Aging and the Respiratory System Flashcards
What happens to the respiratory muscles with aging?
They decline in strength
-> decreased fast twitch fibers, and ability rapidly inspire / expire.
Everything gets worse
How does the chest wall change as we age?
It gets stiffer by calcifying at rib cage articulations
What happens to elastic recoil as you age? Compliance?
Due to alterations in elastin and collagen, elastic recoil declines and compliance incresaes
What happens to TLC, residual volume, and closing volume as you age?
TLC - unchanged (relates to chest wall)
Residual volume - increases, due to increased compliance
Closing volume - due to loss of elasticity - like emphysema (increased compliance, more deadspace, especially in bases)
What is closing volume again?
The amount of air in the lung as the first airways begin to close -> will increase with aging because the airways begin to collapse at higher volumes. Effect is more prominent in the bases
What happens to spirometry with aging?
Decrease in FVC
Decrease in FEV1
Greatest decrease in FEF25-75
What happens to PaO2 per decade and why?
Decrease in 3-4 mmHg, because alveoli have less area for gas exchange
What accounts for the V/Q mismatch in the elderly?
Earlier closure of small airways
- > base has poor ventilation but still good blood flow
- > V/Q is far less than 1 in the bases
- > extra air goes into apices instead -> V/Q will be far greater than 1
How does ventilation rate change with age?
Minute ventilation tends to remain unchanged, but response to hypoxia and hypercapnia is significantly reduced (Worse at exercise)
How does airway clearance change as we age?
Decreased mucus production, cough reflex, and mucociliary clearance rates
How does immunologic protection of respiratory tract change as we age? Why is this consequential?
It actually goes up
- > greater PMNs, antibodies, and incresaed CD4 to CD8 ratio
- > age-related increase in immune response due to repetitive environmental antigenic exposure
-> immune system is no longer fine-tuned -> persistent lowgrade inflammation** of lower respiratory tract
Why is exercise important to preserving lung function?
VO2 max, decreases at 1% per year no matter what past age 20-30. But this decay can be blunted somewhat by starting at a higher max VO2
Why are elderly people so much more vulnerable to pneuomnia?
They have a decreased pulmonary reserve -> pneumonia tends to knock out a little extra of their breathing capacity
What often delays diagnosis of problems, or causes overdiagnosis?
Delays - elderly often come in with more atypical or nonspecific presentations which delay diagnosis
Overdiagnosis - some aging-related changes may mimic disease (i.e. COPD)
Why might pneumonia present with dyspnea in the elderly rather than classical symptoms of fever and cough first?
Because pneumonia knocks out their oxygen uptake
-> aging decreases the pulmonary reserve, triggers dyspnea before there is enough shit in the airway to warrant coughing or a fever from immune response
