Respiratory exam 3 Flashcards
Emphysema
gas exchange is abnormal d/t destruction of alveolar walls
Primary emphysema
rare inherited deficiency of alpha 1 antitrypsin
Alpha 1 antitrypsin
normally inhibits the enzymes that chew up elastin
secondary emphysema
inability of the body to inhibit proteolytic enzymes
caused by smoking/toxin exposure
What does airway obstruct do?
prolongs expiratory phase of respiration and causes the potential for impaired gas exchange d/t mismatching v/q
FVC
forced vital capacity
amount of air that can be expelled forcibly after maximal inspiration
Is FVC increased or decreased with people who have chronic lung disease
increased
Is the FEV decreased or increased in people with chronic lung disease?
decreased
What are examples of restrictive lung disease?
pulmonary fibrosis, pulmonary edema, PNA
What is restrictive lung disease
it keeps the lungs from inflating causing decreased compliance; there is a problem with the lung tissue itself
are tidal volumes and vital capacity decreased or increased with restrictive lung disease?
decreased
Pulmonary fibrosis is caused by:
extra connective tissue/elastin causes increased thickness of respiratory membrane and insufficient gas exchange
pulmonary edema is caused by:
water in the lungs that disrupts balance b/t pressure and capillary permeability
What are examples of pulmonary vascular diseases?
PE, pulmonary hypertension, cor pulmonale, ARDS, respiratory failure
What causes a PE?
clot, thrombus, tissue fragment, lipids, air bubbles
What are the consequences of a PE?
blood backflow to the right ventricle which leads to increased pressure and decreased gas perfusion
What is Virchow’s Triad?
1) stasis of blood
2) increased blood coagulability
3) vessel wall injury
Pleurial effusion
accumulation of fluids in the pleural cavity
what is transudate/hydrothorax and what are some causes?
water
caused by CHF, renal failure, liver failure, nephrosis
What is exudate/empyema and what are some causes?
pus
caused by infection, lupus, RA, malignancies
What is a hemothorax and what are some causes?
blood
chest injury, surgery, vessel rupture, malignancies
What is chyle and what are some causes?
milky fluid from lymph from GI tract
trauma, infection, malignant infiltration
What is secondary atelectasis? what are some causes?
a lung that is collapsed that was previously inflated
causes: airway obstruction(mucous plug), lung compression (pneumothorax, effusion), increased lung recoil (decreased surfactant)
what is primary atelectasis?
insufficient surfactant at birth
what are examples of restrictive lung disease?
Asthma, COPD, Cystic Fibrosis
what is restrictive lung disease?
increased airway resistance and a decreased FEV1
a change in radius causes change in resistance
Asthma
a chronic inflammatory disorder resulting in airflow obstruction with recurrent episodes of wheezing, SOB, chest tightness
FEV1/FVC is decreased»air cannot be expelled quickly enough
What is the pathophysiology of asthma?
IgE and mast cells degranulate causing inflammatory mediators to be released, leading to smooth muscle contraction and increased secretions
FEV1
the maximal amount of air you can forcefully expel in one second
What FEV1 percentage qualifies for obstructive lung disease?
less than 80%
what is epinephrine’s use with asthma and what are some side effects?
it will act as an alpha agonist which may help decrease airway edema as well as providing additional beta-2 agonism
S/E: it has secondary effects on alpha/beta adrenergic receptors elsewhere in the body (tachycardia)
Beta-2 receptors use with asthma
beta 2 receptors are located in the lungs so this would focus on dilating the bronchial smooth muscle with less side effects
Anticholinergics use with asthma
works on inflammation to help open airways
Glucocorticoids use with asthma
works to decrease inflmmation and help open up the constricted airway
What is hypoxemia caused by?
low oxygen in the blood, mismatched ventilation and perfusion
Shunt
venous blood directly joining arterial circulation; poor ventilation with perfusion
what are the causes of a shunt?
obstruction, pulmonary edema, bronchoconstriction
what is hypercapnia?
increased Co2 with hypoventilation
what are some causes of hypercapnia?
depression of respiratory center from medications or anesthesia, disease of the medulla, spinal cord disruption, large airway obstruction
what is the normal range for ventilation-perfusion matching?
0.6-3.0
Ventilation (V)
refers to the air in the lungs available for exchange
Perfusion (Q)
refers to the blood supply in the aveoli
V/Q mismatching
no gas exchange occurs in the alveoli
no ventilation d/t obstruction because of decreased oxygen and paO2
Compliance
measure of the lung and chest wall dispensability
influenced by elastin and collagen
What is compliance determined by?
elastic recoil and surface tension
if there’s high surface tension lungs collapse?
What diseases cause decreased compliance?
pulmonary edema, pulmonary fibrosis
What diseases cause increased compliance?
Emphysema because the tissues are too stretched out
Surface tension
the tendency of molecules exposed to air to adhere to one another; occurs at gas-liquid interference
Surfactant
decreases surface tension to help keep alveoli open against surface tension, produced by type II epithelial cells
Tension pneumothorax
air enters but does not leave
most dangerous because it can lead to obstructive shock d/t compression of vena cava
Pleuric cavity pressure is greater than atmospheric
Open pneumothorax
air enters chest wall d/t trauma
pleuric cavity and atmospheric pressure are about the same
Spontaneous pneumothorax
closed, air blebs/blisters form on surface and cause rupture; smokers
pleural cavity is less than atmospheric pressure
What are the main functions of the respiratory system?
1) Regulates pH by eliminating Co2
2) makes ACE (angiotensin converting enzyme)
3) surfactant
4) inactivation of prostaglandins
5) defense mechanisms ( cough, mucociliary escalator, macrophages, IgA)
What are the conducting airways?
Upper airways, anatomical dead space
nose, pharynx, larynx, trachea, bronchi, and bronchioles
What is the respiratory zone?
respiratory bronchioles, alveolar ducts, alveoli (lung parenchyma)
gas exchange occurs here
Dead space
ventilation without perfusion
what is the respiratory center of the brain?
brain stem and medulla
How does gas exchange occur?
by diffusion
and is dependent upon adequate alveolar ventilation and pulmonary blood perfusion
what is ventilation/perfusion?
V/Q ratio across respiratory membrane
the medulla controls what?
the basic rhythm
the pons does what?
modifies the rhythm
What do central chemoreceptors do?
measure Co2 and pH
they increase RR when Co2 increases or pH decreases
what is the primary respiratory signal?
carbon monoxide (Co2)
what is the secondary respiratory signal?
oxygen
what do peripheral chemoreceptors do?
measures oxygen in arterial blood
they increase RR when o2 is less than 60
Fick’s law of diffusion
occurs in response to a concentration gradient expressed as the change in concentration due to a change in position
