Transcript 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
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This presentation is supported by
HRSA Grant # D54HP23284
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Considerations?
◦ What is patient’s normal functioning status?
◦ How will the patient tolerate stress?
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Frailty
Gait
Exercise Tolerance
Posture
Nutrition
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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
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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:
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Stroke?
Loss of Hearing?
Dementia?
At high risk for post-op cognitive dysfunction?
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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?
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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
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How much muscle mass is Present?
◦ atrophy occurs rapidly after age 30
◦ impossible to return to same muscle mass
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PT is extremely important in the elderly
◦ Plan to have patient mobile ASAP
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Good nutrition is extremely important
◦ Plan supplemental nutrition
◦ Plan to monitor glucose
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Decreased pulmonary elasticity
◦ Lung elastin decreases,
◦ fibrous connective tissue increases:
◦ decreased elastic recoil affecting patency of small
airways
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Decreased alveolar surface area
◦ breakdown alveolar septa
◦ Increased anatomic and alveolar dead space
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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
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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
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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
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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
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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
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Major Heart anatomic changes
◦ increase in heart wall thickness,
◦ myocardial fibrosis
◦ valvular fibrocalcification
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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
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Aging makes patients both volume
dependent and volume tolerant
◦ Expect hypertension and cardiomegaly in these
patients
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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
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Anesthetics depress heart function
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Circulation time is slower
◦ Need to titrate medications slowly and start with
lower dose
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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
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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
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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
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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.
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Do you know how to tell when a senior citizen
is warm?
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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
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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
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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
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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
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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
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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
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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
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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
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The healthy 80 year old has a 50% reduction
in Glomeruli
◦ Glomerular sclerosis further impairs the efficiency
of renal filtration
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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
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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
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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
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Acute renal failure if responsible for 20% of
peri-operative deaths among the elderly
surgical patients
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Other considerations
◦ increased BPH in men,
◦ increased risk of UTI pre-op in women
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Use of urinary catheters is not without risk
and should be removed asap
◦ Insertion needs to be under the best sterile
technique
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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
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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
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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
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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
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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
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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
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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
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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 sympathoadrenal 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
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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
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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.
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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
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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
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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
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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
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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 510%
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
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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
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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
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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 multiorgan disease
◦ 4. Life threatening disease
◦ 5. Not expected to survive the operation
◦ E. Emergency surgery and anesthesia
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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
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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
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