Flashcards in Gerontology Pathophysiology Deck (104):
What is life expectancy?
The average age that members of a population are expected to obtain when premature causes of death are taken out
What is life span?
The average age of all those that die of natural causes , absence of disease or trauma
What factors have increased longevity in the 20th century?
Advanced public health
What age group is said to be elderly?
Those older than 65 years old
What is the fastest growing segment of the population?
Elderly people who are greater than 90 y/o
What often complicates geriatric surgical procedures?
Infections, Organ system failure and prolonged hospitalization
What is senescence?
Progressive deterioration of physiologic functions with aging
What is longevity?
Summation of forces that avoid or retard senescence
What is the formal definition for aging?
Progressive loss of physiologic research necessary to maintain homeostasis
What is frailty?
Loss of physiologic reserve for a specific biologic system, especially in the presence of stressors
Why shouldn't a patients age be solely based on a number?
The elderly are neither a medically nor physically homogenous patient group such that rigid chronologic definition has little value other than administrative or epidemiological applications
What does the term aging suggest about a patients body?
Degenerative changes in structure and functional reserve of organs and tissues
When does functional decline begin to occur in the body?
Anatomic and physiologic changes begin in middle line in almost every system
What are the three elements that contribute to damage to the elderly in the perioperative period?
Limited end organ reserve
Any underlying disease
Actual stress or the peri operative period
What components make up frailty?
What are characteristics of frailty?
Loss of muscle mass/strength
Decreased cognitive function
What is multidimential geriatric syndrome?
Characterized by a loss of physiologic reserve that causes the patient to be vulnerable to adverse events
What helps to identify populations at greatest risk of events in the elderly population?
Biologic markers of age and physiologic reserve
What is the general rule of thumb for loss of organ system function per year?
Normally organ systems lose about 1% of function per year after 30 years of age
What is the hallmark sign of aging?
The lack of functional reserve in response to stress
What is the best indicator for biologic age?
Exercise tolerance, it is an important predictor of post op outcomes in the elderly
How would one determine organ system functional reserve?
Maximum capacity - basal level of function
What organ reserves can be tested prior to surgery?
Cardiopulmonary with stress test
What organ systems functional reserves are assumed for surgery?
Renal, Hepatic, Immune and Nervous system
Why is it important to determine an organ systems functional reserve prior to surgery?
To determine safety margins
How does aging affect cerebral blood flow and brain mass?
Decreased cerebral blood flow and brain mass
Does age affect cerebral auto regulation?
No, cerebral auto regulation is preserved
What is thought to cause a decrease in brain weight with age?
6-7% decrease in brain mass thought to be due to neuronal shrinkage rather than neuronal loss
How is white and gray matter affected by age?
Gray and white matter both decrease and CSF increases
What is thought to contribute to parkinsons disease in the elderly?
Decrease in dopamine in the substantia nigra
What is thought to contribute to senile demential in the elderly?
Decreased Ach in the hypothalamus
What is thought to cause depression in the elderly?
Decrease in Norepinephrine and 5-hydroxytryptamine in the hypothalamus
What neurotransmitter levels seem unaffected by age?
What additional factor other than neurotransmitters are thought to contribute to depression and dementia in the elderly?
Sleep patterns altered, decreased REM sleep
How is memory affected by aging?
Impaired short term memory but long term memory may be preserved
What factors increase an elderly patients risk for post op delirium and cognitive dysfunction?
Mental confusion with difficulty in temporal and spatial orientation
Why are elderly patients prone to orthostatic HoTN?
Impaired postural control
Why do elderly patients often develop arrhythmias?
Impaired autonomic regulation of CV function
Why is it easier to achieve a higher level of anesthesia with a lower volume of LA in the elderly?
There is a decrease in area of the epidural space
What nervous system is affected more by age?
CNS is more effected than the peripheral nervous system
Why are reflexes slower in the elderly patient?
Loss of myelin in PNS and
Decreased number of motor neuron in the spinal cord
What causes an increase in size of the heart in elderly patients?
Concentric ventricular hypertrophy (increase in wall thickness)
What causes concentric ventricular hypertrophy in the elderly?
Response to increase LV after load due to decrease in arterial distensibility
Cardiac myocytes hypertrophy but are less in number
How is cardiac connective tissue affected by age?
Increase in cardiac connective tissue leading to fragmented elastin replaced by collagen and increase wall stiffness and reduces diastolic compliance
What do the elderly depend on for preload?
Markedly dependent on atrial kick for preload
What is the most common supra ventricular rhythm in patients greater than 65y/o?
What can precipitate congestive heart failure in the elderly?
Preoperative increase in blood volume or a decrease in contractility
How is heart rate altered with age?
No alterations of resting heart rate with age, maximum heart rate achievable decreases from 200-->160 b/m
What causes an increase in susceptibility to supraventricular arrhythmias and ventricular ectopy with age?
Fibrous infiltration of SA node with loss of pacemaker cells
Which parts of the heart are unchanged by age?
A-V node and bundle of his
Why is there a decreased responsiveness to cardiac beta adrenergic agonists with age?
Reduced receptor numbers or affinity and there is a decrease in generation of cyclic adenosine monophosphate after beta receptor activation
How are baroreceptors affected by age?
Response to decreased arterial pressure attenuated
May cause postural HoTN
HoTN with PPV, especially if patient is dehydrated
What vessel changes lead to an increased incidence of aortic aneurysms in the elderly?
Less distensible vessels from thickened intimate and media
What is thought to contribute to HTN in the elderly?
Large vessels become tortuous, elongated and dilated
What causes a change in pulse wave of an a-line on an elderly patient?
Normal cushioning effects is impaired, reflected back from peripheral circulation and augments systolic pressure
What is the importance of endothelium?
Important regulator od vasomotor response, coagulation, fibrinolysis, immunomodulation, vascular growth and proliferation
How does aging affect the endothelium?
Aging alters endothelial structure even in absence of disease
What accelerates endothelial function?
Smoking, DM, HTN and hyperlipidemia
What are characteristics of endothelial dysfunction?
Decreased ability to dilate blood vessels in response to physiologic or pharmacologic stimuli
Decrease NO in all vascular beds
Reduced vasodilating response
Diminished B2 and alpha responses
What mechanism is relied on in the elderly to increase SV?
Frank starling mechanism
What respiratory changes are seen in the elderly?
Decreased lung volumes and Reduced efficiency of gas exchange
Why do the elderly exhibit signs similar to that of emphysema?
Alveolar septa lost and decreased surface area
Why us lung recoil decreased with age?
Loss of lung elasticity
How is the residual volume affected by age?
Increased ratio of residual volume to total lung capacity
How are closing volumes affected by age?
Increased closing volume leading to small airway closure at larger lung volumes (tidal volume occurs below closing volume)
What is a common pulmonary problem when inducing the elderly with anesthesia?
V/Q mismatching from anesthetic induced depression of active hypoxia pulmonary casoconstriction
What is the primary cause of decreased lung volumes in the elderly?
Restrictive functional impairment, increased thoracic cage rigidity restricts chest expansion
What compensatory mechanisms are used when the chest wall becomes restrictive in the elderly?
Diaphragm and abdominal muscles compensate
What is the maximum breathing capacity of that of a 20y/o compared to an elderly patient?
20y/o = 100L/min
What is the only lung capacity unaffected by age?
TLC remains relatively constant
How is the VC affected by age?
Progressive loss of VC
How is RV and FRC affected by age?
What is considered to be a normal PO2 in elderly patients greater than 60y/o?
81 mean, 71-90mmHg
Why do the elderly experience a markedly attenuated increase in HR and minute ventilation in response to increases in PaCO2 or decrease in PaO2?
Decreased peripheral chemoreceptor sensitivity
Reduced respiratory muscle activity
Decreased respiratory mechanical efficiency
General respiratory deconditioning
What anesthetic agents further attenuate the response to hypercarbia and hypoxia in the elderly?
Opioids, sedatives and volatile agents
Why do the elderly have a reduced cough effectiveness?
Desensitization of airway epithelial cough receptors and impaired muscle function
When is the highest prevalence of snoring in the elderly?
Highest in the 7th decade, associated with increased risk of stroke
How are the kidneys affected by age?
Renal blood flow and GFR decline
What is thought to cause a decrease in renal mass with age?
Decreased number of functional renal glomeruli, disproportionate loss of cortical nephrons and medullary nephrons relatively preserved
How does the decrease in tubular excretion affect the elderly?
Impaired sodium handeling
Decreased ability to concentrate
Decreased drug excretion and
Impaired fluid handeling
Why does Creatinine remain normal in elderly patients even if pathology is present?
Decline in skeletal muscle mass
Why do elderly patients have a decreased volume of distribution?
They have an increase percent of body fat and decrease intracellular water content
What sex has less synthesis of plasma cholinesterase in the elderly population?
How are enzyme activities of the liver affected by age?
Appears to be preserved
Why is there an increased incidence in glucose intolerance and DM in patients older than 70?
Due to decreased pancreatic function
What changes occur with decreased renin production in the elderly?
May lead to decreased plasma aldosterone production
Why is thermoregulation impaired in the elderly?
Thermal stress poorly tolerated
Age related decrease in muscle mass
Unable to efficiently conserve heat
What an appropriate focus in the pre operative period for the geriatric patient?
Evaluation of physical status and identification of age related disease rather than aging itself
What are the components of Friedman's model and how many places a patient at risk?
Weak grip strength
Slow walking speed
Low physical activity
Three or more of these place a patient at risk and are considered frail
Why do minor insults in the elderly population often result in large changes?
When a complex system fails, it fails with higher order functions first
What is the primary determinants of hospital mortality?
Pre operative disease
The site of surgery
What should be thoroughly assess prior to airway manipulation in the elderly patient?
Extension and rotation of the head: mental status changes could reflect vertebrobasiliar arterial insufficiency or the patient could have cervical arthritis
Cervical arthritis may be present
Why is HoTN often seen in the elderly during induction?
Age related decrease in renal capacity to conserve water and sodium
Why are the elderly sensitive to fluid overload?
Decreased left ventricle compliance
How is pharmacokinetics affected by age?
Overall reduced drug clearance from decreased renal and hepatic function
Why does Reglan in the elderly prolong the effects of succyncholine and remifentanyl?
Interferes with the action of plasma cholinesterase
How is the dose of hypnotics altered with age?
Decrease with age
How should opioid doses be altered in the elderly?
Decreased the initial dose by 25-50% to achieve desirable serum levels and compensate for reduced rate of clearance
Which non depolarizers are unaffected by age?
Atracurium and Cisatracurium (Hofmann elimination)
How should the anesthetic provider dose reversal for the elderly?
Reversal agent dosages are not modified in the elderly
How much does the MAC change with age?
MAC decreases 6.7% per decade of life
What types of surgeries are associated with post op delirium in the elderly?
Ophthalmologic, cardiac and hip surgeries
When does interval delirium occur in the elderly?
POD 1 or 2