robert l. snyder, do, faoca. evaluate potential risk factors for frailty of geriatric patients...
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
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