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


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

  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. <ul><li>Hi, </li></ul><ul><li>  </li></ul><ul><li>> I would like to invite you all to take part in the pain symposium </li></ul><ul><li>> conducted at Yale Medical school annually by Dr Vadivelu. The program targets medical students and aims to provide exposure to pain topics to this group of students. </li></ul><ul><li>> We will be telecasting this conference internationally at the same </li></ul><ul><li>> time. So those of you who cannot attend in person can attend virtually. </li></ul><ul><li>> This year it will be held on March 1 from 1.15 pm to 4.00 pm eastern </li></ul><ul><li>> standard time in the US </li></ul>
  34. 69. <ul><li>> The topics are meant to be a primer for medical students going into </li></ul><ul><li>> all branches of medicine. The flyer is attached with this email </li></ul><ul><li>> To view the webcast, you can go to </li></ul><ul><li>> </li></ul><ul><li>> User id: swwinternational </li></ul><ul><li>> Password: etsusww </li></ul><ul><li>> At the time of the telecast, you should be able to get the video feed </li></ul><ul><li>> when you click on flash live at the top of the screen or wowza live if </li></ul><ul><li>> you are on a iphone, ipad or mobile platform. </li></ul><ul><li>I will be conducting a trial session with just video chat on Monday Feb 28 starting 8 am to 10 am eastern std time in the US. That will be 6.30 pm-8.30 pm in India, 8pm to 10 pm in Thailand. 7am-9 am in Elsalvador </li></ul>
  35. 70. <ul><li>Remember there is 2 way chat, so you can ask questions via chat . The whole idea is for the session to be interactive . </li></ul><ul><li>> You should have a computer, laptop or mobile device with broadband </li></ul><ul><li>> internet connection for best viewing . </li></ul><ul><li>>  </li></ul><ul><li>> The technical aspects of the telecasting are managed by our good </li></ul><ul><li>> friends at east Tenessee State university </li></ul>
  36. 71. <ul><li>Viji Kurup MD </li></ul><ul><li>> Director, Departmental Education , </li></ul><ul><li>> Associate Professor, Dept of Anesthesiology, Yale University School of </li></ul><ul><li>> Medicine, New Haven, CT </li></ul><ul><li>>  </li></ul>
  37. 72. <ul><li>The timings in the different countries who are participating will be as follows: </li></ul><ul><li>March 1, 2012 </li></ul><ul><li>India- 11.45 pm to 2.30 am </li></ul><ul><li>Thailand- 1.15 am to 4 am, March 2, 2012 </li></ul><ul><li>ElSalvador- 12.15 pm to 3 pm </li></ul><ul><li>China- 0215 am to 5 am, March 2, 2012 </li></ul><ul><li>Switzerland- 7.15 pm to 10 pm </li></ul><ul><li>  </li></ul>
  38. 74. Light wand
  39. 76. Retrograde Tracheal Intubation
  40. 78. Airway Bougie
  41. 80. Cricothiroidotomy
  42. 85. Oxygen therapy <ul><li>Oxygen therapy administered as increased inhaled concentration of oxygen is indicated for a PaO2 lower than 60 mmHg. </li></ul><ul><li>Supplemental inspired oxygen is often routinely provided in the post operative period regardless of the duration or type of surgery. </li></ul>
  43. 86. <ul><li>In the presence of chronic obstructive pulmonary disease associated with carbon dioxide retention, graded doses of supplemental oxygen administered via an air entrainment (Venturi) mask increase the patient’s PaO2 to acceptable level </li></ul>
  44. 87. Nasal Cannula <ul><li>Supplemental oxygen can be administered through a nasal cannula with minimal patient discomfort. </li></ul><ul><li>A nasal cannula incorporates two prongs that extend about 1 cm into the patient’s nares and is held in place by an adjustable elastic head strap </li></ul>
  45. 89. <ul><li>Inspired oxygen concentrations achieved with nasal cannula depends on: </li></ul><ul><li>The flow rate of oxygen through the flow meter (L/min) </li></ul><ul><li>Patient’s tidal volume </li></ul><ul><li>breathing frequency </li></ul><ul><li>Volume of nasopharynx </li></ul>
  46. 91. <ul><li>Oxygen flow rate 6L/min gives inhaled oxygen concentrations about 44% </li></ul><ul><li>Excessive flow rates of oxygen may result in air swallowing and gastric distension without increasing inhaled oxygen concentration </li></ul><ul><li>Mouth breathing does not decrease the effectiveness of oxygen therapy delivered by nasal cannula because inspiratory airflow through the posterior pharynx entrains oxygen from the nose </li></ul>
  47. 94. Face Mask <ul><li>Face masks used for oxygen therapy are categorised as: </li></ul><ul><li>Simple </li></ul><ul><li>Partial rebreathing </li></ul><ul><li>Nonrebreathing </li></ul><ul><li>Air-entrainment </li></ul>
  48. 96. Simple Face mask <ul><li>It does not include a valve or oxygen reservoir bag </li></ul><ul><li>can provide inhaled concentration of oxygen between 35% and 50% with O2 flow rate of 5-8 L/min </li></ul><ul><li>Provides little advantage over nasal cannula in term of delivering constant inhaled concentrations of oxygen </li></ul>
  49. 98. Partial Rebreathing <ul><li>Its valveless system that includes an O2 resrvoir bag </li></ul><ul><li>With O2 flow10L/min the inhaled concentration of oxygen are between 50-60% </li></ul>
  50. 100. Non rebreathing <ul><li>It includes a unidirectional valve plus an oxygen reservoir bag </li></ul><ul><li>Inhaled concentration of O2 can reach 100% if the mask was fixed tight on the patient face to completely eliminate entrainment of room air </li></ul><ul><li>The flow rate of oxygen into this system should be sufficient to maintain an inflated reservoir bag </li></ul>
  51. 102. Air-Entrainment (Ventimask) Venturi Face mask <ul><li>It employs the Bernolli principle to entrain large volumes of room air to mix with oxygen flowing through an injector the resultant mixture of gases produces stable inhaled concentrations of oxygen(24-50%) depending on the bore of the O2 injector </li></ul><ul><li>The high flow of gas into the face mask result in constant inhaled concentrations of O2 despite of changes in the patient ventilation </li></ul>