Medic 14 Medic Chapter 15 airway management

upper and lower airway

diaphragm, intercostal muscles, accessory muscles of breathing, and nerves from the brain and spinal cord to those muscles.

Intercostal and diaphragm

all the anatomic airway structures abouve the level of the vocal cords- nose,mouth,oral cavity, and pharynx (throat).

the upper and lower airways

Warm,filter, and humidify air as it enters the body through the nose and mouth

as the air picks up moisture from the soft tissues of the airway.

is a muscular tube that extends from the nose and mouth to the level of the esophagus and trachea.

• Nasopharynx
• Oropharynx
• Laryngopharynx (hypopharynx)

• Larynx Anteriorly
• Esophagus Posteriorly

• 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.

protrude from lateral walls of nasal cavity and increase the surface area of the nasal mucosa, improving warming,filtering ,and humidificaiton of inhaled air.

divides nasophaynx composed of the ethmoid and vomer bones

• 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

cerebrospinal rhinorrhea

cerebrospinal otorrhea

small,horseshoe shaped bone to which the tongue and mandible ,jaw,epiglottis,and thyroid cartilage.

• 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

posterior border of the oral cavity and is an externsion of the soft palate

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

entrance to the pharynx

• lymathic tissues
• palatine tonsils 
• phayrngeal tonsils known as adenoid

• extends from the 4th cervical vertebrae to the xiphoid process
• glottis to the pulmonary capillary membranes

• complex structure formed by many independent cartilaginious strucetures
• marks where the upper airway ends and lower ariway begins

shield shaped structre formed by two plates that join together anteriorly to form the laryngeal prominence

• begins the trachea
• inferior to thyroid carilage
• forms the lowest portion of the larynx
• only upper airway structure that forms a complete ring

• between the thyroid can cricoid cartilage
• bordered laterally and inferiorly by the highly vascular throid gland

• glottic  opening
• space between the vocal cords and the narrowest portion of the adult airwaus

vocal cords`

• superior border of the glottis
• leaf shaped cartilagionious flap prevents food and liquid from entering  the glottis during swallowing

• thyroid carilage by the thyroepiglottic ligament
• base of the tongue by the glossoepiglottic lig
• hyoid bone by the hyoepiglottic ligament

the position of the tongue and epiglottis are changed

anatomic space located between the base of the tongue and the epiglottis

pyramid like carligionious sturectes that form the posterior attachment of the vocal cords  Landmark for ET

• two pockets of tissue on the lateral borders of the laynx
• airway devices inserted here cause tenting

spasmodic closure of the vocal cords which seals off the airway

• conduit for air entry into the lungs
• 10 to 12 inches
• c-shaped cartilagimous rings

• carina
• located at the sternal angle of louis

goblet celss and Beta 2 adnergic recpetors

all blood vessels and the bronchi enter each lung here

expand during inhalaation and become thinner making difusion easier

lack of surfactant leads to aveolar collapse

the process of moving air into and out of the lungs is necessary for oxygenation and respiration

• Inhalation(inspiration)
• Exhalation(expiration)

active muscular part of breathing is governed by boyles law

presssure of gas is inversely proportionate ot its volume

• 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

• 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

• are secondary muscles of breathing and include
• sternocleidomastoid and trapezius muscles of the neck

higher then the air pressure within the thorax

the thoratic cage expands and the air pressure within the thorax decreases, creating a slight vacuum

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

describes the ammount of gas in air or dissolved in liquid such as the blood and is governed by 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

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

• 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

this process occurs in reverse when aterial blood reaches the tissues

• is determind by subtracting the dead space volume(VD) from the tidal volume(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

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

increase dead space volume by creating intrapulmonary obstructuions or acelectasis because of ceratin respiratory diseases

• ammount of air moved through the respiratory tract including dead space in 1 min 
• V_t x respiratory rate=V_M

• represents actual volume of air that reaches that alveoli and parcioates in pulmonary  gas exchange
• V_T  - V_{D x resp rate =} V_A

4200-7000 mL

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

following an optimal insoration, the amount of air that can be forced from the lungs in one exhalation

the amount of air that can be exhaled following normal(relaxed) exhalation ; 1,200 mL

is the air that remains in the lungs after maximal exhalation; about 1,2000 mL

ammount of air that can be forcefull exhaled after full inhalation; in healthy man about 4,800

• the maximum amount of air the lungs can hold
• is Vital capacity + residual volume
• in healthy man is about 6,000

Unlike inhalation does not normally require muscular effort, it is a passive process

• 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

Terminates inhalation to prevent overexpansion of the lungs.

• 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

• 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.

Which is involuntary function, origionates in the brainstem- specifically, in the medulla oblongata and the pons.

primary Autonomic (involuntary)  respiratory center. It is connected to the respiratory muscles by the vagus nerve

rate, depth, and rhythm of breathing in a negative feedback interaction with the pons

• 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

• Medullary respiratory center
• apneustic center of the pons

kee  the blood concentraions of oxygen and carbon dioxide and its acid-base blaence within very narrow ranges

• 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

• monitor cabon dioxide  in arterial blood
• Send signals via the glossopharyngeal nerve and vagus nerve

• 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

the carbon dioxide in the blood readily diffuses across the blood brain barier and combines with water to form carbonic acid

has a secondary and protective role

• 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

chemoreceptors stimulate the dorsal and ventral respiratory groups in the medulla to increase respiratory rate, thus removing more Co2 or acid from the body.

is responsible for initiating inspiration based on info recieved from chemoreceptors

is primarily responsible for motor control of the inspiratory and expiratory muscles.

based on increased arterial co2 levels and pH of CSF

• stimualtes breathing when arterial oxygen levels fall
• typically found in end stage COPD

• increased body temp, respirations increase due to increased metabolic activity
• amphetimines
• pain and strong emotions
• hypoxia

• narcotic analgesics
• benzos
• states of slow metabolic rates

is the process of loading ocygen molecules onto hemoglobin in the bloodsteam

ventilation is possible without oxygenation

is percentage of oxygen in inhaled air

Hb hemoglobin

• reported in g/dl
• 14-16 man
• 12-14 female

• percentage of rbc in whole blood
• 45 52 man
• 37 to 48 woman