Vascular Anesthesia Flashcards

1
Q

3 layers of arterial wall structure

A

Intima (inner layer made of endothelial cells)
Media (contains muscular elastic fibers)
Adventitia (outer CT)

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2
Q

True aneurysm

A

Localized dilatation of an artery including all the layers of the wall

Aneurysm contained inside endothelium

Usually consequence of arterial wall congenital or acquired deficiency

WALL OF ARTERY FORMS ANEURYSM
at least 1 vessel layer is still intact

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3
Q

fusiform

A

circumferential, relatively uniform in shape

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4
Q

Saccular

A

pouch like with narrow net connecting bulge to one side of arterial wall

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5
Q

Aortic dissection

A

MEDICAL EMERGENCY- quickly leads to cardiac failure, rupture of aorta, death

tear in inner wall of the aorta causes blood to flow between the layers of the wall of the aorta, forcing the layers apart

Associated with: HTN, known thoracic aortic aneurysm, Marfan’s syndrome, Ehlers-Danlos syndrome, Loeys-Dietz syndrome

Severe chest or abdominal pain “tearing” inside aorta BF between levels = painful

vomiting, sweating, and lightheadedness may occur

quickly leads to death as a result of not enough BF to the heart or rupture of the aorta

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6
Q

Marfan Syndrome

A
genetic CT disorder 
Abe Lincoln appearance 
(elongation of face is a major clue)
major CV abnormalities:
-heart valves and aorta
-lungs, eyes, dural sac, skeleton, hard palate 
prophylactic ABx
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7
Q

Thoracic Aortic Aneurysm 3 types

A

ascending aorta
transverse arch
descending aorta

ALL UP IN CHEST (THORACIC)

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8
Q

Thoracic Aortic Aneurysm symptoms

A

pain in jaw, neck, and/or upper back
pain in chest and/or back
wheeze, cough, SOB = pressure on trachea
hoarseness = pressure on vocal cords
difficulty swallowing due to pressure on esophagus

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9
Q

ascending aortic aneurysm

A
begins at LV and extends to aortic arch 
age/degenerative disease of aortic wall 
uncontrolled HTN 
long term tobacco use 
inflammation or swelling of aorta 
infxn 
Hx of CT disorders 
Trauma 
family Hx 

typically also need an aortic valve replacement (aneurysm extends into valve and unseats it)

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10
Q

transverse aortic aneurysm

A

2:1 occurrence in male vs. female
50-75 y/o

etiology:

  • degenerative disease
  • atherosclerotic disease
  • chronic dissection

associated conditions:

  • aortic valve disease 30%
  • CAD 15%
  • COPD 20%

typically also need an aortic valve replacement (aneurysm extends into valve and unseats it)

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11
Q

Descending aortic aneurysm causes

A

atherosclerosis
HTN
traumatic injury
untreated infxn (salmonella and syphilis)
bicuspid aortic valve (2 leaflets instead of 3)
genetics (marfan, loeys-dietz, ehlers-danlos)
inflammatory conditions (giant cell arteritis, takayasu arteritis)

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12
Q

Descending aortic aneurysm symptoms

A
back pain or vague chest pain 
difficulty swallowing 
hoarseness 
difficulty breathing (compression on left mainstem bronchus)
cough
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13
Q

DeBakey System

A

anatomical description of the aortic dissection
categorized based on where the original intimal tear is located and the extent of the dissection

TYPE 1 = aneurysm in ascending, propagates at least to the aortic arch and often beyond it distally. Most often seen in patients less than 65 yrs and most lethal

TYPE 2
TYPE 3

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14
Q

The Stanford Classification

A

A and B

is the ascending aorta involved?
if yes, type A =

if no, type B =

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15
Q

Abdominal aortic aneurysms (AAA)

A

M to F = 4:1
Non-Marfan age = 55-75 (Marfan 35-55)
primarily atherosclerotic or marfan

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16
Q

Pre-op considerations

A

check LVH and ischemia on EKG

50% have pulmonary insufficiency

CXR - distortion of trachea and left main bronchus
pre-treat with bronchodilators
cessation of smoking
incentive spirometry (generating some CPAP, pre and post)
8-14% need tracheostomy
will see atelectasis

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17
Q

spinal cord perfusion

A

entire blood supply of SC depends on 2 sets of branches from dorsal aorta
Loss of supply to posterior portion of cord - lose sensory
loss of supply to anterior portion of cord - lose motor

18
Q

neurological considerations

A

incidence of SC ischemia 3.8% to 40%
depends on anatomic location, duration of cross-clamping, degree of dissection, rupture

sometimes done on bypass, get temp down from 37 to 22,

19
Q

Ascending Aorta Recipe

A

EBL 300-400mL
Position = supine
incision = medial sternotomy
Special instrumentation = A-line, CPB
Surgical time = aortic cross clamp 40-120min, CPB 70-150min, total 2.5-5h
Closing considerations = aggressive management of coagulopathy

20
Q

Ascending Aorta Recipe

A

EBL 300-400mL
Position = supine
incision = medial sternotomy
Special instrumentation = A-line, CPB
Surgical time = aortic cross clamp 40-120min, CPB 70-150min, total 2.5-5h
Closing considerations = aggressive management of coagulopathy

Post-op ICU intubated

21
Q

Transverse Arch Recipe

A

EBL = 400-700mL
Position = supine
Incision = medial sternotomy
Special instrumentation = A-line, CPB, hypothermic measures (barbs/propofol, steroids)
Surgical time = aortic cross clamp75-120min, circulatory arrest 30-45 min, CPB 3-4.5min, total 4-6h
closing = aggressive management of coagulopathy
Post-op ICU intubated
Mortality 10-15%

22
Q

Descending Aorta Recipe

A

Induction: prevent HTN with laryngoscopy, intro myocardial ischemia, Left DLT
Positioning: RLD, hips rotated posteriorly 45deg, left draped fwd, chest roll
Maintenance: varies at portions of cases refer to descending thoracic aneurysms

23
Q

Pre-op considerations

A

renal - possible aneurysmal renal artery involvement; 6% of patients need post-op dialysis
GI - possible aneurysmal involvement of mesenteric arteries
hematologic (PT/PTT/INR/Plt/Hct)
Premeds (anx, emergent - full stomach)
high mortality (30-60%)

24
Q

Intra-op considerations cross clamping hemodynamics

A

BV hasn’t changed but vascular space has changed

Blood below clamp back in venous side, valves, one way system
–> sudden relative hypervolemia
increasing pulm congestion and cardiac work bc extra volume
start NTG to vasodilator and encourage pooling of blood in legs and increase VR

build up lactic acid and metabolites below clamp

INCREASED PRE AND AFTER
increased aortic pressure proximal to clamp
decreased EF, CO, Renal BF
increased pulm. occlusion pressure, CVP, CorBF

25
Q

Intra-op considerations cross clamping metabolic changes

A
no BF to lower part of body 
DECREASE tb oxygen consumption/extraction
increase mvSaO2
decrease tb CO2 production 
metabolic acidosis 
epi and norepi 
resp alk
26
Q

amrinone

A

can increase contractility? may not increase cardiac contractility in diseased myocardium
vasodilator
not sure if id use it here

27
Q

beneficial intervention

A

depth anesthesia –> vasoDILATE

28
Q

Renal protection

A

mannitol

29
Q

fenoldopam

A

causes arterial vasodilation
rapid
decreases afterload

30
Q

influences on success

A

level of clamp= greatest impact if patient survives successfully
higher it goes, worse off it will be (preload)
LV function
vasodilator therapy
volume status
duration of clamp
pt temp

31
Q

AORTIC UNCLAMPING

A

decrease myocardium O2 supply and contractility
Decreased:
-ABP, CVP, PAP, VR, CO (sometimes up)
not usually hypovolemia but increased vascular space

32
Q

AORTIC UNCLAMPING hemodynamic changes

A

decrease myocardium O2 supply and contractility
Decreased:
-ABP, CVP, PAP, VR, CO (sometimes up)
not usually hypovolemia but increased vascular space

33
Q

AORTIC UNCLAMPING

A

re-perfusion
increase tb O2 consumption
decreased mvSaO2

34
Q

AORTIC UNCLAMPING

A
re-perfusion
increase tb O2 consumption 
decreased mvSaO2 
increased prostaglandins 
decreased temp 
increased lactate 
metabolic acidosis
35
Q

preemptive therapeutic interventions

TANKS when unclamp

A

insure adequate volume
-increase filling pressures, replace BL, increase fluid administration

DECREASE VA 
DECREASE vasodilators (NTG)
increase vasoconstrictors 

reapply cross clamp for severe hypotension
consider mannitol
consider NaBicarb (usually not)

36
Q

Emergence

A

BP should be closely controlled to decrease bleeding from graft site
adequate pain control
regional???

37
Q

Anesthesia for AAA

A

preserve myocardial, renal, pulm, CNS, visceral organ function
maintain adequate intravascular volume and CO
control BP so as to not cause rupture
anticipate surgical maneuvers that will effect BP and BV

38
Q

Pre-op considerations AAA

A
resp: many have COPD
CV: CAD most common co-ex, BP control 
Renal: know whether aneurysm is supra or infra renal 
hematologic: PT/PTT/INR/plt/Hct 
premed - anx and full stomach, reflux
39
Q

intra-op considerations AAA

A
induction
 low and slow but adequate 
vasoactive drips ready 
patient may be very labile 
minimize stimulation of intubation 

Maintenance
N2O ok but may cause bowel distention
GA with epidural offers good abdominal relaxation
warm patient, large incision but turn off bair hugger when cross clamped (could get 2nd degree burn)

Blood and fluids 
anticipate large BL 
IV 14ga or 7fr x2
rapid infuser, cell saver 
type and cross 8-10 PRBCs 
warm fluids and humidify gases 
maintain UO 
crystalloid and colloid use
40
Q

aortic cross-clamping in general

A

increase preload

increase CVP, pulm occlusion pressure, LVEDP, LV wall tension, segmental wall motion abnormalities
decrease EF and CO

Increases afterload
increase ABP, increase filling pressure, CorBF
decreased perfusion to viscera below the clamp
negative inotropic agents should be used cautiously
check ABGs and electrolytes

ALL WARMING DEVICES BELOW LEVEL OF CROSS CLAMP SHOULD BE OFF DURING CLAMPING TO AVOID THERMAL INJURY

41
Q

intra-op considerations aortic unclamping

A

relative hypovolemia
decreased afterload
lactate washout
surgeon can re-clamp