li>Tracheal stenosis </li></ul><ul><li>Vocal cord paralysis </li></ul><ul><li>Arytenoid cartilage dislocation </li></ul>
  28. 61. Nasotracheal intubation <ul><li>an endotracheal tube is passed through the nose and vocal apparatus into the trachea. </li></ul><ul><li>Indications: </li></ul><ul><li>Intra-oral surgery </li></ul><ul><li>Anatomical abnormalities or disease of the upper airway make direct laryngoscopy difficult or impossible </li></ul><ul><li>When long-term intubation of the trachea is anticipated </li></ul>
  29. 62. Advantages of Nasotracheal intubation <ul><li>More stable tube fixation </li></ul><ul><li>Less chance for tube kinking </li></ul><ul><li>Greater comfort in awake patient </li></ul><ul><li>Fewer oropharyngeal section </li></ul>
  30. 63. Complications unique to Nasotracheal intubation <ul><li>Epistaxis </li></ul><ul><li>Dislodgement of pharyngeal tonsils (adenoid) </li></ul><ul><li>Eustachian tube obstruction </li></ul><ul><li>Maxillary sinusitis </li></ul><ul><li>Bacteremia </li></ul><ul><li>Gastric distension </li></ul>
  31. 64. Flexible Fiberoptic Brochoscope <ul><li>Indications: </li></ul><ul><li>Difficult laryngoscopy/mask ventilation </li></ul><ul><li>Unstable cervical spines </li></ul><ul><li>Poor cervical range of motion </li></ul><ul><li>TMJ dysfunction </li></ul><ul><li>Congenital/acquired upper airway anomalies </li></ul>
  32. 67. Awake Flexible Fiberoptic Intubation <ul><li>Equipment: airway, topical anesthesia, vasoconstrictors, antisialagogues, suction, fiberoptic scope with lubricated ETT </li></ul><ul><li>Indications: Cervical spine pathology, obesity, head and neck tumors, history of difficult airway </li></ul><ul><li>Premedication: Sedation (midazolam, Fentanyl, Ketamine) </li></ul>
  33. 68. Light wand
  34. 70. Retrograde Tracheal Intubation
  35. 72. Airway Bougie
  36. 74. Cricothiroidotomy