Geriatrics Flashcards
How does minute ventilation change in the elderly?
Increases (increased dead space > increased minute vent to maintain CO2)
How does lung compliance change in the elderly?
Increase (think COPD esque) ~ easier to inflate the lungs
Increase in a given volume for a given pressure
How does lung elasticity change in the elderly?
Decreases.
Elastic recoil is lost ~ this promotes small airway collapse.
>increased dead space
>Decrease alveolar surface area
>V/Q mismatch
> increased A-a gradient!
> reduced PaO2
How is chest wall compliance changed with age?
Decreased chest wall compliance.
Chest wall is stiffer and less tendency to expand.
>calcification of joints
>diaphragmatic flattening
>A:P diameter
>decreased intervertebral disc height.
>decreased muscle strength
How does old age alter the response to hypercarbia and hypoxia?
Chemoreceptors are less sensitive
> risk of Hypoventilation
>risk of apnea
> risk of resp failure
***consider bipap and cpap
How does old age affect protective airway reflexes?
Reduced efficacy of cough and swallowing.
> increased risk of aspiration
How does old age affect airway tone?
Decreased muscle strength
> risk of resp failure
> risk of upper airway obstruction
What lung components are INCREASED in old age?
FRC
Residual volume
Closing capacity
What lung components are decreased in old age?
Viral capacity
Inspiratory reserve volume
Expiratory reserve volume
FEV & FEV1
At what age does closing capacity surpass FRC in the supine position?
~ 45 years
At what age does closing capacity surpass FRC in the standing position?
~65
How does old age affect TLC?
Not much
* increase in Residual volume reduces viral capacity
What are the 4 most prevalent cardiac diseases in the elderly?
HTN
CHF
CAD
And MI
What are the best indicators of cardiac reserve?
Exercise tolerance and the ability to perform daily living activities
What is the most common cause of death for the elderly in the postoperative period?
MI
How does the arterial system change with age?
Loss of elastin and increased collagen
> ^SVR
> ^ pulse pressure
> ^ myocardial wall tension
> ^ LV thickness (concentric hypertrophy)
How does the venous system change with age?
Decreased
Loss of elastin and increased collagen
>capacitance fx is diminished
Changes in blood volume cause HUGE changes in pressure
How does myocardial compliance change with age?
Decreased
Impaired relaxation > diastolic dysfunction
>greater pressure to fill
>filling pressure > volume
> ^HR reduces filling time
What is so important in a non-compliant ventricle?
Atrial kick
**increased pressure in that atria can cause Afib (leads to a lack of priming)
How is myocardial hypertrophy?
Increased
Concentric hypertrophy (reduces compliance and impairs relaxation)
How does cardiac conduction change with age?
Decreased
Fibrosis of the conduction system
***loss of SA node tissue
(Increased likelihood of dysrhythmias)
What is Virchow’s triad?
Venous stasis
Hypercoagulability
Endothelial dysfunction
What is PRESERVED in the geriatric heart?
Systolic function
What is increased in the geriatric heart?
SVR
pulse pressure
Prolonged circulation time
What is reduced in the geriatric heart?
Diastolic fx
Stroke volume
HR
Decreased responsiveness to catecholamines
Decreased CO
How is autonomic fx in the geriatric patient?
Decreased.
>reduced baroreceptor activity
> Syncope
> greater Hemodynamic compromise following sympathectomy
How is the SNS tone affected in the geriatric patient?
Increased
**higher NE concentration in the plasma BUT reduced sensitivity
How is PNS tone affect in the geriatric patient?
Decreased
May limit anticholinergic ability
How does age affect the response to catecholamines?
Decreased
> impairs receptor density
> impaired B-receptor and adenylate cyclase coupling
> reduced ability to increase HR during hypotension/stress
How much does MAC decrease for each decade of life after 40?
6%
How much should the dose of IV agent he reduced for the geriatric patient?
30-40%
How does aging affect the neutransmitter activity of the brain?
Reduced activity of Ach, NE, DA, and GABA
How is brain mass affect in the geriatric patient?
Reduced! ~ but does not affect mental capacity
**Gray matter atrophies faster than white.
How does aging affect the peripheral nerves?
Decreased myelinated nerves
What is the most common CNS complication for the elderly?
Postoperative delirium
What are the traits of postoperative delirium?
Onset: early post-op period
Presentation: easy to identify (disordered behavior, perception, memory)
Risk factors:
> D: drugs
> E: electrolyte imbalance
> L: lack of drugs (withdrawal)
> I: infection
> R: reduced sensory input
> I: intracranial dysfunction
> U: urinary retention/fecal impaction
> M: myocardial event
Tx: treat underlying cause, antipsychotics, and minimize poly pharmacy
What are the traits of postoperative cognitive dysfunction?
Onset: weeks to months after surgery
Presentation: difficult to pinpoint (impaired concentration/ comprehension)
Risk factors:
> advanced age
> cardiac surgery
> long duration of surgery
> high asa status
> low education
Tx: no specific tx
How does the elderly patient response to neuraxial anesthesia?
> Increased sensitivity of nerve tissue to local anesthetics (decreased number of myelinated nerves, diameter and conduction velocity)
increased sensitivity to intrathecal anesthetics ~ reduced CSF
increased sensitivity to epidural anesthetics ~ reduced epidural space
increased difficultly placing blocks
**reduced response to epi test dose (greater risk of false negative response)
What factor remains the unchanged in the geriatric patient?
Serum creatinine
How does aging affect the kidney?
> Decreased renal blood flow
Decreased renal mass ~decrease glomeruli
Decreased creatinine clearance ~ reduced as a function of renal blood flow
GFR ~ decreases by 1 mL/min/year
decrease response to acid load
decreased aldosterone (inability to conserve sodium - risk of dehydration
decreased antidiuretic hormone response
Which protein production is increasing in a geriatric patient?
Alpha-1 acid glycoprotein
How does aging affect the liver?
> decreased hepatic mass
decreased hepatic blood flow
decreased perioperative hepatic function
decreased albumin production
decreased pseudocholinesterase production
decreased phase 1 reactions (phase 2 stay the same!)
decreased first pass metabolism
How does aging affect drug circulation?
Slower IV induction
Faster inhalation induction
How does aging adjust surface area to body mass ratio?
Increased d/t Reduced lean body mass
How does aging affect the total body fat?
Increased ~ increased Vd of lipophilic drugs
How does aging affect lean body mass?
Decreased
Less muscle causes:
> Decreased nasal metabolic rate
> Decreased total body water
> Decreased blood volume
> Decreased plasma volume
> decreased plasma binding (increased free fraction~ albumin; decreased free fraction of basic drugs ~ 1-acid glycoproteins)
> decrease rate of recovery from volatile anesthetics
What should the anesthetic provider anticipate for hydrophilic drugs in the geriatric population ?
Smaller Vd ~ higher than expected plasma concentration for a given dose
What is the most sensitive indicator of renal function and drug clearance
Creatinine clearance
