Major Vascular II Flashcards
1
Q
What is an aneurysm?
A
A localized enlargement of an artery caused by a weakening of the arterial wall
2
Q
Multifactorial causes of an aneurysm.
A
- Adventitial elastin degradation
- Chronic inflammation
- Concomitant aortoiliac occlusive disease (20-25%)
3
Q
An aortic dissection is a rupture of which layer?
A
Intimal layer
This will create a false lumen and pooling of blood in the aneursym, tempoary tamponade.
Eventual expansion and rupture.
4
Q
Risk factors for Abdominal Aortic Aneurysm
A
- Frequent in elderly men (8%)
- Smoking
- Family history of AAA
- Atherosclerotic disease
5
Q
Risk factors for Thoracic Aortic Aneurysm
A
- Congenital syndromes
- Trauma
- Aortic cannulation
- Bicuspid aortic valve
6
Q
Risk of rupture R/T luminal diameter of aneurysm: 5.0 to 5.9 cm
A
3-15%
7
Q
Risk of rupture R/T luminal diameter of aneurysm: 6.0 to 6.9 cm
A
10-20%
8
Q
Risk of rupture R/T luminal diameter of aneurysm: 7.0 to 7.9 cm
A
20-40%
9
Q
Risk of rupture R/T luminal diameter of aneurysm: > 8.0 cm
A
30-50%
10
Q
The surgical mortality rate for abdominal aortic aneurysm
A
2-4%
11
Q
The surgical mortality rate for thoracic aortic aneurysm
A
20%
12
Q
The mortality rate of abdominal aortic aneurysm if ruptured prior to hospital admission
A
90%
13
Q
Risk of paraplegia with thoracic aortic aneurysm
A
4-40%
14
Q
Risk of renal failure with thoracic aortic aneurysm
A
3-30%
15
Q
Risk of respiratory failure with thoracic aortic aneurysm
A
8-14%
16
Q
Classify the aneurysm aneurysm.
Characteristics.
A
- Saccular Aneurysm
- Eccentric dilation
- Variably sized neck
17
Q
Classify the aneurysm aneurysm.
Characteristics.
A
- Fusiform Aneurysm
- Uniform dilation of the entire circumference
- More common than saccular aneurysm
18
Q
How are thoracic aortic aneurysms typically discovered?
A
Typically found on imaging and routine exams
19
Q
What are the symptoms of thoracic aortic aneurysm?
A
- Non-specific symptoms
- Hoarseness
- Stridor
- Dysphagia
- Upper body edema
- Acute, sharp pain
- BP pressure changes
- Absence of peripheral pulses
20
Q
What methods are used to diagnose thoracic aortic aneurysm?
A
- CXR: widened mediastinum
- CT/MRI
- TEE (easy and safe in acute dissection)
- Angiography
21
Q
What are the three aortic branches?
A
- Brachiocephalic trunk (Innominate Artery)
- Left common carotid artery
- Left subclavian artery
22
Q
What do the yellow arrows indicate?
A
- Widened mediastinum
- Thoracic aortic aneurysm
23
Q
Describe the type of aortic dissection and the percentage of occurrence.
A
- DeBakey I
- Stanford A
- Proximal
- 60%
24
Q
Describe the type of aortic dissection and the percentage of occurrence.
A
- DeBakey II
- Stanford A
- Proximal
- 10-15%
25
Describe the type of aortic dissection and the percentage of occurrence.
* DeBakey III
* Stanford B
* Distal (no involvement w/ ascending aorta arch)
* 25-30%
26
Classic abdominal aortic aneurysm triad.
* Hypotension
* Back pain
* Pulsatile mass
27
Most AAA will rupture into what space?
Left retroperitoneum
28
Why delay euvolemic resuscitation in AAA?
* Keep hypotensive to limit pressure into the false lumen
* Rupture can create a temporary retroperitoneal tamponade, slowing down the bleeding briefly.
29
The gold standard for diagnosing an AAA?
Angiography
30
Preop Anesthetic Management for Aneurysm Repair
* Assessment of Organ System (Previous MI, Cardiac, CABG/CEA, CHF, etc)
* Hx of COPD/Smoking (PFT/ABGs)
* Renal Protection (preop hydration, avoid low CO)
* Avoid nephrotoxic drugs (dye)
31
Anesthesia Induction Considerations for Aneurysm Repair
* Minimize hypertension/ rupture
* Consider DLT for exposure for TAA
* CVP/PAP/Flo-Trac
* A-line
* Hotline
* Warmer (underbody)
* Heparin/ACT/Reversal
32
The most common approach used in aneurysm repair
* Trans-peritoneal
* Aorta can be accessed through peritoneum
33
Complications with a trans-peritoneal approach for aneurysm repair
* More fluid shifts
* Ileus
* Pulmonary complications
* Longer ICU stay
34
When would a retroperitoneal approach (later border of left rectus muscle) be used in an aneurysm repair?
* Obesity
* COPD
* Previous abdominal surgeries
35
Complications with a retroperitoneal approach for aneurysm repair
* More hernias
* Chronic wound pain
* Poorer visualization
36
The benefits of using the retroperitoneal approach for aneurysm repair.
* Less fluid shifts
* Less pulm/abd issues
37
What will happen to SVR during intraoperative aortic clamping?
Increase SVR
38
What will initially happen to CO during intraoperative aortic clamping?
Decrease CO (no HR change)
39
Impedance to aortic flow will release ____________
Catecholamines
40
What is the change in renal vascular resistance from aortic clamping?
Resistance increases by 70%
41
Aortic clamping will activate vasoconstriction, which will have what effect on preload?
Increase preload
42
Interventions to mitigate the effects of aortic clamping.
* Small boluses of vasodilators prior to clamp (Nitroglycerine/Cardene)
* Preload alteration
* Normalize/ replace blood loss with PRBC as Hct drops
* Use of epidural catheter (vasodilation)
## Footnote
You are trying to get blood to leave the central circulation and go to the periphery to increase preload
43
What will happen to SVR during intraoperative aortic unclamping?
Substantial drop in SVR
44
What are the causes of hypotension from aortic unclamping?
* Blood pooling
* Hypoxia-mediated vasodilation
* Accumulation of metabolites
45
Interventions to mitigate the effects of aortic unclamping.
* Prepare for sudden hemodynamic collapse
* Fluids to CVP goal (fill up the tank)
* Decrease VA
* Small does of vasoconstrictor (neo pushes)
* Labs (ABG/Hct/K+)
* Ask the surgeon to unclamp judiciously
* Consider: Calcium, bicarb, low dose pressors)
46
Which arm will be used to measure NIBP during aortic clamping?
Right
47
Desired MAP above and below the aneurysm
* 100 mmHg above
* 50 mmHg below
48
What does a TEG measure?
* Viscoelastic properties of a clot
* Clot Strength
* Clot Formation efficiency
* Clot Fibrinolysis
49
What does the R-time of a TEG indicate?
Reaction time to clot formation
50
What does the K-time of a TEG indicate?
Time for the clot to achieve a certain clot firmness
51
What does the α-Angle of a TEG indicate?
Rate at which clot develops
52
What does the MA of TEG indicate?
Maximum strength of the clot/ platelet number
53
What does the LY30 indicate on a TEG?
Percent of clot lysis after 30 minutes
54
Which part of the spinal column reflects the sensory tracts?
Dorsal spinal column
55
Which part of the spinal column reflects the motor tracts?
Anterior spinal column
56
When can local anesthetics be added to an epidural during an aneurysm repair?
After aortic unclamping and stabilization
57
Damage to the posterior spinal arteries will affect which tract?
Sensory Tract (Paresis)
58
Damage to the anterior spinal artery will affect which tracts?
Motor Tract (Paraplegia)
59
The artery of Adamkiewicz most commonly arises at the level of _________ (range)
T9 to L2
60
The anterior radicular artery is usually between these levels.
T9 to T11
61
What causes GI and renal ischemia during aneurysm repair?
↑ SVR and ↓ CO when aortic clamps are on
62
Clamp distal to left subclavian artery will have what percent decrease in renal flow?
What about clamps applied below the kidneys (infrarenal)?
* 90% decrease in flow (distal to left subclavian)
* 30% decrease (infrarenal)
63
The benefits of using a left heart bypass to maintain lower body perfusion during aneurysm repair.
* Allows adjustment of flow
* Oxygenator unnecessary
* Relieves ↑ afterload
* Full bypass dose of heparin not required
64
Why would deep hypothermic circulatory arrest (DHCA) be used in aortic aneurysm repair?
* Brain protection
* Improved Visualization
* Blood control
65
Body temp for DHCA?
18-20 C
66
Blood flow for DHCA?
400-500 cc/min
67
How long can a body be in DHCA before a significant increase in brain injury?
* 30 mins
* Anything over 40 mins can hurt the brain
68
What area does an endovascular aneurysm repair focus on?
Descending thoracic aorta and abdominal aorta
69
Complications that may arise if a stent is placed in areas where the aneurysm has a high-pressure aortic flow?
* Kinking
* Structural Failure
* Device Migration
70
Anesthesia Management of Endovascular Aneurysm Repair
* General/regional/sedation
* Arterial line
* Large bore IV access
* Blood availability
* Heparin/ACT/Protamine like any vascular procedure
71
Complications of Endovascular Aneurysm Repair
* Endoleaks
* Vascular injury during deployment
* Inadequate sealing
* Migration
* Frame fracture
* Thrombosis of stent
72
What does ALARA stand for in radiation safety?
As Low As Reasonably Achievable
73
Contrast dye can increase creatine by how much?
25% increase in Cr usually 2-3 days post-op
## Footnote
Limit contrast amount
Provide adequete hydration
74
Risk factors for contrast-induced nephropathy
* Contrast load
* Pre-existing disease
