Cardiac III pathophysiology Flashcards
(105 cards)
1
Q
6 general risk factors for perioperative cardiac morbidity and mortality for non-cardiac surgery?
A
High risk surgery
Hx of ischemic heart disease
Hx of CHF
Hx of cerebrovascular disease
DM
Serum creatinine > 2mg/dL
2
Q
What issue confers the greatest risk of perioperative MI?
A
Unstable angina (angina at rest)
3
Q
What are ACC/AHA guidelines for minimum time before elective surgery if a patient has had an acute MI, and why?
A
Minimum of 4-6 weeks from acute infarction should pass before elective surgery.
The highest risk of reinfarction is greatest within 30 days of an acute MI.
4
Q
AHA/ ACC guidelines based on surgical procedure classify which surgical procedures as high risk ( risk > 5 percent)?
A
Emergency surgery (especially in the elderly)
Open aortic surgery
Peripheral vascular surgery
Long surgical procedure with significant volume shifts and/or blood loss.
5
Q
Factors that reduce oxygen delivery?
A
Decreased Coronary Flow
Decreased Ca02
Decreased Oxygen extraction
6
Q
Factors that increase oxygen demand?
A
Tachycardia Hypertension SNS stimulation Increased wall tension Increased end diastolic volume Increased afterload Increased contractility
7
Q
Decreased coronary flow reduces oxygen delivery, what variables cause decreased coronary flow?
A
increased HR
increased end diastolic pressure
decreased aortic pressure
decreased vessel diameter (spasm or hypocapnia)
8
Q
The failing ventricle must have a defect in its ability to do what two things? (Heart failure)
A
fill and/or empty
9
Q
What is systolic heart failure?
A
The ventricle does not empty well
10
Q
What is diastolic heart failure?
A
The ventricle does not fill properly
11
Q
When the myocardium’s pumping action fails to satisfy the body’s metabolic demands this is known as?
A
Heart Failure
12
Q
What is the hallmark of systolic heart failure? (2)
A
decreased EF with an increased end-diastolic volume.
13
Q
What commonly causes systolic heart failure?
A
Volume overload
14
Q
What is the defining characteristic of diastolic dysfunction?
A
symptomatic heart failure with a normal EF
15
Q
The heart is unable to relax and accept the incoming volume because ventricular compliance is reduced, this is known as?
A
diastolic heart failure
16
Q
Cardiac remodeling can be reversed by what two type of drugs?
A
ACE inhibitors (-pril drugs)
Aldosterone inhibitors (spironolactone)
17
Q
What induction medication can cause issues as it reduces SNS tone while simultaneously reducing myocardial contractility in the CHF patient?
A
Propofol
18
Q
if a drug ends in -sartan then it is most likely what kind of drug?
A
angiotensin II receptor antagonist (ARB)
19
Q
if a drug ends in -pril then it is most likely what kind of drug?
A
ACE inhibitor
20
Q
If a drug ends in -dipine then it is most likely what kind of drug?
A
Calcium channel blocker
21
Q
If a drug ends in -zosin then it is most likely what kind of drug?
A
alpha adrenergic receptor blocker
22
Q
If a drug ends in -lol then it is most likely what kind of drug?
A
beta adrenergic receptor blocker
23
Q
How do a1 antagonists decrease blood pressure?
A
decrease vascular calcium leading to vasodilation
decreased SVR (afterload)
24
Q
What is inotropy?
A
contractility
25
what is chronotropic?
heart rate
26
what is dromotropy?
conduction velocity
27
what are the cardio selective B1 antagonists?
MAABE
metoprolol, acebutolol, atenolol, bisoprolol, esmolol
28
name the mixed a1/b1/b2 antagonist drugs (3)
carvedilol
labetalol
bucindolol
29
what is labetalol a:B antagonistic potency:
IV
PO
```
IV = 1:7
PO = 1:3
```
30
How do Beta blockers that block B1 receptors work (this would be all the beta blockers)
DECREASED: inotropy, chronotropy, dromotropy.
Decreased renin release by juxtaglomerular apparatus
31
All of the clinically used CCBs bind to what subunit of what channel?
alpha-1 subunit of the L- type calcium channel
32
If you want to reduce the HR in a patient with tachycardia, a-fib, or atrial flutter what two CCB would be your pick?
verapamil and diltiazem
33
Which two CCB target the myocardium mostly (compared to the vascular smooth muscle)?
verapamil
| diltiazem
34
Which calcium channel blockers are known to cause vasodilation which leads to decreased SVR?
end in -pine
35
Which CCB target vascular smooth muscle mostly?
end in -pine
36
In what type of patient would you want to preserve contractility while reducing the heart rate?
reduced EF patient
37
ranked from highest to lowest which CCB impair contractility?
verapamil
nifedipine
diltiazem
nicardipine
38
If a patient has decreased contractility which drug is a better choice than verapamil?
diltiazem
39
Which CCB is the only CCB proven to reduce M&M from cerebral vasospasm?
Nimodipine
40
which CCB is useful as a coronary antispasmodic?
Nicardipine
41
Which three vasodilators (CCB) are best used in the treatment of hypertension from elevated SVR?
Nifedipine
Amlodipine
Nicardipine
42
What is the preferred technique for pericardiocentesis?
Local anesthetic
43
If general anesthesia must be performed for a patient with pericardial tamponade then what is the best induction agent and why?
Ketamine, it preserves SNS tone / activates it which increases HR, contractility, and afterload.
The patient in tamponade has decreased contractility so they are dependent on HR and afterload for BP
44
Can you use opioids for pericardial tamponade anesthesia?
Yes, but avoid high dose opioids
45
What type of ventilation should be maintained for tamponade anesthesia and why?
best to maintain spontaneous ventilation, PPV can impair venous return and cardiac output.
46
HR goal in cardiac tamponade?
Maintain, since SV is reduced the CO is dependent on HR
47
Preload goal in cardiac tamponade?
Maintain or increase
avoid: PPV, hypovolemia, venous pooling
48
Contractility goal in cardiac tamponade?
Maintain or increase
Inotropes may be required
49
Afterload goal in cardiac tamponade?
Maintain
afterload is essential to compensate for decreased SV and CO
50
What is Amaurosis fugax?
blindness in one eye , which is a sign of impending stroke.
| this occurs to people with carotid stenosis
51
How does having carotid stenosis cause blindness in one eye?
Emboli travel from the internal carotid artery to the ophthalmic artery. This impairs perfusion of the optic nerve and causes retinal dysfunction.
52
What percentage of patients with high grade stenosis have blindness in one eye?
25%
53
During a CEA what is the best method to assess cerebral perfusion and neurologic integrity?
Awake patient
54
EEG monitors cortical electrical function, what does it not detect?
does not detect subcortical problems
55
Cerebral Perfusion Pressure = ?
MAP - CVP (or ICP whichever is higher)
56
Postoperative stroke after CEA is usually due to what?
The result of embolic phenomena - not hypotension or hyperperfusion
57
What is Embolic stroke treated with?
recombinant tissue plasminogen activator
58
Unstable angina is defined as?
Angina at rest,
new onset angina (less than 2 months),
increasing symptoms (intensity, frequency, duration) duration exceeds 30 minutes,
and symptom have become less responsive to medical therapy.
59
The highest risk of reinfection is greatest within how many days from acute MI?
within 30 days
60
ACC/AHA guidelines recommend a minimum of how many weeks before considering elective surgery in a patient with recent MI?
4-6 weeks
61
Best leads to monitor for intraoperative ST changes in a patient with previously normal EKG or no EKG on file?
(list in order of importance)
```
V3
V4
V5
III
aVF
```
62
If a patient has CAD then what are the best lead combinations to monitor with a five cable EKG and also a three cable EKG
Five cable : V3, aVF, MCL5 III
Three cable EKG: aVF and MCL5
63
When is lead II the best to monitor?
dysrhythmias with a narrow QRS where P wave analysis is critical for diagnosis
64
Intraoperatively if HR decreases and thus causes decreased 02 supply what can you do?
Give an anticholinergic or Pace the patient
65
Three causes of systolic HF?
MI
Valve insufficiency
Dilated cardiomyopathy
66
Is concentric hypertrophy part of systolic or diastolic heart failure?
concentric = diastolic heart failure
67
Does hypertrophic cardiomyopathy cause diastolic or systolic HF?
diastolic HF
68
Is the preload high or low already in systolic HF?
Already high (diuretics if too high)
69
Why is it best to use a TEE with diastolic HF?
LVEDP does not correlate with LVEDV
70
Formula for Coronary Perfusion pressure?
Aortic DBP - LVEDP
you may have to use a line or BP cuff diastolic in place of aortic DBP
you may have to use PAD in the place of PAOP which was taking the place of PAOP
71
```
Anesthetic considerations for systolic dysfunction includes?
preload:
afterload:
heart rate:
contractility:
```
preload: its already high, so don't let it get any higher
afterload: decrease to reduce the LV workload
heart rate: maintain high/normal range
contractility: Inotropic support as needed
72
rank the highest 02 consumption activities to the lowest. (5)
Heart rate = Pressure work > contractility > wall stress > volume work
73
Some calcium channel blockers target the vascular smooth muscle while others target the myocardium, tell me which ones target what and what that different targeting does?
dihydropyridines target mostly vascular smooth muscle and that decreases SVR
Non- dihydropyridines (diltiazem and verapamil) target the myocardium which decreases chronotropy, inotropy, dromotropy, and coronary vascular resistance
74
Tell me the two CCB that are potent vasodilators?
| Which one is available in IV form?
Nicardipine and Nifedipine
Nicardipine is available IV
They both decrease SVR
75
In Pulmonary hypertension is your PAOP elevated, normal, or low?
normal
76
In Cardiac tamponade tell me the characteristic hemodynamic data of your CPV, PADP, and PAOP?
ELEVATED (all of them)
77
In Left ventricular failure is your CVP elevated, normal, or low?
elevated
78
In acute respiratory distress syndrome is your CVP elevated, normal, or decreased?
decreased
79
What does administering protamine over 10-15 min do?
reduces the likelihood of systemic vasodilation as well as pulmonary vasoconstriction (both side effects of protamine)
The rate of injection does not impact the probability of anaphylaxis
80
Where does the artery of Adamkiewicz arise from?
typically T9-T12 and in 75% of the population on the left side
81
What is Becks syndrome?
When an aortic cross clamp is placed above the Adamkiewiz it may cause ischemia to the lower portion of the anterior spinal cord, resulting in anterior spinal artery syndrome or Becks syndrome. This manifests as flaccid paralysis of the lower extremities coupled with bowel and bladder dysfunction and loss of temp. and pain sensation.
Sensation and proprioception remain intact.
82
Thoracic cross clamp times greater than 30 min. pose significant risk for cord ischemia and protective strategies should be employed: what do these protective strategies include?
moderate hypothermia (30-32 degrees)
CSF drainage- CSF shunting from the brain towards the spinal column during clamping can exert excessive pressure on the spinal cord. (you want the spinal cord to have less fluid present)
Proximal hypertension during cross clamp (MAP - 100 mmHg)
Avoidance of hyperglycemia
Partial CPB (left atrium to femoral artery)
Drugs - corticosteroids, CCB, and or mannitol
83
What kind of drug is losartan?
oral angiotensin II receptor antagonist
84
How does losartan work?
it combats hypertension by antagonizing angiotensin II at the AT1 receptor. It does NOT affect the activity of angiotensin converting enzyme
85
What does losartan do to lithium reabsorption?
increases lithium reabsorption by the kidneys which can result in lithium toxicity
86
What does losartan and ACEIs do to maternal and fetal mortality?
increases maternal and fetal mortality.
87
What is a potential side effect of losartan?
potential for hyperkalemia, the risk is increased in the patient receiving potassium sparing diuretics
88
Who is more likely to have Brugada syndrome and what is it?
ion channelopathy in the heart. Common in males from southeast Asia. Diagnostic EKG findings include RBBB and ST segment elevation in the precordial leads V1-V3
89
What is the most common repolarization defect?
Long QT syndrome
90
What does your QT interval have to be in order to be considered long QT interval?
greater than 440 ms
91
What is a feared complication of long QT syndrome?
Torsade de pointes
92
What syndrome is described:
Pre-excitation syndrome that leads to paroxysmal SVT.
EKG shows short PR interval (less than 12 msec)
deltal wave
wide QRS complex
WPW syndrome
93
Too much aldosterone is produced what disease is this?
Conn's disease (hyperaldosteronism)
94
Too much glucocorticoid is produced what syndrome is this?
Cushing's syndrome (hyperadrenocorticism)
95
catecholamine secreting tumor - usually in the adrenal gland is known as?
Pheochromocytoma
96
Most common cause of secondary hypertension?
Renal artery disease
97
What is Hashimoto's disease
autoimmune disease that attacks the thyroid gland, causes hypothyroidism
98
Poiseuille's law describes what?
laminar flow through a tube.
99
What is Bernoulli's principle?
describes flow through a constriction. At the site of constriction, the fluid's velocity increase, creating a pressure drop at the point of constriction
100
Spinal cord blood supply consists of?
2 posterior spinal arteries (dorsal cord = sensory)
1 anterior spinal artery (anterior cord = motor)
101
The posterior cord, is it sensory or motor?
sensory
102
Anterior spinal artery syndrome is also know as what?
Beck's syndrome (NOT TRIAD)
103
S/sx of Beck's syndrome include:
flaccid paralysis of the lower extremities (motor)
Bowel and bladder dysfunction (motor)
Loss of temp. and pain sensation (impaired spinothalamic tract)
Touch and proprioception are preserved (intact dorsal column which is sensory)
104
What is Becks Triad and when does it occur?
distended jugular vein
hypotension
muffled heart sounds
consequence of cardiac tamponade
105
What is the one and only draw back of a centrifugal pump?
it lacks an occlusion point, if there is an excessively high afterload, blood backs up towards the venous circulation, which reduces the patient's circulating blood volume.
