Exam 2: Old peeps Flashcards
What is Aging?
Universal and progressive physiologic process
* Decreasing end-organ reserve
* Decreased functional capacity
* Increased homeostatic imbalance
* Increasing incidence of pathophysiologic processes
S3
Nervous system and aging
Memory decline is related to inability to complete ____.
ADL’s
*40% of people > 60 y/o
Not inevitable
S5
Nervous system and aging
Changes in the nervous system associated with aging include what three things?
- Cerebral Atrophy
- ↓ Gray matter (neuronal shrinkage - there’s only a small amount of loss)
- ↓ White matter (increase in ventricular size on kahoot, and progressive loss of memory, balance and mobility)
WAG
S6
Brain ventricle size will ____ with age.
increase
S6
Nervous system and aging
Which of the following neurotransmitters show a decrease associated with aging?
Dopamine
ACh
NE
Serotonin
Glutamate
Dopamine
ACh
NE
Serotonin
Glutamate is unchanged
S7
Coupling of CMRO₂, CBF, and EEG is increased or decreased due to aging?
Trick question. CMRO₂ and CBF, decrease in a parallel fashion therefore the EEG remains unchanged secondary to aging.
S7
Neuraxial changes
Is epidural space increased or decreased due to aging?
Decreased
S8
Neuraxial changes
What occurs with dura permeability secondary to aging?
Dura permeability increases. therefore less of a dose to get to therapeutic level
S8
Neuraxial changes
What occurs with CSF volume secondary to aging?
Volume of CSF decreases. less dilution of agent
S8
neuraxial changes
What two changes are seen in myelinated fibers of dorsal and ventral nerve roots secondary to aging?
↓ diameter of roots
↓ number of roots
this increases susceptibility of block
S8
Elderly patients are more/less sensitive to neuraxial and peripheral nerve blocks?
more sensitive
S9
Peripheral
Decreases in what two characteristics of the peripheral nervous system are noted secondary to aging?
- Inter-Schwann cell distance
- Conduction velocity
A shorter internodal length leads to fewer “jumps” and therefore a slower conduction velocity
S9
thump-thump
What cardiac changes are noted due to aging?
- ↓ myocyte number
- ↓ SA node cells (tachy or brady syndromes)
- ↓ conduction velocity
- Thickened LV & aortic valve
- ↓ contractility
- ↓ β-adrenergic sensitivity
- ventricular stiffness which leads to higher filling pressures
Maya Sits Very Left And Contradicts Bill’s Views
S10-11
thump-thump
What happens to vasculature as we age? Why?
Vessels become more stiff
- ↓ collagen & elastin
- ↓ Nitric Oxide vasodilation
- early wave deflection - increased afterload, diastolic dysfunction
NO Catching Waves
s12
The tennis court
What two physiologic factors are decreased in the lungs as we age?
- ↓ Elastic recoil
- ↓ Surfactant
S13
Tennis court
What anatomic structures of the lungs become enlarged as we age? What is the result?
- Bronchioles and alveolar ducts become enlarged
-
early collapse of small airways during exhalation.
- ↑ anatomic dead space
- ↑ closing capacity (AKA the CC volume is greater than a young lung)
- impaired gas exchange
S13
tennis court
Loss of vertebral height and calcification of vertebrae lead to what three respiratory system consequences?
- Barrel chest
- Diaphragmatic flattening
- Chest wall stiffening (increased WOB)
CBD
S14
tennis courts
Will the following see an increase or a decrease due to aging-related lung changes?
- Vital Capacity
- Closing Capacity
- Residual Volume
- Total Lung Capacity
- ↓ VC
- ↑ CC
- ↑ RV
- TLC about the same
S15
tennis courts
Decreased muscle mass and increased closing capacity will make FEV₁ decrease by ____% per decade.
6-8%
S16
tennis courts
What are the results of weaker pharyngeal muscles from aging-related changes?
- ↓ secretion clearance
- ↓ esophageal motility (aspiration risk)
- ↓ protective upper airway reflexes
- Inefficient coughing (suction aggressively)
SEPI
S16
tennis courts
Whats the most important mechanism of action for aging-related A-a gradient changes? (V/Q)
FRC & CC mismatch increasing
Increasing shunt w/ decreasing arterial oxygenation.
S17
The beans
What renal consequences are there to aging?
- ↓ GFR (comorbidities may exacerbate)
- ↑ Urinary retention
- ↑ UTI’s
- Blunted response to aldosterone, vasopressin & renin (trouble adjusting to fluid and e-lytes)
UUG RAV
S18
GFR drops about ____ per decade over 50 yo
10 mL/min
lecture Dr M
Butts and guts
Which phase of liver metabolism is more affected by aging?
Phase I more impaired: oxidation, reduction, hydroysis via CYP450)
Phase II ok: acetylation and conjugation
S19
I guess I remember these words 😅
butts and guts
What are the components of Phase I liver metabolism?
- Oxidation-Reduction
- CYP450 Hydrolysis
meds that are metabolized through phase 1 have the most compromise anesthesia and narcotics will have a prolonged affect
S19
butts and guts
What is the mechanism for increased PONV in the elderly?
Trick question. Less PONV in the elderly.
Avoid Prochlorperazine, promethazine, & metoclopramide.
zofran is your BFF for the oldies
S19
dem bones
With aging, muscle mass and strength will ____ while subcutaneous fat will ____. With the msk system we also see ____ wound healing and ____ of dem bones
- decrease
- decrease (hard to thermoregulate)
- impaired
- osteoarthritis
S20
What is the vasoconstriction threshold?
Thermoregulation and the temp in which the body begins to vasoconstrict
* is it comparable in infants, children and adults
* 1 degree C less for adults over 60yo
S21
operative risk
FYI slide
- US adults aging
>65 increasing rapidly over next 3 decades - What is ”old age”
- Denney/Denson….high mortality 90 y/o and up
- Djokovi/Hedley-Whyte….ASA status predicted mortality
- Del Guercio/Cohn…uncorrectable comorbidity in SICU; 100% mortality
- Finlayson et al. high mortality from nursing home residents
S23
What are 6 significant predictors of 6month & 1 year mortality for the elderly?
- Impaired cognition
- Recent fall
- ↓ Albumin
- Anemia
- Functional dependence
- Comorbidities
FACIA-R
S24
the vulnerable brain
How does neuroinflammation happen with the eldery in surgery?
S25
Neurotoxicity factors
What four factors are thought to be involved in the pathogenesis of dementia?
- Amyloid beta plaques
- Tau
- Ca⁺⁺
- Neuroinflammation (TNF and IL)
CANT
S25-26
Where do amyloid beta plaques accumulate intracellularly?
Trick question. Amyloid accumulates extracellulary.
S27
What are amyloid plaques thought to do in the CNS?
- Originally thought to be toxic (now not so much?)
- May Disrupt cell membranes
- they are a fragment of synaptic origin
Function actually unknown, synaptic origin.
S27
What results were seen (regarding amyloid β) with mice who were administered volatile anesthetic?
- Studied with halothane
- Young mice had improved memory/learning after halothane exposure
- Old mice had accelerated dementia
More study necessary - unclear translation to humans.
S28
What medication class can cause a significant increase in amyloid plaques?
Volatiles Anesthetics
S28
Tau
What is the neurofibrillary tangle?
- Phosphorylated and aggregated 𝜏 protein
- Destabilizes microtubules
- Decreases in temperature 2-3 degrees C increases amount of 𝜏
tauopathy
PAMT
S29
Tau
What is destabilized by neurofibrillary tangles?
Microtubules
S29
Tau
Decreases in temperature by ___ °C will increase the amount of τ protein.
2-3 °C
S29
Tau
Repeated exposure to what drug class will cause an increase in phosphorylated τ protein?
volatile anesthetics (specifically halothane, isoflurane, & sevo)
increases phosphorylated tau
S29
Flip card to see graph of Amyloid and Tau relations to symptoms.
S30
Release of what ion is exaggerated due to anesthesia? What receptors are involved?
Release of Ca⁺⁺ from ryanodine and IP₃ receptors of endoplasmic reticulum.
S31
Exaggerated Ca⁺⁺ release in the brain is thought to be linked to ______________.
neurotoxicity
S31
Volatile anesthetics are known to cause malignant hyperthermia, how does this relate to Ca release and neurotoxicity?
- Neurotoxicity d/t increased calcium is hypothesized to be a less dramatic release of Ca++
- if we inhibit the Ca++ release, will this delay or decrease the neurotoxicity?
- one school of thought is that the pt may have a genetic sensitivity that may have a RYR defect - but less dramatic than MH
- dantrolene? as a Ca++ inhibitor prophylactcally?
S31
Does dantrolene cross the blood brain barrier?
No
S31
Neuroinflammation contributes to cognitive decline through the release of which three inflammatory factors?
- Cytokines
- IL-6
- TNFα
S32
What anesthetic drugs (mentioned in lecture) could be used to counteract inflammation?
Sus, because I checked and only one of these crosses the BBB.
Dexamethasone
Ketorolac
Lidocaine (actually can cross BBB)
S32
General anesthesia (especially in older populations) is thought to contribute to ______.
POCD (Post-op cognitive dysfunction)
depends on the drug, duration of exposure and magnitude of exposure
S33
What gas is thought to contribute the most to POCD?
Isoflurane > desflurane > propofol
S33
What studies support the theory of anesthesia related to post-operative cognitive dysfunction?
Bedford 1955
“Adverse cerebral effects of anesthesia on old people”
1193 patients > 50 y/o
Received general anesthesia
Mental deterioration in 10% of these pts…long-term or permanent
S34-35
Anesthesia is ____ for POCD, whilst surgery is likely ____.
Causative; additive
Dr M
7 Anesthesia implications for the oldies
- Using neuraxial/regional anesthesia when possible
- Avoid long-acting NMBD and reverse adequately
- Opioid sparing strategies
- Neutralization of stomach acid with non-particulants
- Consider using EEG based titration
- Avoid hypotension
- Pad skin and nerves (pay special attention to body temp)
S37
What occurs to drugs due to decreased cardiac output secondary to aging?
- Slower distribution to site of action
- Slower redistribution
- Slower distribution to metabolic organs
S38
What neuromuscular junction changes contribute to drug challenges in an aging patient?
- ↑ distance between axon and motor end plate
- ↓ concentration of ACh receptors
- ↓ ACh in presynaptic vesicle
- ↓ ACh release
S39
What drug changes are seen in an aging patient regarding kidney/liver dependent metabolism?
- Prolonged drug effect
- Decreased drug need during maintenance
- Delayed recovery phase for non-depolarizing NMB’s
S40
What drug changes do we see if the drug is not dependent on Kidney or liver metabolism?
- No significant prolongation of effect
- Essentially same requirements during maintenance
- Essentially no delay in recovery phase
S40
What do we see specifically with pulmonary resection and the elderly?
- Mortality 80-92 y/o 3%
- Respiratory complications 40% (2x more than younger population)
- Cardiac complications 40% (3x more than younger population)
- Lobectomy mortality is more acceptable (especially with newer techniques)
- Pneumonectomy mortality excessive
S41
What is the algorithm for preoperative assessment of Thoracic surgery patients?
S42
How is predicted post-operative FEV₁ (PPO FEV₁) calculated?
(Preop FEV₁ %) x (1 - % of lung tissue removed/100)
S43
If: Preop FEV1 70% and RLL removed
ppoFEV1 = 70 x (1-29/100) = 50%
How many lung segments are there?
42 total
S43
How many lung segments are in the LUL?
10
S43
How many lung segments are in the RLL?
12
S43
How many lung segments are in the RUL?
6
S43
How many lung segments are in the RML?
4
S43
The right middle lobe and right lower lobe are resected in a critically ill patient. How much lung tissue was removed in this surgery?
16/42 = 38%
S43
Predict the post-operative FEV₁ for a patient who had their right lower lobe removed. The patients preoperative FEV₁ is 70%.
(Preop FEV₁ %) x (1 - % of lung tissue removed/100)
PPO FEV₁ =70 x ( 1 - 28/100) = 50
S43
What is the “triad” of preoperative thoracotomy assessment?
S44
How would the CRNA manage extubation on a post-thoracotomy patient if the PPO FEV₁ is >40% ?
If > 40%, extubate in OR if awake, warm, & comfortable (AWaC)
S45
How would the CRNA manage extubation on a post-thoracotomy patient if the PPO FEV₁ is 30 - 40% ?
Consider extubation based on:
- Exercise tolerance
- DLCO
- V/Q
- Comorbidities
S45
How would the CRNA manage extubation on a post-thoracotomy patient if the PPO FEV₁ is <30% ?
- Staged weaning from ventilator
- Consider extubation if >20% plus thoracic epidural anesthesia in place.
S45
