Appropriate airway management - ANS*Steps must be performed in order. Bypass steps
that do not apply.*
a. Open and maintain a patent airway.
b. Recognize and treat airway obstructions.
c. Assess ventilation and oxygenation status.
d. Administer supplemental oxygen.
e.Provide ventilatory assistance.
Upper airway - ANSConsists of all anatomic airway structures above the glottic opening.
*1. Tongue*
a. Must be manipulated
b. Tends to fall back into the posterior pharynx in unresponsive patient
*2. Pharynx*
a. Muscular tube that extends from the nose and mouth to the esophagus and trachea
b. Composed of:
i. Nasopharynx
ii. Oropharynx
iii. Laryngopharynx (hypopharynx)
Lower airway - ANSExtends from the glottis to the pulmonary capillary membrane.
1. *Larynx*
2. *Thyroid cartilage*
3. *Cricoid cartilage (cricoid ring)*
4. *Cricothyroid membrane*
5. *Glottis*
6. *Trachea*
1. Larynx - ANS-Complex structure formed by many independent cartilaginous structures
-Marks where the upper airway ends and lower airway begins
2. Thyroid cartilage - ANS-Shield-shaped structure formed by two plates that join in a "V"
shape anteriorly to form the laryngeal prominence
i. Known as the Adam's apple
ii. More pronounced in men
iii. Can be difficult to locate in obese or short-necked patients
-Suspended from the hyoid bone by the thyroid ligament
-Directly anterior to the glottic opening
3. Cricoid cartilage (cricoid ring) - ANS-Lies inferiorly to the thyroid cartilage
-Forms the lowest portion of the larynx
-More prominent in females
,4. Cricothyroid membrane - ANS-Located between the thyroid and cricoid cartilage
-Site for emergency surgical and nonsurgical access to the airway
-Bordered laterally and inferiorly by the highly vascular thyroid gland
5. Glottis - ANS-Narrowest portion of the adult airway
-Vocal cords are located at the lateral borders of the glottis.
-Epiglottis is located at the superior border of the glottis.
-ET intubation requires visualizing the epiglottis, glottis, and vocal cords before inserting the
ET tube.
6. Trachea - ANS-Immediately descends into the thoracic cavity
-Not a straight tube, which is key to understand when placing an ET tube
The respiratory and cardiovascular systems work together to ensure that: - ANS1. A
constant supply of oxygen and nutrients is delivered to every cell.
2. Waste products are removed from every cell.
Ventilation - ANS-Physical act of moving air into and out of the lungs
1. *Inhalation* is the active, muscular part of breathing.
2. *Exhalation* is a passive process and does not normally require muscular effort.
Oxygenation - ANS-Process of loading oxygen molecules onto hemoglobin molecules in the
bloodstream
-Requires adequate *FiO2 (Percentage of oxygen in inhaled air)*
Respiration - ANS-Process of exchanging O2 and CO2-->
1. *External respiration (Also called pulmonary respiration)*: Process of exchanging O2 and
CO2 between the alveoli and blood in pulmonary capillaries.
2. *Internal respiration (Also called cellular respiration)*: Exchange of O2 and CO2 between
the systemic circulation and the body's cells.
Pathophysiology of Respiration - ANS-Multiple conditions can inhibit the body's ability to
effectively provide oxygen to cells.
1. Disruption of pulmonary ventilation, oxygenation, and respiration will cause immediate
effects on the body.
a. Must be recognized and corrected immediately
b. Important to distinguish a primary ventilation problem from a primary oxygenation or
respiration problem
2. Every cell needs a constant supply of oxygen to survive.
a. Some tissues are more resilient than others.
b.Sufficient levels of external respiration and perfusion are required.
3. Hypoxia, ventilation-perfusion ratio and mismatch, factors affecting ventilation, factors
affecting oxygenation and respiration, and acid-base balance.
,1. Hypoxia - ANSTissues and cells do not receive enough oxygen --> Death may occur
quickly if not corrected.
- Varying signs and symptoms
a. Onset and degree of tissue damage often depend on the quality of ventilations.
b. Early signs include restlessness, irritability, apprehension, tachycardia, and anxiety.
c. Late signs include mental status changes, a weak pulse, and cyanosis.
d. Responsive patients often report dyspnea and may not be able to speak in complete
sentences.
-Best to administer oxygen before signs and symptoms appear
2. Ventilation-perfusion ratio and mismatch - ANS-Air and blood flow must be directed to the
same place at the same time (ventilation and perfusion must be matched).
-Failure to match ventilation and perfusion (V/Q mismatch) lies behind most abnormalities in
oxygen and carbon dioxide exchange.
-In most people, normal resting minute ventilation is approximately 6 L/min.
a. Resting alveolar volume: Approximately 4 L/min
b. Pulmonary artery blood flow: Approximately 5 L/min
c. Overall ratio of ventilation to perfusion: 4:5 L/min, or 0.8 L/min
-Because neither ventilation nor perfusion is distributed equally, both are distributed to
dependent regions of the lungs at rest. However, an increase in gravity-dependent flow is
more marked with perfusion than with ventilation.
--> Ratio of ventilation to perfusion is highest at the apex of the lung and lowest at the base.
-When ventilation is compromised but perfusion continues:
a. Blood passes over alveolar membranes without gas exchange.
b. CO2 is recirculated into the bloodstream.
i. Results in V/Q mismatch
ii. Could lead to severe hypoxemia if not recognized and treated
-When perfusion across the alveolar membrane is disrupted:
a. Less O2 is absorbed into the bloodstream; less CO2 is removed (V/Q mismatch).
b. Can lead to hypoxemia --> Immediate intervention is needed to prevent further damage or
death.
3. Factors affecting ventilation - ANSA patent airway is critical for the provision of O2 to
tissues. Intrinsic and extrinsic factors can cause airway obstruction.
*1. Intrinsic factors*: infection, allergic reactions, and unresponsiveness.
a. The tongue is the most common obstruction in an unresponsive patient.
b. Some factors are not necessarily directly part of the respiratory system. Ex...
i. Interruptions in the central and peripheral systems.
ii. Medications that depress the central nervous system.
iii. Trauma to the head and spinal cord.
iv. Neuromuscular disorders.
, v. Neuromuscular blocking agents.
c. Allergic reactions
i. Swelling (angioedema) can obstruct the airway.
ii. Bronchoconstriction can decrease pulmonary ventilation.
*2. Extrinsic factors*: trauma and foreign body airway obstruction.
a. Trauma to the airway or chest --> Requires immediate evaluation and intervention
b. Blunt or penetrating trauma and burns can disrupt airflow through the trachea and into the
lungs --> Quickly results in oxygenation deficiencies
c. Trauma to the chest wall can lead to inadequate pulmonary ventilation. Example: A
patient with numerous rib fractures or a flail chest may purposely breathe shallowly in an
attempt to alleviate pain from the injury (Respiratory splinting) --> Can result in decreased
pulmonary ventilation
**Proper ventilatory support is crucial.
*3. Hypoventilation & Hyperventilation*-
*a. Hypoventilation*: occurs when CO2 production exceeds CO2 elimination.
*b. Hyperventilation* occurs when carbon dioxide elimination exceeds carbon dioxide
production.
--> Hypoventilation and hyperventilation could represent the body's attempt to compensate
for various abnormal conditions. For example, if the pH of the blood alkalotic, the patient's
breathing may become slow or shallow in an attempt to retain CO2 to decrease the pH<--
*4. Hype
4. Factors affecting oxygenation and respiration - ANS*1. External factors:*
a. External factors in ambient air. Examples: Atmospheric pressure, partial pressure of
oxygen --> At high altitudes, the percentage of oxygen remains the same, but partial
pressure decreases because total atmospheric pressure decreases. -- > Closed
environments may also have decreases in ambient oxygen. Examples: Mines and trenches
b. Toxic gases displace oxygen in the environment. --> CO inhibits the proper transport of
oxygen to tissues
*2. Internal factors:*
a. Conditions that reduce the surface area for gas exchange also decrease the body's
oxygen supply.
b. Medical conditions may also decrease surface area of the alveoli by damaging them or by
leading to an accumulation of fluid in the lungs.
c. Nonfunctional alveoli inhibit the diffusion of oxygen and carbon dioxide --> Called
intrapulmonary shunting
d. Submersion victims and patients with pulmonary edema have fluid in the alveoli-->
i. Inhibits adequate gas exchange at the alveolar membrane
ii. Results in decreased oxygenation and respiration
iii. Exposure to certain environmental conditions or occupational hazards. Examples: High
altitudes, epoxy resins
iv. Can result in anaerobic respiration and an increase in lactic acid accumulation.
e. Other conditions that affect cells include:
i. Hypoglycemia --> Oxygen and glucose levels decrease
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