Mechanism of aging

The progressive physiologic process is characterized by:

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 _____ & neurotransmitter production is also _________ 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?

Decreased number & size of ____ in the ______ & ______?

Are elderly more or less sensitive to a neuraxial block?

Decreased volume of the epidural space

Decreased CSF volume

Decreased number & size of fibers in the dorsal and 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 or dec. 2nd mess. coupling) 

ANS dysfunction in the elderly

How is thermoregulation changed in the elderly?

Impaired thermoregulation

Increased risk for hypothermia & heat stroke

ANS dysfunction in the elderly

What predisposes the elderly to orthostatic hypotension & syncope?

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

Hypoxemia

Hypercarbia

Structural changes in the lung 

Loss of elastic recoil

Increased lung compliance

Altered surfactant production

Loss of alveolar surface area

Increased

The closing capacity (CC) is the volume in the lungs at which its smallest airways, the alveoli collapse. The alveoli lack supporting cartilage and so depend on other factors to keep them open. The closing capacity is greater than the residual volume (RV), the amount of gas that normally remains in the lungs during respiration, and specifically, after forced expiration. This is because closing capacity is equal to closing volume plus residual volume. This means that there is normally enough air within the lungs to keep these airways open throughout both inhalation and exhalation. As the lungs age, there is a gradual increase in the closing capacity. This also occurs with certain disease processes, such as asthma, chronic obstructive pulmonary disease, and pulmonary edema. Any process that increases the CC by lowering the functional residual capacity (FRC) can increase an individual's risk of hypoxemia, as the small airways may collapse during exhalation, leading to air trapping and atelectasis

Closing Capacity vs FRC

Younger 

44

66

Older

Increase in closing capacity is the primary mechanism of ______ change with elderly.

How fast does our GFR decline?

about 50%

1-1.5% per year following young adulthood

How fast does our RBF decline?

What occurs with creatinine clearance and concentration/dilution ability?

Even though the creatinine clearance is decreased with elderly you normally do not see an increase in creatinine b/c these pts also have less muscle mass...if you do see an increase in creatinine that is a red flag of ________?

10% per decade

Progressive decrease in creatinine clearance

Decreased ability to concentrate and dilute urine

renal issues

Increased Vd for lipid soluble drugs

Decreased plasma volume

Decreased plasma protein binding

Decreased hepatic conjugation (phase 2)

Decreased renal elimination

Whites

Asians

Smoking

ETOH abuse

Ca deficiency

Estrogen deficiency

Male hypogonadism

CA

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)

Define perioperative:

*Note: review table on slide 27 

Pharyneal Dysfunction

(swallowing issues/ inc. secretions)

Adequate postop respiratory function

Presence of autonomic dysfunction

the term includes the 3 phases of surgery; preop, intaop, and postop

Keep a high index of suspician for age related disease

Assess functional reserve

Atherosclerosis related (CV, CNS, Renal)

DM

Pulmonary

Dementia

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

When should you start beta blockers prior to surgery?

100%

several weeks before

No!

Started the morning of surgery there is an association with increased incidence of stroke & all-cause mortality.

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

Also reduce dosages of the sedative-hypnotics

Review slide 33

There is an increased incidence of postoperative pulmonary complications due to: (4)

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

Age-associated memory impairment

Mild cognitive impairment

Age-associated cognitive impairment

Cognitive impairment, no dementia

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 - 36.6%

3 months - 5.7%

Discharge - 30.4%

3 months - 5.6%

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 _____

CNS

lipid

water

plasma protiens

hepatic & renal metabolism