Geriatrics Flashcards
4 physiologic changes:
- Basal organ function unchanged
- Decreased functional reserve
- Decreased ability to compensate
- Hearing loss
Mechanism of aging for all organ systems:
Aging is associated with a loss of physiologic reserve that increases the vulnerability to disease
-decreases ability to compensate for stress
Risk of death double every what?
8.5 years
When one examines periop mortality, the risk of death also double with that?
Rough every additional decade of age
CV and autonomic aging makes BP inherently more unstable during anesthesia, primarily due to (3)
- Exaggerated responses to changes in ventricular filling
- Exaggerated responses to changes in sympathetic nervous system activity
- Impaired baroreflex control of BP owing to a decrease response to beta-receptor stimulation
Concomitant vascular disease may lead to what?
Organ hypoperfusion at BP that would be easily tolerate by a young, healthy adult
Baroreflex begins with high and low pressure baroreceptors that send info to where?
Medulla via vagus and glossopharyngeal nerves
The most prominent defect of the baroreflex in elderly subjects is the failure to mount as vigorous of what?
Cardiac response
Why is there a failure in cardiac response?
Decrease in beta-receptor responsiveness
The change in sympathetic nervous system activity that accompanies a change in BP is actually enhanced or declined with age?
Enhanced
Alpha receptor, vasoactive component of the baroreflex is effective or not effective?
Just as effective as in young adults, if not more so
Most prominent and consequential changes for CV are: (3)
- Decrease in response to beta-receptor stimulation
- Stiffening of the connective tissue in arteries, veins, and heart
- Increase in activity of the sympathetic nervous system
Less important changes of CV include: (2)
- Gradual myocyte death without replacement
2. Diminished response to atropine
Systolic HTN include: (3)
- Loss of elasticity in the arterial tree
- Ventricles that contract with good strength by more slowly than young hearts
- Poor tolerance of hypovolemia
What are the 3 diminished chronotropic and inotropic response to anything that involves beta-receptor stimulation?
- Exercise
- Exogenous catecholamine administration
- Baroreflex
L ventricular hypertrophy is due to?
Increased impedance to ejection of SV
Coronary artery disease with people > than what age have a what % chance of developing significant CAD?
70 years
50%
Decreased max HR attainable due to what 2 things?
- “Beta-blockade” that occurs with aging
2. Fibrosis/atrophy of the conducting system that occurs
Cardiac reserve is maintained by what?
Frank starling mechanism
CO increased by an enhance SV resulting from an increase of what?
End diastolic volume
Induction times of IV agents and inhaled agents?
IV agents: delayed
Inhaled agents: shorter onset
Frank starling mechanism is a dependence on a catecholamine mediated increase in what 2 things?
HR and inotrophy
Sarcomere stretch enhances the sensitivity of the contractile proteins to calcium, thereby increasing the strength of contraction
Frank starling mechanism
Ventricle response less effectively to what?
Beta receptor stimulation
Since ventricles response less effectively to beta receptor stimulation, then the ventricle must depend almost solely on what?
Frank starling mechanism
90% of 80 year old patients have what heart issue?
Regurgitation
Pacemaker cell reduced by 90% at what age?
70
What specific dysrhythmias increases with age?
Afib
Ability for old heart to withstand stress is significantly increased or decreased?
Decreased
Max body oxygen consumption is the product fo what 3 things?
- CO
- Oxygen carrying capacity of the blood
- Ability of the body to extract oxygen from the blood
With age, max oxygen consumption decreases at approximately how much per decade? And decline steepens after what age?
10%; 60
Decrease in max CO is the primary contributor to the decline owing to the decrease in what?
Max HR
Rule of thumb for max HR?
220 - age
There is a moderate decrease in resting what with age?
SV
Do hemoglobin levels decrease with age?
No
Ventricles must overcome what in order to eject blood?
Aortic pressure
The strength of a given contraction is largely determine when during a contraction?
Beginning
If most of the effort of the contraction is used up just to overcome aortic pressure, what does the SV look like?
Very little
The ventricle must increase its contractile effort and will do so by what 2 things?
- Increasing contractility
- Increasing end-diastolic volume to increase the sarcomere stretch (Frank-Starling curve or length-tension relationship)
OR BOTH
The inability to increase contractility as easily as in a young heart makes the elderly heart more dependent on what?
Ventricular filling
One can expect the elderly heart to be less tolerant to what?
Hypovolemia
Elderly patients have decline in what 2 things at peak exercise?
SV and HR
Inability of these individuals to augment stroke volume is caused by: (4)
- Decrease in the ability of the heart to increase diastolic filling
- Decrease in systolic pump function caused by an increased afterload
- Intrinsic myocardial contractile defects
- Greater diminution of the cardiovascular response to beta-adrenergic stimuli
During exercise, mixed venous oxygen levels increase or decrease and why?
decrease dramatically, mostly because exercising muscle is capable of extracting as much as 90% of the delivered oxygen
Training improves maximal body oxygen consumption to the same or less degree in young and old and what does it improve?
Same; increase in LVED volume
Elderly women improve their oxygen consumption primarily by what?
increasing oxygen extraction
Two mechanisms cause this increase in systolic blood pressure (systolic HTN):
- Stiffening of the arteries typically leading to systolic hypertension
- The speed of transmission of the pressure wave
Approximately half of the stroke volume still remains where?
thoracic aorta at the end of ejection
a stiffened thoracic aorta will develop a higher or lower pressure with the increase in volume in comparison to a softer, more balloon-like aorta?
Higher
In the elderly, the pressure wave travels faster or slower through a stiff artery than a pliable artery
Faster
The wave pressure wave returns to the heart when?
Latter part of the ejection rather than diastole
The increased pressure in late ejection places a strain where?
LV
strength of the contraction does what during ejection progresses?
Decreases
In the elderly, the returning wave increases pressure when and what does that cause the heart to do?
Late in ejection so the heart must work harder to eject
Heart strain stimulates what?
Muscle growth
The systolic hypertension, particularly the late systolic hypertension, causes what?
Ventricular hypertrophy
The veins contain at least what % of the body’s blood?
75%
responsible for maintaining a relatively constant central blood volume (lungs and heart) despite changes in posture or changes in blood volume
Veins
If there is inadequate blood volume in the veins, venous pressure does what?
drops significantly in stiff veins and there is inadequate venous pressure to support atrial filling