Geriatrics

Question 1

What is 1 MET?

Answer 1

3.5mLO2/kg/min

Or, about 250mL/min for 70kg patient

Question 2

Minute ventilation in the eldely

Answer 2

Increases to compensated for the increase in dead space 2/2 small airway closure

Question 3

Lung elasticity

Answer 3

Decreases, resulting in slower of small airways and the lung to be overfilled with gas.

Increased dead space
Decrease alveolar surface area
Increased A-a gradient
VQ mismatch
Decreased PaO2
Altered lung volumes

Question 4

Chest wall compliance

Answer 4

Decreased

This is because of:

• Flatter diaphagm
• Increased AP diameter
• Decreased intercostal mass
• Joint falcification
• Loss of intervertebral disc height

Results in increased WOB

Question 5

Consequences of loss of elastic recoil

Answer 5

Airways don’t spring back. They inflate, but don’t spring bag. It’s like inflating a plastic shopping bag. On exhalation, and pressure in the chest becomes positive, these flimsy airways collapse, and the air in the shopping bag is trapped.

Question 6

What does it mean when closing capacity surpasses FRC?

Answer 6

Closing capacity is the volume of air that must be in the lungs to prevent airway collapse.
If it surpasses FRC, it means that airways will collapse during normal tidal breathing.

This happens at age 45 in the supine position and will happen at age 65 in the standing position.

This collapse results in increased dead space, VQ mismatch, and a reduction in PaO2.

Question 7

Vital capacity in elderly

Answer 7

Reduced.

The chest wall is less compliant and muscles are weaker and diaphragm is weaker. Can’t take in a huge breath.

Question 8

What is special about alpha 1 acid glycoprotein in the elderly?

Answer 8

It binds to basic drugs, and it’s production is actually INCREASED in the elderly

Acid binds with base!

Question 9

Albumin binds what types of drugs?

Answer 9

Acidic drugs

Albumin is decreased in the elderly

Question 10

Pseudocholinesterase in the elderly

Answer 10

Decreased

Question 11

Liver function in the elderly

Answer 11

Hepatocytes work normally!

What’s reduced is hepatic BF and hepatic mass. Periop hepatic function is decreased as well.

Question 12

Phase I and II reactions in the elderly

Answer 12

Phase I (oxidation, reduction, and hydrolysis) are reduced.

Phase II (conjugation and acetylation) are unchanged