Anesthesia Implications for Geriatrics - Exam 2 Flashcards
Nervous System
Memory decline is r/t ________, ________, and the aging brain.
- dementia
- alzheimer’s
elderly more active & read = less cog. decline
Nervous System
What are the 3 neuro structural changes in the elderly?
- Cerebral atrophy
- decreased gray matter (neuronal shrinkage)
- decreased white matter (increase ventricle size)
progressive loss of memory, imbalance, mobility
Nervous System
What are 4 reasons why elderly need less doses of LA in neuraxial?
- decreased epidural space
- increased permeability of dura
- decreased CSF volume
- decreased diameter/# of myelinated fibers in dorsal & ventral nerve roots
Nervous System
Peripheral nervous system
________ - ________ cell distance is decreased.
Why is conduction velocity decreased?
What does this make elderly more sensitive to?
- inter-schwann cell
- decreased myelination across nerve fibers
- Neuraxial & PNB
Cardiac
What 2 types of cells decrease in #?
- Myocytes
- SA node cells - susceptible to tachy & brady
Cardiac
Why do the elderly have LV wall thickness?
- increased afterload from years of HTN
more pressure the heart has to pump against = L heart strain
Cardiac
What happens to SVR and vascular compliance w/ aging?
- increased SVR (afterload)
- decreased vascular compliance
Cardiac
What happens w/ the aortic valve and aging?
- becomes thick & calcified = aortic stenosis
Cardiac
What does LV hypertrophy cause contractility to do? (increase/decrease)
What does the increased LV stiffness lead to?
- contractility decreases
- higher LV filling pressures (LVEDP) ventricle does not stretch w/ more volume
Cardiac
What happens w/ beta-adrenergic sensitivity and the elderly?
- pts have a decreased response to beta stimulation
- they can’t increase HR and EF in stress
- more prone to decompensation - neuraxial esp.
Cardiac
Why do the elderly have increased vascular stiffness?
- b/c of breakdown of collagen & elastin
Cardiac
What does a reduction in the levels of endogenous NO lead to?
- less NO related vasodilation
- coronaries can’t dilate optimally in times of stress
Cardiac
Increased vasc. stiffness leads to an early ________ ____ ________.
What does this mean?
- pressure wave deflection
- pressure travels through stiff vessels faster - returns to heart in systole instead of diastole
Cardiac
What effects does an early pressure wave deflection have on afterload and diastolic function?
- increased afterload
- less diastolic blood flow - less support for DBP - less coronary perfusion
Pulmonary
What are the 3 main structural changes that happen w/ aging?
- loss of elastic recoil & surfactant
- enlarged bronchioles and alveolar ducts
- loss of vertebral height, calcification of vertebrae and intercostal cartilage
Pulmonary
The loss of elastic recoil causes lung compliance to do what?
- increase
- easier to get air in lungs/harder to get air out b/c collapse of small airways
Pulmonary
Enlarged bronchioles and alveolar ducts happen as a result of what?
This leads to an increased ________ ________, and impaired ____ ________.
- early collapse of small airways in exhalation
- increased closing capacity
- impaired gas exchange
increased physiological DS (alveolar)
Pulmonary
What changes does loss of vertebral height & calcification of vetebrae/intercostal cartilage cause?
- barrel chest
- diaphragm flattening
- CW stiffness
- SOB on exertion
- increased WOB
Pulmonary
What are the 5 main functional changes that happen w/ the pulmonary system and aging?
- decreased VC
- increased CC
- increased RV
- decreased muscle mass
- weaker pharyngeal muscles
Pulmonary
VC =
IRV + Vt + ERV
amount of air that can be moved in and out of the lungs
Pulmonary
CC =
What happens w/ FEV1 in response to decreased muscle mass & increased closing capacity?
CC = CV + RV
* the point at which the small airways close
* FEV1 decreases 6-8% per decade
Pulmonary
What happens w/ TLC?
- stays the same d/t compensation over time
Pulmonary
What does weaker pharyngeal muscles cause w/ aging?
- decreased clearance of secretions
- less efficient coughing
- aspiration risk d/t decreased esophageal motility
- less protective upper airway reflexes
Pulmonary
What causes a VQ mismatch w/ aging?
- FRC increases, BUT CC increases more
- airways can close in normal Vt
- shunt increases = less arterial oxygenation
Renal
How much does GFR decrease by?
What conditions exacerbate a decline in renal function?
- GFR decreases by 1mL/min/m2/yr or 10mL/min/m2/decade after 30y/o
- DM, HTN, drugs, IVP contrast, dehydration
Renal
Elderly pts have a decreased response to what 3 hormones?
- aldosterone = hyponatremia
- vasopressin (ADH) increased = dilutional hyponatremia
- renin
trouble balancing F/E
GI & Hepatic
What phase of liver drug metabolism is affected more by aging?
- phase 1 (oxidation, reduction, hydrolysis) - CYP450
- phase II - not affected (acetylation, conjugation)
GI & Hepatic
What drugs that we commonly give are metabolized w/ phase I?
- narcotics & anesthetics
- prolonged effects in elderly
GI & Hepatic
Do elderly have less or more PONV?
What drugs should we avoid?
- less
- avoid Prochlorperazine (Compazine), Phenergan, Reglan b/c SE
Musculoskeletal
What are the 4 main changes that happen w/ the MS system and aging?
- muscle mass & strength decline
- subQ fat thins - less ability to thermoregulate
- impaired wound healing
- OA
Thermoregulation
Why are the elderly more prone to hypothermia?
- Vasoconstriction threshold lowers
- they won’t vasoconstrict until they get to a lower temp
- 1 degree C less for adults 60-80
What 3 things can we do to optimize surgical healing in elderly?
- ensure adequate hydration
- maintain normothermia
- ensure good tissue oxygenation
What are the significant predictors of 6 month - 1 yr mortality in elderly?
- impaired cognition
- recent fall
- hypoalbuminemia - compromised healing
- anemia - tissue oxygenation
- functional dep. to do ADLs
- comorbidities
Neurotoxicity
What are the 4 substances involved in the pathogenesis of dementia?
- amyloid B
- Tau
- Calcium
- Neuroinflammation (TNF, IL)
Neurotoxicity
What is amyloid B?
What is its relationship w/ neurotoxicity/dementia?
- protein fragment - develops when synapse breaks down
- accumulates extracellularly in amyloid plaques
- may disrupt cell membranes
- does not build up permanently
Neurotoxicity
How is amyloid B neurotoxic?
- interferes w/ synaptic fx
- impairs neurotransmission
- cog decline
Neurotoxicity
What is Tau?
- protein that normally stabilizes microtubules (neurons)
Neurotoxicity
How does Tau contribute to neurotoxicity/dementia?
- it is hyperphosphorylated and aggreated into Tau chunks
- disrupts the internal structure of neurons - cell death
Neurotoxicity
What is the relationship b/w temp and Tau?
- decrease in temp 2-3 deg. C = increased Tau
- Tau is not cleared w/ severe hypothermia
Neurotoxicity
What are the anesthesia precautions w/ Tau?
- repeated exposure to Halothane, Iso, & Sevo = increased phosphorylation of Tau
Neurotoxicity
How does Calcium release cause neurotoxicity?
- exaggerated release (ryanodine or IP3 receptors)
- MH - genetic predisposition w/ volatiles or succ
- causes - mitochondrial damage, cell death, neuronal dysfunction & death
Neurotoxicity
How does neuroinflammation contribute to cog. decline?
- release of inflammatory factors
- cytokines
- IL-6
- TNfa
Neurotoxicity
What are possible drugs for anti-inflammatory prophylaxis?
- dexamethasone
- lidocaine
- toradol
Anesthesia & Brain
What anesthetic agents are most associated w/ cog decline?
- Iso > Des > Prop
TIVA maintenance of choice
Risk Factors for the development of POCD: (6)
- increasing age
- duration of anesthesia
- lower SES
- 2nd surgery
- post op infection
- resp. complications
What are 7 anesthetic implications we can do for the elderly?
- neuraxial/regional anesthesia
- avoid long-acting NMBD & reverse adequately
- opioid sparing strategies
- Neutralize stomach acid w/ non-particulates (Bicitra)
- EEG based titration
- avoid HoTN - can’t compensate
- pad skin & nerves
Drug Challenges
What are the drug challenges r/t decreased CO?
- slower distribution to site of action
- slower redistribution
- slower distribution to metabolic organs
slower onset & clearance
less redose of meds needed
Drug Challenges
What are the 4 drug challenges r/t the NMJ?
- increased distance b/w axon & motor end plate
- decreased concentration of Ach
- decreased amount of Ach in presynaptic vesicle
- decreased release of Ach
less efficient NMJ - less NMBD required
Drug Challenges
What happens to drugs that depend on kidney/liver metabolism?
- prolonged effect & DOA
- decreased re-dose needed in maintenance
- delayed recovery for non-depolarizers
What is the pre-op assessment for thoracic non-cardiac surgery?
- TTE - r/o pulm. HTN
- poor exercise tolerance, DM, CAD, or CHF
- perfusion imaging w/ dobutamine stress test or persantine thallium scan
- coronary angio
- surgical revascularization
- case by case management
if no to any of the above = candidate for lung resection surgery
What is the formula for ppoFEV1?
ppoFEV1 = pre-op FEV1% x (1- % lung tissue removed/100)
What do we want a ppoFEV1 to be before we extubate our pts?
at least 40%
What 3 things are a part of the “three-legged” stool of pre-thoracotomy resp. assessment?
- Respiratory mechanics
- cardiopulmonary reserve
- lung parenchymal function
Pre-thoracotomy resp. assessment
How do we assess Resp. Mechanics?
- FEV1 ppo >40%
- MVV
- RV/TLC
- FVC
Pre-thoracotomy resp. assessment
How do we assess cardiopulm. reserve?
- VO2 max (>15mL/kg/min)
- stair climb > 2 flights
- 6 min walk
- exercise SpO2 <4%
pre-thoracotomy resp. assessment
How do we assess lung parenchymal function?
- DLCO (ppo > 40%)
- PaO2 > 60
- PaCO2 < 45
Post-thoracotomy anesthetic management
What do we do if ppoFEV1 is > 40%?
extubate in operating room if:
* pt is AWaC
* (alert, warm, and comfortable)
Post-thoracotomy anesthetic managment
What do we do if the ppoFEV1 is 30-40%?
consider extubation based on:
* exercise tolerance
* DLCO >40%
* V/Q scan
* associated diseases
Post-thoracotomy anesthetic management
What do we do when the ppoFEV1 is < 30%?
- Staged weaning from mechanical ventilation
- consider extubation if > 20% plus: thoracic epidural analgesia
How many subsegments are in the R lung?
RUL: 6
RML: 4
RLL: 12
How many subsegments are in the L lung?
LUL: 10
LLL: 10
