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Anesthesia for Vascular Surgery
TCU Anesthesia for Vascular Surgery
138
Medical
Graduate
02/01/2010

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Term
Vascular surgery requires the _______ with resulting _____ which can cause organ damage and production of ______.
Definition
interruption of arterial blood flow, tissue ischemia, anaerobic metabolites.
Term
Clamping and unclamping of arteries causes changes in ________ and activation of _______.
Definition
left ventricular afterload, cardiovascular reflexes
Term
T/F: Patients undergoing major vascular surgery usually have underlying involvement of one or more organ systems.
Definition
True
Term
________is the major factor of morbidity intraoperatively and postoperatively with vascular pts.
Definition
myocardial dysfunction.
Term
______is the most common etiology for peripheral vascular disease.
Definition
atherosclerosis
Term
plaques can develop into ________ or cause the __________.
Definition
total obstructive lesions, formation of connective tissue.
Term
Aneurism formation and dissection as well as emboli formation are the later stages of atherosclerosis where there is a loss of ______ that lead to _____.
Definition
arterial wall compliance, ulceration.
Term
List the 5 major arterial sites that are particularly susceptible to atherosclerotic lesions: _______, ______,_____,_____,______.
Definition
coronary arteries
carotid bifurcation
infrarenal abdominal aorta
iliac arteries
superficial femoral artery
Term
Emboli can form as the _____ is exposed to the blood.
Definition
subendothelium
Term
The main reasons why the 5 most common sites are prone to atherosclerosis are due to _______ and _____.
Definition
bifurcations, changes in hemodynamic shear forces.
Term
Name 3 main factors in hemodynamic shear forces.
Definition
velocity, elasticity, pulsatile flow
Term
In general, most of the causes of atherosclerosis are/are not self-inflicted?
Definition
they are. smoking, sedentary, DM, HTN, hyperlipidemia, and obesity. The only 3 that are not modifiable are age, male gender and family history.
Term
T/F: The pathophysiology of atherosclerosis on a cellular level is known.
Definition
F: It is unknown.
Term
T/F: Men have a genetic susceptibility to atherosclerosis.
Definition
True
Term
Endothelial injury caused by ______ allows the blood to come in contact with _____. Then, _____ adherence and degranulation stimulate ______ migration from the ____ to the _____. Thus this is a _______ problem.
Definition
hemodynamic shear stress, subendothelium, platelet, arterial smooth muscle cell, media, intima. Connective tissue.
Term
the cellular response includes:
migration of ______ from the blood to the intima, intimal ______ accumulations, intimal _______ proliferation, _____-_____ macrophage _____, and organic _____ deposition.
Definition
macrophages, lipid, smooth muscle, lipid-laden, necrosis, calcium
Term
Disruption of the plaque can cause plaque ____ and ____ with resulting _____ and _____ distal to that acute thrombosis.
Definition
rupture, ulceration, spasm, ischemia.
Term
______ therapy is the mainstay of medical therapy for PVD.
Definition
antiplatelet
Term
You should continue your pt on ASA until the DOS for ____ and _____ surgery.
Definition
carotid, lower extremity vascular. (bigger vascular cases--AAA--individualize the ASA therapy)
Term
Name 3 drugs to systemically anticoagulate a pt with acute ischemia.
Definition
Heparin, Coumadin, Dextran (imporoves microcirculation)
Term
What is the primary concern regarding antiplatelet therapy and regional anesthesia?
Definition
Hematoma; specifically a spinal or epidural hematoma.
Term
You want to do a regional technique for a fem-pop bypass. When can heparin be given? Lovenox?
Definition
Heparin: 60 minutes after the spinal; Lovenox: 2 hours after the spinal.

You should monitor the PTT/ACT levels so that they are 1.5-2 times normal.
Term
Heparin or Lovenox is more likely to cause a spinal/epidural hematoma?
Definition
Lovenox. It has a higher bioavailability and a longer half-life than heparin.
Term
WIth lovenox, the FDA reported that emergency surgery to evacuate an epidural hematoma occurred in ______% of pts and that paraplegia occurred in ____% of pts.
Definition
65, 37.2
Term
Men/women are more likely to have a spinal/epidural hematoma?
Definition
women
Term
Half-life of heparin:
Half-life of lovenox:
Definition
1-2 hours
4-8 hours
Term
A pt received a lovenox injection at 8 pm the previous evening, when is the earliest time a spinal/epidural can be safely performed?
Definition
6 am (10-12 hours after the last dose)
Term
With a CEA, an epidural catheter should/should not be left in overnight and removed the next day?
Definition
should. The first dose of LMWH should be started 2 hours AFTER catheter removal.
Term
Pts with heparin antibodies develop ______.
Definition
decreased platelet counts. This is HIT. Heparin induced thrombocytopenia.
Term
_____ is one of the most common immune-mediated drug reactions.
Definition
HIT
Term
HIT is caused by _____ antibodies that recognize complexes of ____ and ____ leading to _____ activation.
Definition
igG, heparin, platelet factor 4, platelet
Term
With HIT, there are procoagulant, platelet-derived microparticles and possibly the activation of _____ that cause ____ generation.
Definition
endothelium, thrombin
Term
Patients with HIT can be anticoagulated with a ______ inhibitory agent such as _____ or ____. These agents have longer/shorter half-lives than heparin and their metabolism depends on _____.
Definition
thrombin, Argatroban, Lepirudin, longer, renal function.
Term
T/F: the interactions of Lepirudin and Argatroban and regional anesthesia are not clear.
Definition
True.
Term
T/F: Attempts at controlling BP or electrolyte imbalances rapidly may be more hazardous than leaving the condition untreated.
Definition
True
Term
The patients with the greatest risk for perioperative and postop complications have _____ CAD, poor _____ and ______ (or greater)
Definition
left main, LV function, triple vessel CAD
Term
____ almost always indicated increased perioperative risk.
Definition
an abnormal resting EKG.
Term
A ______ is one of your best indicators for perioperative complications.
Definition
an abn EKG!!!
Term
besides anything other than NSR on an EKG, what is another big concern on an EKG, and what leads will you specifically look at?
Definition
LVH: Big S waves in V1, large R waves in V5 and T wave inversion with asymmetry in V5-6.
Term
Raby et al found that ____ of pts with preop ischemia had intraop complications.
Definition
1/3
Term
What is the cutoff for EF in pts receiving major vascular surgery? Why?
Definition
want an EF > 35% because studies indicate that 80% of those with an EF < 35% suffered MIs after major vascular surgery.
Term
Name 3 methods to determine preop cardiac risk for major vascular surgery.
Definition
EKG, holter monitoring and dipyridamole-thallium scan.
Term
Mass-General's dipyridamole-thallium scan yielded two important observations: ______ is not a risk factor by itself and an area of _______ is associated with an adverse outcome.
Definition
old MI, area of redistriubution
Term
If a pt is found to have a markedly positive dipyridamole-thallium scan, what might be your recommendation?
Definition
To have a CABG before, in conjunction with or very soon after vascular sx. You should also quantify the degree of redistribution.
Term
Should pts with a negative dipyridamole-thallium scan have a PA catheter and extended ICU care?
Definition
Not necessarily. They are at a lower cardiac risk than someone with a positive scan.
Term
Name 5 cardiac risk-reducing interventions for major vascular sx.
Definition
1. Invasive monitoring (art lines)
2. Forced air warming (bair hugger, hotline)
3. stress-reducing anesth technique (regional, high-dose narcotic)
4. perioperative beta blockade*****
5. Prolonged ICU care
Term
State the timelines for peripheral vascular sx after angioplasty; after CABG.
Definition
1 week s/p angioplasty, 6-8 weeks s/p CABG
Term
If you are doing the anesthesia for a combined AAA and CABG sx, in general, which procedure would you expect to occur first?
Definition
the CABG then the AAA so that the heart is healthier to withstand the changing preload and afterload associated with aortic cross-clamping.
Term
Elective AAA repair should probably be performed before, simultaneously or within 2 weeks of CABG because of the increased risk for ______.
Definition
aneurism rupture after CABG.
Term
Two main goals for perioperative cardiac monitoring are:
Definition
1. Detect myocardial ischemia
2. Identify abn of preload, afterload and ventricular function
Term
ST segment depression occurs in __-__% of pts undergoing vascular sx.
Definition
20-50
Term
The greatest sensitivity for detecting myocardial ischemia is through the use of ___ or ___, especially in combination with _____.
Definition
V5 or V4, Lead II...take-home; monitor 2 leads
Term
Holter monitoring has shown that intraoperative time may be the most/least stressful for pts with CAD.
Definition
LEAST. Pts are more likely to have ischemic episodes and an MI during emergence and in the immediate postop period.
Term
hypothermia and shivering can increase stress by ___-___%
Definition
300-600
Term
why might pts in the immediate postop period be more likely to have a thrombotic ischemic cardiac event?
Definition
due to heparin reversal
Term
Which is a better indicator for mocardial ischemia PA cath or TEE?
Definition
TEE. You will see abn wall motion. Most PCWP elevations appear to be associated with tachycardia and HTN suggesting inadequate anesthesia.
Term
T/F: Nifedipine and NTG have been proven to reduce the risk of intraoperative myocardial ischemia.
Definition
F. Nifedipine precipitously drops the BP and can lead to an MI, and prophylactic NTG has not been shown to decrease the incidence of cardiac ischemia in pts with CAD.
Term
Name 4 adverse effects of Esmolol.
Definition
Take this as a general beta-blockade question.
1. Increase SVR
2. Decreased CO
3. Bronchospasm
4. Conduction delays
Term
Epidural anesthesia reduces preload/afterload/both.
Definition
Both. It will decrease myocardial oxygen demand, but the concern is with neuraxial hematoma.
Term
The use of alpha-2 agonists with major vascular surgery (clonidine, mivazerol, dexmedetomidine) reduces ____, ____ and _____.
Definition
HTN
tachycardia
NE levels
Term
In general for vascular pts, you don't want the HCT to be less than ___%, but for high-risk pts, you want the HCT to a minimum of ____%.
Definition
28%, 30%
Term
Hypothermia causes increased _______ and _______.
Definition
adrenergic tone, postoperative myocardial ischemia...so aggressively warm pts and conserve heat during/after sx.
Term
Besides beta blockade, what other drug can help to control a pt's hemodynamics and not impede his emergence?
Definition
Lidocaine
Term
Hypertrophied hearts are more prone to systolic/diastolic dysfunction and can lead to _____ postoperatively.
Definition
diastolic, pulmonary edema
Term
The hypertrophied LV of a chronic HTN pt can lead to increased risk for _____ ischemia.
Definition
subendocardial
Term
beta adrenergic blockers are well-tolerated in pts with claudication, despite concerns of peripheral ____ and ____.
Definition
vasoconstriction, bronchospasm
Term
Both calcium channel blockers and ACEI are used in major vascular sx, but name a complication of ACEI in pts with renal stenosis.
Definition
prerenal azotemia.

ACEI also cause hypotension following induction of anesthesia by decreasing sympathetic tone and HR.
Term
A diabetic may have ____ to ____ of their normal insulin dose on DOS.
Definition
1/3 to 1/2. Best evidence practice states that glucose levels should be monitored throughout the surgery.

***CAD is ubiquitous in DM pts***
Term
What do all of these have in common?
Elevated fibrinogen
Antithrombin III deficiency
Protein C/Protein S deficiency
HIT syndrome
Definition
hypercoagulable states which may lead to occlusion of vascular grafts.
Term
Pts with preop renal insufficiency have ______ of postop renal failure, as well as ________ complications and death.
Definition
increased risk, cardiac
Term
Ideally, when should dialysis pts have dialysis before sx?
Definition
The day before sx. If the day of; anticipate hypovolemia
Term
What drug might you want to avoid in pts with renal failure?
Definition
Sux
Term
______ and mitral valve ____ are more common in pts undergoing dialysis, which can predispose them to ______ postoperatively.
Definition
LVH (big S in V1, big R in V5, T invert V5-V6)
calcification
pulmonary edema
Term
_____ is the most common cause of carotid artery disease.
Definition
atherosclerosis
Term
carotid artery plaques are found bilaterally in the bifurcations ___% of the time.
Definition
50
Term
Changes in the _______ of the lumen and ______ of blood cause a buildup of plaque in the carotid arteries.
Definition
internal diameter, turbulence
Term
Formation of plaque at the carotid bifurcation is probably due to altered _________ accompanying the _________into ____ of different sizes.
Definition
hemodyanmic conditions, division of a vessel, lumens
Term
______ or ______ from plaque can cause a ____ or a _____.
Definition
Thrombosis, debris, stroke, TIA
Term
How can some pts have 100% occlusion of their carotid artery and not have a CVA?
Definition
Because the occlusion gradually occurred, and there is enough collateral circulation from the Circle of Willis.
Term
Amaurosis fugax
Definition
transient attacks of monocular blindness on the ipsilateral side
Term
Always last < 24 hours
Definition
TIA
Term
>24 but < 72 hours
Definition
RIND
Term
___-___% is considered to be a "high grade stenosis"
Definition
70-75%
Term
> 72 hours, usually with neurological deficits afterwards
Definition
CVA
Term
Used to predict the extent of stenosis
Definition
Duplex scan. Presence of high velocities and turbulent flow.
Term
Provides measurements as to the size and morphology of atheromatous plaque.
Definition
Angiography.

Can also document aortic arch and intracranial disease.

Carries about a 1% risk of neuro deficit.
Term
Which of the following does not produce similar symptoms of carotid artery disease: intracerebral tubors, AVM, A fib, valvular heart disease, dialated cardiomyopathy
Definition
None of the above
Term
What is the max diastolic BP that is acceptable for a CEA?
Definition
110 torr
Term
Pharmacological treatments of carotid artery disease may include aspirin and/or _________. Aggrenox has the two drugs combined.
Definition
dipyridamole
Term
hyper/hypoglycemia may adversely affect neurological outcome after temporary or global ischemic events. Avoid ______ solutions also.
Definition
Hyperglycemia, LR
Term
A pt comes to you for CEA sx and is on coumadin. Advise him to stop the coumadin ____ days before sx. If he is started on a heparin gtt, make sure the gtt is turned off _____ hours prior to surgery.
Definition
3 days, 4 hours
Term
Studies report different/similar M&M with CEA sx under GA or MAC/regional. Therefore, there is clear/no clear evidence to support a technique.
Definition
similar, no clear
Term
Sensory blockade of ____-_____ must be achieved for a regional to work for a CEA sx.
Definition
C2-C4
Term
What is the most accurate neurological monitoring device?
Definition
The pt
Term
One benefit of doing a CEA under GA is ______ protection.
Definition
cerebral. Decreased CMRO2, decreased CBF, redistributed blood flow to ischemic areas
Term
Name two big complications of a cervical plexus block.
Definition
Local anesthetic toxicity, total spinal
Term
Goal of induction for CEA.
Definition
Maintain stable hemodynamics
Term
What is the preferred induction agent for a pt undergoing CEA sx?
Definition
There is no preferred induction agent; just know how to use your drugs. You can put a carotid to sleep with 80 mg propofol and have stable hemodyanmics. Do a SLOW induction and be prepared to use vasopressors if the pt gets hypotensive.
Term
Can you use N2O for a carotid case?
Definition
yes, barring no pt contraindications
Term
State the ranges for a remifentanil gtt
Definition
0.05 mcg/kg/min-0.6mcg/kg/min
Term
While Isoflurane has some potential to protect against cerebral ischemia more than the other inhalational agents, you would need _____ MAC to achieve a max protection.
Definition
2
Term
How do we know that ISO can be cerebral protective?
Definition
because it shows decreased frequency of EEG-detected cerebral ischemic changes during CEA.
Term
2 main goals of intraoperative management are:
Definition
cerebral protection
coronary protection...and these two goals are often in conflict.
Term
During CEA surgery, maintain the pt's BP within_________range.
Definition
their high-normal
Term
Increasing the BP to augment cerebral blood flow can increase afterload or contractility which _________consumption
Definition
increases myocardial oxygen
Term
Blood flow in the hypoperfused areas of the brain are thought to be _______ dependent
Definition
pressure
Term
________ is thought to be the major cause of CVA during and after CEA sx, accounting for _____-____% of deficits.
Definition
thromboemboli, 65-95%
Term
Most embolic events with a CEA occur preop/induction/maintenence/emergence/postop
Definition
postop
Term
In general, what is better for a CEA pt: deep anesthesia and phenylephrine or light anesthesia without phenylephrine
Definition
light anesthesia without phenylephrine
Term
Phenylephrine _____ ejection fraction and causes ____ in pts with CAD.
Definition
lowers, dilatation
Term
In addition to maintaining the pts BP within _____ for a CEA, you should also maintain the CO@ ______.
Definition
within high-normal range, within high-normal range
Term
why does moderate hyperglycemia worsen neurological injury?
Definition
Due to increased anarobic glycolysis that increases cerebral lactic acidosis.
Term
Avoid fluids with _____ and ______ for CEA pts.
Definition
dextrose, lactate
Term
Hemodilution with ____ or ____ may be used to reduce blood viscosity and improve microcirculation; decreasing cerebral ischemia and helping to prevent thromboembolic events.
Definition
Dextran, hetastarch
Term
If no shunt is used in a CEA, collateral blood flow via ________ supplies the brain.
Definition
Circle of Willis
Term
Shunt placement is associated with an embolic stroke rate of ____% which is high/low.
Definition
0.7, low
Term
3 technical problems of shunt placement for CEA:
Definition
1. air embolism
2. kinking of shunt
3. injury to vessel wall
Term
If the surgeon does not use a shunt for a CEA, he can either _______ for a pulse, or more/less commonly, measure _______.
Definition
palpate the distal end of the clamped carotid artery, the stump pressure (mean pressure distal to the carotid clamp)
Term
A stump pressure above ____ torr is considered to be sufficient to prevent ischemia.
Definition
60
Term
With measuring a stump pressure, there are a large number of false positives/negatives, meaning there is/is not enough pressure for collateral circulation to the brain.
Definition
negatives, not enough
Term
Transcrania doppler studies, intraoperative EEG evaluations, MEPs/SSEPs
Definition
Other methods surgeons determine if they need a shunt for a CEA
Term
best indicator for need of a shunt for CEA.
Definition
Intraoperative EEG
Term
T/F: No monitoring of neurophysiologic monitors has been shown to improve the neurological outcome of pts.
Definition
True. Probably because EMBOLISM, NOT HYPOPERFUSION is the most common cause of perioperative stroke.
Term
Prior to cross-clamping, _____ is given.
Definition
Heparin, 50-100 units/kg (usually 5,000-10,000 units)
Term
Hypertension/hypotension and tachycardia/bradycardia tend to occur with clamping of the carotids. Hypertention/hypotension and tachycardia/bradycardia tend to occur with unclamping the carotids.
Definition
Hypotension, bradycardia, hypotension, bradycardia
Term
If you encounter repeated episodes of hypotension and bradycardia with clamping the carotids, you can ask the surgeon to give ______ to ________. If the surgeon does this, anticipate _________ postoperatively.
Definition
local infiltration of lidocaine, abolish the vagal response.
hypertension
Term
It is important to be aware of your narcotics for CEA cases because______.
Definition
You will need to do a neuro assessment in the OR after extubation.
Term
With CEA surgery postoperatively, hypo/hypertension is more common.
Definition
hypertension
Term
Postop from CEA surgery, ____ and ____ can precipitate myocardia ischemia and failure, and ______edema and/or hemorrhage.
Definition
HTN, tachycardia, cerebral
Term
Postop HTN should be treated when the systolic is > ____ and diastolic is >_____
Definition
160, 95
Term
Hyperperfusion syndrome is an ______ of CBF of up to ______% and occurs ______ days postop.
Definition
increase, 200, several days (so you will not usually see this unless you do your f/u visit several days postop)
Term
Ipsilateral h/a, face/eye pain, sz, cerebral hemorrhage
Definition
cerebral hyperperfusion syndrome
Term
What is the most common postop complicatio from a CEA?
Definition
MI
Term
Related to airway, what is a postop complication of CEA sx?
Definition
Recurrent laryngeal nerve injury--horseness, dysphagia but NO RESPIRATORY complications
Term
Wound hematomas occur in ___% of CEA cases postoperatively.
Definition
2
Term
5 year mortality rate of untreated AAA_____. 10 year mortality rate of untreated AAA_____.
Definition
81%, 100%
Term
______ is thought to be the primary cause of AAA in _____% of pts.
Definition
ATHEROSCLEROSIS, 90
Term
Formula for law of La Place:
Definition
T = P x r

T is wall tension, P is transmural pressure, r is vessel radius.
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