Geriatric Pt- Lecture 1 Flashcards
What produces higher than anticipated plasma concentration of IV agents?
decrease in blood volume
What happens to Vd of H20 soluble meds in geriatric patients?
Vd decreases so plasma concentrations are higher than normal
What happens to the Vd of fat sol meds in geriatric population?
longer 1/2 life because of increase in body fat and may cause extension of pharmacologic properties and slower excretion from the body
Three theories of aging process?
1- programmed aging (killer gene), 2- telomere shortening, 3- gradual, cumulative process of damage and deterioration
What is “safety margin for function above basal needs?”
functional reserve
When does functional reserve peak? Then what happens?
30 years. Gradually declines over next few decades and experiences steeper decline after age 80
What simple test can you measure functional reserve w?
4 METs
What causes the decline in basal metabolism in geriatric pts?
change in body composition- less skeletal muscle, more fat
What happens to the total body water and how much does blood volume decrease in elderly?
decreases; 20-30%
Why are elderly patients more susceptible to hypotension with shifts in position?
decreased blood volume and decreased total body water
What is one thing that stays intact in the elderly CNS system?
autoregulation
What 5 things decrease in the elderly CNS?
brain mass (primarily frontal lobe of cerebral cortex), # of neurons, synthesis of NTs, synthesis of functional receptors, CBF
What structure that affects thermoregulation in CNS does not function well in elderly?
hypothalamus
Why does hypothermia last longer in elderly? What does hypothermia d/t anesthetic elimination?
less effective peripheral vasoconstriction, decreased basal metabolic rate, high ratio of surface to body ratio mass; slows it, prolongs recovery, impairs coagulation, increases chance that pt will shiver (increases O2 consumption 400%)
How much should Propofol doses be lowered in elderly?
15%
MAC decreases how much per decade?
6%
Is the elderly heart more or less compliant?
less
Why is atrial contraction more important in maintaining adequate ventricular filling in the elderly patients?
because the combination of ventricular hypertrophy and lower myocardial relaxation result in late diastolic filling and diastolic dysfunction
Why is HTN common in elderly and what type of HTN is it (concentric or eccentric)?
common d/t loss of ventricular elasticity; concentric
Do elderly have a decreased, same, or increased amt of catecholamines?
increased
3 reasons why elderly have difficulty increasing CO
diminished baroreceptor responses, endogenous physiological beta blocked, reduced efficacy of beta agonists
What do the cardiovascular changes in the elderly do to drug circulating time?
prolong it
What type of onset do IA versus IV drugs have in elderly?
faster with IA, slow onset of IV drugs
What leads to loss of vascular elasticity in elderly?
decrease in elastin production and increase in collagen damage
What does decrease in elasticity and compliance do to PVR, afterload, and vascular system?
stiffens
What does the pulse pressure do in the elderly?
widen
What causes the overall stiffening of atria and ventricles?
loss of collagen
What is something that predisposes the elderly to arrhythmias?
calcification of conducting system, including loss of SA node
Patients with diastolic dysfunction, which is very common in the elderly, are dependent upon what for filling?
atrial kick
This corresponds to the amount of O2 consumed by a 70 kg male at rest (around 3 mL of O2/kg/min)?
MET
3 causes of higher BP in elderly?
increased PVR, decreased arterial elasticity, cardiac workload
What causes a decreased TV in elderly?
VC
Why is there an increased work of breathing?
inelastic chest and closure of small airways
At what age does the PaO2 decrease? And why?
75+ (PaO2 83); attributed to premature closing of small airways and decreased surface area for gas exchange so therefore, a VQ mismatch and less efficient gas exchange
What type of vent settings should you avoid in the elderly pt with increased wob?
avoid high pressure, high TV, consider PEEP, and lower FiO2
What causes the VQ mismatch?
increase in compliance
What type of response do the elderly have to hypercapnea and hypoxia?
diminished response
What is necessary for maintaining small airway diameter?
elastic recoil
Increased compliance does what to the airway diameter?
decreases/narrows and increases closing volume
Closing volumes exceed FRC at what age in erect position and what age in supine position?
65; 45
What can prevent small airway collapse?
greater lung inflation
Why are elderly patients at an increased risk for aspiration?
diminished protective airway reflexes
What type of change is seen in hepatic enzyme function in elderly?
little change
What happens to the liver size and blood flow in elderly?
decrease
Hepatic blood flow decreases what percentage per decade?
10%
At what age does liver volume begin to increase?
50%
What happens to the rate of hepatic plasma clearance?
reduced rate
How does elderly hepatic function affect drug reactions?
there is an increase in drug reactions w hepatic problems
What does the reduced rate of plasma clearance d/t hepatic ftn in elderly do to the clinical effects of most IV anesthetics?
prolongs the effects
What do you have to be mindful about with elderly and their livers and narcotics?
risk of respiratory depression
What are 4 exceptions to hepatic function in elderly prolonged effects of most IV anesthetics?
Cisatracurium, Atracurium, Suxxs, Esmolol
Vd of hydrophillic versus lipophillic drugs in elderly patients because of liver function
decreased Vd in hydrophillic, which is caused by increase in plasma concentration; increased Vd of lipophillic drugs caused by decrease in plasma concentration
What happens to the renal blood flow, renal mass, GFR, and labs in elderly?
decrease, decrease, decrease, remain unchanged
Decreased renal drug clearance particularly of hydrophillic or lipophillic drugs?
hydrophillic
Best indicator of renal drug clearance?
creatinine clearance
What type of response to renal changes in the elderly cause to aldosterone and ADH?
decreased response
Drugs with renal elimination have shorter or longer duration in elderly?
longer
Older patients have tendency to lose what electrolyte?
Na
What happens to PNS vs SNS tone/activity in elderly?
decreased PNS, increased SNS
What happens to SVR, SBP, SV, CO in elderly?
increase, increase, decrease, decrease
What happens to the size of central airway versus small airway in elderly?
increases, decreases
Decrease/increase in lung compliance and decrease/increase in chest wall compliance?
increase, decrease
Most everything in elderly decreases except for these 5 things:
storage size for lipid sol drugs, sympathetic neural activity, lung compliance, reserve vol and FRC, closing vol, and closing capacity
Midazolam has what 1/2 life in elderly?
6 hours versus 2 in younger person
Greater Vd does what to reservoir? Lesser Vd does what to plasma concentration?
increases; increases
Increased body fat means what endocrine wise?
insulin resistance
Elderly lose heat how much faster than younger adults?
twice
Skeletal muscle mass decreases around what percentage?
10%
What does decreased muscle mass do to resting O2 consumption and CO?
decrease, decrease
Why must you be careful with titration of muscle relaxants, especially Vec and Roc in elderly?
decreased liver mass and decreased skeletal muscle mass
Which compartment loses water more in the elderly-ICF or ECF?
ICF
Up to a __% decrease in plasma volume in elderly?
30
What does a decrease in plasma volume do to drug concentrations?
increases
Decreased plasma protein binding means what for those drugs highly protein bound?
increase in free plasma concentration
Risk to benefit ratio on those patients> 65 depend on what 4 factors?
age, physiological status and coexisting diseases according to ASA, whether surgery is elective or urgent, type of procedure and home care
What do you need to do to the dose of General, MAC, and local anesthesia in elderly?
DECREASE
Decrease dose of induction agents how much in older patient?
30-40%
What happens to the levels and duration of action with SAB in elderly?
get higher faster and last longer
Positives about regional anesthesia in elderly?
lower PDPH, lower incidence of hypoxemia if heavy sedation avoided, decreased DVT and blood loss
Negative about regional anesthesia in elderly?
post op residual paresthesias are more common
What is the most frequent type of anesthetic complication in elderly?
neurological
How long is cognitive decline after surgery reversible?
3 months
Post operative cognitive dysfunction is different from delirium how?
It’s a progressive development of symptoms and is subtle
Predictors of post operative cognitive decline?
age, low education level, preop cognitive impairment, depression, surgical procedure, low albumin, prior stroke or TIA
Most accurate indicator of kidney function in elderly?
GFR
Ratio of GFR to creatinine clearance decreases/increases in elderly?
decreases
4 preop lab tests reasonable for all geriatric pts?
BUN, Cr, Hg, albumin
What is the MET score for walking around house, take care of yourself, walk a block on level ground?
MET 1
MET score for doing light work around the house like dusting or walking dishes; climb a flight of stairs or walk up a hill?
MET 4
participating in strenuous sports is how many METs?
> 10
5 criteria for frailty scale?
weight loss, decreased grip strength, exhaustion, low physical activity, slowed walking speed
patients with severe nutrition risk should have nutrition support how many days prior to surgery?
10-14
