Geriatric Anatomy, Physiology, and Pathophysiology

Question 1

Technically, what is the difference between the terms

‘elderly’, ‘geriatric’, and ‘aged’?

Answer 1

In scientific literature, ‘elderly’ and ‘geriatric’ are synonymous
terms that both describe patients over the age of 65. The term
‘aged’ refers to patients over the age of 80.
Longnecker DE, Newman MF, Brown DL, Zapol WM.
Anesthesiology. 2nd ed. New York: McGraw-Hill; 2012: 277.

Question 2

How does glomerular filtration rate change with age?

Answer 2

The glomerular filtration rate decreases about 1 mL/min each
year after age 40. This can reduce renal excretion of drugs to a
level where dosing adjustments need to be made by age 60. By
age 80, over half of the glomeruli are lost.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893-894.

Question 3

How is brain mass affected by aging?

Answer 3

Brain mass decreases (as much as 30% by age 80).
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1220.

Question 4

How is the blood circulatory time affected by aging?
How does this affect intravenous and inhalation
induction times?

Answer 4

The blood circulatory time is prolonged in the elderly. As a
result, intravenous induction will progress more slowly as it
takes longer for the administered drugs to reach their target
sites. Inhalation induction, however, will proceed more quickly
as the reduced blood flow leads to less uptake of the anesthetic
and the FA/FI ratio will approach 1 more quickly.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1215.

Question 5

How is blood volume affected by aging?

Answer 5

Blood volume decreases with age.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1221.

Question 6

How does the decline in overall endocrine function in

the elderly affect anesthetic management?

Answer 6

Typically, it does not. The exception may be that elderly
patients tend to have higher insulin requirements
perioperatively, even when a diagnosis of diabetes is not
present. They exhibit a lower insulin response to glucose loads
as well as increased insulin resistance in skeletal muscle.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 894.

Question 7

How is renal sodium management affected in the

elderly? Why?

Answer 7

In elderly patients, the kidneys are not as effective at eliminating
excess sodium, nor are they as effective at retaining sodium.
This is due primarily to a reduction in the secretion of
aldosterone.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 894.

Question 8

How is CNS activity affected by age?

Answer 8

CNS activity decreases with age.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1220.

Question 9

ow do liver mass and hepatic blood flow change

with age?

Answer 9

Liver mass decreases with age and accounts for most of the 20-
40% decrease in hepatic blood flow with age.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.

Question 10

How do cerebral blood flow and CMRO2 change with

age?

Answer 10

As CNS activity and neuronal density decrease, so does
cerebral blood flow and CRMO2.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1220.

Question 11

How does renal mass change with age?

Answer 11

The mass of the renal cortex decreases by 20-25% with age.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.

Question 12

Why is thermoregulation impaired in elderly patients?

Answer 12

They have a lower basal metabolic rate, a higher incidence of
hypothyroidism, a high proportion of body surface area to body
mass, and their ability to produce peripheral vasoconstriction to
reduce heat loss is not as effective.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1215.

Question 13

How does the thermoregulation differ between
younger and older patients clinically? What are the
advantages and disadvantages of these differences?

Answer 13

Temperature regulation is impaired in elderly patients. The
advantage is that shivering can increase oxygen consumption
by 400% and lead to hypoxia, acidosis, and cardiopulmonary
complications rapidly in elderly patients. The disadvantages are
that drug metabolism can be impaired with hypothermia, as can
platelet function, and the risk for infection is greater.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1215.

Question 14

How do plasma protein levels change with age?

Answer 14

Serum albumin decreases slightly with age, but alpha-1 acid
glycoprotein levels are usually unchanged or even experience a
slight increase.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.

Question 15

How does total body water change with age? Where

does most of this change occur?

Answer 15

Total body water decreases with age, primarily due to the
decrease in cellular water from the loss of muscle mass and
increase in adipose tissue.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.

Question 16

At what age does functional organ performance

peak?

Answer 16

Typically, functional organ reserve peaks at age 30 and then
begins a gradual decline from that point on.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.

Question 17

Do normal, age-related changes in hepatic function
require dose-adjustments for medications in the
elderly?

Answer 17

Yes. Age-related decreases in hepatic function can result in a
prolongation of the effects of typically used anesthetic agents.
In particular, the plasma clearance of opiates is reduced.
Careful titration, and in some cases, smaller doses may be
warranted to prevent delayed awakening.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1219.

Question 18

How does the response to beta-adrenergic agents

change in the elderly?

Answer 18

Because they have a decreased response to beta-adrenergic
stimulation, the response to drugs that rely on beta-adrenergic
stimulation is diminished.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 911.

Question 19

Why are geriatric patients more susceptible to

hypotension under anesthesia?

Answer 19

Geriatric patients are at a higher risk for intraoperative
hypotension due to dehydration which can result from a
diminished thirst mechanism, chronic use of diuretics, and a
decreased capacity for sodium and water conservation by the
kidneys. Limited responsiveness to beta-adrenergic drugs and
decreased cardiac contractility that is exacerbated by
anesthesia drugs also contribute to the likelihood of
hypotension under anesthesia.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 651.

Question 20

What is the incidence of postoperative cognitive

dysfunction in elderly patients?

Answer 20

Postoperative cognitive dysfunction occurs in 10-15% of all
elderly patients undergoing anesthesia. It is not related to
perioperative hypotension or hypoxia and results in a varying
inability to perform simple mental tasks. It typically resolves
spontaneously within three months.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 651.

Question 21

What factors increase the risk of osteoporosis in the

elderly?

Answer 21

Calcium and vitamin D deficiency, excessive alcohol intake,
cancer, immobilization, male hypogonadism, estrogen
deficiency, and chronic corticosteroid administration are all
known risk factors that increase the likelihood of osteoporosis.
Postmenopausal hormone replacement therapy, calcium and
vitamin D supplementation, weight-bearing exercise, and
calcitonin administration are all known effective ways to treat or
prevent osteoporosis.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 645.

Question 22

How does the risk for autoimmune disorders change

with age?

Answer 22

The risk of autoimmune disorders increases with age.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 645.

Question 23

How do laryngeal reflexes change with advanced

age?

Answer 23

Protective laryngeal reflexes such as coughing and swallowing
decrease with increasing age, resulting in pulmonary
inflammation and loss of alveolar surface area due to repeated
microaspirations and contamination of the lower airway with
enteric organisms.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 644.

Question 24

Elderly patients have an increased peripheral
vascular resistance. Why is this and what are the
eventual effects?

Answer 24

The increase in peripheral vascular resistance in the elderly
occurs primarily due to progressive loss of arterial distensibility
and leads to concentric left ventricular hypertrophy. The cardiac
output may decrease due to myocardial fiber atrophy, but as the
increase in afterload is greater than the decrease in cardiac
output, hypertension usually results.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1215.

Question 25

What is primarily responsible for the decrease in

brain mass with age?

Answer 25

The loss in mass is primarily due to a loss of gray matter
neurons in the cortex, particularly the frontal lobes. White
matter is not significantly altered.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1220.

Question 26

How are plasma norepinephrine levels different in

the elderly?

Answer 26

Plasma norepinephrine levels are increased in elderly patients.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1220.

Question 27

What surgical procedure has the highest risk for

postoperative delirium in elderly patients?

Answer 27

Although postoperative delirium can occur following any type of
surgical procedure, it is most common in orthopedic surgery
and cardiac surgery. Up to 60% of elderly patients undergoing
orthopedic surgery experience delirium and up to 32% of
patients undergoing cardiac surgery have reported symptoms of
delirium.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1220.

Question 28

How does the heart rate response to hypoxia and

hypovolemia change with aging?

Answer 28

Similar to infants, the elderly have a diminished tachycardic
response to hypotension, hypovolemia, or hypoxia.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 908.

Question 29

What are the major age-related changes in the

cardiovascular system?

Answer 29

There is a decreased response to beta-receptor stimulation, the
myocardium stiffens, the veins and arteries lose elasticity,
sympathetic activity increases, parasympathetic activity
decreases, and the conduction system may become fibrotic
leading to conduction abnormalities.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 897.

Question 30

How do closing volume and closing capacity
compare to functional residual capacity in the
anesthetized elderly patient? What is the result?

Answer 30

The closing volume is increased in the elderly patient.
Functional residual capacity also increases with age due to an
increase in residual volume. Under anesthesia, the closing
capacity is greater than the functional residual capacity, making
the patient prone to atelectasis in dependent areas of the lungs.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1217.

Question 31

How is total lung capacity affected by age? Forced

vital capacity? FEV1? Closing volume?

Answer 31

The total lung capacity decreases slightly or is unchanged. The
loss of elastic recoil around the alveoli results in a decrease in
the forced vital capacity and FEV1. The closing volume
increases.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1217.

Question 32

How would you expect the alveolar surface in the
lungs to change with age? What accounts for this
change?

Answer 32

By age 70, the alveolar surface area available for gas exchange
reduces by about 15%. The cause is an overall reduction in
collagen and the elasticity of the lungs.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1217.

Question 33

How is MAC affected by age?

Answer 33

MAC decreases by about 4% per decade after the age of 40.
Hines RL, Marschall KE. Stoeltings Anesthesia & Co-Existing
Diseases. 6th ed. New York, NY: Churchill-Livingston; 2012:
650.

Question 34

How do renal function tests change with age?

Answer 34

Due primarily to fibrotic changes and decreased mass in the
renal cortex, glomerular filtration rate and creatinine clearance
decrease with age. The BUN increases gradually with age.
Even though creatinine clearance decreases, the reduced
muscle mass and creatinine production associated with
increased age result in an unchanged serum creatinine level.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 911.