BMH Med. J.2020;
7(Suppl): Early Online. Geriatrics &
Gerontology Initiative: International Workshop on Care of
the Elderly
Do Anesthesia Risks Increase in Older Adults?
EK Ramadas
Address for Correspondence: Dr. EK Ramadas, DA, MD, DNB,
HOD Anaesthesiology, Baby Memorial Hospital Ltd., Kozhikode,
Kerala, India. Email: drekramdas@yahoo.co.in
Abstract
Age may bring wisdom but it also brings a greater chance of
health problems, and some health problems might require
surgery to make you better. In fact, 1 in 10 people who have
surgery are 65 or older. Usually we refer to patients aged ≥65
years as the elderly, but there is no precise definition of
‘the aged’, ‘the elderly’ or ‘advanced age’ as there is no
specific clinical marker of the ‘geriatric’ patient, and
ageing does not occur abruptly. Approximately 15% of the
Western population, and about 25% of surgical patients are
aged ≥65 yr. Half of these will undergo surgery in the
remainder of their life time. Age itself is an independent
morbidity and mortality risk factor.
Key words: Geriatrics, anaesthesia, elderly
Aging is a progressive physiologic process characterized by:
1. Decreased end-organ reserve
2. Decreased functional capacity
3. Increasing imbalance of homeostatic mechanisms
4. Increasing incidence of pathologic processes
Let us now see various age related physiological alterations
and there implications in the perioperative period.
Physiological changes
Nervous system: Memory decline occurs in more
than 40% of individuals older than 60 years of age. There is a
decrease in the volume of gray and white matter. The decrease
in gray matter volume is thought to be secondary to neuronal
shrinkage or neuronal loss. Such loss results in gyral atrophy
and increased ventricular size. Decreases in brain reserve are
manifested by increased sensitivity to anesthetic medications,
increased risk for perioperative delirium and postoperative
cognitive dysfunction.
Neuraxial changes:Age related neurological changes are:
a) Reduction of the area of the epidural space,
increased permeability of the dura, and decreased volume of
CSF.
b) The diameter and number of myelinated fibers in the
dorsal and ventral nerve roots are decreased.
c) Decreased conduction velocity in peripheral nerves.
These changes tend to make elderly
individuals more sensitive to neuraxial and peripheral nerve
blocks (PNBs).
They are more prone to Dementia and Delirium and these are
associated with poorer rehabilitation outcomes and higher
surgical mortality.
Cardiovascular changes
Heart: Changes in heart could be a decrease
in myocytes number, left ventricular wall thickening,
aortic valve sclerosis, mitral annular calcification,
decreased conduction fiber density or decrease in sinus node
cell number. Functionally, these changes translate to
decreased contractility, increased myocardial stiffness and
increased ventricular filling pressures and decreased
β-adrenergic sensitivity. Ageing is associated with
structural and functional changes in the coronary vasculature,
which could affect myocardial perfusion with advancing age
Vascular: The large arteries dilate, their walls
thicken, and smooth muscle tone increases, as a result,
vascular stiffness increases with advancing age. This is
related to breakdown of elastin and collagen and alterations
in nitric oxide–induced vasodilation. Functionally, these
changes are observed as elevated MAP and pulse pressure.
Decreased ventricular compliance and increased afterload,
compensatory prolongation of myocardial contraction, decreased
early diastolic filling time make contribution of atrial
contraction to late ventricular filling more important. This
explains why cardiac rhythm other than sinus is often poorly
tolerated in elderly individuals.
Changes in the autonomic system with aging include: a)
decrease in response to β-receptor stimulation b) increase in
sympathetic nervous system activity.
Cardiac response to increased flow demand in the young and the
elderly are different. The young meet the increased flow
demand primarily by β‐adrenoceptor‐mediated augmentation of
heart rate and contractility, thus preserving preload reserve.
In contrast, the elderly employ primarily the preload reserve
to augment cardiac performance, thereby losing additional
cardiovascular reserve and becoming susceptible to cardiac
insufficiency.
Respiratory System
Changes in control of respiration, lung structure, mechanics,
and pulmonary blood flow place the elderly patients at
increased risk for perioperative pulmonary complications.
A) Centrally: Ventilatory responses to hypoxia, hypercapnia,
and mechanical stress are impaired secondary to reduced CNS
activity. The respiratory depressant effects of
Benzodiazeoines (BZD), opioids, and volatile anesthetics are
exaggerated.
B) Structural changes in the lung with aging include loss of
elastic recoil with enlargement of the respiratory bronchioles
and alveolar ducts, tendency for early collapse of the small
airways on exhalation, progressive loss of alveolar surface
area.The functional results of these changes are increased
anatomic dead space, decreased diffusing capacity and
increased closing capacity.
C) Loss of height and calcification of the vertebral column
and rib cage lead to a typical barrel chest appearance with
diaphragmatic flattening, making the diaphragm less efficient,
and its function is impaired further by a significant loss of
muscle mass associated with aging. Functionally, the chest
wall becomes less compliant, and work of breathing is
increased.
D) Residual Volume increases by 5- 10% per decade. Vital
capacity decreases. Closing capacity (CC) increases with age.
The change in the relationship between FRC and CC cause an
increased ventilation-perfusion mismatch (increased shunt) and
represent the most important mechanism for the increase in
alveolar-arterial oxygen gradient. In younger individuals,
Closing Capacity (CC) is below FRC. At 44 years of age, CC
equals FRC in the supine position, at 66 years of age, CC
equals FRC in the upright position. Increased closing capacity
and depletion of muscle mass causes a progressive decrease in
FEV1 by 6% to 8% per decade. Hypoxic pulmonary
vasoconstriction is blunted and may cause difficulty with
one-lung ventilation. Pneumonia may be presented by
uncharacteristic features such as confusion, lethargy, and
deterioration of general condition.
Renal and Hepatic changes with age
Renal mass may decrease 30% by age 80 years with a
decrease in functioning glomeruli. RBF decreases about 10% per
decade. There is a progressive decline in creatinine clearance
with age, yet with “normal” aging, S.Cr. remains relatively
unchanged because muscle mass also decreases with aging.
So, S. Cr. is a poor predictor of renal function in elderly
patients. Functional changes in the kidneys with aging include
alterations in electrolyte handling and the ability to
concentrate and dilute urine. Renal capacity to conserve
sodium is decreased. This, paired with a decreased thirst
response, may place an elderly patient at risk for dehydration
and sodium depletion.
Liver volume decreases approximately 20% to 40% with aging.
Hepatic blood flow decreases about 10% per decade.There is a
variable decrease in the liver's intrinsic capacity to
metabolize drugs.
Other problems
Polypharmacy: The number of medications used is
directly proportional to the likelihood of having an adverse
drug reaction with an incidence of 5 - 35% in patients older
than age 65 years.
Malnutrition: The prevalence of malnutrition
ranges from 15% to 26% among hospitalized elderly patients.
Surgical patients who are malnourished have increased
morbidity and mortality and increased length of stay.
Dehydration: Dehydration accounts for
approximately 6% of admissions (in USA) and is often
associated with hypernatremia and accompanied by infection,
e.g. pneumonia and UTI.
Immobility: Bed rest leads to ventricular
atrophy, hypovolemia, and orthostatic intolerance. Prolonged
bed rest causes decreases in muscle mass, which may influence
pulmonary function.
Depression: Depression is estimated to occur in
10% of the community-dwelling population older than age 65
years. The presence of depression may influence the occurrence
of delirium and length of stay, and have a significant impact
on postoperative quality of life. Antidepressants should be
continued during the perioperative period as discontinuing
antidepressants may increase symptoms of depression and
confusion.
Hypothermia: Advancing age predisposes the
patient to perioperative hypothermia. Contributing factors
include, frail constitution, reduced metabolic rate, reduced
subcutaneous fat layer, major and long operations, and
impaired thermoregulation. Unintentional hypothermia has been
associated with myocardial ischemia, angina, and hypoxemia
during the early postoperative period.
Pharmacological changes: Factors that affect the
pharmacologic responses of elderly patients include changes in
(1) plasma protein binding, (2) drug metabolism, (3) body
content, (4) pharmacodynamics. The main plasma binding protein
for acidic drugs is albumin and for basic drugs is α1-acid
glycoprotein. The level of albumin decreases with age, whereas
α1-acid glycoprotein levels increase. The effect of
alterations in plasma binding protein on drug effect depend on
which protein the drug is bound to, and the resulting change
in fraction of unbound drug. Changes in body composition with
aging reflect a decrease in lean body mass, an increase in
body fat, and a decrease in total body water (TBW). A decrease
in TBW could lead to a smaller central compartment and
increased serum concentrations after bolus administration of a
drug. In addition, the increase in body fat might result in a
greater volume of distribution and prolonged effect of a given
medication. Depending on the degradation pathway,
decreases in liver and kidney reserve can affect a drug's
pharmacokinetics profile.
Preoperative Evaluation
Common diseases of elderly patients may have a major impact on
anesthetic management and require special care and diagnosis.
Cardiovascular disease and diabetes are particularly prominent
in this population. Laboratory and diagnostic studies,
history, physical examination, and determination of functional
capacity should attempt to evaluate the patient's physiologic
reserve. Laboratory testing should be guided by the patient's
history, physical examination, and proposed surgical
procedure, and should not be based on age alone. The decision
to operate should not be based on age alone, but should
reflect an assessment of the risk-to-benefit ratio of
individual cases.
Anesthetic Management
Airway management: Mask ventilation and
laryngoscopy may be challenging especially in edentulous or
debilitated patients.
Older patients may come to the OR with depleted volume because
of, nil by mouth orders, reduced thirst, age‐related decline
in renal capacity to conserve water and salt,
disease‐associated fluid and electrolyte losses, inadequate
intravenous fluid substitution and more frequent use of
diuretics.
Because of decreased left ventricular compliance and limited
β‐adrenoceptor responsiveness, the elderly, particularly those
with hypertension, must be expected to be more sensitive to
fluid overload. Careful volume assessment (volume dependant
yet volume intolerant) is very important. More frequent and
severe hypotension on induction of anaesthesia must be
anticipated in the elderly because of the effects of the
anaesthetics which occur on top of age‐related impaired
cardiovascular compensatory mechanisms. So, more judicious use
and selection of agents, and slow titration of reduced doses
during induction and maintenance of anaesthesia, are required
with advancing age
The dose of intravenous anaesthetics decrease with age, due to
an age-related decrease in the initial distribution volume of
the drug resulting in higher serum drug levels. Morphine
clearance is decreased in elderly patients. Patients with
renal insufficiency may have impaired elimination of morphine
glucuronides, and this may account for some of the enhanced
analgesia from a given dose of morphine. Sufentanil,
alfentanil, and fentanyl are approximately twice as potent in
elderly patients. These findings are primarily related to an
increase in brain sensitivity to opioids with age, rather than
alterations in pharmacokinetics. There is an increase in brain
sensitivity to remifentanil with age. Remifentanil is
approximately twice as potent in elderly patients, and one
half the bolus dose is required.
Muscle Relaxants: Generally, age does not
significantly affect the pharmacodynamics of muscle relaxants.
Duration of action may be prolonged, however, if the drug
depends on liver or renal metabolism.
Neuraxial Anesthesia and Peripheral Nerve Blocks:
Age has no effect on duration of motor blockade with
bupivacaine spinal anesthesia. The time of onset is decreased,
however, and spread is more extensive with hyperbaric
bupivacaine solution. In epidural anesthesia, time of onset is
shorter, and extent of block is greater. Reduced plasma
clearance of local anesthetics observed in elderly patients
can become a factor during repeated dosing and continuous
infusion techniques prompting a reduction in top-up doses and
infusion rates.
Anesthetic Technique: It is recommended to use
shorter acting anesthetics, opioids, and muscle relaxants in
caring for elderly patients. When comparing inhaled
anesthetics, there does not seem to be a significant
difference in recovery profile of cognitive function.
Desflurane is associated with the most rapid emergence.
Regional versus General Anesthesia: Specific
effects of regional anesthesia may provide some benefit.
First, regional anesthesia affects the coagulation system by
preventing postoperative inhibition of fibrinolysis. Regional
anesthesia may decrease the incidence of DVT after total hip
arthroplasty. In lower extremity revascularization, regional
anesthesia is associated with a decreased incidence of
postoperative graft thrombosis compared with GA. Second, the
hemodynamic effects of regional anesthesia may be associated
with decreased blood loss in pelvic and lower extremity
surgery. Third, regional anesthesia does not require
instrumentation of the airway and may allow patients to
maintain their own airway and level of pulmonary function. Use
of regional anesthesia does not seem to decrease the incidence
of postoperative cognitive dysfunction compared with general
anesthesia.
Postoperative Considerations: The incidence of
common postoperative morbidities is 17% for atelectasis, 12%
for acute bronchitis, 10% for pneumonia, 6% for heart failure
or myocardial infarction (or both), 7% for delirium, and 1%
for new focal neurologic signs. Elderly patients may be
at higher risk for aspiration secondary to the progressive
decrease in laryngopharyngeal sensory discrimination. In
addition, dysfunctional swallowing predisposes elderly
patients to aspiration. Pulmonary complications are the third
leading cause of postoperative morbidity in elderly patients
undergoing noncardiac surgery.
Delirium: The incidence of postoperative
delirium in elderly patients varies widely depending on the
type of surgery. Incidence is 10% after major elective
surgery, but higher after cardiac surgery. Delirium is a
syndrome characterized by acute onset of variable and
fluctuating changes in level of consciousness accompanied by a
range of symptoms. “The essential feature of a delirium is a
disturbance in consciousness that is accompanied by a change
in cognition that cannot be better accounted for by a
preexisting or evolving dementia”. Risk and precipitating
factors for delirium include cognitive impairment or
depression, sleep deprivation, immobility, polypharmacy, pain,
ICU admission, visual impairment, hearing impairment, and
dehydration. Anesthetic interventions include correction of
metabolic and electrolyte disorders, perioperative
continuation of pharmacologic therapy for neuropsychiatric
disorders, avoiding triggering agent drugs (e.g.,
anticholinergics, Benzodiazepines) or inadequately controlled
pain. Delirium has been associated with greater intraoperative
blood loss, postoperative blood transfusions, and
postoperative hematocrite less than 30%.
Postoperative Cognitive Dysfunction: Short-term
changes involve multiple cognitive domains, such as attention,
memory, and psychomotor speed. Cardiac surgery is associated
with a higher incidence of cognitive decline compared to major
non-cardiac surgery. Predictors of early postoperative
cognitive decline include age, low educational level,
preoperative cognitive impairment, depression, and surgical
procedure. Short-term cognitive dysfunction may be attributed
to microemboli (especially with cardiac surgery),
hypoperfusion, systemic inflammatory response, anesthesia,
depression, and genetic factors. Postoperative cognitive
decline after major non-cardiac surgery is reversible in most
cases, but may persist in approximately 1% of patients.
Long-term cognitive changes may be related to underlying
cerebrovascular disease risk factors, such as blood pressure,
cholesterol, and diabetes mallitus.
Treatment of Acute Postoperative Pain: Experimental
and clinical studies provide support for the notion of an
age-related decrease in pain perception. Evaluation of pain,
in a severely cognitively impaired individual, is difficult
even for a geriatrician. The combination of pain assessment
and drug dose adjustment provides challenges in the management
of postoperative pain in elderly patients. Several general
principles should be kept in mind when managing frail elderly
patients. First, it is important to try to incorporate
multiple modalities of analgesia, such as intravenous PCA
(patient controlled analgesia) and regional nerve blocks.
Second, the use of site-specific analgesia is a helpful
adjunct, local nerve blocks for upper limb
surgeries and neuraxial analgesia or intercostal nerve block
for thoracotomy. Third, whenever possible, NSAID’s and
Paracetamol should be used, keeping in mind, however, the
alterations in dose requirements that occur with age.
Elderly patients are expected to increase every year. Of these
individuals, many will require surgery. These patients
typically presents for surgery with multiple chronic medical
conditions, in addition to the acute surgical illness. Age is
not a contraindication to anaesthesia and surgery; however,
perioperative morbidity and mortality are greater in elderly
than younger surgical patients.
Further Reading
1. Chris Dodds, Irwin Foo, Kerri Jones, Shiv Kumar Singh and
Carl Waldmann. Peri-operative care of elderly patients for
specialist and non-specialist anaesthetists – an urgent need
for change. Perioper Med. 2013;2:6C.
2. WFSA. World Anaesthesia Tutorial of the week. Anaesthesia
in the Elderly, Dr Nigel Hollister.
3. Harari D, Hopper A, Dhesi J, Babic-Illman G, Lockwood L,
Martin F: Proactive care of older people undergoing surgery
(‘POPS’): designing, embedding, evaluating and funding a
comprehensive geriatric assessment service for older elective
surgical patients. Age Ageing. 2007;36:190-6.
4. National Confidential Enquiry into Patient Outcome and
Death (NCEPOD): Elective & Emergency Surgery in the
Elderly: An Age Old Problem. 2010. Available from:
www.ncepod.org.uk/2010eese.htm
5. Dyer CB, Ashton CM, Teasdale TA: Postoperative delirium. A
review of 80 primary data-collection studies. Arch Intern Med.
1995;155:461-5.
6. Radtke FM, Franck M, Schneider M, Luetz A, Seeling M, Heinz
A, et al. Comparison of three scores to screen for delirium in
the recovery room. Br J Anaesth. 2008;101:338-43.
7. Hodkinson, HM. “Evaluation of a mental test score for
assessment of mental impairment in the elderly.” Age and
Ageing. 1972;1(4): 233-8.
8. Kelly F, Mulder R. Anaesthesia for the elderly patient.
Update In Anaesthesia. 2002;15.
9. Joshi K, Kumar R, A Avasthi. Morbidity profile and its
relationship with disability and psychological distress among
elderly people in Northern India. Int J Epidemiol.
2003;32:978-87.
10. Eun-kyung Woo, Changsu Han, et al. Morbidity and related
factors among elderly people in South Korea: results from the
Ansan Geriatric (AGE) cohort study. BMC Public Health.
2007;7:10.
11. Behrends M, DePalma G, Sands L, Leung J. Association
between intraoperative blood transfusions and early
postoperative delirium in older adults. J Am Geriatr Soc. Mar
2013;61(3):365-70.
12. Bettelli G. Anaesthesia for the elderly outpatient:
preoperative assessment and evaluation, anaesthetic technique
and postoperative pain management. Curr Opin Anesthesiol.
2010,23:726-31.
13. Stevens JD. A new local anesthesia technique for cataract
extraction by one quadrant sub-Tenon’s infiltration. Br J
Ophthalmol. Nov 1992;76(11):670-4.
14. Parker MJ, Handoll HHG, Griffiths R, Urwin SC. Anaesthesia
for hip fracture surgery in adults (Review) Cochrane Libr.
2004; 3.