Lecture 3: Pulmonary system Flashcards
Functions of the respiratory system:
1) Gas exchange: of O2 and CO2
2) Acid-base balance: removing CO2 in body, which reduces H+ (to reduce acidity)
3) Phonation: production of sound (speech, singing)
4) Pulmonary defense: protection from bacteria, dust, toxic particles
5) Pulmonary metabolism: metabolize substrates for energy and nutrients in lungs
Phonation means
Production of sound
Consists of the nasal cavities, sinuses, pharynx, tonsils, and larynx
Upper airway
Consists of the conducting airways, including the trachea, bronchi, and bronchioles
Lower airway
Where gas exchange happens
Terminal alveoli
What are the 3 components of the right superior lobe of the lung?
1) Apical (top)
2) Posterior
3) Anterior
What are the 2 components of the middle lobe of the right lung?
Lateral
Medial
What are the 5 components of the inferior lobe of the R lung
1) Superior
2) Medial Basal
3) Anterior basal
4) Lateral basal
5) Posterior basal
What are the 4 parts of the superior lobe of the L lung?
1) Apicoposterior
2) Anterior
3) Superior lingular
4) Inferior lingular
What are the 4 parts of the inferior lobe of the left lung?
1) Anteriormedial basal/superior
2) Medial basal
3) Lateral basal
4) Posterior basal
Exchange of gas between external environment and alveoli in lungs
Alveolar ventilation
Flow of blood to the alveolar capllaries and tissues
* Both are needed for movement of O2 and CO2 and for their exchange
Perfusion
Partial pressure of O2 and CO2 in alveoli are determined by a relationship between what two variables?
Ventilation
Perfusion
What do we want our ventilation perfusion ratio to be?
As close to 1 as possible
V/Q = ventilation/perfusion
V = alveolar ventilation rate
Q = perfusion rate
What is normal alveolar ventilation?
4L/min
What is normal pulmonary blood flow?
5L/min
What is a normal ventilation perfusion ratio?
0.8
v/q = 4L/min air / 5L/min blood = 0.8
So slightly more blood than air typically, but we want this ratio as close to 1 as possible
What two things impact the V/Q ratio? (3)
Gravity
Body position
Cardiopulmonary dysfunction
When is perfusion the greatest? (what positions)
Gravity dependent area
* think lower lobes of lungs when sitting
* so more blood flow when gravity is pushing the blood down is what I think this is saying
this is why its harder to breathe when lying down than it is sitting up
V/Q mismatch = inequality in the relationship between ventilation and perfusion
Ventilation in excess of perfusion =
* What can cause this
Dead space
Caused by pulmonary embolus
* think embolism killing a bunch of the alveoli and capillaries that get blood flow to them, but theres still the same amount of ventilation
Will cause V/Q mismatch
Perfusionis in excess of ventilation
* what causes this
Shunt
Alveolar collapse from secretion
What if V/Q increases?
* ventilation is higher than perferfusion (think the ratio being over 1)
* Delivery of O2 increases and CO2 removal increases (because you’re breathing out more I guess)
* PO2 increases, PCO2 decreases in alveoli
What is V/Q decreases? (meaning theres more bloodflow than airflow)
* perfusion is greater than ventilation
* O2 removal greater than its delivery, CO2 delivery increases
* PO2 decreases, PCO2 increases in alveoli - so we have a CO2 buildup which is bad
Pathology that causes V/Q mismatch
* causes: asthma, COPD, PE, bronchopneumonia, interstital lung disease, heart failure
Not worried about #’s but be able to define the defintions of all of them
Pulmonary Function Tests:
Provide information about:
* The integrity of the airways
* The function of the respiratory musculature
* The condition of the lung tissue themselves\
*
Maximal inhalation followed by maximal exhalation, measuring volume of air and time
Spirometry
Volume of air inspired during normal quiet respiration
Tidal volume
volume of air inspired forcefully over and above tidal inspiration with max effort
Inspiratory reserve volume
Volume of air expired forcefully over and above tidal inspiration with max effort
Expiratory reserve volume
Volume of air that remains in lung at the end of max expiration
Residual volume
Volume of air that remain in lungs at the end of normal expiration
Functional residual capacity
Volume of air expired forcefully after forceful inspiration
Vital capcity
Maximal air in lung after max inspiration
total lung capcity
Total Lung Capcity =
Vital capacity + Residual volume
Is TLC lowered or elevated in obstructive lung diseases?
Elevated
air gets trapped in and they can’t get it out (think barrel chest)
What happens to TLC in chronic restrictive lung diseases?
Its lowered
They’re restrictive so they have issues expanding, meaning not as much air can get in meaning their TLC is lower
Maximum volume of gas the patient can exhalge as forcefully and as quickly as possible (theres no time limit here)
Functional vital capcity
Volume of air that is exhaled during the first second of the FVC and reflects the airflow in the large airways
FEV1
What is a normal FEV1/FVC ratio?
75%
What FEV1/FVC ratio denotes a restrictive lung disease?
80-90%
meaning they can’t get as much in (restrictive) so FVC is lower, meaning that they’re able to blow out a greater percentage because the total air in the lungs is lower
What FEV1/FVC ratio denotes an obstructive lung disease?
<75% = obstructive
Can’t get air out, so that FEV1 number is lower when compared w/ that FVC #
Normal = green
Restirive is that first second - expelling almost everything in that first second
O = obstructive - expelling same amount as normal, just takes forever (hard time getting air out)
What is minute volume ventilation (VE)?
* whats the equation?
VVolume of air expired in one minute
VE = TX x respiratory rate
* because its essentially the volume of air (all those breaths = TV) times the # of time you do it
What is peak expiratory flow?
Max flow of air during the beginning of a forced expiratory maneuver
Volume of air that occupies the non-respiratory conducting airways
Anatomic dead space
Normal breathing that is effortless and at a rate of 8-16 breaths per minute
Eupnea
Rapid breathing at a rate of greater than 16 breaths per minute
Tachypnea
Slow breathing at a rate of less than 8 breaths per minute
Bradypnea
Cessation of breathing
Apnea
High pitched squeaking sounds usually heard on expiration that are caused by bronchospasms and evident with asthma, airway obstruction, or COPD
Wheeze
Snoring sound that may be caused by cystic fibrosis, COPD, or bronchiectasis
Rhonchi
High pitched sounds heard just before the end of inspriation caused by pulmonary edema, early stages of CHF, pneumonia, or atelectasis
Fine crackles
Short, low-pitched sounds heard on inspiration and expiration. The sound is similar to that of blowing through a straw under water. Coarse crackles are caused by air moving through fluid; they occur in pneumonia, COPD, CHF, and pulmonary edema
Corase crackles
Continuous musical sounds with a constant pitch that is cuased by narrow airway. It occurs in croup, epiglottitis, or foreign-body aspiration
Stridor
its some kind of obstruction
Obstructive lung disease:
* Asthma
* Bronchiectasis
* Chronic bronchitits/Cystic fibrosis
* Emphysema
Characterized by airflow limitation that is particularly noticeable during forced expiration
COPD = umbrealla term
What is the most common cause of COPD?
Smoking
Both obstructive and restrictive lung disease lead to tissue destruction, airflow limitations, and impaired gas exchange
Chronic inflammation of the airways and parenchyma and vascular destruction
* does it progress fast or slow?
* is it reversible?
* Describe the pathway
COPD
progresses slowly, only partially reversible (alveoli can’t really be repaired)
inflammation –> mucus production –> ciliary dysfunction –> bronchoconstriction = expiratory flow limitation
can’t get air out
Type 2 pneumocyte destruction is associated w/ what disease?
* What does this produce?
COPD
produces sarfactant
What does end stage COPD reuslt in?
Cor pulmonale (right heart failure)
ABCDE of COPD
Remember this is all obstructive - these are blue bloaters (think barrel chest because they can’t get air out)
A - Asthma
B - Bronchiectasis
C - Cystic Fibrosis/Chronic Bronchitits
D - Decreased FEV1/FVC Ratio
E - Emphysema
Causes: Inhaled irritatnts, smoking, alpha-1 antitrypsin deficiency (genetic)
COPD progression:
Airway thickening continues:
* Mucus production
* Cilia dysfunction
* Remodeling - leaves scaring in tissue - traps air inside
* Inflammatory exudate
That remodeling leads to trapped air inside –> increased residual volume (its air that can’t get out, its trapped) –> lung hyperinflation
Alveoli are destoryed - because were not expanding and reducing, theres air trapped inside so they stay consistently expanded
What COPD stage is this: normal spirometry with chronic productive cough
Stage 0
What COPD stage is this: FEV1/FVC less than 70% and FEV1 at least 80% predicted normal
Stage 1
What COPD stage is this: FEV1/FVC less than 70% and FEV1 50% to 79% predicted for stage IIA and 30% to 49% predicted for IIB
Stage 2
Fev1/FVC less than 70% and FEV1 less than 30% predicted
Stage 3 (severe)
memorize these classifications for COPD
showing that when you stop smoking it slows dow the rate of COPD significantly
What is the gold standard for diagnosis and monitoring of COPD
Spirometry
w/ COPD:
increased TLC, RV (air gets trapped), FRC
normal or decreased VC
Reduced flow rates
Impaired diffusing capcity
Cystic fibrosis:
* genetic
Multisystem disorder:
* CF affects every organ system that has epithelial surfaces
* Pulmonary, intestine, and pancreatic involvement
Parenchyma: thick mucus, recurrent bacterial infections
Intenstines: thick mucus that interferes w/ nutrient absorption and results in malnourishment and low weight
Pancrease: exocrine pancreatic insufficiency, which affects both gastrointestinal fucntion (fat maldigestion) and the growth and development of individuals w/ CF
Other organs affected include the upper airway (sinus infections), male reproductive tract (obstructive azoospermia), and sweat glands (elecated sodium chloride levels in sweat)
Cystric Fibrosis Presentation:
* salty skin
* Frequent lung infections
* Wheezing and/or shortness of breath
* Poor growth and slow weight gain despite a healthy appetitite
* Frequent greasy, bulky stools and/or difficult bowel movements
* Lung sounds tend to be unremarkable, or diminished
Abnormal reduction in lung expansion
Restrictive Lung Disease
What happens to TLC in restrictive lung diseases?
* What about Fev1/FVC ratio?
Decreases
Ratio stays constant. This is because both of these numbers shrink, so you’re expelling less air, however, you already have less air in the lungs to begin w/, keeping it balanced
decreased TLC, 80%, preserved FEV1/FVC ratio > 70% (so normal)
* Reductions in almost all, but normal flow rates (so the flow of air is fine, everything is just lessened because you can’t get as much air in)
Restrictive Lung Disease: - Parenchymal tissue
* Atelectasis
* Pneumonia
* Pulmonary fibrosis
* Acute Respiratory distress syndrome
* Pulmonary edema
* Neonatal respiratory distress syndrome
Restrictive lung disease: - Pleurae tissue - blood/fluid in the pleural cavity can make it hard for the lungs to expand, making it a restrictive lung disease
* Pleural effusion
* Pleural fibrosis
* Pneumothorax
* Hemothorax
Restrictive lung disease: Ventilatory pump dysfunction
* Impaired respiratory drive
* Neurologic and neuromuscular disease - SCI
* Muscle weakness
* Lung hyperinflation
* Thoracic deformity - think stenosis keeping you from expanding
* Connective tissue disorders - think hardneing of things making it hard to expand
* Extrathoracic conditions
so w/ obstructive the RV is actually larger
w/ resitrictive the total volume of everything is lower because you can’t get as much in
can you have resitrictive and obstructive lung disease at the same time
Yes
Combined (both obstructive and restrictive)
Pulmonary edema
* increased pressure from elevated L heart pressures (blood backs up into lungs I guess)
* Increased permability from acute lung injury
Occupational and environmental
* Asthma
* Pneumoconiosis
* Hypersensitivity pneumonitits
* Inhaled injuries
Other Pulmonary Disorders
* Pulmonary emboli and infarct - dislodged DVT. Affects perfusion
* Pulmonary HTN
* Cor Pulmonale
* Respiratory Failure
* Sleep Apnea
* Lung cancer
KNOW: Obstructive lung disease causes alveoli degrigation (because air gets trapped in them)
Which pulmonary disorder is most likely to result in myasthenia gravis
a) COPD
b) RLD
c) Sepsis
d) Asthma
Myasthenia gravis
* neurlogical disorder - makes it hard to actually expand lungs
B
Myasthenia gravis (MG) is a neuromuscular disorder that causes weakness in the skeletal muscles, including those involved in respiration. MG can lead to respiratory muscle weakness, which results in a restrictive pattern on pulmonary function tests (PFTs). Patients with MG often develop restrictive lung disease (RLD) due to impaired diaphragmatic and intercostal muscle function, leading to reduced lung volumes and ineffective ventilation.
restrictive = everything is normal or less than it should be
parenchyma = lung tissue
Pulmonary fibrosis = scaring in lungs
Which of the following pulmonary values is most likely for a diagnosis of atelectasis
and pneumonia?
a. Increased tidal volume
b. decreased FEV1
c. normal FEV1/FVC ratio
d. increased vital capacity
c - because its a restrictive lung disease and restrictive lung diseases have a normal FEV1/FVC ratio, however, they’re both reduced
TEST: - for exercise testing
Absoulte Contraindications - red flags
* Recent history of myocardial infarction (MI), unstable angina, symptomatic cardiac arrhythmias, or severe aortic stenosis
* Ongoing heart infection or thromboembolic disease such as deep venous thrombosis (DVT)
* Febrile state
* Patient has not recovered from acute illness
* Emotional Disorder
* Inability to safely walk on a treadmil or pedal an ergometer due to orthopedic condition
relative contraindications - yellow flags
* prior history of coronary heart disease or cardiac arrhythmias
* Painful msk disease
* uncontrolled hypertension
* Metabolic disease that impairs low-level EX
* Uncontrolled diabetes
* complicated pregnancy
* Cognitive disability
Indirect Index of myocardial oxygen demand
* equation
Rate Pressure Product
RPP = HR x Systolic BP
Exercise Intolerance:
* resting tachycardia or increasing arrhythmias
* Lack of or excessive HR/BP response to exercise
* Angina
* > 10 mm DROP in SBP with increase in workload (after initial rise)
* Excessive dyspnea (difficulty breathing)
* Claudication
* Pallor, lightheadedness, dizziness
* Slow HR recovery
* Extreme fatigue 1-2 hours after EX - this can just be if the pt is unconditioned
