Medic 14 Medic Chapter 15 airway management

  1. Objective:
    Describe the major structures of the respiratory system, including the upper and lower airway.(pp. 712-717)
  2. Airways is divided into the
    upper and lower airway
  3. Structures that help us breath include
    diaphragm, intercostal muscles, accessory muscles of breathing, and nerves from the brain and spinal cord to those muscles.
  4. What muscles are responsible for regular rise and fall of the chest that accompany normal breathing.
    Intercostal and diaphragm
  5. Upper airway consists of
    all the anatomic airway structures abouve the level of the vocal cords- nose,mouth,oral cavity, and pharynx (throat).
  6. Larynx is considered the point of division between
    the upper and lower airways
  7. Major functions of the upper airway:
    Warm,filter, and humidify air as it enters the body through the nose and mouth
  8. Humidification is accomplished
    as the air picks up moisture from the soft tissues of the airway.
  9. Pharynx
    is a muscular tube that extends from the nose and mouth to the level of the esophagus and trachea.
  10. Pharynx is composed of the
    • Nasopharynx
    • Oropharynx
    • Laryngopharynx (hypopharynx)
  11. Laryngopharynx opens into the
    • Larynx Anteriorly
    • Esophagus Posteriorly
  12. Ciliated mucous membrane of the nasopharynx is
    • extremely delicate and has a rich blood supply, is used to keep contaminants and other small particles out of the repiratory tract.
    • bleeding in this area cannot be controlled by direct pressure.
  13. Turbinates
    protrude from lateral walls of nasal cavity and increase the surface area of the nasal mucosa, improving warming,filtering ,and humidificaiton of inhaled air.
  14. Nasal septum
    divides nasophaynx composed of the ethmoid and vomer bones
  15. Caution: deviated septum w/ Nasal airway device
  16. Paranasal sinuses
    • are the frontal and maxillary sinuses
    • they prevent contaninants from entering the respiratory tract and act as tribuatary for fluid to and from the eustachian tubes and tear ducts
    • Facture of the bones that comprise the sinuses may cause CSF to leak from the nose  or from the ears
  17. CSF from nose
    cerebrospinal rhinorrhea
  18. CSF from ears
    cerebrospinal otorrhea
  19. Hyoid bone
    small,horseshoe shaped bone to which the tongue and mandible ,jaw,epiglottis,and thyroid cartilage.
  20. Palate
    • forms the roof of the mouth and separates the oropharynx and nasopharynx
    • Anterior portion formed by the maxilla and palitine bones, called the hard palate
    • soft palate posterior to hard palate
  21. Platoglossal arch
    posterior border of the oral cavity and is an externsion of the soft palate
  22. Uvula
    soft tissue structure that resembles a punching bag and extensnds in the platoglossal arch at the base of the tongure and posterior aspect of the oral cavity
  23. palatopharygeal arch
    entrance to the pharynx
  24. tonsils
    • lymathic tissues
    • palatine tonsils 
    • phayrngeal tonsils known as adenoid
  25. Lower airway
    • extends from the 4th cervical vertebrae to the xiphoid process
    • glottis to the pulmonary capillary membranes
  26. Larynx
    • complex structure formed by many independent cartilaginious strucetures
    • marks where the upper airway ends and lower ariway begins
  27. Thyroid cartialge
    shield shaped structre formed by two plates that join together anteriorly to form the laryngeal prominence
  28. Cricoid cartilage
    • begins the trachea
    • inferior to thyroid carilage
    • forms the lowest portion of the larynx
    • only upper airway structure that forms a complete ring
  29. Cricothyroid membrane
    • between the thyroid can cricoid cartilage
    • bordered laterally and inferiorly by the highly vascular throid gland
  30. Glottis
    • glottic  opening
    • space between the vocal cords and the narrowest portion of the adult airwaus
  31. Lateral borders of the glottis are the
    vocal cords`
  32. epiglottis
    • superior border of the glottis
    • leaf shaped cartilagionious flap prevents food and liquid from entering  the glottis during swallowing
  33. Epiglottis is attached to the
    • thyroid carilage by the thyroepiglottic ligament
    • base of the tongue by the glossoepiglottic lig
    • hyoid bone by the hyoepiglottic ligament
  34. As the hyoid bone moves
    the position of the tongue and epiglottis are changed
  35. Vallecula
    anatomic space located between the base of the tongue and the epiglottis
  36. artenoid cartilages
    pyramid like carligionious sturectes that form the posterior attachment of the vocal cords  Landmark for ET
  37. Piriform fosse
    • two pockets of tissue on the lateral borders of the laynx
    • airway devices inserted here cause tenting
  38. Layrngospasm
    spasmodic closure of the vocal cords which seals off the airway
  39. Trachea
    • conduit for air entry into the lungs
    • 10 to 12 inches
    • c-shaped cartilagimous rings
  40. Trachea divides into right nd left ainstem bronchi at the
    • carina
    • located at the sternal angle of louis
  41. trachea and bronchi are lined with
    goblet celss and Beta 2 adnergic recpetors
  42. Hilium
    all blood vessels and the bronchi enter each lung here
  43. bronchi etc etc
  44. Aveloi
    expand during inhalaation and become thinner making difusion easier
  45. Atelectasis
    lack of surfactant leads to aveolar collapse
  46. Pulmonary ventilation
    the process of moving air into and out of the lungs is necessary for oxygenation and respiration
  47. Two phases of ventilation
    • Inhalation(inspiration)
    • Exhalation(expiration)
  48. Inhalation
    active muscular part of breathing is governed by boyles law
  49. Boyles law
    presssure of gas is inversely proportionate ot its volume
  50. Process of inhalation
    • During inhalation the diaphragm and intercostal muscles contract
    • when the diaphragm contacts, it desends and enlarges the thoratic cage from top to bottom and intercostal muscles contract they lift the ribs up and out.
    • combined actions enlarge the thorax in all directions and then air enters the lungs due  to pressure shift
  51. Diaphragm
    • is a specialzed skeletal muscle 
    • innervated by the phrenic nerve
    • voluntary and involuntary
    • acts as involuntary when voluntary function ceases 
    • when CO2 rises in the blood autonomic regulation of breathing resumes under control of the brainstem
  52. accessory muscles
    • are secondary muscles of breathing and include
    • sternocleidomastoid and trapezius muscles of the neck
  53. Atmospheric pressure is normally
    higher then the air pressure within the thorax
  54. During inhalation
    the thoratic cage expands and the air pressure within the thorax decreases, creating a slight vacuum
  55. Negative pressure ventilation
    due to the vacuum caused by the pressure differential causing diffusion of air into the lungs untill the pressures are equal. at this point the air stops moving and inhalation stops
  56. partial pressure
    describes the ammount of gas in air or dissolved in liquid such as the blood and is governed by henrys law
  57. Henrys law
    • states that the ammount of gas in a solution varies directly with the partial pressure of gas over a solution
    • in other words as pressure of a gas over a liquid decreases the ammount of gas dissolved into the liquid will decreases and visa versa
  58. Henrys law practically states
    tjat molecules of a gas can be dissolved in a liquid and remain in a liquid as long as the liquid is in apressurized closed container
  59. deoxygenated arterial blood from the heart as a Pao2 that is lower then the Pao2 in the alveoli so the body atempts to
    • equalize the partial pressure which results in oxyen diffusion acreoss the alveoar capillary membrane in the blood
    • Co2 diffuses into the alveoli and is eliminated as waste during exhalation
  60. oxygen and carbon dioxide both diffuse untill the partial pressure in the air and blood is equal and then
    this process occurs in reverse when aterial blood reaches the tissues
  61. alveolar volume
    • is determind by subtracting the dead space volume(VD) from the tidal volume(VT) 
  62. Tidal voume (VT)
    • a measure of the depth of breathing in ml of air that is moved in or out of the respiratory tract during one breath
    • 5-7 mL/kg in healthy adults
    • 6-8 ml/kg in infants/children
  63. Dead space volume (VD)
    the portion of tital volume that does not reach the alveoli and therefore does not participate in gas exchange approx 150 mL in healthy man
  64. Psysiologic dead space
    increase dead space volume by creating intrapulmonary obstructuions or acelectasis because of ceratin respiratory diseases
  65. Minute volume (VM)
    • ammount of air moved through the respiratory tract including dead space in 1 min 
    • Vx respiratory rate=VM
  66. Aveolar munute volume (VA) or Aveolar ventilation
    • represents actual volume of air that reaches that alveoli and parcioates in pulmonary  gas exchange
    • VT  - VD x resp rate = VA
  67. Ideal Aveolar ventilation =
    4200-7000 mL
  68. Inspiratory reserve volume
    amount of air that can be inhaled in addition to the normal tidal volume which is normally about 3,000 mL in a healthy adult
  69. Functional reserve capacity
    following an optimal insoration, the amount of air that can be forced from the lungs in one exhalation
  70. Expiratory reserve volume
    the amount of air that can be exhaled following normal(relaxed) exhalation ; 1,200 mL
  71. Residual volume
    is the air that remains in the lungs after maximal exhalation; about 1,2000 mL
  72. Vital capacity
    ammount of air that can be forcefull exhaled after full inhalation; in healthy man about 4,800
  73. Total lung capacity
    • the maximum amount of air the lungs can hold
    • is Vital capacity + residual volume
    • in healthy man is about 6,000
  74. Exhalation
    Unlike inhalation does not normally require muscular effort, it is a passive process
  75. Process of exhalation
    • as the chest expands, mechanical receptors, known as stretch receptors in the chest wall, and bronchioles send a signal to the apneustic center via the vagus nerve to inhibit the respiratory center and exhalation occurs
    • This  feedback loop is called the hering breuer reflex
  76. Hering breuer reflex
    Terminates inhalation to prevent overexpansion of the lungs.
  77. Exhalation mechnical process
    • the diaphragm and intercostal muscles relax which increases intrapulmonary pressure.
    • natural elasticity or recoil of the lungs passively removies the air
    • when the size of the thoracic cage decreases, air in the lungs is compressed into a smaller space.
    • the air pressure within the thorax then becomes higher then the outside pressure and the air is pished out through the trachea
  78. Changes in rate and depth of ventilation to accomidate oxygen demand are regulated by
    • the pH of the CSF, which is directly related to the amount of carbon dioxide dissolved in the plasma portion of the blood (Paco2)
    • in healthy people when oxygen levels rise, the respiratory center suspends breathing until a riseing carbon dioxide level stimulates the respiratory center to begin breathing again.
  79. Neural control of breathing
    Which is involuntary function, origionates in the brainstem- specifically, in the medulla oblongata and the pons.
  80. The medulla is the
    primary Autonomic (involuntary)  respiratory center. It is connected to the respiratory muscles by the vagus nerve
  81. The medullary center controls the
    rate, depth, and rhythm of breathing in a negative feedback interaction with the pons
  82. Apneustic center of the pons is the
    • secondary control center if the medulla fails to initiate breathing
    • influences the respiratory rate by increasing the number of inspirations per minute
    • The increase is balence by the pneumotaxic center, which has an inhibitory response on inspiration.
    • respiratory rate results from the intercation between these two centers
  83. Centers that control respiratory rate by interactions with each other are
    • Medullary respiratory center
    • apneustic center of the pons
  84. The goal of the respiratory system is to
    kee  the blood concentraions of oxygen and carbon dioxide and its acid-base blaence within very narrow ranges
  85. Chemoreceptors
    • monitor variables and provide feedback to the respiratory centers to adjust rate and depth of respiration on the bodys need
    • constantly monitor chemical composition of the body fluids. 
    • Located in the carotid bodiesm in the aortic arch, and in the central chemoreceptors
  86. Chemoreceptors in the aortic arch and carotid bodies
    • monitor cabon dioxide  in arterial blood
    • Send signals via the glossopharyngeal nerve and vagus nerve
  87. Central chemoreceptors
    • monitor the pH of the CSF and are located adjacent to the respiratory centers in the medulla
    • very sensitive to small changes in pH and provides  for fine tuning of the blody's acid base balence
  88. the acidity of the CSF is an indirect measure of the amount of carbon dioxide in the arterial blood because
    the carbon dioxide in the blood readily diffuses across the blood brain barier and combines with water to form carbonic acid
  89. the amount of oxygen dissolved in the blood plasma (Pao2)....
    has a secondary and protective role
  90. Pao2
    • Chemoreceptors located inthe aortic arch and carotid boies respond to ecreases in Pao2 by sending messages to the respiratory centers to increase breathing.
    • In normal condtions these chemorecptors serve as a backuo to the primary control of ventilation, which is based on the level of CO2 in the blood and pH of the CSF
  91. When serum CO2 or hydrogen ion levels increase because of a medical condition of trauma involing the respiratory system....
    chemoreceptors stimulate the dorsal and ventral respiratory groups in the medulla to increase respiratory rate, thus removing more Co2 or acid from the body.
  92. Dorsal respiratory group
    is responsible for initiating inspiration based on info recieved from chemoreceptors
  93. Ventral respiratory group
    is primarily responsible for motor control of the inspiratory and expiratory muscles.
  94. Primary respiratory drive
    based on increased arterial co2 levels and pH of CSF
  95. Hypoxic drive
    • stimualtes breathing when arterial oxygen levels fall
    • typically found in end stage COPD
  96. Reasons respiratory rate increases
    • increased body temp, respirations increase due to increased metabolic activity
    • amphetimines
    • pain and strong emotions
    • hypoxia
  97. Decrased respiratory rates
    • narcotic analgesics
    • benzos
    • states of slow metabolic rates
  98. oxygenation
    is the process of loading ocygen molecules onto hemoglobin in the bloodsteam
  99. oxygenation cannot occur without ventilation and
    ventilation is possible without oxygenation
  100. FIo2
    is percentage of oxygen in inhaled air
  101. 95% of the protein in a red blood gell is
    Hb hemoglobin
  102. Hemoglobin levels
    • reported in g/dl
    • 14-16 man
    • 12-14 female
  103. hematcrit
    • percentage of rbc in whole blood
    • 45 52 man
    • 37 to 48 woman
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Medic 14 Medic Chapter 15 airway management
Chapter 15 Airway management