Anesthesia for Geriatric Patients

Report
‫بسم هللا الرحمن الرحيم‬
Anesthesia for the
Geriatrics
By
Ahmed El-Shaer
MSc, MD anesthesia, MSc Pain Management
Objectives
1- Define the geriatric population
2- enumerate the anesthetic problems for
a Ger. Pt.
3- mention the different methods for
avoiding these problems
4- Categorize patients according to risk
5- Mention the ethical considerations for
dealing with the old aged pts
• The elderly (≥65 yr) population is the fastest
growing part of the population in many parts
of the developed world.
• Perioperative morbidity becomes more
frequent in the elderly with steep increases
after the age of 75.
• Aging is a universal and progressive
physiological phenomenon clinically
characterized by degenerative changes in both
the structure and the functional capacity of
organs and tissues.
• Aging increases the probability of a person to
undergo surgery.
Physiology and
pathophysiology of aging
• Age alters both pharmacokinetic and
pharmacodynamic aspects of anesthetic
management.
• The functional capacity of organs declines
and co-existing diseases further contribute
to this decline.
Cardiovascular
• Geriatric patient means:
decreased beta-adrenergic responsiveness
increased incidence of conduction
abnormalities, bradyarrythmias & HTN.
Fibrotic infiltration of cardiac conduction
pathways
conduction delay & atrial and
ventricular ectopics.
 increased reliance on Frank-Starling
mechanism for cardiac output.
• It is important to consider fluid administration
carefully:
non compliant older heart (diastolic
dysfunction) + decreased vascular
compliance small changes in venous
return will
large changes in ventricular
preload and cardiac output
elderly patient compensates poorly for
hypovolemia & exaggerated transfusion.
Cardiovascular effects of aging
Respiratory
• COPD, pneumonia, sleep apnea
very
common.
• Closing volume increases with age
• FEV1 declines 8-10% per decade due to
reduced pulmonary compliance.
• PaO2 progressively with age d.t.
– V/Q mismatch
– anatomical shunt.
Respiratory effects of aging
• Thus, it is recommended that elderly patients
are transferred to PACU with oxygen via nasal
cannula.
• Postoperative respiratory complications are
most common in geriatric patients.
• The most significant clinical predictor of
adverse pulmonary outcome is the site of
surgery, with thoracic and upper abdominal
surgery having the highest pulmonary
complication rate.
Renal function
• Renal BF and nephron mass with age
increased risk of acute renal failure in the
postoperative period.
• Serum creat. remains stable due to a reduction
in muscle mass(!).
• Impairment of sodium handling, conc. ability and
diluting capacity predisposes elderly pts to
dehydration and fluid overload.
Nervous system
• As the nervous system is the target for
virtually every anesthetic drug, age
related changes in nervous system
function have essential implications for
anesthetic management.
Nervous system
Aging results in decreased
• nervous tissue mass
• neuronal density
• concentration of neurotransmitters
• norepinephrine and dopamine receptors.
Nervous system
That’s Why:
• Dosage requirements for local and general
anesthetics are reduced.
• Administration of a given volume of epidural
anesthetic results in
– more cephalic spread,
– though a shorter duration of sensory and motor
block.
Nervous system
Elderly patients:
• take more time to recover from GA especially
if they were disoriented preoperatively.
• experience varying degrees of delirium.
• sensitive to centrally acting anticholinergic
agents.
• The % of delirium is less with regional
anesthesia, provided there is no additional
sedation.
Pharmacology
• The circulating level of albumin (binding
protein for acidic drugs) decreases with age.
• While the level of α-1 acid glycoprotein
(binding protein for basic drugs) increases.
• The decrease in total body water leads to a
reduction in the central compartment and
increased serum concentrations after a bolus
administration of a drug.
• On the other hand, the increase in body fat
results in a greater volume of distribution,
thus prolonging drug action.
• Drug metabolism could probably be altered by
the aging effect on hepatic or renal function.
TO SUM-UP
• The elderly are more sensitive to
anesthetic agents and generally require
smaller doses for the same clinical effect,
and drug action is usually prolonged.
anesthetic agents in the elderly
Inhalation drugs:
• Minimum alveolar anesthetic conc. (MAC)
decreases approximately 6% for every
decade.
• Due TO
– altered activity of neuronal ion channels associated with
cholinergic, nicotinic and GABA receptors.
– Alterations in ion channels, synaptic activity and
receptor sensitivity.
Opioids:
• The elderly require less doses for pain relief.
• Morphine clearance is decreased.
• Sufentanil, alfentanil, and fentanyl are twice as
potent in the elderly, d.t. increased brain
sensitivity.
• Remifentanil is more potent in geriatric pts.
• For All: infusion rates should be titrated.
Neuromuscular blockers:
• The duration of drug action may be prolonged
if their metabolism depends on renal or
hepatic excretion.
• Cisatracurium undergoes Hofmann
degradation ,so, unaffected by age.
Peripheral nerve blocks:
• The duration of analgesia may be prolonged
with age depending on the baricity of the
bupivacaine solution.
• When using 0.75% ropivacaine for nerve
blocks, age is a major factor in determining the
duration of motor and sensory block.
• When GA carries great risk for the pt,
regional anesthesia could provide an
excellent solution.
Preoperative evaluation
• it is very important to determine the patient’s
status and physiologic reserve in the preanesthetic evaluation.
• The risk from anesthesia is more related
with the presence of co-existing disease
than with the age of the patient.
• If the condition can be optimized before
surgery this should be done without delay, as
long delays increase morbidity rates.
• DM and CV diseases are very common.
• Pulmonary complications are one of the
leading causes of postoperative morbidity, so,
pulmonary optimization is essential.
• History, physical examination, Lab. and
diagnostic studies are of great importance.
• Some more issues that must be always in
mind in a geriatric patient is the
significant possibility of depression,
malnutrition,
immobility
and
dehydration.
• It is important to determine the cognitive
status of an elderly patient.
• Cognitive deficits are associated with poor
outcomes and higher perioperative morbidity.
• It is controversial whether general anesthesia
accelerates the progression of senile
dementia.
• lower doses of premeds.
• Opioid premed is valuable only if there is
severe preoperative pain.
• Anticholinergics are not required since salivary
gland atrophy is usually present.
• H2 antagonists are useful to reduce the risk of
aspiration.
• Metoclopramide could be used to promote
gastric emptying, although risk of extrapyramidal
effects is higher.
Intraoperative care and anesthetic
management
• Advanced age is not a contradiction for either
GA or RA.
• Some aspects of RA may benefit the pt.:
– It prevents postoperative inhibition of
fibrinolysis
decreases the incidence of DVT
after total hip arthroplasty.
– The hemodynamic effects of RA may reduce
blood loss in pelvic and lower extremity
operations.
– More important, the patient maintains his
airway and pulmonary function.
• Advanced age and general anesthesia are
associated with hypothermia, so;
Maintenance of normothermia is important as
hypothermia
to myocardial ischemia &
hypoxemia in the early postop. period.
• In case of general anesthesia, it is of major
importance to titrate drug doses and it would
be wise to use short acting drugs.
• The use of peripheral blocks promises
favorable outcomes without compromising
airway or hemodynamics.
• However, peripheral blocks have shown to last
longer d.t. some anatomic changes in geriatric
patients.
Postoperative care
• Pulmonary problems are of major importance
in the postoperative period.
• Shorter hospitalization is badly needed.
• Minimal-invasion surgery and regional over
general anesthesia when possible, could
probably lead to a more favorable outcome
for geriatric patients
• Postop. Pain!!
• Common causes of postoperative
morbidity:
•
•
•
•
•
•
•
Atelectasis
Heart failure
Pneumonia
Delirium
Neurological disease
Acute bronchitis
Myocardial infraction
Postoperative delirium
• Postoperative delirium is common in the
elderly in the postoperative period.
• It can result in increased morbidity, delayed
functional recovery, and prolonged hospital
stay.
• In surgical patients, factors such as age,
alcohol abuse, low baseline cognition, severe
metabolic derangement, hypoxia,
hypotension, postop. Pain and type of surgery
appear to contribute to postoperative
delirium.
• Anesthetics, esp. anticholinergics and
benzodiazepines, increase the risk for
delirium.
• Despite the above recommendations,
postoperative delirium in the elderly is poorly
understood.
• Research is needed to define the effects of
hypoxemia on cerebral function and whether
oxygen therapy has any benefits.
The geriatric-anesthesiologic intervention
program:
• pre- and postop. geriatric assessment,
• early surgery,
• thrombosis prophylaxis,
• oxygen therapy,
• prevention and treatment of perioperative
decrease in BP, and
• vigorous ttt of any postoperative complic.
In Conclusion
• Elderly patients are uniquely vulnerable and
particularly sensitive to the stress of trauma,
hospitalization, surgery and anesthesia.
• Accordingly, minimizing perioperative risk in
geriatric patients requires:
– meticulous preoperative assessment of organ function
and reserve,
– meticulous intraoperative management of coexisting
disorders,
– Careful drug selection & dosage titration,
– Careful fluid therapy,
– RA better than GA
– Proper psychological preparation & management
– and alert postop. pain control.

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