Geriatric Anesthesia

Question 1

In general, are most plasma protein levels increased, decreased, or unchanged in the elderly? What important protein is an exception?

Answer 1

Most are unchanged or slightly decreased such as albumin. An important exception is alpha-1 glycoprotein which is increased; this is clinically relevant because it binds basic drugs such as local anesthetics and opioids.

Question 2

How is renal function altered in the geriatric patient?

Answer 2

GFR and renal blood flow is decreased but serum creatinine remains unchanged due to a decrease in muscle mass and creatinine production.

Question 3

What is the best indicator of drug clearance in the geriatric patient?

Answer 3

Creatinine clearance

Question 4

What happens to residual volume with aging?

Answer 4

It increases with age.

Question 5

What changes occur in total lung capacity with age?

Answer 5

Specific (height-adjusted) TLC does not change with age (absolute TLC decreases slightly)

Question 6

How do functional residual capacity and vital capacity change in the elderly?

Answer 6

FRC usually only increases slightly (10%) with age. Vital capacity is significantly decreased with age.

Question 7

How is vital capacity altered in the older adult? What accounts for this change?

Answer 7

VC decreases in the older adult due to a progressive increase in residual volume.

Question 8

What changes occur to closing volume and closing capacity in the older adult?

Answer 8

They both increase progressively with age. (recall CC = CV + RV)

Question 9

How do closing capacity and FRC compare when the 45 yr old patient is in the supine position?

Answer 9

Closing capacity and FRC are about equal.

Question 10

At approximately what age does closing capacity equal or exceed FRC in the awake, upright individual?

Answer 10

65 years old

Question 11

What is the estimated closing volume in a young, healthy adult? What is the estimated closing volume in a 70 year old?

Answer 11

Closing volume is 30% of total lung capacity in the 20 year old and increases to about 55% of TLC at 70 years old.

Question 12

What happens to FEV1 with age?

Answer 12

It decreases due to loss of elastic recoil, decrease in small airway diameter, and airway collapse with forced expiration.

Question 13

What signs of pulmonary disease are exhibited by elderly patients?

Answer 13

Elderly patients have signs of both restrictive and obstructive disease. They have decreased chest wall compliance, consistent with restrictive disease, whereas the lung parenchyma is more compliant, leading to obstructive disease signs and symptoms.

Question 14

How do PaO2 and PaCO2 change with age?

Answer 14

PaO2 decreases steadily with age, reaching normal values of 80 mmHg by age 70. This is due to VQ mismatch (specifically shunting) caused by closing capacity encroaching upon and eventually exceeding FRC. PaCO2 remains relatively constant.

Question 15

Write an equation that shows how the PaO2 can be estimated for a given age. Predict the PaO2 of a 78 year old patient.

Answer 15

PaO2 = 102-age/3. PaO2 = 102-78/3 = 102-26 = 76 mmHg

Question 16

How does the PaCO2-PACO2 gradient change with age?

Answer 16

The gradient increase with age because there is a progressive increase in VQ mismatching with age.

Question 17

Does the Vd/Vt ratio generally increase, decrease, or remain the same in the geriatric population?

Answer 17

With advancing age, dead space increases (increased Vd), therefore the Vd/Vt ratio will also increase because the fraction of the tidal volume that is dead space increases. This is clinically relevant because increased Vd requires increased minute ventilation and increased work of breathing to maintain alveolar ventilation.

Question 18

How does the ventilatory response to hypoxemia or hypercapnia in the elderly compare to that seen in younger patients?

Answer 18

The elderly have a decreased ventilatory response to both hypercapnia and hypoxemia by about 50% or more, predisposing them to increased episodes of apnea.

Question 19

How does chest wall compliance and pulmonary lung compliance differ in the elderly compared with a young, healthy adult?

Answer 19

Chest wall compliance is decreased and pulmonary compliance is increased.

Question 20

Identify 7 cardiovascular changes that occur with aging.

Answer 20

1) Decreased arterial compliance and venous capacitance 2) Increased SVR, systolic blood pressure, and pulse pressure 3) left ventricular hypertrophy and diastolic dysfunction 4) Diminished adrenergic receptor sensitivity 5) Decreased baroreceptor sensitivity 6) calcification and fibrosis of conduction system and conduction system abnormalities 7) Decreased cardiac output and increased circulation time

Question 21

How do cardiac output and stroke volume in the elderly compare with cardiac output and stroke volume in the young adult?

Answer 21

Cardiac output decreases with age but stroke volume does not change with age.

Question 22

What population – other than persons with atrial fibrillation, atrial flutter, or junctional rhythms – are particularly dependent upon atrial contraction to achieve adequate ventricular filling?

Answer 22

Geriatric and elderly individuals are particularly depending on atrial contraction due to associated diastolic dysfunction.

Question 23

What physiologic change places the geriatric person at risk for aspiration?

Answer 23

Decreased laryngeal reflexes.

Question 24

An elderly patient becomes hypotensive and tachycardic when going from supine to upright position. Why?

Answer 24

Autonomic dysfunction. Baroreceptor reflexes are impaired.

Question 25

What two important changes in the autonomic nervous system take place with aging?

Answer 25

1) decrease in response to beta-receptor stimulation

2) increase in SNS activity

Question 26

Why do geriatric patients have a decreased response to beta-antagonists?

Answer 26

The beta receptor has a reduced affinity for beta-adrenergic receptor antagonists and agonists.

Question 27

Why is the elimination of midazolam prolonged in the elderly?

Answer 27

Decreases in hepatic blood flow and possibly decreases in hepatic metabolism may cause as much as a doubling of elimination half-time in the elderly.

Question 28

What is the most common postoperative complication in older adults?

Answer 28

Postoperative delirium

Question 29

After what type of surgery is postoperative delirium most common in the elderly?

Answer 29

It is more common after orthopedic (35% after emergent hip surgery) and cardiac procedures.