Chapter 41: Oxygenation Part 1 (A&P) Flashcards
Three steps in the process of oxygenation
- Ventilation
- Perfusion
- Diffusion
Ventilation
moving gases in and out of the lungs.
Perfusion
the ability of the CV system to pump oxygenated blood to the tissues and return deoxygenated blood to the lungs
Diffusion
exchange of the respiratory gases in the alveoli and capillaries of the body tissues by concentration gradients.
Poor diffusion is present in patients with
- pulmonary edema (fluid CHF)
- pulmonary infiltrates (pneumonia infection)
- pleural effusion (fluid between the visceral and parietal pleura)
- lobectomy
- pneumothorax (lung collapse due to air in space around lung)
The amount of energy expended on breathing depends on what 3 factors?
- rate and depth of respirations
- lung compliance
- airway resistance
Inspiration
active process triggered by chemical receptors in the aorta
Expiration
passive process: depends on elastic recoil ability of the lungs
Lung Compliance
ease of which the lungs can expand.
Lung Compliance decreases in diseases such as:
- pulmonary edema
- interstitial and pleural fibrosis
- congenital or traumatic structural abnormalities (kyphosis or rib fracture)
Airway resistance includes
asthma, tracheal edema
Surfactant
chemical produced in the lungs to keep the alveoli from collapsing.
Diseases processes can alter the lung elasticity (ability to recoil) such as
COPD: Emphysema
COPD: Emphysema
-accessory muscles are used to increase lung volume but in the long term is not efficient and the patient will fatigue and decompensate.
In patients with emphysema, assess for
-elevation of the clavicles during inspiration -> leads to air hunger, ventilatory fatigue and decreased lung expansion.
Atelectasis
- collapse of the alveoli.
- prevents normal exchange of oxygen and CO2
decreased lung compliance =
increased airway resistance
increased airway resistance =
increased use of accessory muscles
increased use of accessory muscles =
increased work of breathing
increased work of breathing results in:
increased energy expenditure, metabolic rate, need for more oxygen, and need for elimination of CO2
Lung volumes include
- tidal volume
- residual volume
- forced vital capacity
tidal volume
normal amount of air exhaled after a normal inspiration (usually around 500 ml)
residual volume
amount of air left in the alveoli after expiration (necessary to keep alveoli expanded)
forced vital capacity
amount of air that can be removed from the lungs during forced expiration