Disorders of Lung Expansion & Gas Exchange

(week 5 pt.4)

when lung expansion is limited there is a ___ in lung compliance → lungs are harder to expand. Decreased lung ____ → decreased tidal volume → inc work of _____, rapid shallow breathing

decrease, expansion, breathing

tidal volume

the amount of air that moves in or out of the lungs with each normal respiratory cycle

compliant lungs ___ more w/ the ____ inspiratory effort

expand, same

stiff lungs ___ less and with the same ___ effort

expand, inspiratory

limited lung expansion can lead to __/__ mismatch and/or diffusion impairment → ____

V/Q, hypoxemia

atelectasis

collapse of alveoli/lung tissue

atelectasis is caused by

obstruction, compression, and decreased surfactant

collapse of alveoli/lung tissue (w/atelectasis) ___ alveolar ventilation while ___ may continue →. __ V/Q mismatch

decreases, perfusion, low

a complete collapse (w/ atelectasis) → ___ → hypoxemia

shunt

obstruction of an alveoli (w/atelectasis) →

trapped air is absorbed

compression of an alveoli (w/atelectasis) →

external pressure collapses alevoli

decreased surfactant of an alveoli (w/atelectasis) →

increased surface tension → collapse

pulmonary fibrosis

excess fibrous/connective tissue within the lung

with pulmonary fibrosis repeated injury/inflammation can lead to

abnormal repair

when ___ tissue accumulates in the interstitium it leads to ___, stiff lung tissue (pulmonary fibrosis)

fibrous, thickened

potential causes of pulmonary fibrosis

idiopathic, autoimmune disease, environmental/occupational exposures, radiation/medications

consequences of pulmonary fibrosis include:

• decreased compliance

• impaired diffusion

impaired diffusion is caused by ___ interstitium → inc. diffusion distance → decreased ___ diffusion & hypoxemia

thickened, oxygen

interstitium

fluid-filled spaces located between cells in the lining of the respiratory tracts

pulmonary edema

excess fluid in the lung interstitium and/or alveoli

two causes of pulmonary edema include

• increased hydrostatic pressure

• increased capillary permeability

cardiogenic=

pressure problem

noncardiogenic=

permeability problem

(w/pulmonary edema) an increase in hydrostatic pressure → increased ___ pressure, fluid pushed out of capillaries, commonly ____

capillary, cardiogenic

(w/pulmonary edema) increased capillary permeability → injury to alveolar-___ barrier, fluid + ___ leak into lung, commonly ___

capillary, proteins, noncardiogenic

cardiogenic pulmonary edema is caused by

increased hydrostatic pressure

noncardiogenic pulmonary edema is caused by

increased capillary permeability

as fluid accumulates (w/pulmonary edema) increased ___ distance, decreased ___ ventilation, and ___ lung compliance occur

diffusion, alveolar, decreased

when increased diffusion distance occurs (w/pulmonary edema)

fluid increases the distance between alveolar air & blood

when decreased alveolar ventilation occurs (w/pulmonary edema)

fluid in the alveoli displaces air available for gas exchange

when decreased lung compliance occurs (w/pulmonary edema)

fluid makes the lungs stiffer and harder to expand

gas exchange w/pulmonary edema ___ V/Q → may approach ___ as alveoli fill w/ ___ → hypoxemia

low, shunt, fluid

ARDS patho we need to know

• acute, diffuse inflammatory lung injury

• alveolar injury & surfactant dysfunction

pathway of acute, diffuse inflammatory lung injury (ARDS): triggering ___ → intense inflammatory response → ___to alveolar epithelium + ___ endothelium → inc alveolar-__ permeability → protein-rich fluid ___ interstitium and alveoli → noncardiogenic pulmonary edema

insult, injury, capillary

ARDS

acute respiratory distress syndrome

Alveolar injury & surfactant dysfunction w/ ARDS: injury to type __alveolar cells → ___surfactant production, surfactant may also become inactivated

II, decreased

Alveolar injury & surfactant dysfunction w/ ARDS leads to ___surfactant → ___ surface tension, this causes alveoli instability → collapse (___) → decreased ___ compliance → decreased __ of affected alveoli

decreased, increased, atelectasis, lung, ventialtion

as ventilation falls w/ ARDS: ___filling + collapse → decreased ; ____ continues, V/Q approaches ___ → intrapulmonary ___→ severe hypoxemia, supplemental oxygen may have ___ effect

alveolar, perfusion, 0, shunt, limited

severe ARDS can lead to

respiratory failure

diffuse lung ___→edema +___ collapse → shunt → severe ___

injury, alveolar, hypoxemia