Transcript ELDERLY PATIENTS - Ardabil University of Medical Sciences

ELDERLY PATIENTS
Dr Masood EntezariAsl
Introduction
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The use of health care resources, including surgical
services, is disproportionately higher in the elderly
than in their younger counterparts
Many elderly patients who were denied surgical
treatment in the past because of their age now
routinely undergo operative procedures as a result
of improvement in anesthetic, surgical, and medical
care
Approximately 35% of all surgical procedures arc
performed in elderly patients
NORMAL PHYSIOLOGIC CHANGES
WITH AGING
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Functional and structural changes occur in most of the
organ systems with aging (Table)
The rate of aging varies in these organ systems and
is influenced by genetic factors, environment, and
diet
Cardiovascular System
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Aging in healthy individuals affects the peripheral
vasculature through increases in wall thickness and the
diameter and vascular stiffness of the aorta and large
arteries
Systolic and mean arterial blood pressure increases with
widening of the pulse pressure
Aortic impedance and systemic vascular resistance increase,
and there is a decrease in β-adrenergic-mediated
vasodilatation of the systemic vasculature
Aging also affects the heart through increases in left
ventricular wall thickness secondary to enlargement of
cardiac myocytes
Myocardial compliance is decreased, with a reduction in the
early diastolic filling rate and compensatory augmentation
of the contribution of atrial contraction to late left ventricular
filling
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Ventricular diastolic dysfunction, with prolonged relaxation, should
be considered in any elderly patient who has a history of decreased
exercise tolerance
Despite the common belief that systolic cardiac function decreases
with age, it is recognized that in the absence of coexisting
cardiovascular disease, resting systolic cardiac function is well
preserved, even at very advanced ages
Other cardiovascular-related changes in aging include sclerosis and
calcification of the cardiac conduction system and thickening of the
aortic valve cusps
Turbulent blood flow caused by thickening of the aortic valve cusps
results in the midsystolic ejection murmur that is commonly present in
elderly individuals
In addition, the incidence of aortic stenosis increases with aging
secondary to cusp calcification because of mechanical wear and tear
on the collagenous core of the valve cusp
Pulmonary System
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With aging, the central airways increase in size with a resultant
increase in the anatomic and physiologic dead spaces
Small airways decrease in diameter secondary to loss of connective
tissue support
However, total airway resistance is unchanged, possibly because of
opposite changes in the distal and proximal airways
There is a progressive loss in elastic tissue and an increase in the
amount of collagen within the lung parenchyma
Lung elastic recoil and tethering support of the small airways are
both reduced with consequent dilatation of respiratory bronchioles
and alveolar ducts
This results in an approximately 15% reduction in the functional
alveolar surface area available for gas exchange by the age of 70
years
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Chest wall compliance decreases with aging
Decreased intervertebral space and age-associated
kyphoscoliosis lead to decreased chest height and
increased anteroposterior diameter, which may alter
respiratory mechanics
Respiratory muscle strength decreases with aging
secondary to multiple factors such as selective
denervation of skeletal muscle fibers and atrophy
and degeneration of motor nerves and muscle fibers
Static and dynamic lung volumes also undergo age
related changes
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The loss of elastic elements results in increased lung
compliance and residual volume
As a result, functional residual capacity (FRC) is increased,
though to the lesser degree than residual volume, because
the decrease in chest wall compliance in part counteracts
the decrease in lung recoil
In contrast, total lung capacity decreases minimally, mainly
secondary to a decrease in inspiratory muscle strength and
a loss of height
Vital capacity declines progressively with aging because of
decreases in chest wall compliance, loss of lung elastic
recoil, and decreases in respiratory muscle strength
As a result of loss of tethering support of the small airways,
closing volume and closing capacity increase
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Closing capacity approaches or exceeds FRC, and the
decreased ability of elderly individuals to keep the airways
open during expiration and to reopen collapsed alveoli
during inspiration results in an increase in ventilation-to
perfusion mismatching
Although closing capacity and closing volume increase during
general anesthesia, the deterioration in arterial oxygenation
during general anesthesia is more related to the development
of atelectasis in the dependent lung areas with the formation
of a shunt, changes that have not been reported to be
influenced by aging
Airway reflexes are more sluggish in elderly patients
secondary to diminished laryngeal and pharyngeal responses
The cough reflex is less efficient, and the risk for pulmonary
aspiration is increased
Gastrointestinal System
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The swallowing and motility function of the esophagus
and the gastric emptying time are usually unchanged
with aging
Liver size decreases progressively with aging, and it is
estimated that by the age of 80 years, liver mass is
decreased by 40% with a parallel decline in hepatic
blood flow
However, the content of both microsomal and
nonmicrosomal liver enzymes is unchanged with aging
Liver function test results are generally normal
Renal System
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The kidneys lose approximately 50% of their functional glomeruli with similar
decreases in renal blood flow by 80 years of age
The decline in both renal mass and renal blood flow occurs primarily in the
cortex with compensatory changes in the juxtamedullary region
The glomerular filtration rate is decreased by 30% at 60 years of age and
by 50% at 80 years of age
In addition, elderly individuals have a decreased ability to dilute and
concentrate urine and to conserve sodium
The decrease in renal function with aging may affect the pharmacokinetics
(prolonged elimination half-times) of certain drugs used in anesthesia
The overall decline in renal functional reserve usually has no effect on an
elderly individual's ability to maintain extracellular fluid volume and
electrolyte concentrations
Similarly, serum creatinine remains relatively stable because of a parallel
decrease in overall skeletal muscle mass
However, in situations in which renal blood flow is compromised, the
decreased renal functional reserve characteristic of elderly individuals may
increase the risk for perioperative renal insufficiency or failure
Central Nervous System
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Aging is associated with a progressive loss of neural tissue and a parallel
reduction in cerebral blood flow and cerebral oxygen consumption
On average, 30% of total brain mass is lost by 80 years of age
In addition, the number of neuroreceptors generally declines with aging in
various regions of the central nervous system
For example, a reduction is seen in the number of serotonin receptors in the
cortex, acetylcholine receptors in multiple brain regions, and dopamine
receptors in the neostriatum
Levels of dopamine in the neostriatum and substantia nigra are also
decreased
These structural changes are not necessarily associated with a decline in
cognitive function
However, the incidence of postoperative delirium and cognitive dysfunction is
higher in elderly individuals
Patients with a history of cognitive impairment are at even higher risk for
further impairment postoperatively
Pharmacokinetic and
Pharmacodynamic Changes
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The pharmacokinetics of drugs is influenced by
changes in :
- plasma protein binding
- the percentage of body content that is fat
or skeletal muscle (lean mass)
- circulating blood volume
- metabolism and excretion of drugs
PROTEIN BINDING
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With aging, protein binding sites are reduced
secondary to both quantitative (decreased level of
circulating protein) and qualitative changes
In addition, elderly individuals frequently take
multiple medications that might interfere with the
binding of drugs to protein active sites (Table)
These changes may increase the level of free,
unbound drug in plasma with a resulting enhanced
pharmacologic effect
Drugs Often Taken by Elderly Patients That May
Contribute to Adverse Effects or Drug Interactions
LEAN AND FAT BODY MASS
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Older individuals have decreased skeletal muscle
mass and an increased percentage of body fat
These changes result in an increased ability to store
lipid-soluble drugs, which may lead to a more
gradual and prolonged release of the drugs used
during anesthesia from lipid storage sites and,
consequently, an increased elimination time and
prolonged effect
CIRCULATING BLOOD VOLUME
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Circulating blood volume generally decreases with
aging and results in a higher than expected initial
plasma drug concentration for the same amount of
drug administered
Gradual declines in hepatic and renal function may
lead to decreased metabolism and prolonged
elimination of drugs and their metabolites and thus
may contribute to a more gradual decline in plasma
drug concentrations and a prolonged effect of
anesthetic drugs
BasaL MetaboLic Rate
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The basal metabolic rate declines with aging, and
elderly surgical patients may have difficulty
maintaining normothermia during general anesthesia
The development of hypothermia may lead to slower
metabolism and excretion of drugs in elderly patients
Furthermore, hypothermia may lead to shivering, which
will increase the basal metabolic rate and oxygen
consumption and result in arterial hypoxemia or
myocardial ischemia, or both
Endocrine Changes
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Endocrine changes occur with aging
The response of arginine vasopressin (formerly known as antidiuretic
hormone) to hypovolemia and hypotension is reduced, but it remains
sensitive to changes in serum osmolarity
The renal tubules are less sensitive to this hormone and atrial natriuretic
peptide
During hyperglycemia, insulin release is impaired
However, because of increased peripheral tissue resistance and decreased
clearance, plasma insulin levels are elevated, which results in an enlarging
fat depot
Serum levels of renin and aldosterone decline, and the response of both
hormones to sodium restriction and postural changes is blunted, with a
decreased ability conserve sodium and excrete potassium
In contrast, adrenocorticotropic hormone, cortisol, catecholamine production
by the adrenal medulla, and thyroid-stimulating hormone and thyroxine
levels are unchanged with aging
PR-EOPERATIVE
EVALUATION AND
ANESTHETIC
CONSIDERATIONS
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The prevalence of coexisting diseases increases with aging (Table)
In older individuals undergoing surgery, the most common coexisting
diseases are systemic hypertension, diabetes mellitus, cardiovascular
disease, pulmonary disease, neurologic disease, and renal disease
Optimizing the patient's medical condition before surgery is essential
because baseline health status is an important predictor of
postoperative complications
However, for elderly patients, delaying surgery to optimize a
medical condition must be weighed against the risk of delaying
surgery because emergency surgical treatment is associated with
higher morbidity and mortality
Furthermore, delaying certain surgical procedures, such as cancer
surgery, may substantially alter the patient's prognosis
In this regard, communication among the anesthesiologist, surgeon,
and primary care physician is critical to developing an optimal plan
regarding the timing of each elderly patient's surgery
Age-Related Concomitant Diseases in
Elderly Patients
Laboratory Testing
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Data suggest that routine laboratory testing should
not be performed simply on the basis of age alone
but, rather, it should be based on a thorough
preoperative evaluation to determine coexisting
medical conditions and on the type of planned
surgical procedures
This approach is likely to be more cost-effective
than routine testing in all elderly patients
ELECTROCARDIOGRAM
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Elderly patients with a history of coronary artery disease may
benefit from a preoperative 12-Jead electrocardiogram (ECG) to
determine the presence and location of any previous myocardial
infarction, left ventricular hypertrophy, conduction abnormalities, and
ST-T wave changes indicative of ischemia
If an abnormality is present, comparison with a previous ECG is
needed to determine the timing of the occurrence
However, in elderly patients, abnormalities on the preoperative ECG
are common and of limited value in predicting postoperative
cardiac complications in noncardiac surgery
The low specificity of the preoperative ECG in predicting
postoperative cardiac complications also suggests that a normal
ECG does not rule out occult cardiac disease
CHEST RADIOGRAPH
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In patients undergoing high-risk surgery, a chest
radiograph may be useful in providing noninvasive
information
regarding
ventricular
function
(cardiomegaly may indicate an ejection fraction
<40%)
The pulmonary vasculature should also be examined
to rule out preoperative congestive heart failure
However, the cost-effectiveness of routine
preoperative chest radiographs in elderly patients
undergoing surgery has not been defined
EVALUATIONOF CARDIAC STATUS
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Because the prevalence of cardiovascular disease
increases with aging, evaluation of cardiac status is
an integral part of the preoperative evaluation of
elderly patients
Poor functional
status
chronic pain
secondary to:
cardiac causes
physical
deconditioning
obesity
Blood Pressure Control
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Systemic hypertension (systolic blood pressure ≥180 mm Hg, diastolic blood
pressure ≥1l0 mm Hg) increases the risk for cardiac and cerebrovascular
disease
Adverse intraoperative events in hypertensive patients include
perioperative myocardial ischemia, cardiac dysrhythmias, and
cardiovascular lability
Although data are limited, there is little evidence of increased
perioperative cardiac risk if systolic blood pressure is less than 180 mm Hg
or diastolic blood pressure is less than 110 mm Hg
Even though there is no evidence that deferring anesthesia and surgery
reduces peri operative risk, careful determination of the baseline blood
pressure range for each patient is critical and requires more than one
measurement preoperatively
If systemic blood pressure is consistently elevated, optimization with
appropriate antihypertensive drugs preoperatively is often recommended
for elective surgery
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Checking compliance with blood pressure medication is important
because elderly patients frequently take multiple medications, and
therefore preoperative instructions on which medications to
discontinue need to be carefully conveyed
In patients scheduled for urgent or emergency surgery with a
preinduction systolic blood pressure higher than 180 mm Hg or
diastolic blood pressure higher than 110 mm Hg, induction of
anesthesia may proceed carefully, often with invasive monitoring
In these patients, administration of a small dose of an anxiolytic
drug before induction of anesthesia may result in more gradual
lowering of systemic blood pressure
In elderly patients with uncontrolled systemic hypertension who are
about to undergo emergency surgery, the use of continuous invasive
blood pressure monitoring and postoperative surveillance in the
intensive care unit may be indicated
Protection from Perioperative
Myocardial Ischemia
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Postoperative myocardial ischemia is the strongest clinical predictor of
adverse postoperative cardiac events in high risk surgical patients, with
most ischemic events occurring within the first 24 hours after surgery
Therefore, reducing the number and duration of perioperative ischemic
events by improving the myocardial oxygen supply demand balance during
surgery may potentially improve postoperative cardiac outcomes
Reduction of myocardial metabolic oxygen demand can be achieved by
perioperative administration of β-blockers to decrease myocardial
contractility and heart rate
Elderly patients (≥ 65 years of age) who have one or more risk factors
(systemic hypertension, current smoking, hypercholesterolemia, diabetes
mellitus) may benefit from prophylactic perioperative β-blockade as
evidenced by decreased circulating levels of troponin I
However, in elderly patients at low risk for ischemic heart disease, this
prophylactic therapy may be potentially costly and unnecessary
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Because sympathetic nervous system tone is increased with aging,
administration of β-blockers during the peri operative period may result in
hypotension, especially in the presence of relative hypovolemia secondary
to preoperative fasting
Furthermore, autonomic control of hemodynamics in the elderly may be
compromised as a result of the decrease in baroreceptor reflex activity
with aging
Because perioperative tachycardia is one of the most important
hemodynamic abnormalities that has been shown to be associated with
myocardial ischemia, the adequacy of the heart rate response to βblockers is critical to guide therapy
Individualized dosing of β-blockers for control of postoperative myocardial
ischemia rather than a fixed-dose regimen may be more beneficial
because patients with coronary artery disease have different coronary
anatomy and therefore different ischemic thresholds
Physical Examination
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Elderly individuals are more likely to be edentulous, and although
removal of dentures preoperatively may facilitate direct
laryngoscopy and tracheal intubation, positive pressure ventilation by
facemask may be difficult
Range of neck motion should be evaluated because older individuals
may have limitations as a result of degenerative spine disease
Auscultation of the carotid arteries over the neck bilaterally is helpful
to rule out carotid artery disease but requires confirmation by
carotid ultrasound if loud carotid bruits are present
Auscultation of the heart may reveal additional heart sounds such as
S₃ or S₄ which are commonly associated with decreased left
ventricular compliance
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A midsystolic ejection murmur is often present in elderly
patients secondary to thickening of the aortic cusps or
calcification, or both
A laterally displaced point of maximal impulse together
with increased heart size on the chest radiograph
suggests cardiomegaly
Auscultation of the lungs is performed to evaluate the
presence of rales or wheezes, which may be associated
with congestive heart failure or lung disease (or both)
Examination of the extremities should be performed to
rule out the presence of peripheral edema, which may
be indicative of congestive heart failure
Risk Assessment
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Although elderly patients are at increased risk for perioperative morbidity
and mortality, advanced age by itself is not a contraindication to surgery
General factors that should be evaluated when performing a preoperative
risk assessment include age, functional status, cognition, nutrition, and
comorbid conditions (cardiac, pulmonary, renal, and endocrine disease)
When both age and comorbidity are considered, the latter is a better
predictor of adverse postoperative outcomes
Functional limitation increases perioperative risk, and preoperative evaluation
of functional status with common measures such as activities of daily living
and instrumental activities of daily living is informative (Table)
Preoperative cognitive status has been shown to be associated with adverse
postoperative outcome and functional recovery, thus emphasizing that
assessment of preoperative baseline cognitive status may be useful
Depression is also common in elderly patients and may increase peri
operative morbidity, including postoperative delirium
Activities of Daily Living and Instrumental
Activities of Daily Living
Management of Preoperative
Medication
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Elderly patients are typically taking multiple prescription and over-the-counter
medications
In general, all antihypertensive and cardiac medications should be continued until
surgery, with the exception of diuretics, which are preferably withheld on the day of
surgery because the patient will be fasting before surgery
For those taking aspirin or warfarin for treatment of cerebral vascular or coronary
artery disease, atrial fibrillation, or deep vein thrombosis, the risks associated with
discontinuing anticoagulation should be weighed against the benefits of reduced
bleeding from discontinuation of such drugs
Warfarin is typically withheld (often four doses) to allow normalization of the
international normalized ratio(INR)
In case of emergency surgery, fresh frozen plasma(FFP) or vitamin K can be
administered to reverse warfarin's effects
For patients at high risk for thromboembolism, such as those with a prosthetic heart
valve, a history of pulmonary embolism, or a recent history of deep vein thrombosis,
a transition using low-molecular-weight heparin or intravenous heparin is indicated
when oral anticoagulation is discontinued
Antibiotic prophylaxis is indicated for patients with valvular heart disease and mitral
valve prolapse
INTRAOPERATIVE
MANAGEMENT
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No single anesthetic drug or technique has been
demonstrated to be superior for elderly surgical
patients
However, familiarity with the pharmacokinetics of
anesthetic drugs and how age-related changes may
affect drug dosing is important
Adjustments of Anesthetic and Adjuvant
Drugs in Elderly Patients
Inhaled Anesthetics
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The minimum alveolar concentration (MAC) for various
inhaled anesthetics is reduced by approximately 6%
per year after the age of 40 years
The onset of action of volatile anesthetics may be more
rapid if cardiac output is reduced, particularly for more
lipid-soluble drugs, but decreased lung function
secondary to an increased shunt fraction has an
opposite effect
Recovery from the depressant effects of volatile
anesthetics may be more prolonged because of an
increased volume of distribution secondary to increased
body fat and decreased pulmonary gas exchange
Intravenous Anesthetics and Neuromuscular
Blocking Drugs
Dose requirements for barbiturates, opioids, and
benzodiazepines are likely to be decreased in
elderly patients
OPIOIDS
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The elimination half-time of fentanyl is longer in
elderly patients than younger patients because of
the larger volume of distribution
As a result, depression of ventilation and prolonged
analgesia may ensue with the same dose
administered to younger patients
Decreased hepatic clearance may contribute to
prolonged opioid effects, especially when high does
of these drugs are administered to elderly patients
PROPOFOL
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Propofol is highly lipid soluble and produces rapid loss of
consciousness when administered intravenously
A decreased induction dose or slow titration is
recommended for elderly patients
A decrease in age-related clearance of propofol may result
in reduced anesthetic requirements with aging
Propofol, because of its negative inotropic and vasodilatory
effects, may give rise to exaggerated decreases in systemic
blood pressure when used for induction of anesthesia in
elderly patients
Despite these characteristics, propofol may be superior to
thiopental for recovery of mental function
ETOMIDATE
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Etomidate produces rapid loss of consciousness and
has been frequently chosen for induction of
anesthesia in elderly patients with cardiovascular
instability
The initial volume of distribution of etomidate is
decreased such that an 80-year-old patient
requires less than half the dose of etomidate to
produce the same magnitude of depression on the
electroencephalogram as in younger patients
MIDAZOLAM
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Midazolam has increased potency and decreased
clearance in elderly individuals
Context-sensitive half-times are prolonged
Accordingly, doses of midazolam should be
decreased and a longer duration of action is
expected
NEUROMUSCULAR BLOCKING DRUGS
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Despite age-related changes in the neuromuscular junction, the
effects of depolarizing and nondepolarizing neuromuscular blocking
drugs are not altered in elderly patients
Rather, the altered pharmacokinetics of these drugs in older
individuals is secondary to decreases in renal and hepatic function
and the altered volume of distribution that accompanies aging
Clearance is decreased for nondepolarizing neuromuscular blocking
drugs (vecuronium, rocuronium) that are dependent on either the
kidneys or the liver for elimination from plasma
The duration of action of atracurium and cisatracurium is not
prolonged because these drugs are eliminated by Hofmann
degradation, which is independent of renal and hepatic clearance
mechanisms
Monitoring of neuromuscular function and recovery is important in
elderly patients because incomplete recovery of neuromuscular
function may lead to a higher incidence of postoperative pulmonary
complications
Regional Anesthesia
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Cardiovascular responses to either spinal or epidural anesthesia may be
exaggerated in older individuals
The decrease in cardiac output is thought to primarily be due to a
decrease in stroke volume
Treatment of the resultant hypotension typically consists of the
administration of crystalloid solutions or vasopressors such as
phenylephrine
Surgical procedures that are amenable to regional anesthesia include
transurethral resection of the prostate(TURP), orthopedic procedures such
as hip or knee replacement, inguinal herniorrhaphy, and minor
gynecologic procedures
Technical difficulties in performing regional anesthesia probably reflect
age-related decreases in the intervertebral spaces and scoliosis
A thorough examination of the targeted spinal segment must be
performed before initiating regional anesthesia
Intraoperative Monitoring
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Because of the prevalence of coexisting disease
involving the cardiac and pulmonary systems,
consideration should be given to using invasive
monitoring such as arterial and central venous
catheterization in elderly patients undergoing major
surgical procedures, which are likely to be
prolonged and include large body fluid shifts
Postoperative Pain Therapy
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The concept that pain perception decreases with aging
and that elderly individuals have a low tolerance of
opioids is unsubstantiated
Elderly individuals are commonly afflicted with
osteoarthritis disease that results in chronic pain, which
may influence requirements for postoperative pain
medications
In addition, because elderly surgical patients have an
increased likelihood of postoperative delirium or
cognitive dysfunction, or both, assessment of the
adequacy of postoperative pain control may be
difficult
STRATEGIES TO IMPROVE
PERIOPERATIVE
MANAGEMENT AND
POSTOPERATIVE
OUTCOME
Decreasing Cardiovascular
Complications
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Cardiovascular complications (cardiac dysrhythmias, myocardial
ischemia, congestive heart failure)may influence postoperative
outcomes in elderly patients
Perioperative planning includes:
(1) identifying elderly patients who are at higher
risk for postoperative cardiovascular complications
(2) optimizing preoperative medical therapies
(3) modifying known risk factors preoperatively
(pharmacologic therapy(
(4) planning of postoperative care (pain control,
admission to intensive care units)
Assessment of Cardiac Function
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Congestive heart failure is a common problem in the
elderly population
It is estimated that congestive heart failure will
develop in 10% of persons 80 years and older and
will lead to increased mortality within 2 years
Because clinical signs or a history of congestive
heart failure is associated with postoperative
cardiac complications, special attention should be
directed to preoperative optimization of heart
function in elderly surgical patients
DIAGNOSIS OF CONGESTIVE HEART
FAILURE
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Clinical diagnosis of congestive heart failure can be
particularly challenging in elderly patients because
of the lack of typical symptoms and physical
findings
When present, symptoms of congestive heart failure
are often nonspecific and frequently misdiagnosed
as symptoms of concomitant disease (chronic
pulmonary disease) or interpreted as changes
associated with aging
DIASTOLIC CONGESTIVE HEART
FAILURE
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Despite the common preservation of left ventricular systolic function,
congestive heart failure may result from left ventricular diastolic
dysfunction
Patients with diastolic congestive heart failure have a leftward shift in
the pressure-volume relationship such that their hearts operate on the
steep portion of the curve (Fig)
Small changes in volume may result in substantial increases in
diastolic pressure to the extent that pulmonary congestion may occur,
even at relatively normal left ventricular volume
Such changes may be accentuated by exercise, and many elderly
individuals with diastolic dysfunction exhibit exercise intolerance as
one of their major symptoms
Other symptoms may include dyspnea, cough, edema, or fatigue
Preoperatively, noninvasive approaches to diagnosing diastolic
dysfunction include Doppler echocardiography and radionuclide
ventriculography
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With Doppler echocardiography, measurement of the
ratio between the peak early filling wave (E wave) and
the atrial filling wave (A wave) is a useful screening tool
for detecting abnormal left ventricular relaxation (Fig)
Disorders associated with diastolic dysfunction include
systemic hypertension, coronary artery disease,
cardiomyopathies, diabetes, chronic renal disease, aortic
stenosis, and atrial fibrillation
Potentially reversible causes of diastolic congestive
heart failure in elderly patients include myocardial
ischemia and accelerated hypertension
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Perioperative goals in elderly patients with diastolic
dysfunction include :
(1) maintenance of normal sinus rhythm and
a
slow heart rate
(2) control of systemic blood pressure
(3) optimization of blood volume
(4) detection and treatment of myocardial ischemia
The use of invasive monitoring such as central venous
pressure or pulmonary artery catheterization may be
indicated in managing patients with a history of
congestive heart failure secondary to diastolic
dysfunction
Treatment of diastolic congestive heart failure may
include pharmacologic interventions (Table)
Pharmacologic Management of
Diastolic Dysfunction
Impact of Anesthetic Technique on
Cardiovascular Complications
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The view that regional anesthesia is better than
general anesthesia in reducing adverse cardiac
outcomes has not been consistently demonstrated
There is no difference in 30-day mortality in
patients undergoing major abdominal surgery with
epidural or spinal anesthesia versus general
anesthesia
Decreasing Perioperative Pulmonary
Complications
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Advanced age is not considered to be an independent risk factor for
perioperative pulmonary dysfunction
In contrast, other factors that have been shown to be associated with
postoperative pulmonary complications include:
(1) emergency surgery
(2) anatomic site of surgery (upper abdominal and
thoracic procedures)
(3) duration of anesthesia
(4) general anesthesia
(5) hypercapnia
(6) history of smoking
(7) obesity
(8) preexisting pulmonary disease (COPD and asthma)
CIGARETTE SMOKING
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Cessation of cigarette smoking and the use of oxygen
therapy may improve outcomes in patients with COPD
Preoperative cessation of smoking immediately before
surgery serves only to decrease carboxyhemoglobin levels
(half-time of about 6 hours)
Prolonged cessation of smoking (8 weeks) is necessary to
result in a decrease in postoperative pulmonary
complications because of the period necessary for
improvement in mucociliary action and a decrease in mucus
secretion
Differentiation of reversible and irreversible airflow
obstruction is important to guide the use of anti-inflammatory
medications, β₂-agonists, and anticholinergic agents
ASTHMA
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Asthma is often under diagnosed and not optimally treated in elderly
individuals
There is a tendency to label elderly patients with symptoms of airflow
obstruction as having COPD
Differentiation between asthma and COPD is important because the
therapeutic strategies may be different
A post bronchodilator increase in forced exhaled volume in 1 second (FEV1)
of200 ml or 15% is considered a sign of reversibility of airflow obstruction
and suggests a diagnosis of asthma rather than COPD
However, an overlap between asthma and COPD may be more common in
elderly patients because older asthmatics may have a propensity for
irreversible airway obstruction and some patients with smoking-related
COPD may have some response to bronchodilator therapy
Although pulmonary function tests assess the presence and severity of the
disease, they do not have great predictive value for postoperative
pulmonary complications
Treatment
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Administration of β-agonists is relatively safe in elderly patients,
although systemic absorption of inhaled β- agonists may result in
tachycardia, systemic hypertension, and skeletal muscle tremors
Patients with asthma may be receiving corticosteroid therapy, which
may result in adverse effects such as osteoporosis, psychiatric
disturbances, and exacerbation of chronic conditions such as systemic
hypertension and diabetes mellitus
Patients being treated with corticosteroids should receive
supplemental corticosteroid before induction of anesthesia
Medication such as β- blockers may exacerbate asthma
The use of selective β-blockers such as metoprolol or atenolol is
preferable for the treatment of systemic hypertension or congestive
heart failure
Intraoperative Management
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INITIATION OF POSTOPERATIVE PAIN MANAGEMENT:
Epidural analgesia with local anesthetics and opioids provides
considerable benefit in terms of pulmonary outcomes after surgery,
including :
(1) a decrease in the incidence of atelectasis,
pulmonary infections, and complications
(2) better postoperative pain relief than with
parenteral opioids
(3) shorter time to tracheal extubation
(4) less time in the intensive care unit
Indeed, the quality and possibly the modality of postoperative pain
relief may be more important than the choice of intraoperative
anesthetic
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INTERVENTIONS TO IMPROVE POSTOPERATIVE PULMONARY
FUNCTION
Certain intraoperative strategies may improve pulmonary function
Measures such as adding positive end-expiratory pressure (5 to 10
cm H20) can increase FRC and restore the closing capacity-to-FRC
ratio
The use of higher inspired oxygen concentrations (FI02) may provide:
(1) a better proinflammatory and antimicrobial response of
alveolar macrophages than that associated with30%oxygen
(2) a lower incidence of postoperative nausea and vomiting
(3) a reduced incidence of surgical wound infections
A high FI02 does not influence postoperative pulmonary mechanical
dysfunction or alter the incidence of postoperative complications such
as pulmonary atelectasis
Reducing Postoperative Delirium
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Delirium, an acute disorder of attention and cognition,
occurs in 14% to 50% of hospitalized medical patients
(especially elderly patients) and is accompanied by a
mortality rate ranging from 10% to 65%
In general, delirium is the manifestation or symptom of
an underlying medical illness for which multiple causes
exist
Delirium can be superimposed on dementia or other
neurologic disorders associated with global cognitive
impairment
As a result, the course of delirium can vary considerably
and depends on resolution of the causative factors
PREDISPOSING FACTORS
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Factors that predispose elderly patients to delirium include :
- aging processes in the brain
- structural brain disease
- a reduced capacity for homeostatic regulation
and
therefore resistance to stress
- visual and hearing impairment
- a high prevalence of chronic disease
- reduced resistance to acute diseases
- age-related changes in the pharmacokinetics and
pharmacodynamics of drugs
Sleeping disorders, sensory deprivation or overload, and
psychological stress resulting from bereavement or relocation
to an unfamiliar environment are common precipitants of
delirium
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Certain drugs administered during anesthesia may be
associated with postoperative delirium, but it is not
possible to determine whether elimination of these
drugs will actually lead to a lower incidence of
delirium postoperatively
Controversy persists regarding whether any
anesthetic technique (regional versus general) has an
impact on postoperative delirium
Earlier studies suggested an association between
general anesthesia and a higher incidence of
cognitive dysfunction relative to epidural anesthesia
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However, recent studies have concluded that there was no
relationship between anesthetic technique and the
magnitude or pattern of postoperative cognitive dysfunction
Intraoperative hypotension does not appear to influence the
occurrence of postoperative cognitive dysfunction
Until more definitive clinical studies become available,
minimizing the number of medications used, avoiding
arterial hypoxemia and extremes of hypocapnia or
hypercapnia, and providing adequate postoperative pain
control appear to be the best approach to minimizing the
occurrence of postoperative delirium in elderly surgical
patients