Exam 2 - pulmonary Flashcards Preview

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Flashcards in Exam 2 - pulmonary Deck (54):
1

Term: Ventilation

gas transport in and out of the lungs during inspiration and expiration

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Term: respiration

gas exchanges across alveoli-capillary tissue

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Term: perfusion

circulation of blood through tissues

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Mech of ventilation: inspiration

all due to pressure changes
-inspiration = pressure in alveolar is LOWER than atmospheric

***diaphragm ACTIVELY lowers, thorax raises and expands

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mech of ventilation: expiration

pressure changes result in air flow
- exhale = alveolar pressure is HIGHER than atmospheric

**diaphragm relaxes and PASSIVELY elevates, thorax lowers to resting position

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mech of ventilation: compliance

-distensibility of the lungs
-relates to ease of inflation and chest wall expansion during inspiration

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mech of ventilation: elasticity

-recoil, tendency to return to original size
-elastin and collagen fibers, surface tension

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mech of ventilation: surface tension

-contributes to elasticity by acting to collapse the alveoli
- surfactant acts to reduce surface tension

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Mech of ventilation: airway resistance

-Flow = delta P / R
-resistance = 8 micro l/(pi r^4)

upper airways - responsible for most airway resistance

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bronchial smooth muscle innervated by

ANS

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inhale vs exhale: airways open or close

inhale = airways are pulled open

Exhale = airways collapse and increase resistance

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how does gas exchange occur in the lungs?

diffusion

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diffusion of gases across alveolar membrane affected by??? (3 things)

1) pressure/concentration gradients (high to low)
2) surface area (total amount of alveolar-capillary interface)
3) thickness of membrane (thickness can impede exchange)

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Ventilation perfusion ratio

-gas exchange is optimized when ventilation matches perfusion
-actual V:Q (ventilation:blood flow) = ~.8
- gravity, position, and dysfunction affect ratio
-generally, vent and perfusion are greatest in gravity dependent areas

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Dead space (lungs)

when perfusion < ventilation (PE)

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Shunting (lungs)

when perfusion > ventilation (alveolar collapse from secretions)

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Gas transport: O2

-dissolved in plasma (PO2)
-bound to hemoglobin (pulse ox toys! - ~97%)

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Gas transport: CO2

-dissolved in plasma (PCO2)
- bound to hemoglobin (30%)
- bicarbonate (60%)

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Acid-base balance of breathing

- breathing removes acid from blood in from of CO2
(inc breathing = reduce CO2 = reduce H+ = increase in pH)
(dec breathing = increase CO2 = increase H+ = dec pH)

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Acid - base breathing equation

CO2 + H20 H2CO3 H+ +HCO3-

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Neural - respiratory control
-automatic and voluntary

automatic = brainstem
voluntary = cerebral cortex

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Chemical - respiratory control

chemoreceptors in carotids and aortic arch
- CO2, H+ ions, and O2

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Non-chemical (respiratory control)

-coughing, sneezing, bronchoconstriction, and mucus secretion occur in lungs as protective reflexes to irritants

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Restrictive dysfunction (gen def)

abnormal reduction in pulmonary ventilation

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Obstructive dysfunction (gen definition)

-diseases of the airways, producing obstruction to expiratory airflow

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Restrictive dysfunction: characterized by

-decreased chest wall or lung compliance
-dec lung volumes and capacities
-inc work of breathing (inc pressures required for normal TV, inc energy expenditure, dec TV and inc RR)

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Signs and symptoms of restricted lung dysfunction

-rapid, shallow breathing
-tachypnea
-hypoxemia
-accessory muscle use
-diminished breath sounds
-dec lung vol and capacities
-crackles
-dyspnea
-cough
-weight loss
-muscle wasting

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Restricted lung dysfunction eventually may lead to

-pulmonary hypertension
-cor pulmonale
-severe hypoxia
-ventilatory or cardiac failure

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Restrictive conditions (main categories)

pulmonary
connective tissue
musculoskeletal
neuromuscular
other (cancer, surgery, etc)

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Restrictive lung dysfunction TREATMENT

-correct underlying cause if possible

-supportive (supplement O2, antibiotic therapy, interventions for ventilation or prevent accum of secretions, good nutrition)

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Pulmonary fibrosis (what it is)

Interstitial lung disease

-inflam process involving alveolar wall
-leads to progressive scarring (fibrosis)

*progressive, stead decline in lung funct, often with acute exacerbations
*poor prognosis

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Pulmonary fibrosis (what causes it)

- idiopathic (2/3 of cases. risk factors = environmental, genetic, age over 50 usually)

-other causes: infectious agents, environ and occupational inhalants, drugs, healing scar tissue

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Pulmonary Fibrosis TREATMENT

-lack of evidence supporting most treatments
-response to treatment is unpredictable
-lung transplant is the ONLY definitive therapy

34

Pneumoconiosis (general and risk severity)

-lung diseases resulting from inhalation of industrial substances (dusty lungs)

risk depends on many things (type/duration/intensity of exposure, presence of underlying pulmonary disease, smoking history, particle size and water solubility)

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Pneumoconiosis (most common population)

- among miners, sandblasters, stonecutters, asbestos workers, insulators, and agriculture workers

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Pneumoconiosis (pathogenesis)

-variable
-may be rapid onset or last years without clinical manifestations

-dust particles taken up by macrophages
-may activate and/or damage macrophages causing release of mediators
-macrophages containing particles may accumulate in nodules or lesions in the lung, connective tissue, and lymphatic tissues.
-can lead to excessive fibrosis and scarring of lung tissue

37

Systemic sclerosis or scleroderma (what it is)

-autoimmune disease
-excessive collagen deposition in the skin, but can affect internal organs including the lungs
-inflammation leads to fibrosis
-with progression of fibrosis, capillaries become involved causing pulmonary hypertension and cor pulmonale

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systemic sclerosis or scleroderma (disease course, treatment)

-unpredictable disease course
-treatment = immunosuppressive medications and drugs targeting pulmonary HTN (although could be bad drugs)
-lung transplant may be an option for some

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Most common cause of death from scleroderma

Lung disease

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Atelectasis (definition)

collapse/incomplete expansion of alveoli in part or all of a lung

obstructive.
non-obstructive (collapse, compression)

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Atelectasis (what does it result from)

-hypoventilation or ineffective secretion clearance
-inactivity
-thoracic or abdominal incisional pain
-compression of lung
-diaphragm weakness/paralysis
-pneumonia
-foreign body obstruction

42

Types of lung cancer

-small cell lung cancer (20%)

-non-small cell lung cancer (80%)
(squamous cell, adenocarcinoma = most common, large cell)

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Most common type of non-small cell lung cancer

adenocarcinoma

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Most cases of lung cancer are linked to what?

cigarette smoking (~80%)

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Most common site of lung cancer metastases?

Adrenal

**also the lungs are a common site of metastases from other types of cancer

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Lung cancer (symptoms)

symptoms = productive cough, dyspnea, hemoptysis, recurrent infection
May also have fatigue, weight loss, weakness (vague systemic symptoms) or bone pain, headaches, jaundice (metastasis)

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Lung cancer (treatment and prognosis)

Treatment and prognosis depends on stage

treatments can be: chemotherapy, radiation, surgery, and hormone therapies

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Pulmonary edema: inc pulmonary capillary hydrostatic pressure

L sided heart failure
PE

= transudate

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Pulmonary edema: inc pulmonary capillary membrane permeability

ARDS
pna
infection

=exudate

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Pulmonary edema: dec plasma protein

liver cirrhosis

=transudate

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Pulmonary edema: inc fluid accum in interstitial space and alveoli

-inc hydrostatic pressure
-inc membrane permeability
-dec plasma protein
-altered lymphatic function

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ARDS

"Acute respiratory distress syndrome"

-acute respiratory failure that follows systemic or pulmonary insult (severe trauma, sepsis, burns, aspiration, embolism, etc)
-diffuse alveolar damage

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ARDS clinical manifestations

-respiratory distress
-dyspnea
- hyperventilation
- atelectasis
- hypoxia and cyanosis

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ARDS treatment

-first aimed at underlying pathology (sepsis, pneumonia)
-supportive therapy (ventilation)

*high mortality rate (>40%)
***many recover pulmonary func but may have physical or cognitive impairments (some get scarring and interstitial fibrosis)