vascular procedures 5/6 Flashcards
0
Q
what are positives of having an epidural during aortic surgery
A
- can blunt catecholamine response
2. less hypotension than spinal
1
Q
how long do you want to wait after doing patient epidural before giving heparin during procedure
A
2 hours
2
Q
what is the spinal risk of aortic cross-clamping
A
ischemia d/t interruption of great radicular artery (artery of adamkiewicz) which may lead to paralysis (paraplegia)
3
Q
what type of process is atherosclerosis
A
inflammatory process of arterial tree with endothelial dysfunction
4
Q
6 steps leading to aneurysm:
A
- plaque formation (stenosis or obstruction)
- thrombosis causes acute ischemia
- emboli from atheramatous debris
- decerase of distal blood flow
- weakening of the arterial wall
- aneurysm
5
Q
12 risk factors for aneurysm:
A
- HTN
- hypercholesterolemia and triglycerides
- genetic predisposition
- smoking
- heredity
- C reactive protein
- male gender
- caucasian
- sedentary lifestyle
- type A personality
- diabetes
- obesity
6
Q
what is takayasu’s arteritis?
A
called pulseless disease
it is an inflammatory disease of the aorta in which one or more branches of the aortic arch become occluded
7
Q
- what is thromboangitis obliterans?
2. who does it occur mostly in?
A
- a chronic vascular occlusive disease of peripheral arteries and veins (affects extremities)
- occurs mostly in smokers
8
Q
common sites for arthreosclerotic lesions:
A
- coronary arteries
- carotid bifurcations
- abdominal aorta
- iliac and femoral arteries
9
Q
s/s of atherosclerosis:
A
- intermittnend claudication (improves with activity)
- cramping
- tiredness
- pain
- weakness
10
Q
Management of atherosclerosis (medical & behavioral):
A
- exercise
- smoking cessation
- asa
- control HTN and DM
- antiplatelet therapy: (cox 2)
- adenosine diphosphate (adp)antagonists: (ticlid, plavix)
- glycoprotein (IIb/IIIa) inhibitor: (integrilin, reapro)
11
Q
surgican tx for atherosclerosis:
A
(revascularize the artery via:)
- stent placement
- transluminal angioplasty
- endarterectomy
- thromboctomy
- bypass procedure
12
Q
name 4 types of bypass procedures for atherosclerosis:
A
- aortofemoral
- axillofemoral
- femfem
- fempop
13
Q
what does the presence of collateral circulation provide in PVD patients
A
cardiovascular stability
14
Q
if a patient is on anticoagulants, what must you do as far as anesthesia?
A
reverse anticoagulation (ffp, vitamin k, protamine) prior to spinal or epidural or they will need GA
15
Q
monitoring for arterial bypass procedure
- what leads?
- blood pressure?
- GI/GU?
A
- II & V5
- arterial line
- foley and OGT
16
Q
crossclamping may cause the release of ‘what’ mediators which does ‘what’ to cardiac?
A
cross clamping causes the release of THROMBOXANE A2 which may lead to cardiac instability ( thromboxane is a vasoconstrictor)
17
Q
5 metabolic changes associated with crossclamping
A
- increased plasma catecholamines (epi and norepi are released-stimulate B1 receptors which increase HR and myocardial oxygen demand)
- acidosis (increase oxygen free radials, lactic acid, prostglandins, thromboxane, cytokines)
- activation of renin-angiotensin system
- neutrophil and platelet sequestration (causing blood clotting and constriction of vessels)
5 complement activation
19
Q
what symptoms may be seen with traction on mesentery of abdomen (Mesentary Traction Syndrome)?
A
- tachycardia
- hypotension
- decreased SVR
- increased C.O.
- facial flushing
20
Q
- what factors are released in response to major surgical stress?
what do they control?
A
- -cytokines (such as interlukin 1B, or 6)
- tumor necrosis factor
- plasma catecholamines
- cortisol - neuroendocrine responses and inflammatory responses (tachycardia, increased temp, leukocytosis, tachypnea, fluid sequestering)
21
Q
- what nerve monitoring should be done with aortic cross clamping
- what happens to cause nerve issues?
- what is the end result of blocking this artery?
A
- motor evoked potentials
- blocks the greater radicular artery (artery of adamkiewicz) which services the anterior (motor) portion of the spinal cord
- motor paralysis
22
Q
- what happens below the clamp?
- what does this accumulation cause
- what happens when the clamp is released?
A
- hypotension below the clamp causes the accumulation of metabolites of anerobic metabolism (serum lactate)
- accumulation of metabolites cause decreased SVR (vasodilation) and vasomotor paralysis
- release of cross clamp causes the SVR to decrese systemically and blood is sequestered into previously dilated veins (increased venous capitance) causing decreased venous return (in essence SEVERE hypotension).
23
Q
- what is the best method for the surgeon to release the clamp or bi-femoral clamps?
- what is it called when blood pressure drops during declamping?
A
- slowly or one at a time
2. “Declamping Shock Syndrome”
24
Q
what is the treatment PRIOR to the releasing the clamp?
A
- prehydrate
- turn off nitrates (nitro and nipride)
- work in some neosynephrine
25
what is the best cardiac monitor for AAA repairs?
TEE
26
1. what is the normal diameter of the aorta?
| 2. what is size or change that warrants surgical repair?
1. normal aorta=1.2-2 cm in diameter
| 2. 1.5x normal diameter (3 cm)
27
what is the primary focus of on a vascular case
cardiovascular stability
28
1. what chemical is released during cross clamp release?
2. what causes its release?
3. what does its release cause?
4. what is the only positive to its release?
1. venous endothelian-1
2. tissue ischemia
3. causes hemodynamic alterations; has a vasoconstricting and vasodilating effect on vessels
4. has a positive inotropic effect on heart
29
what items should you have ready for a AAA surgery?
1. iv fluids...
2. iv drips...
3. blood bank...
4. lab tubes...
5. syringes of what should be drawn up or available?
1. iv bags (.9 )spiked to blood tubing via blood warmer with LR on a level 1 infuser or pressure bags
2. nitro, nipride, dobutamine (or primacor), epi, norepi, neosynephrine
3. blood and blood products on hold
4. lab tubes for cbc, lytes, coags, T&C, LFTs
5. ephedrine syringe drawn up; also cacl-, nahco3, magnesium ivpb;
30
1. what monitoring should be done on a AAA repair patient?
| 2. what lines?
1. monitoring:
- ecg leads II and V5
- -PA catheter (swan) or vigileo for fluid calculations, SV, SVR, LVSWI
- -TEE if available (to monitor valves, left ventric fxn and wall motion (EF)
- -defibrillator patches
2. lines:
- -arterial line (a must!!!)
- -central line/ cordis (for PA catheter insertion)
- -2 large bore (18g) IVs (along with CL)
- -foley
31
what happens to blood pressure during cross clamping?
goes up-hypertension
32
1. what happens to afterload during crossclamping?
| 2. what does this lead to?
1. afterload increases during cross clamping
| 2. this causes decreased C.O. and ventricular dilation
33
1. what could potentially happen to the kidneys during cross clamping?
2. what about spinal cord?
1. renal artery vasoconstriction
| 2. spinal cord ischemia (especially anterior/ motor) leading to paralysis
34
what happens to venous return during cross clamping?
venous return decreases
35
what happens to pulmonary pressures with clamp release?
pulmonary pressures increase (pulm HTN) with clamp release
36
what should you expect in regards to fluid loss with AAA repair?
large losses of ECF d/t evaporation, third spacing and large blood losses
37
where is the majority of blood lost thru
back bleeding from the lumbar and inferior mesenteric arteries after the vessels have been clamped and the aneurysm is opened
38
1. renal preservation: what can be done?
| 2. what is the best method of preventing renal failure?
1. diurese the patient to prevent renal damage
- -maintain CO and intravascular volume
- -renal dose dopamine or fenoldopam
2. preventing hypovolemia is the best prophylaxis against renal failure
39
1. what is the mannitol dose for renal
| 2. what is the action
1. 12.5 grams (200 mg/kg) over 3-5 minutes; give 20-30 minutes prior to aortic clamping
2. improves renal cortical flow during cross clamp
- -reduces ischemia induced renal vascular endothelial cell edema and vascular congestion;
- -acts as a scavenger of free radicals, decreases renin secretion and increases renal prostaglandin synthesis.
40
1. What gastrointestinal artery may become ischemic with cross clamping?
2. What part of the colon is affected?
1. Inferior mesenteric
| 2. Left colon
41
Systemic effects of cross-clamping:
- blood pressure?
- afterload? & C.O.?
- ventricles?
- spinal cord?
- renal artery?
- venous return?
- hypertension
- increased afterload causing DECREASED CARDIAC OUTPUT
- increased afterload leads to ventricle dilation
- potential spinal cord ischemia
- reflex renal artery constriction
- DECREASED VENOUS RETUR
42
Effects of clamp release:
- Pulmonary artery pressure?
- blood pressure?
- pH & lactate levels?
- PA PRESSURE INCREASES
- systemic HYPOTENSION
- sequestered lactic acid from legs is released decreasing pH ( some)
