ALTERATIONS IN OXYGENATION
Alveoli - Functional unit of lung interconnected by pores of Kohn that produce surfactant;
Each adult has 300 million alveoli arranged in clusters which are surrounded by capillary bed
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ALTERATIONS IN OXYGENATION
Alveoli - Functional unit of lung interconnected by pores of Kohn that produce surfactant;
Each adult has 300 million alveoli arranged in clusters which are surrounded by capillary bed
Gas exchange occurs via diffusion and depends on ventilation-perfusion ratio
Normal –fully-functional alveoli & good blood supply allow for maximum gas exchange
Impaired Gas exchange:
Alveoli is constricted, blocked or collapsed; blood passes alveoli without max gas exch.
Blood supply is blocked not giving alveoli adequate blood supply
Lung Tissue Properties:
Compliance – Expandability of lung which depends on surface tissue of alveoli & connective tissue of lungs →
elastin gives lungs stretchability
Normal – easily stretched when take a deep breath
Low – stiff/difficult to inflate → pulmonary fibrosis or morbid obesity
High – lungs lost elasticity (overdistended) → returning CO2 such as with emphysema r/t loss of some
alveolar wall→ lose recoil → overinflation
Elastic Recoil – ability of lungs to reduce in volume after being stretched
Respiratory Defense Mechanisms –
Filtration of air
Mucocilliary Clearance
Cough reflex
Reflex Bronchoconstriction
Alveolar Macrophages
Respiratory System Age Related Changes - respiratory peak @ age 25
Lifetime exposure to environmental stimuli – pollution; occupational hazards
Concurrent chronic disease – CAD, CHF, DM, COPD, alcoholism
Structural alterations – decr ability to take a deep breath; diminished vital capacity ( max amt of air inhaled &
exhaled in a cycle)
◦ ↓ in elastic recoil
◦ ↓ in chest wall compliance
◦ AP diameter increases
◦ Kyphoscoliosis with advancing age
◦ Alveolar surface decreases
Defense Mechanism Changes – decr ability to clear secretions, incr URI, Incr r/f aspiration
◦ ↓in cilia function
◦ ↓cough reflex
◦ ↓effectiveness of alveolar macrophages
◦ Muscle atrophy of pharynx and larynx
Decrease in Physical Mobility – pulling of secretions in lungs → r/f pneumonia
Respiratory Assessment Interview
Current respiratory problem
◦ Restlessness → 1
st indication of problem with oxygenation
◦ changes in breathing pattern/dyspnea
dyspnea – shortness of breath → @ rest, exercise, climbing stairs??; factors that relieve/worsen;
sudden/gradual; lying flat?; S/S of other diseases (CHF, anaphylaxis, etc.)
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