Vascular Anesthesia Pt. 3 (Exam II) Flashcards
1
Q
What are some of the multifactorial reasons for why a vascular aneurysm may form?
A
- Adventitial Elastin Degradation
- Chronic Inflammation
- Concomitant Aorto-iliac Occlusive Disease
2
Q
What is, definitionally, a vascular dissection?
A
A rupture of the intimal layer of a vessel
3
Q
What are risk factors for an abdominal aortic aneurysm?
A
- Elderly male
- Smoking
- Family hx of AAA
- Atherosclerotic disease
4
Q
What are risk factors for a thoracic aortic aneurysm?
A
- Congenital syndromes
- Trauma
- Aortic cannulation
- Bicuspid Aortic Valve
5
Q
What size cm aneurysm is associated with the lowest risk (<0.5%) of rupture?
A
< 4 cm
6
Q
What size cm aortic aneurysm is associated with the highest (30 - 50%) chance of rupture?
A
8cm or greater
7
Q
What are the mortality rates for abdominal aortic aneurysms?
A
8
Q
What are the risk percentages associated with thoracic aortic aneurysms?
A
9
Q
What kind of aneurysm is depicted below?
A
Saccular
10
Q
What kind of aneurysm is depicted below?
A
Fusiform
11
Q
What type of aneurysm is characterized by eccentric dilation and a variably sized neck?
A
Saccular
12
Q
What type of aneurysm (saccular or fusiform) is more common?
A
Fusiform
13
Q
What type of symptoms might suggest a thoracic aneurysm?
A
- Hoarseness
- Stridor
- Dysphagia
- Upper body edema
- Acute, sharp pain
- BP changes
- Absence of peripheral pulses
Very non-specific.
14
Q
What is suggested by the chest x-ray below?
A
Thoracic aneurysm
15
Q
Aortic Aneurysm Classification Chart
Memorize.
A
16
Q
What is the classic triad of AAA symptoms?
A
- Hypotension
- Back pain
- Pulsatile mass
17
Q
What space do most AAA’s rupture into?
A
Left Retroperitoneum
18
Q
What three factors help avoid renal injury during aortic repairs?
A
- Preop hydration
- Avoidance of ↓CO
- Avoidance of nephrotoxic drugs (i.e. dye)
19
Q
What are the cons associated with a trans-peritoneal AAA repair approach?
A
- More fluid shifts
- Possible ileus
- Possible pulmonary complications
- Longer ICU stay
20
Q
What are the pros associated with a retroperitoneal AAA repair approach?
A
- Less fluid shifts
- Less pulmonary & abdominal sequelae
21
Q
What are the cons associated with a retroperitoneal AAA repair approach?
A
- More hernias
- Chronic wound pain
- Poorer visualization
22
Q
Where is incision made with a retroperitoneal AAA repair approach?
A
- Lateral border of left rectus muscle
23
Q
What patient conditions might indicate a retroperitoneal AAA repair approach?
A
- Obesity
- COPD
- Previous abd surgeries
24
Q
What is the first immediate consequence of aortic clamping?
A
↑SVR
25
What occurs due to the increase in SVR from aortic cross clamping?
- ↓CO
- Catecholamine release
- ↑ renal vascular resistance
- ↑ preload
26
How long do renal hemodynamic changes last beyond unclamping?
- 30 min
27
Post-operative mortality in AAA repairs will quadruple if what condition secondary to aortic cross clamping occurs?
Acute Renal Failure
28
What two hemodynamic "things" are needed once the aorta is cross-clamped?
- ↑ Contractility
- Coronary flow
29
What are some things we do just prior to aortic clamping?
- Small bolus of vasodilator
- Normalize/replace blood loss
- Consider epidural catheter
30
Why are vasodilators used to prior to aortic cross clamping?
This helps move blood to the periphery and thus increase preload & perfusion post-clamping.
31
What major hemodynamic changes occur with aortic unclamping?
- Substantial ↓SVR
- Hypotension
32
What is the cause of hypotension post aortic clamping?
- Blood pooling
- Hypoxia-mediated vasodilation
- Accumulation of metabolites
33
What drugs can help us prevent severe hypotension on aortic unclamping?
- Ca⁺⁺
- HCO₃⁻
- Low-dose pressors
- ↓ VAA's
34
Encouraging the surgeon to unclamp _____ can help prevent hemodynamic collapse.
gently (or judiciously)
35
Where is the upper aortic clamp typically placed in a AAA repair?
- Distal to subclavian artery
- Inbetween subclavian & common carotid
*
36
Where would you place an art line for an Aortic repair requiring clamping?
Right arm or right femoral
(Left subclavian and left femoral will be occluded).
37
A MAP of _____mmHg is preferred above the aortic clamp.
100 mmHg
38
A MAP of _____mmHg is preferred below the aortic clamp.
50 mmHg
39
An ACT of _____ish or greater is required in aortic surgeries.
250
40
TEG Review Cards
41
Which type of evokes would be useful for tracking any damage to the dorsal column?
SSEP's
Sensory = Dorsal column
42
Which part of the spinal cord is typically more damaged by aortic clamping?
Anterior portion of spinal cord
MEPs = **impractical due to NMBD usage**.
43
What is the study consensus on the usage of mannitol, dopamine, and fenoldopam for the purpose of renal protection in AAA repair cases?
All of the above drugs show inconclusive evidence for renal protection.
44
What is used postoperatively for AAA repair pain?
Epidural catheter
45
Why are epidural opioids preferred over LA in epidurals for AAA repair patients?
- LA's are implicated in more hypotension and thus anterior spinal artery syndrome.
46
What is anterior spinal artery syndrome?
Condition of paraplegia, back pain, loss of temperature and pain, and autonomic dysfunction below the level of aortic clamping.
47
When can local anesthetics be utilized in an epidural for aortic repair?
After unclamping and stabilization of blood pressure
**I.e. postoperatively**.
48
What major radicular artery comes off around T9 - T11?
Artery of Adamkiewicz
49
What technique can be used to help prevent post-operative paraplegia from clamping affecting the artery of adamkiewicz?
- Spinal catheter draining CSF (less CSF = more room for hematoma formation, etc.)
*Not a routine method*.
50
A clamp placed distal to the left subclavian results in a ___% decrease in renal blood flow.
90%
51
A clamp placed infrarenal will result in a ___% drop in renal flow.
30%
*Though clamped below renal arteries, catecholamine release, metabolites, etc will effect renal flow*.
52
Is a full bypass dose of heparin required for left heart bypass for an aortic repair?
No
53
What technique is used for repair of a significant ascending aortic aneurysm?
DHCA (Deep Hypothermic Circulatory Arrest)
54
What temperature is targeted for DHCA?
18 - 20° C
55
How much is CO decreased to during ascending aortic aneurysm repair?
400 - 500 cc/min
56
How long is the safe zone for DHCA?
30min
*>40 min = brain injury*.
57
What is mortality for ascending aortic repairs requiring circulatory arrest?
10 - 15% (according to book)
58
What is the "R" time in the following TEG?
What is this "R" time dependent on?
- Time from start of test to initial fibrin formation
- Dependent on clotting factors
59
What is the "K" time in the following TEG?
What is this "K" time dependent on?
- Time from initial fibrin clot to to 20mm of clot strength
- Dependent on fibrinogen
60
What is the α angle in the following TEG?
What is this α angle dependent on?
- Measures the rate of clot formation
- Dependent on fibrinogen
61
What does MA stand for in the following TEG?
What is MA dependent on?
- MA = Maximum Amptidude (size & overal strength of fibrin clot)
- Dependent on platelets primarily (also a little fibrinogen).
62
What does MA stand for in the following TEG?
What is MA dependent on?
- MA = Maximum Amptidude (size & overal strength of fibrin clot)
- Dependent on platelets primarily (also a little fibrinogen).
63
What is the the LY30 on the following TEG?
- Percentage decrease in amplitude 30 minutes post MA.
- Showcases fibrinolysis
64
What is a normal TEG "R" value?
4 - 8 min
65
What is a normal TEG "K" value?
1 - 4 min
66
What is a normal α-angle?
47 - 75°
67
What is a normal TEG MA?
55 - 73 mm
68
What is a normal LY30%?
0 - 8%
69
What are some possible treatment options for the massively increased cardiac afterload from aortic clamping?
- ↑ Anesthetic (propofol or VAA)
- Nitroglycerin or Nitroprusside
70
What should be limited prior to aortic clamping in order to minimize a hyperdynamic cardiac state?
Fluids
(less preload = less contractility = less strain on heart)
71
What systemic change occurs from aortic unclamping?
Systemic Acidosis
72
What hemodynamic changes occur during aortic unclamping?
- ↓ sBP
- ↓ Contractility
- ↓ SVR
- ↓ preload
- ↓ CO
- ↓ pH
**Essentially everything drops**.
73
What is the treatment for aortic unclamping?
- ↓ Anesthetics
- Fluids
- Vasopressor boluses
74
Does nitroglycerin primarily decrease preload or afterload?
Primarily preload (though some arterial vasodilation occurs as well).
