Anesthesia for vascular surgery 3

Question 1

EVAR technique is used for all types of

Answer 1

aortic diseases- traumatic injuries, ruptures, dissections, thoracic, and abdominal aneurysms

Question 2

The EVAR technique is useful because it is

Answer 2

less invasive
reduced M&M
shorter hospital stay

Question 3

Anesthesia technique for EVARs includes

Answer 3

MAC with local/regional vs. GA
-consider pt functional status (can they lay flat?), co-morbidities, aneurysm complexity, and surgical urgency (full stomach?)

Question 4

Steering guiding sheaths for EVARS may require _________ arm arterial cut down**

Answer 4

left

Question 5

Anesthesia considerations for EVARs includes

Answer 5

spinal cord-extensive collateral network 
hemodynamic management 
preservation of organ perfusion 
blood loss and intravascular volume
temperature
radiation safety

Question 6

The artery of adamkiewicz is located at

Answer 6

T9-T12

Question 7

The Preserve trial found that the two most important factors that contribute to CIN are the

Answer 7

contrast load and the preexisting kidney disease*******

limiting the contrast load & adequate hydration to decrease the viscosity of the iodine-based dyes

Question 8

Early EVAR complications include

Answer 8

paraplegia, stroke, ARI, aneurysm rupture, pelvic hematoma

Question 9

Late EVAR complication sinclude

Answer 9

endoleaks, aneurysm rupture, device migration, limb occlusion, graft infection

Question 10

Endoleaks are normally treated by

Answer 10

balloon angioplasty of the proximal attachment site so that the desired seal is obtained through remodeling of the stent-graft

Question 11

If endovascular treatment or endoleak fails or is not possible, then

Answer 11

open surgical treatment is indicated

Question 12

Considerations for open abdominal aortic reconstruction includes

Answer 12

large incisions & extensive dissections
clamping & unclamping of the aorta or tis major branches
varying duration of organ ischemia- reperfusion
significant fluid shifts
temperature fluctuations
activation of neurohumoral and inflammatory responses

Question 13

The two most common sites of chronic atherosclerosis include

Answer 13

the infrarenal aorta & the iliac arteries

Question 14

Patients undergo surgery for aortoiliac occlusive disease only if

Answer 14

they are symptomatic

-claudication & limb-threatening ischemia

Question 15

Management of aortoiliac occlusive disease includes

Answer 15

direct reconstruction- Gold-standard
extra anatomic or indirect bypass grafts
catheter based endoluminal techniques

Question 16

The pathophysiology of aortic cross-clamping is complex & depends on the following factors:

Answer 16

level of the cross-clamp
status of the left ventricle
degree of periaortic collateralization 
intravascular blood volume & distribution, activation of the sympathetic nervous system
anesthetic drugs & techniques
heparinization
monitor ACTs

Question 17

The aortic cross clamp results in arterial __________ above the clamp and arterial ________ below the clamp

Answer 17

hypertension****

hypotension***

Question 18

Common ischemic complications of aortic cross clamp include

Answer 18

renal failure
hepatic ischemia
coagulopathy
bowel infarction 
paraplegia

Question 19

Thoracic aortic cross clamping leads to an increase in

Answer 19

mean arterial pressure
central venous pressure
pulmonary wedge
and mean pulmonary arterial

Question 20

Thoracic aortic cross clamp leads to a decrease in

Answer 20

EF
Cardiac index
no change in HR

Question 21

A normal intact heart can withstand large increases in

Answer 21

volume without significant ventricular distension or dysfunction

Question 22

An impaired heart with reduced myocardial contractility & coronary reserve may respond to an increase in volume conditions with

Answer 22

marked ventricular distension leading to acute left ventricular dysfunction & myocardial ischemia

Question 23

_________ activation resulting from increased aortic pressure should depress the heart rate, contractility, and vascular tone

Answer 23

Baroreceptor

Question 24

Cross-clamping of the thoracic aorta decreases ______ by approximately 50%

Answer 24

total-body O2

Question 25

Blood flow through tissues & organs below the level of aortic occlusion is dependent on ________ and is independent of ________

Answer 25

perfusion pressure******* | independent of cardiac output

Question 26

_______ should be used when aortic cross clamp is applied to decrease afterload, wall stress, and myocardial oxygen demand

Answer 26

Vasodilators- nitroprusside, nitroglycerine, nicardipine, & clevidipine

Question 27

Perfusion to distal organs is dependent on ________which originate _______ to the clamp or shunts

Answer 27

collaterals; proximal

Question 28

Aortic cross clamp management includes

Answer 28

acute increase in SVR & decreased CO avoid long-acting medications the higher the clamp, the more significant impact on perfusion to vital organs thoracic> supraceliac> infrarenal

Question 29

______ remains the strongest predictor of postoperative renal dysfunction

Answer 29

Preoperative renal insufficiency*******

Question 30

Renal failure after repair results from

Answer 30

preexisting renal dysfunction, ischemia during cross-clamping, thrombotic or embolic interruption of renal blood flow, hypovolemia and hypotension

Question 31

Renal sympathetic blockade with epidural anesthesia to a T6 level does

Answer 31

not prevent or modify the severe impairment in renal perfusion and function

Question 32

Renal protection may include

Answer 32

mannitol 12.5 g/70 kg low-dose dopamine (1-3 mcg/kg/min) can be injected directly into renal artery by surgeon controversial- mannitol, loop diuretics, methylprednisolone & dopamine

Question 33

Patients with _______ & _______ are most vulnerable to the stress imposed on the cardiovascular system by aortic cross-clamping

Answer 33

preexisting impaired ventricular function & reduced coronary reserve

Question 34

Goals during cross clamping include

Answer 34

``` reduce afterload (nitroprusside or clevidipine) maintain normal preload (IV fluid) maintain cardiac output (inotropes, MAP goals) ```

Question 35

Aortic unclamping may result in

Answer 35

hypotension reactive hyperemia washout of vasoactive & cardio-depressant mediators pulmonary hypervolemia

Question 36

The hemodynamic response to unclamping depends on many factors including the

Answer 36

level of aortic occlusion, total occlusion time, use of diverting support, and intravascular volume

Question 37

If hypotension persists for more than a few minutes after removal of the cross clamp, consider

Answer 37

unrecognized bleeding or inadequate volume replacement

Question 38

Therapeutic interventions for unclamping include

Answer 38

``` decrease inhaled anesthetics decrease vasodilators increase fluid administration give vasoconstrictors reapply cross-clamp for severe hypotension consider mannitol consider sodium bicarbonate ```

Question 39

Techniques for open AAA include

Answer 39

GA/ETT, regional, combined, low volatile propofol vs. etomidate fentanyl or sufentanil esmolol, nitroprusside, nitroglycerin, clevidipine, phenylephrine boluses ready heparin IV 100-300 units/kg- monitor ACT; protamine

Question 40

Monitors for open AAA include

Answer 40

TEE +/- cerebral oximetry +/- potential for rapid blood loss- central line, PIVs, a-line (awake?), PAC no longer recommended cell saver, cross-matched blood

Question 41

Describe temperature management for open AAA

Answer 41

forced warming upper body, fluid warmers | lower body should not be warmed during the cross-clamp period because doing so can increase metabolic demands

Question 42

_______ should be avoided because acute stress on the aneurysm can cause rupture

Answer 42

HYPERTENSION

Question 43

The heart rate* should be maintained at

Answer 43

or below baseline because myocardial ischemia is often related to the heart rate

Question 44

_______ may be deferred until the aortic rupture is surgically controlled in the OR

Answer 44

Euvolemic resuscitation**** - the resultant increase in BP without surgical control of bleeding may lead to loss of retroperitoneal tamponade, further bleeding, hypotension, and death

Question 45

Postoperative treatment of AAA include

Answer 45

aggressively control hypertension & tachycardia LOS is variable pain-epidural vs. PCA

Question 46

__________ (3 things) must be maintained before extubation after AAA

Answer 46

hemodynamic, metabolic, and temeprature

Question 47

Complications of AAA include

Answer 47

MI, pneumonia, sepsis, renal failure, decreased tissue perfusion, hypothermia