Principles of Anesthesia II Unit II Flashcards
(316 cards)
Memory decline occurs in what percentage of people over 60?
40%
Neuronal shrinkage leads a decrease in what?
Decrease in grey matter
Decrease in white matter increases what in size?
Ventricular size
Decrease in white matter causes progressive loss of what?
Memory, balance, mobility
What neurotransmitter release is significantly reduced as you age? Which is not affected?
Dopamine, Ach, norepi and serotonin. Glutamate is unchanged.
CRMO, CBF and EEG are generally unchanged with age
What neuraxial changes occur as you age?
Decreased epidural space
Increased permeability of dura
Decreased volume of CSF
Decreased diameter/number of myelinated fibers in dorsal and ventral nerve roots
What PNS changes occur as you age?
Inter-Schwann cell distance decreased
Conduction velocity decreased
In general, elderly are more sensitive to neuraxial and peripheral blocks
What cardiac changes occur as you age?
Myocyte number decreases
LV wall thickens
SA node cells decrease – sensitive to tachy/brady arrhythmias
Conduction velocity decrease
Thickened and calcific aortic valve
Decreased contractility, increased ventricular stiffness (higher filling pressure)
Less beta-adrenergic sensitivity (less fight/flight response, you lose the ability to increase HR and CO during stress)
many of these changes are d/t increased afterload as you age
What increases vascular stiffness as you age?
Breakdown of collagen and elastin
Less NO related vasodilation
Early wave deflection…increased afterload, diastolic dysfunction
What pulmonary changes occur as you age?
Loss of elastic recoil and loss of surfactant = increase in lung compliance and decrease in elastic recoil
Enlarged bronchioles/alveolar ducts coupled with early collapse of small airways during exhalation = increase in anatomic dead space, increased closing capacity and impaired gas exchange
Lost of vertebral height and calcification of vertebrae lead to what pulmonary changes?
Barrel chest
Diaphragmatic flattening
Chest wall stiffness….increased work of breathing
How do VC, CC and RV change as you age?
VC decreases, CC increases and RV increases
How much does FEV1 decrease per decade?
6 - 8% d/t decrease in muscle mass and increase in CC
What relationship has the greatest effect on the alveolar-arterial oxygen gradient?
The relationship between FRC and CC, as the mismatch increases, shunt also increases and arterial oxygenation declines
How much does GFR decrease each decade after 30?
About 10% each decade
Why does aging reduce the body’s ability to adjust fluid and e-lytes?
The body has a blunted response to aldosterone, vasopressin, renin
Metabolism of drugs requiring what types of metabolism are affected by aging? What types of drug metabolism are not affected by aging?
Affected by aging: Phase I metabolism = oxidation, reduction, hydrolysis. Very common in narcotics and anesthetics
Not affected by aging: Phase II metabolism = acetylation and conjugation
What occurs to subQ fat as you age?
SubQ fat thins
How much does temperature change in the 60 - 80 year old range?
About 1 degree C less than infants/children/younger adults
What are the listed significant predictors of 6 - 12 month mortality?
Impaired cognition
Recent fall
Hypoalbuminemia
Anemia
Functional dependence
Comorbidities
Surgery and anesthesia cause peripheral inflammatory responses. In a vulnerable brain, what negative outcomes can occur because of this inflammaion?
Dysfunctional anti-inflammatory response leads to an exaggerated neuroinflammation and acceleration of AD pathology causing long-term cognitive decline
What are the neurotoxic factors that are the pathogenesis of dementia?
Amyloid B, Tau, calcium and neuroinflammation
How does amyloid B accumulate? Proposed MOA in causing neuro-degeneration?
It’s a fragment of synaptic origin - its released as synapses break down. The proposed MOA is they coagulate to form amyloid plaques that disrupt cell membranes over time
What is the relationship of temperature and Tau?
Decreases in temperature lead to increases in Tau