Systemic Changes Flashcards
Systolic hypertension
Progressive, gender independent
Systolic HTN is Due to
fibrosis of elastic tissues which Raises ventricular wall
tensions, workload
Workload increase Causes
hypertrophy of ventricle
↓Arterial compliance→
• Aorta to arterioles stiffen = HTN
• Pressure must ↑ to stretch stiffer vessels
↑ Afterload→↑ Ventricular workload→
Concentric Hypertrophy
• Why does concentric hypertrophy occur?
Atherosclerosis →↑conductance of pressure wave in aorta and arteries →Reflectant waves from arterioles and branch points returns to heart quicker than normal →↑resistance at end of systole→ hard for heart to overcome
EKG changes for older
Left Ventricular Hypertrophy
Cardiac output
• However demand may be down
• So ↓ not noticeable at rest
may ↓
CO: Under stress, the ↓ is noticeable
when demand outstrips capacity
CO stress noticed
- CHF
- MI
- Exercise
- Stress
- Surgery
Chronotropy and Inotropy
Aging abd Beta
↓ responsiveness to β adrenergic agonists
Aging and catecholamines
↓ response to catecholamines
Aging and Beta Blockers
Response to β blockers is preserved
Aging and Parasympathetic tone
Par. tone declines (less response to atropine and glyco)
Sympathetic tone
↑ with aging
Aging, Limited response to
glycopyrrolate and atropine
Ability to cope with perioperative stress
is impaired
↑ demand that cannot be met
• Sepsis or shivering may
Elderly patients cannot compensate by______ and ______. They compensate by
increasing CO and HR. They compensate by vasoconstriction
Baroreceptor Reflex :Stretch receptors
Impaired in aging
Elderly prone to
orthostatic hypotension
Baroreceptor Reflex exacerbated by
Exacerbated by diuretics and medications
- One of the most important considerations
* Age related changes
↓ of elasticity of bony thorax
Laryngeal structures change with age
Protective reflexes blunted
Aspiration more common
Alveoli Become
dilated• ↑ compliance COPD-like
Aging and elasticity
↓ elasticity (Air trapping occurs d/t small
airway closure)
Surface area change
decrased from 75m2 to 60m2 by 70 years
Changes in chest wall and muscle strength
Stiffened chest wall + ↓ muscle strength → ↓effective cough
Changes in parenchymal compliance
↑ parenchymal compliance
Takes longer to passively exhale ↓ motor power
Inspiratory capacity (IC) is compromised because of the combined effect of modest
↓ in total lung capacity (TLC) and modest ↑ in functional residual capacity (FRC)
Vital capacity (VC) and aging
↓ because of the ↓ in IC and the ↑ in residual volume
Additionally: Alveolar dead space
↑
PaO2 Declines from
95 to 73 by age 75 remaining stable.
What is the 70-70 rule
At 70 yo, normal PaO2 = 70 mm Hg
Hypoxic Pulmonary Vasoconstriction blunted by
stiffening lung parenchyma
Responses to hypoxemia
↓
Sensitivity to respiratory depression with non-narcotics
like benzodiazepines.
↑
Electrolyte Impaired, handling of
Na handling
• Dehydration
• Impaired dilution
Hormones and aging
↓ response to ADH and Aldosterone
Disposition to these electrolytes disturbances
↑ hypokalemia and hyperkalemia
In older adults, As fxn is compromised,
drug clearance affected
Hepatic microsomes older adults
intact and functional
Hepatic mass____ with aging
↓ ; This impairs drug clearance
Most common cause for prolonged effects of narcs
Because Hepatic mass is decreased
Effect of aging: decrease hepatic mass
↓ the amount of plasma esterases
Drugs taken by elderly may affect fxn
Cimetidine affect benzodiazepine biotransformation
CNS effects of aging: Brain • Most metabolically active affected the most • ↓Neurotransmitter synthe
• Reduces brain size
CNS effects of aging: Brain
• Reduces brain size
Neuronal
↓ highly selective
Neuronal
↓ highly selective
Most _________affected the most
metabolically active
Neurotransmitter synthesis
↓
Generalized depletion of:
- acetylcholine
- Norepinephrine
- Tyrosine
- Dopamine
↑ activity of:
COMT – Catecholamine-o-methyl-transferase and
MAO – Monoamine Oxidase• Break down neurotransmitters
Up regulation mechanisms
Depressed in elderly patients
Aging and response to neurotransmitters
Usually respond to ↓ in neurotransmitters
Consequence of ↓ cerebral mass
↓ CBF
Hyperventilation CO2 response
Hyperventilation CO2 response intact
Auto regulatory mechanisms
intact
Intelligence: Not affected by aging are
Long term memory, language skills and personality are not affected by aging
There may be a ↓ in
short term memory, hearing acuity, visual acuity and response times
Peripheral nervous system: meissner’s
Exponential ↓ in meissner’s corpuscle
Evoked potentials and aging
• ↓
Aging and End plate
• ↓ number of end plates
Aging number of receptors
• However ↑ number of receptors
Therefore no change in NMB doses why?
↓ number of end plates • However ↑ number of receptors • Negates ↓ • Therefore no change in NMB doses
Threshold intensities
up for pain
Autonomic Nervous System
Paradoxically in_______
Marked ↓ in
hyper adrenergic state
• in β adrenergic response
NE levels at
2 – 3 times normal
NE levels at
2 – 3 times normal
Adrenal tissue mass changes
declines
Autonomic reflexes and aging
impaired in the elderly
Elastin and collagen and aging
Loss of elastin
Increased collagen
Systolic function and aging
Autonomic Nervous System – cont.
Anesthetic techniques that blunt the nervous system may cause
greater changes in the elderly i.e. spinal/ epidural anesthetics
Elderly patients with CHF with
high adrenergic tone could have catastrophic effects under anesthesia
Baroreceptor and aging
Barosensitivity decreases
Body heat
• ↓ in production
Time to return patient to normal temperature
↑ with ↑ age
Insulin and aging
↓ Sensitivity to Insulin; Increase resistance to insulin
Plasma NE is
Increased
Elderly at ↑ risk for
inadvertent intra-operative hypothermia
• Oxygen consumption is
↓
• Heat production
↓
Aging and ADH
Decreased Response to ADH
ALDOSTERONE and aging
DECREASED ability to conserve sodium, –> risk for dehydration
All decreased, Not affected
Alpha 1 glycoprotein (increased
First pass metabolism is
decreased
Anesthetics
Increased VD of propofol
Faster induction wtih sevoflurane
Rate of recovery from volatile anesthetis is
Decreased
Closing capacity and aging
Increase closing
3 changes because of increased Closing capacity
VQ matching
Decreased PaO2
Increased Dead space
TLC stays
Same
At age does CLOSING CAPACITY EXCEED FRC while laying supine?
45 years
Most significant risk factor for Cancer
age
Best describe post op cognitive dysfunction
Following cardiac surgery
The most significant risk factor is increasing age.
2 increased in elderly
Pulse pressure
NE plasma concentration
Patient with Parkinson’s showing signs of EPS
Diphenhydramine
Lung compliance is
Increased
Minute ventilation is
Increased
Calculating MAC 40 decrease
Mac x 0.94 ^(# of decade decrease)
Bolus doesn’t go to sleep as fast why?
Slower rate of transfer to target organs
Desflurane
Can mimic sympathetic, May increase BP
Most important cause of prolonged drug activity in elderly is
DECREASE in LIVER MASS
Glomeruli and age
1/2 glomeruli decrease by 80 years old
Aging and insulin
Decrease insulin secretion, with increase resistance
Aging does production of insulin
NO change
Why does MAC decrease
Brain is smaller
AVOID those drugs in Parkinson
DROPERIDOL and METOCLOPRAMIDE
Good for premedication and intraop sedation for parkisons
Diphenhydramine
Alveoli changes
overdistended alveoli
Small airway changes
Collapse because of distended alveoli
Sodium changes s DIH
Diluting capacity decrease
Impaired NA handling
Concentrating ability decrease
Changes put at risk for dehydration and fluid overload
Liver mass and hepatic blood flow
decrease
Hepatic function decline in
proportion to the decrease in liver mass
Diastolic DYSFUNCTION not equivalent to ?
What happens to filling pressure?
FAILURE
Filling pressure increase
Hypercapnia and hypoxia response is
Decreased n
BUN _____. Cr is ______. Creatininge clearance
increase; UNCHANGED; DECREASED
Neuroendocrine response to stress is
preserved or only slighly decreased
Use drugs such as ________why?
Atracurium, or cisatracurium, NOt dependent on hepatic or renal function or flow
The reduce Vd for water soluble drugs can lead to
Greater plasma concentrations
The increase Vd for lipid soluble drugs can
decrease their plasma concentration
Is the dose of succinylcholine affected by age ?
Best bet for NDNMB
NO,
vec and roc affected due to hepatic excretion and aging associated with loss of liver mass
Atra and cisa
Associated with increase post op delierium
Benzo and anticholinergics