unit 5

purpose and general function of pulmonary

• transport of oxygen from air to blood. oxygen is necessary for cellular metabolism

• removal of carbon dioxide from the blood. carbon dioxide is a waste product from metabolism

• two areas: upper respiratory tract and lower respiratory tract

branching tree

air delivery

nose warms air and traps antigens

nasopharynx - lymph tissue in mouth and throat

bronchi

bronchioles

diffusion

gas exchange of o2 into blood for delivery to organs

high → low

upper respiratory tract

nose, mouth, and nasopharynx

• common passage for air and food

• epiglottis protects opening into larynx. closes over glottis at swallowing to prevent aspiration

larynx

• two pairs of vocal cords

trachea

• lined by pseudostratifed ciliated epithelium

• c-shaped rings of cartilage

lower respiratory tract

bronchial tree

trachea branches into:

• right and left primary bronchi

• bronchioles

• alveolar ducts

• alveoli - lined by simple squamous epithelium and surfactant to reduce surface tension and maintain inflation

resting

atmospheric pressure - 760 mm Hg

intrapleural pressure - 756 mm Hg

inspiration

1. muscles contract. chest wall moves out

2. diaphragm descends

3. intrapulmonic pressure becomes negative (usually less than atmosphere - 758 mm Hg)

4. intrapleural pressure becomes more negative (754 mm Hg)

5. air - 760 mm Hg flows in

expiration

1. muscles relax. chest wall moves inward

2. diaphragm ascends

3. intrapleural pressure remains negative

4. intrapulmonic pressure becomes positive (greater than atmosphere - 763 mm Hg)

Medulla and pons

primary control centers for breathing

chemoreceptors

detect changes in carbon dioxide levels, hydrogen ion, and oxygen levels in blood or cerebrospinal fluid

central chemoreceptors located in the medulla, peripheral chemoreceptors in the carotid bodies

respiratory control - normal cycle

1. increased Pco2 in blood and CSF

2. stimulates central chemoreceptors in medulla

3. stimulates inspiratory muscles

4. increases respiratory rate

5. removes more co2 from body

6. decreased Pco2

7. decreased chemoreceptor stimulation

8. slow respirations

9. retain more co2

hypoxic drive - elevated Pco2 levels (emphysema)

happens because there are inadequate levels of oxygen

1. chronic elevation of co2 levels

2. medullary chemoreceptors become insensitive to high Pco2. think that the abnormal co2 levels is normal

3. Pco2 increase, Po2 decreases slightly

4. no increase in respiration

5. marked decrease in o2 levels

6. very low Po2 stimulates peripheral chemoreceptors

7. inspiratory muscles stimulated

8. increased respiration

9. remove co2 and take in more o2

10. Pco2 decreases, Po2 increases

11. respirations slow

signs and symptoms of respiratory disease

• sneezing - reflex res[onse to irritation in upper respiratory tract

  • assists in removing irritant

  • associated with inflammation or foreign material

• coughing

  • irritation caused by nasal discharge

  • inflammation or foreign material tract

  • caused by inhaled irritants

• sputum

• breathing patterns and characteristics - associated with obstruction of airways

  • eupnea

  • Kussmaul respirations

• wheezing or whistling sounds

• stridor

stridor

high-pitched crowing noise

usually indicates upper airway obstruction

eupnea

normal breathing

kussmaul respirations

deep rapid respirations - typical for acidosis; may follow strenuous exercise (trying to blow off excess CO2)

yellowish-green, cloudy, thick mucus sputum

often indication of a bacterial infection

rusty or dark-colored sputum

usually sign of pneumococcal pneumonia

very large amounts of purulent sputum with foul odor sputum

may be associated with bronchietctasis

thick, tenacious mucus sputum

asthma or cystic fibrosis, blood-tinged sputum - may result from chronic cough; may also be sign of tumor or tuberculosis

hemoptysis sputum

blood-tinged (bright red) frothy sputum, usually associated with pulmonary edema

common cold

sinusitis

epiglottitis

influenza

scarlet fever

Upper respiratory tract infections

bronchiolitis

pneumonia

severe acute respiratory syndrome

covid-19

tuberculosis

histoplasmosis

anthrax

Lower respiratory tract infections

bronchiolitis

caused by respiratory syncytial virus (RSV)

transmitted by oral droplet

virus causes necrosis, inflammation in small bronchi and bronchioles

signs of bronchiolitis

wheezing and dyspnea, rapid shallow respirations, cough, rales, chest retractions, fever, malaise

treatment for bronchiolitis

supportive and symptomatic

tidal volume

amount of air exchanged with quiet inspiration and expiration (500 mL)

residual volume

amount of air remaining in the lungs after forced expiration (1200mL)

vital capacity (VC)

maximal amount of air that can be moved in and out of the lungs with a single forced inspiration and expiration

nose, mouth, and nasopharynx

common passage for air and food

epiglottis protects opening into larynx

• closes over glottis at swallowing to prevent aspiration

larynx

two pairs of vocal cords

trachea

lined by pseudo stratified ciliated epithelium

c-shaped rings of cartilage

bronchial tree

trachea branches into:

• right and left primary bronchi

• bronchioles

• alveolar ducts

• alveoli - lined by simple squamous epithelium and surfactant to reduce surface tension and maintain inflation

ventilation

process of inspiration and expiration

• airflow depends on pressure gradient (Boyle’s law) high to low

• atmospheric pressure higher than pressure in alveoli. inspiration

• pressure in alveoli higher than in atmosphere. expiration

hypercapnia

carbon dioxide levels in the blood increase

carbon dioxide easily diffuses into CSF

• lowers pH and stimulates respiratory center

• increased rate and depth of respirations (hyperventilation)

• causes respiratory acidosis - nervous system depression

hypoxemia

marked decrease in oxygen

• chemoreceptors respond

• important control mechanism in individuals with chronic lung disease - move to hypoxic drive

hypocapnia

caused by low carbon dioxide concentration (low partial pressure of carbon dioxide) in blood

• may be caused by hyperventilation. excessive amounts of CO2 expired

• causes respiratory alkalosis

gas exchange

flow of gases between the alveolar air and blood (external respiration)

depends on the relative concentrations (partial pressures) of the gases

each gas in a mixture moves along its partial pressure gradient, independent of other gases (dalton’s law) - high to low

factors affecting diffusion of gases

partial pressure gradient

thickness of respiratory membrane

• fluid accumulation in alveoli or interstitial tissue impairs gas exchange

total surface area available for diffusion

• if part of alveolar wall is destroyed, surface area is reduced, so less exchange

ventilation-perfusion ratio

• ventilation (air flow) and perfusion (blood flow) need to match for maximum gas exchange

oxygen

about 1% of oxygen is dissolved in plasma

most is bound (reversibly) to hemoglobin

binding and release of oxygen to hemoglobin depends on Po2, Pco2, temp, and plasma pH

carbon dioxide

waste product from cellular metabolism

about 7% dissolved in plasma

about 20% reversibly bound to hemoglobin

most diffuses into red blood cells

spirometry - pulmonary function test (PFT)

test pulmonary volumes and airflow times

also can be used a prevention for infection

arterial blood gas determination

checks oxygen, carbon dioxide, bicarbonate, serum pH

oximetry

measures o2 saturation

exercise tolerance testing

for patients with chronic pulmonary disease

radiography

helpful in evaluating tumors

evaluate infections

bronchoscopy

perform biopsy

check site of lesion or bleeding

culture and sensitivity tests

sputum testing for presence of pathogens

determine antimicrobial sensitivity of pathogen

sounds of respiratory disease

breath sounds - heard on physical exam

rales

rhonchi

absence

absence

non-aeration or collapse of lungs (no air movement)

rhonchi

deeper or harsher sounds from thicker mucus

rales

light bubbly or crackling sounds, with serous secretions

dyspnea

feeling of not able to take deep breaths

subjective feeling of discomfort

may be caused by increased CO2 or hypoxemia

often noted on exertion, such as climbing stairs

severe dyspnea indicative of respiratory distress

flaring of nostrils

use of accessory respiratory muscles

retraction of muscles between or above ribs

orthopnea

Difficulty breathing when lying down

usually caused by pulmonary congestion

paroxysmal nocturnal dyspnea

sudden acute type of dyspnea

common in patients with left sided congestive heart failure

cyanosis

bluish coloring of skin and mucous membranes

caused by large amounts of unoxygenated hemoglobin in blood

pleural pain

results from inflammation or infection of parietal pleura

friction rub

soft sound produced as rough, inflamed, or scarred pleural move against each other

clubbed digits

results from chronic hypoxia associated with respiratory or cardiovascular disease

painless, firm, fibrotic enlargement as the end of the digit

hypoxemia

inadequate oxygen in blood

hypercapnea

increased carbon dioxide in blood

common cold

viral infection

more than 200 possible causative agents

spread through respiratory droplets

hand washing and respiratory hygiene important in prevention

symptomatic treatment

secondary bacterial infections may occur

signs and symptoms of common cold

nasal congestion, copious watery discharge

mouth breathing, change in the tone of voice

possible sore throat

headache

slight fever

malaise

cough may develop

infection and inflammation may spread to cause pharyngitis, laryngitis, or acute bronchitis

treatment of common cold

symptomatic and supportive

• unless bacterial infection develops secondarily

antiviral drugs

may reduce symptoms and duration

reduces risk to infect others

sinusitis

usually bacterial infection

analgesics for headache and pain

course of antibiotics often required to eradicate infection

laryngotracheobronchitis (croup)

common viral infection, particularly in children

common causative organism

infection usually self limited

epiglottitis

swelling of the larynx, supraglottic area and epiglottis

• may obstruct air way

• spasm of larynx common if area is touched with instruments

acute infection - common in children ages 3 to 7

usually caused by Haemophilus influenzae type B

rapid onset; fever and sore throat

child sits in tripod position

drooling and difficulty swallowing

heightened anxiety

epiglottitis treatment

oxygen and antimicrobial therapy

influenza

viral infection

three groups of influenza viruse

• type A (most prevalent), types B & C

• viruses constantly mutate

sudden, acute onset with fever, marked fatigue, aching pain in the body

• may also cause viral pneumonia

• mild case of influenza may be complicated by secondary bacterial pneumonia

• commonly, deaths in flu epidemics result from pneumonia

treatment for influenza

symptomatic and supportive

antiviral drugs

• amantadine

• zanamivir

• oseltamivir

prevention is highly recommened

• respiratory hygiene

• vaccination is recommended for most individuals

scarlet fever

caused by group A B-hemolytic Streptococcus

symptoms:

• typical “strawberry” tongue

• fever, sore throat

• chills, vomiting, abdominal pain, malaise

treatment:

• antibiotics

bronchitis

inflammation of the trachea or large bronchial tree

inflammation from branching lining

• viruses bacterial allergens or inhaled irritants

virus causes necrosis, inflammation in small bronchi and bronchioles

bronchitis signs, diagnosis, treatment

signs

• wheezing and dyspnea, cough, low grade fever, malaise, pharyngitis

diagnosis

• H&P, chest x-ray

treatment

• supportive and symptomatic

bronchiolitis

viral infections of the bronchioles (RSV)

can spread to alveoli and cause collapse and respiratory failure

bronchiolitis manifestations

nasal drainage, nasal congestion, cough, wheezing, rapid and shallow respirations, chest retractions, dyspnea, fever, tachycardia, and malaise

bronchiolitis treatment

oxygen therapy, intubation, cool humidity, increased fluids, keeping the child calm, bronchodilators, and corticosteriods

pneumonia

classification of pneumonias based on:

• causative agent: viral, bacterial, fungal

• anatomical location of infection: throughout both lungs, or consolidated in one lobe

• pathophysiological changes: changes in interstitial tissue, alveolar septae, alveoli

• epidemiological date: nosocomial, community acquired

lobar pneumonia

all of one or two lobes

cause: streptococcus pneumoniae

inflammation of alveolar wall and leakage of cells, fibrin, and fluid into alveoli causing consolidation. pleura may be inflamed

onset sudden and acute

signs: high fever and chills. productive cough with rusty sputum. rales progressing to absence of breath sounds in affected lobes

lobar pneumonia manifestations

sudden onset

systemic signs

• high fever with chills, fatigue, leukocytosis

dyspnea, tachypnea, tachycardia

pleural pain

rales

productive cough

• typical rusty-colored sputum

confusion and disorientation

bronchopneumonia

scattered small patches

cause: multiple bacteria

inflammation and purulent exudate in alveoli often arising from prior pooled secretions or irritation

onset insidious

signs: mild fever. productive cough with yellow-green sputum. dyspnea

interstitial pneumonia (primary atypical pneumonia, PAP)

scattered small patches

common in older children and young adults

cause: influenza virus mycoplasma

interstitial inflammation around alveoli. necrosis of bronchial epithelium

onset variable

signs: variable fever, headache. aching muscles. nonproductive hacking cough

legionnaires’ disease

caused by legionella pneumophila

• thrives in warm, moist environments

• often nosocomial infection

difficult to identify - requires specific culture medium

untreated infections

• cause severe congestion

• necrosis in the lung

• possible fatal

pneumocystis carinii Pneumonia

a type of atypical pneumonia

occurs as an opportunistic infections

often found in patients with AIDS

appears to be inhaled

causes necrosis and diffuse interstitial inflammation

onset marked with difficulty breathing and nonproductive cough

severe acute respiratory syndrome (SARS)

acute respiratory infection

causative microbe - SARS-associated coronavirus

• transmission by respiratory droplets - close contact

• first signs: fever, headache, myalgia, chills, anorexia, possibly diarrhea

• later signs: effect on lungs evident - dry cough, marked dyspnea; areas of interstitial congestion, hypoxia; mechanical ventilation may be required

sars treatment

antivirals, glucocorticoids

high fatality rate

risk factors (monitored to prevent outbreaks)

• travel to endemic or epidemic area

• close contact with such a traveler

presence of a cluster of undiagnosed atypical pneumonia cases

employment involving close contact with the virus

• active cases quarantined until clear of infection

covid 19

SARS Co V-2 virus

originated in Wuhan, China

caused worldwide pandemic

rapid attachment and damage to lung cells

subsequent variants infect upper respiratory

can cause “cytokine storm” immune reactions

elderly, immunocompromised, those with comorbidities (diabetes, obesity, etc)

covid 19 signs and symptoms

fever or chills

coughing/sneezing

difficulty breathing/shortness of breath

fatigue

temporary loss of taste

muscle/body aches

headaches

sore throat

nausea/vomiting

covid 19 treatment

various therapeutic regimens such as hydroxyquinilone, Remdesivir, Ivermectin, monoclonal antibodies

new drugs continually under development

vaccines available for prevention of infection and spread

covid 19 diagnosis

antibody (serological) tests

diagnostic tests - primarily PCR

tuberculosis cause

cause: mycobacterium tuberculosis transmitted by oral droplets from persons with active infection

• somewhat resistant to drying and many disinfectants

• can survive in dried sputum for weeks

• destroyed by ultraviolet light, heat, alcohol, glutaraldehyde, formaldehyde

• normal neutrophil response does not occur

• cell-mediated immunity normally protection

occurs more frequently with:

• people living in crowded conditions

• immunodeficiency

• malnutrition

• alcoholism

• conditions of war

• chronic disease

• HIV infection

tuberculosis primary infection

primary infection is asymptomatic

when organism first enters the lungs

• engulfed by macrophages - local inflammaton

• if cell mediated immunity is inadequate:

  • mycobacteria reproduce and begin to destroy lung tissue

  • this form of disease is contagious

tuberculosis secondary or reinfection with TB

occurs when client’s cell-mediated immunity is impaired because of:

• stress

• malnutrition

• HIV infection

• age

mycobacteria begin to reproduce and infect lung

then again becomes active TB, which can be spread to others

signs and symptoms of tuberculosis

secondary or active stage:

• anorexia

• malaise

• fatigue

• weight loss

• afternoon low-grade fever and night sweats develop

• cough is prolonged and becomes increasingly sever and, as cavitation develops, more productive

• sputum becomes purulent and often contains blood

tuberculosis if cell-mediated immunity is adequate

some bacilli migrate to lymph nodes - granuloma - formation of tubercle (contains live bacilli) - walled off and calcifying

tubercle may be visible on chest radiograph

bacilli may remain viable in a dormant stage for years

individual’s resistance and immune responses high, bacilli remain walled off

primary or latent infection - individual has been exposed and infected, but does not have disease and is asymptomatic

individual cannot transmit disease

active tuberculosis (primary or secondary)

organisms multiply, forming large areas of necrosis

• cause large open areas in lung - cavitation

cavitation promotes spread into other parts of lung

• infection may spread into pleural cavity

cough, positive sputum, radiograph showing cavitation

disease in this form is highly infectious when there is close personal contact over a period of time

military or extrapulmonary tuberculosis

rapidly progressive form more common in children < 5 years

early dissemination to other tissues

if lesions are not found in the lungs, this is not contagious

common symptoms include weight loss, failure to thrive, and other infections such as measles

tuberculosis diagnostic test

first exposure or primary infection

• indicated by positive tuberculin (skin) test results

active infections

• acid-fast sputum test

• chest radiograph

• sputum culture and sensitivity

tuberculosis treatment

long-term treatment with a combination of drugs. length of treatment varies from 6 to 12 months

effective treatment requires monitoring and follow-up and is expensive

TB is becoming an increasingly serious problem because of:

• homelessness and crowding in shelters

• HIV infection

• lack of health care

• multidrug resistant TB