Mechanism of aging 

The progressive physiologic process is characterized by:

IN ALL ORGANS

Declining end-organ reserve

Decreased functional capacity

Increasing imbalance of homeostatic mechanisms

Increasing incidence of pathologic processes

As we people age they start to loss neuronal mass; do they loss more white or gray matter? 

What compensates for this decrease in brain mass?

CBF is inc or dec & neurotransmitter production is also inc or dec as you age?

Gray matter decreased more than white matter

compensatory increase in CSF volume centrally

Decreased cerebral blood flow

Decreased neurotransmitter production

Describe the neuraxial nervous system as we age:

Volume of epidural space?

Neuraxial CSF volume?

Dec or inc number & size of dorsal and ventral roots?

Are elderly more or less sensitive to a neuraxial block?

Decreased volume of the epidural space

Decreased CSF volume

Decreased # & size of fibers in the dorsal & ventral roots

Increased sensitivity to neuraxial block

Decreased parasympathetic outlflow

 increased sympathetic outflow

 decreased response to beta adrenergic stimulation

down regulation of receptors d/t excess SNS outflow and  dec. 2nd mess. coupling (cAMP)

ANS dysfunction in the elderly

How is thermoregulation changed in the elderly?

Impaired thermoregulation

Increased risk for hypothermia & heat stroke

Impaired baroreceptor sensitivity

autonomic dysfunction

Decreased maximum HR, CO, & SV

(decreased functional RESERVE = fine until stressed)

LVH

Systemic HTN

Increased incidence of CAD

Increased incidence of valvular sclerosis

Decreased beta-adrenergic sensitivity

decreased ability to increase HR or contractility to aid in maintaining CO

impaired ventilatory response

Structural changes in the lung 

Loss of elastic recoil = incr. lung compliance

Altered surfactant production

Loss of alveolar surface area

decreased chest wall compliance

Increased

Closing Capacity vs FRC

Younger 

44 (supine)

66 (upright)

Older

Increasing closing capacity is the primary mechanism of ______ increase with the elderly.

about 50% 

decreases 10% per decade after 30yrs or you can say decreases 1% per year following young adulthood

How fast does our RBF decline?

What occurs with creatinine clearance (best estimation of GFR) and concentration/dilution ability?

Why do you not see an increase in creatnine levels in the healthy older adult? Will the BUN increase?

10% per decade

Progressive decrease 

Even though the creatinine clearance is decreased with elderly you normally do not see an increase in creatinine levels b/c these pts also have less muscle mass. and thus less creatine production to be processed by the kidneys. BUN does gradually increase with age.

20-40% reduction in liver mass 

Function is usually adequately preserved in the absence of coexisting pathology

Increased Vd for lipid soluble drugs

Decreased Vd for water soluble drugs

Decreased plasma volume

Decreased plasma protein binding

Decreased hepatic conjugation (phase 2)

Decreased renal elimination

 most unchanged 

albumin slightly decreased

alpha glycoprotein slightly increased

white/asian

Smoking

ETOH abuse

Ca deficiency

Estrogen deficiency

Male hypogonadism

cancer

immobilization

Chronic corticosteroid use

Who knows?

Possibly genetic, environmental, infectious

Resting Tremor

Muscle Regidity

Bradykinesia

(slowness and lack of coordination of mvmt)

Continuation of the anti-Parkinsons drug regimen

Avoidance of drugs which might exacerbate signs & symptoms

Phenothiazines

Butyrophenones -- ie Haldol/Droperidol

Metoclopramide

When dealing with Parkinsons Disease perioperatively we have to pay special attention to?(3)

Pharyneal Dysfunction

(swallowing issues/ inc. secretions)

Adequate postop respiratory function

Presence of autonomic dysfunction

Atherosclerosis related (CV, CNS, Renal)

DM

Pulmonary

Dementia

Incidence of adverse drug reactions w a pt on 10 drugs?

When should you start beta blockers prior to surgery?

100%

several weeks before

Is there a difference between Regional & GA in regards to morbidity and mortality with the elderly?

What are 2 benefits of regional anesthesia in the elderly?

No difference in morbidity and mortality

Decreased incidence of DVT

Decreased blood loss w/ select surgeries

(also better pain management)

Should we reduce MAC in the elderly?

If so how much?

Hell Yes!

6% reduction per decade

No, age has minimal to no effect on MR 

per Ron

Impaired laryngeal protective reflexes

Impaired hypoxic & hypercarbic ventilatory drive

Reduced strength of respiratory muscles

Increased ventilation/perfusion mismatch

List 6 common postop complications in patients older than 65 years & their % of occurrence?

What is the single most common complication with elderly and surgery?

Atelectasis 17%

Acute Bronchitis 12%

Pneumonia 10%

Heart Failure/MI 6%

Delerium 7%

New focal neurologic deficit 1%

PULMONARY ISSUES

What is very critical to reducing postop pulmonary complications?

This may also decrease the incidence of post op ______?

post op pain management

post op delirium

disordered thinking

The orienting narrative of the patient's existence is replaced by a coherent & convincing hallucination

PT IS NOT ORIENTED

A deterioration in the speed & accuracy of executive & memory function

ORIENTED BUT SLOWED FUNCTION

Currently a research finding as opposed to a diagnosis

What is cognitive reserve?

What is believed to be a measure of cognitive reserve?

Theory proposed to explain the significant changes occurring on brain imaging prior to behavioral changes being noted.

Years or level of education

Decreased light sensitivity

Loss of blue/green perception

Decreased reading speed

Altered visual search patterns

maintained

Prolonged

Age over 70

Hx of ETOH abuse

Baseline cognitive impairment

Severe physical impairment

Abnormal pre-op lytes or glucose

Non-cardiac thoracic

AAA surgery (2 points)

Everything else is 1 point

Sensory impairment

Severe illness

Baseline dementia

Dehydration

 SSBD

Post op delerium scale

0 Points

Post op delerium scale

1-2 points

Post op delerium scale

3 or more points

1. Anticholinergics
2. Benzodiazipines
3. Meperidine
4. Tricyclic antidepressants
5. 1st generation antihistamines
6. High dose H2 blockers

The Elderly

Lower Educational Level

Advanced Age

Metabolic Problems

Previous CVA

LAMP

Discharge - 41.4%

3 months - 12.7%

inability to downregulated nociceptive system

inability to handle the huge stress response that occurs with continued pain

Elderly have the following changes in regards to drug metabolism

Increased sensitivity of the ____

Increased Vd for ____ soluble drugs

Decreased Vd for ____ soluble drugs

Decreased ______

Decreased _____ and _____ metabolism

CNS

lipid

water

plasma protiens (albumin)

hepatic & renal metabolism

1. age
2. patient's preop status
3. coexisting disease
4. elective vs emergency surgery

1. thoracic
2. intraperitoneal
3. major vascular

Increased or decreased in the Elderly:

muscle mass

fat

total body water

dec. muscle mass

inc. fat

dec. total body water

1. inc body surface area to body mass ratio
2. dec basal metabolic rate
3. hypothyroidism
4. less effective vasoconstriction

Younger pts shiver at _ deg C & elderly shiver at _ deg C. 

How much does shivering increase O2 consumption?

36.1

35.0

400%

Why do you see an increase in systolic BP in the elderly?

What happens to the diastolic pressure? 

decr. arterial compliance

DBP is unchanged but since SBP is increased = inc PP

its effects are indirectly increased b/c the elderly pt is resistant to adrenergic agonist = the PNS is less opposed

---- though overall PNS activity is decreased and SNS is increased in the elderly.

Are the following parameters inc or dec in elderly:

circulation time

CO/CI

Resting HR

SBP

DBP

baroreceptor function

LV compliance

afterload

chronotropic & inotropic response

Why are the elderly more prone to CHF?

This risk is increased with which arrythmia?

More dependent on an inc. in EDV than inc HR to produce an increase in CO. Also kidneys are less able to conc. and dilute urine.

AFIB - need arial kick for 20% of EDV

work of breathing is increased 

d/t inc airway resistance and dec chest wall compliance and dec muscle strength and increased alveolar compliance (dec elasticity).

slight increase in FRC

↓ ERV

↑ RV

d/t loss of elasticity of alveoli thus an inc in closing volume

1. sluggish insulin response to hyperglycemia

2. resistance to the effects of insulin in periphery

Elderly and the liver:

liver mass

CYP450 enzymes

liver blood flow

plasma cholinesterase levels

all decreased

plasma cholinesterase levels dec in MEN

Sensory block _______ w/ spinal & _______ segmental dose w/ epidurals. 

Epidural volume tends to result in a more extensive _____ spread of anesthetics but is accompanied by ______ DOA and _____ motor block.

The elderly and their kidneys (inc or dec):

BUN

ADH response

GFR concentrating ability

serum creatinine

kidney mass

renal BF

risk for hyperkalemia

risk for hypokalemia

response to aldosterone

unchanged for both Suc and NDMR

(onset may be slower just d/t slow cir time)

IV induction is slow d/t slow circ time

Inhalation induction is more rapid d/t dec CO

1. inc Vd d/t inc fat
2. dec hepatic metabolism (halothane)
3. dec pulmonary gas exchange

Change in the elderly: anesthetic consequence

dec. vascular volume

decr. protein binding

inc. lipid storage sites

dec. renal & hepatc BF

increase dose for equal HR response

(adrenergic receptors. less sensitive)