Geriatric Anesthesia Robert L. Snyder, DO, FAOCA

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Evaluate potential risk factors for frailty of geriatric patients prior to surgical intervention.

Evaluate Pulmonary and Cardiovascular risks in the pre-surgical patient

Evaluate the Musculoskeletal System and its relationship to the pre-surgical patient

Use American Society of Anesthesiologists risk status as a predictor of surgical outcomes

Objectives

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This presentation is supported by HRSA Grant # D54HP23284

Disclosures

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Considerations?◦ What is patient’s normal functioning status?◦ How will the patient tolerate stress?

Frailty Gait Exercise Tolerance Posture Nutrition

Evaluation and Observation

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Indicator of post-op wellness Bodily functions changing 80 year old, 50% kidney function pO2 on room air is 60 Declining muscle mass at age 30 Hypothermia and decreased metabolism Strength to preform adl Drug absorption and distribution decreased

Frailty

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Is the patient depressed? Is loss of neurotransmitters significant? What other disease is present? Have they lost loved ones? Remember dementia and confusion are worse

after surgery Has the patients had:

◦ Stroke? ◦ Loss of Hearing?◦ Dementia? ◦ At high risk for post-op cognitive dysfunction?

Mental Status

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How will the patient be positioned for surgery?

Can cervical mobility be maintained for airway management?

Can mobility during surgery be maintained? ◦ if patient is prone for laminectomy?◦ If lateral mobility is needed for carotid surgery?◦ If extension is needed for thyroid, shoulder and

craniotomy surgery?

Musculoskeletal Assessment

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Is there periodontal disease ? Is there chronic inflammation or indicators

of possible vascular disease? Does the patient have teeth?

◦ Poor nutrition ◦ Worse prognosis post-op

How much muscle mass is Present?◦ atrophy occurs rapidly after age 30 ◦ impossible to return to same muscle mass

Musculoskeletal Assessment

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PT is extremely important in the elderly◦ Plan to have patient mobile ASAP

Good nutrition is extremely important◦ Plan supplemental nutrition ◦ Plan to monitor glucose

Musculoskeletal Assessment

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Decreased pulmonary elasticity ◦ Lung elastin decreases, ◦ fibrous connective tissue increases: ◦ decreased elastic recoil affecting patency of small

airways Decreased alveolar surface area

◦ breakdown alveolar septa ◦ Increased anatomic and alveolar dead space

Respiratory System

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Calcification leads to decreased chest wall compliance

FRC increases modestly Residual volume increases at the expense of

respiratory reserve volume, therefore vital capacity becomes significantly compromised

Closing volume and closing capacity also increase until FRC is affected

Therefore, small airways close even during tidal breathing

Respiratory System

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Closure of small airways results in desaturation occurring during induction of anesthesia

Normal pre-op pO2 ◦ On a 20 year old is 95◦ On an 80 year old, it is 60

Decreased reduction and ventilatory response to imposed hypoxia and hypercapnia.

Increased periodic breathing (apnea) during sleep makes them more prone to have apnea and obstruction of the airway in the PACU

Respiratory System

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Narcotics depress respiratory drive and the elderly are starting out with a low pO2

Oxygen free radicals are harmful to the brain, so we want to get them off of oxygen ASAP.

Adverse respiratory events in the elderly after narcotics is due to higher initial plasma concentrations rather than increased sensitivity

Pulse Ox does not indicate adequate respirations, the pCO2 can be greater than 100 with pulse ox reading 99% because of supplemental oxygen

Respiratory System

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Cardiovascular System Compromised◦ Decreased blood volume and often anemic ◦ Do not tolerate large fluid shifts leading to CHF or

A-Fib◦ Left ventricle is not as compliant nor is the

vasculature Major Heart anatomic changes

◦ increase in heart wall thickness, ◦ myocardial fibrosis ◦ valvular fibrocalcification

Cardiovascular System

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Major Heart anatomic changes (con’t)◦ Decreased ventricular compliance, ◦ small changes in volume or venous capacitance

become increasingly important to cardiovascular stability

Aging makes patients both volume dependent and volume tolerant◦ Expect hypertension and cardiomegaly in these

patients

Cardiovascular System

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Valvular heart disease may require a special monitor◦ Avoid spinal anesthesia with moderate to severe

aortic and mitral stenosis◦ Conversely, aortic and mitral regurg benefit from

spinal anesthesia as reduced afterload improves forward flow from decreased PVR

Anesthetics depress heart function

Cardiovascular System

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Circulation time is slower◦ Need to titrate medications slowly and start with

lower dose Medication complications

◦ Many patients are on blood thinners, beta blockers, calcium channel blockers, anti-arrhythmics, statins and aspirin

◦ Depending on type of surgery, blood thinners may need to be continued and may need to bridge therapy

◦ Continue beta blockers, but do not start them acutely before surgery except in specific instances

Cardiovascular System

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Medication complications (con’t)◦ Combination of new beta blockers and anesthesia is

often disastrous◦ Marked hypotension occurs that is not very

responsive to vasopressors Old hearts are similar to baby hearts without

clean coronaries◦ They respond to the need for increased cardiac

output primarily by increasing heart rate more than stroke volume

◦ The vascular system is stiff with decreased volume so it will not be helpful in increasing cardiac output

Cardiovascular System

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Aging patients have decreased body mass, ◦ Very important to keep the patient warm ◦ Normothermia will help the patient metabolize the

drugs, clot, and prevent post-op shivering ◦ Shivering can increase myocardial oxygen

consumption by 100%◦ Please warm the fluids, always warm blood and

use warm air heaters on the patient pre-op, intra-op and post-op for best outcome.

Do you know how to tell when a senior citizen is warm?

Cardiovascular System

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50-65% of the elderly have C.V. disease C.A.D. has been found in completely

symptom free 70 year olds P.A catheter analysis shows fewer than 15%

of elderly patients are physiological normal in respect to hemodynamic and respiratory function

Almost 25% had severe and intractable functional abnormalities that lead to post-op death

Cardiovascular System

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Hepatic function decreases with age not because of microsomal or non-microsomal enzyme activity

Loss of hepatic mass significantly impairs liver, ◦ this occurs without any other age related

processes◦ By age 80, the liver is reduced in size by 40%◦ Benzodiazepine metabolism slows down more in

men than women

Liver Function

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Loss of hepatic mass◦ There is a significant reduction in plasma

cholinesterase activity◦ Splanchnic blood flow decreased in proportion to the

loss of tissue, therefore the decrease to the liver is significant

The elderly have a universally progressive decrease in their ability to handle a glucose load◦ Healthy persons over 40 years require 90-95 minutes

to return to normal FBS vs. Younger patients requiring only 65 minutes on average

◦ Less lean body mass (muscle mass) to handle carbohydrate storage is one reason

Liver Function

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Glucose Metabolism◦ Elderly experience insulin antagonism vs.

impairment of insulin function◦ No evidence of deceased rate of insulin secretion

or timing of release in response to a glucose challenge

◦ It is essential to monitor glucose more carefully in the elderly and avoid huge carbohydrate loads

◦ High incidence of type 2 diabetes in the elderly◦ Keep the blood sugar under 200

Liver Function

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Glucose metabolism (con’t)◦ If pre-op FBS is greater than 300, cancel surgery if

possible and get the blood sugar under control◦ WBC’s do not work well in high glucose

environment: high risk of post-op infection◦ Treat patient with IV insulin: consider continuous

IV insulin infusion ◦ Be aggressive in treating high blood sugars◦ Post-op infections have a high morbidity and

mortality

Liver Function

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Elderly at high risk for post-op ileus, because of the surgical site or narcotics for pain and lack of ambulation

Post-Op Interventions◦ Consider using peripheral nerve blocks, local

anesthetics, NSAID’s (reduce dose because of kidneys), Tylenol IV to reduce narcotic usage

◦ Consider OMM to help stimulate bowel motility◦ Any modality to decrease the morbidity caused by

post-op ileus

Liver Function

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Renal Changes in the aging patient:◦ Effects of aging in the kidney is caused by tissue

atrophy as well◦ 30% of renal mass is lost by age 80◦ This loss would be greater if parenchymal cortical

atrophy were not off set to some degree by an increase in fat and by diffuse interstitial fibrosis

The healthy 80 year old has a 50% reduction in Glomeruli◦ Glomerular sclerosis further impairs the efficiency

of renal filtration

Renal System

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Renal Changes in the aging patient (con’t)◦ Without hypertension or clearly defined ASVD,

aging further compromises renal function through a profound effect on the renal vasculature

◦ Total renal blood flow decreases by 10% per decade in the adult years

◦ Both GFR and renal plasma flow decline more sharply than would be expected from the change in renal mass

◦ GFR falls more slowly than the renal plasma flow because of compensatory increase in filtration function

Renal System

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Renal Changes in the aging patient: (con’t)◦ Kidneys have decreased responsiveness to ADH ◦ Decreased maximum absorption rate for glucose◦ Impaired ability to conserve sodium or concentrate the

urine◦ Serum Creatinine in the elderly often remains normal

despite impaired GFR because of a marked reduction in skeletal muscle to total body mass

◦ Decreased renal vascularity and decreased cardiac output in the elderly implies increased susceptibility to renal ischemia

◦

Renal System

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Post-Op Interventions◦ The elderly plod along with decreased function

fairly well until challenged by IV dye, NSAID’s, gross water and electrolyte imbalance

◦ Try to prevent insults when possible◦ Elderly surgical patients do not need a special

fluid: they just need meticulous management of fluid and electrolytes

Acute renal failure if responsible for 20% of peri-operative deaths among the elderly surgical patients

Renal System

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Other considerations ◦ increased BPH in men, ◦ increased risk of UTI pre-op in women

Use of urinary catheters is not without risk and should be removed asap◦ Insertion needs to be under the best sterile

technique

Renal System

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Age related changes in both structure and function of the human brain and nervous system are well known: their relationship is not

Ambiguity persists because of the inability to distinguish between the effects of aging vs. age related diseases

CNS changes in the Aging patient◦ Aging does decrease brain size◦ The average weight of an 80 year old brain is 18%

less than a 30 year old brain

Central Nervous System

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CNS changes in the Aging patient (con’t)◦ The most rapid decrease in mass and compensatory

increase in CSF volume occurs after the 6th decade◦ Aging in effect produces a form of low pressure

hydrocephalous. ◦ Most of the shrinkage reflects the loss of neurons,

not atrophy of supportive glial cells which constitute approximately half of the brain mass.

◦ Average rate of attrition is 50,000 cells per day from an initial pool of 10 billion cells

◦ Neuronal cell loss is selective and actual rate of loss varies greatly at different ages

Central Nervous System

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CNS changes in the Aging patient (con’t)◦ Specialized neuronal subpopulations particularly

those involved in the synthesis of neurotransmitters undergo the greatest attrition

◦ 30-50% of neurons in cerebral and cerebellar cortices, thalamus, locus ceruleus, and basal ganglia disappear by the end of the 9th decade

◦ The higher, more complex aspects of intelligence: language skills, aesthetics, and personality do not seem to decrease with age

Central Nervous System

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CNS changes in the Aging patient (con’t)◦ Despite a long established bias that aging is

associated with senile deterioration of mental function: most recent studies that storage of information, comprehension, and long term memory are well maintained in health persons through the 8th decade

◦ Some decrease in short term memory, visual and auditory reaction time probably occurs

◦ Auto regulation of cerebral, vascular resistance and response to changes in blood pressure is also well maintained

◦ Cerebral vasoconstriction response to hyperventilation remains intact in normal brain tissue

Central Nervous System

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CNS changes in the Aging patient◦ Patients who have risk factors for stroke and

atherogenesis have lower cerebral vasomotor reactivity◦ Coincident with neuronal loss in specialized areas are

depletions of dopamine, norepi, tyrosine, serotonin, and perhaps other neurotransmitters

◦ Simultaneously, the activity of catabolic enzymes such as monoamine oxidase and catechol-o-methyl-transferase increase

Aging produces a generalized increase in the thresholds for virtually all forms of perception including vision, hearing, touch, proprioception, smell, peripheral pain and temperature responses

Central Nervous System

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This deafferination may be accelerated in changes at specialized sense organs, however, anatomic changes at more central sites are also responsible

Decreasing conduction pathways in the peripheral nervous system and spinal cord along with decreased velocity and amplitude of electrical transmission

Dynamic muscle strength, control and the ability to maintain steadiness in the extremities is 20-50% lower by age 80

Despite attrition and fibrosis in the sympatho-adrenal pathways in the peripheral nervous system, and decrease an adrenal mass by 15% by age 80, plasma levels of EPI and nor-EPI are 2-4x higher

This is both at rest and response to exercise induced stress

Central Nervous System

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These elevated levels are not clinically apparent because of a marked reduction in autonomic end organ responsiveness associated with aging

Beta-agonists have a significantly decreased ability to enhance the velocity and force of cardiac contractility

Autonomic reflex responses that maintain cardiovascular homeostasis in young adults progressively and universally decreased in the elderly

Central Nervous System

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Baroreflex response, vasoconstrictor response to cold, beat to beat heart rate response to changes in position are all less rapid in onset, smaller in magnitude, and less effective in stabilizing the BP in the elderly

The autonomic system is underdamped and less tightly regulated

Therefore, anesthetic agents have a greater effect on our aging patients.

This effect is even more pronounced if endogenous autonomic activity has been high before surgery to compensate for disease processes: CHF, bowel obstruction, sepsis, etc.

Central Nervous System

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These folks tent to crash badly on induction and respond poorly to treatment

Widely believed that elderly patients metabolize drugs at a slower rate than younger adults

Only limited clinical or experimental evidence exists to support this theory.

There is a very wide inter-individual variation in the rate of drug metabolism.

There are great complexities in metabolic pathways of certain drugs (i.e.: benzodiazepines) with active metabolites

Central Nervous System

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Rate of redistribution of a drug may be more important than the rate of metabolism

There is a great deal of difficulty in controlling external factors in humans such as hormones, tobacco and alcohol intake that also affect the rate of metabolism

In addition, there is lack of complete information about age-dependent changes in the sensitivity of the brain to CNS drugs

Central Nervous System

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Anesthetic requirement is quantified by minimum alveolar concentration (MAC) of an inhaled agent or the median effective dose (ED50) of an IV anesthetic drug, required to abolish a response in 50% of subjects◦ Increasing age, the relative MAC or ED50 requirement

decreases progressively◦ This occurs regardless of the drug, and can be as high as

30%◦ Mechanism for the increased sensitivity is not known◦ The consistency across a diverse group of molecules

suggests physiology and not pharmacology is more involved

MAC

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The rate of change in sensitivity parallels the rate of decrease in cortical neurons, neuronal density in the cortex, decrease an absolute cerebral metabolic rate and the age related decrease in brain neuro-transmitter activity

Intraop mortality is now rare ICU’s can prolong short term survival of even

patients that cannot recover from surgery Current standard for comparing rate of

perioperative complications should be at least 30 days after surgery

MAC

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The complex interaction between pathophysiologic, pharmacologic and technical interventions in modern surgery frequently makes it impossible to establish a clear of single cause of perioperative morbidity/mortality

Most modern studies mostly refer to gross periop survival Current estimates of 30 day periop mortality for adequately

prepared surgical patients 65 or older are 5-10% Although this value is less than one half reported 30-40

years ago, it is still 3-5x that of young adults 1 year mortality for geriatric patients approaches 20%, this

figure includes non-surgical factors 3 major risk factors that affect outcome: need to perform

emergency surgery, operative site and the physical status at the time of surgery as rated by the ASA risk status 1-5

MAC

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Emergency surgery increases risk 3-10 fold by numerous factors ◦ 1. The facilities personnel and time available for surgery are

not equivalent for elective surgery◦ 2. Inadequate preparation cursory preop evaluation: lacking

correction of blood volume, pH, electrolytes and oxygenation prior to surgery

◦ 3. Acute hemorrhage, dehydration, ischemia and acidosis ◦ 4. Infection and sepsis

◦ Site of surgery is a major determinate of risk◦ Cataract surgery: extremely low risk◦ Surgery on major body cavity increases risk/mortality◦ Colon resection rates of mortality equal intra-thoracic and

major vascular procedures

MAC

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The risk of death is 10-20x that of hernia repair or TURP

ASA Risk Status 1-5◦ 1. Total healthy◦ 2. Mild to moderate disease that is well controlled◦ 3. Moderate disease, poorly controlled or multi-

organ disease◦ 4. Life threatening disease◦ 5. Not expected to survive the operation◦ E. Emergency surgery and anesthesia

MAC

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Recent improvements in our understanding of the physiology and pharmacology of aging have occurred because investigators have been able to separate the effects of aging per se from the consequences of age related disease

Aging produces progressive atrophy, fibrosis, and a loss of elasticity in virtually all tissues and organs

Consequences of these changes are measurable from the peak of somatic maturity, in the 3rd decade of life, through the middle adult years and then into the period of accelerated senescence during the 8th decade

We do well to maintain basal requirements and even moderate demands, but the functional reserve and maximal capacity of all organ systems are significantly reduced

Summary

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The higher instance of co-existing disease puts the elderly at greater risk for periop morbidity and mortality

Optimal anesthetic management of the elderly requires adequate diagnosis and treatment of concurrent diseases

It is very important to optimize your patient preop Meticulous attention to the details of preparation, positioning

of the patient and the use of monitoring techniques allow us to optimize the care of each patient

Although increased age (greater than 65) is a risk factor, advanced age by itself can no longer be considered a contra-indication to well managed anesthesia and surgery

I hope that this presentation has provided you with an insight into the importance of evaluating each patient prior to surgery and how you can assist in their pre-op care and prepare for their post-op management

Summary