CHAPTER 26 CRAP

Question 1

What is #1 cause of AAA (90% of patients?)

Answer 1

atheroscelerosis

Question 2

aneurysmal vessel dimensions correspond to which LAW?

Answer 2

LaPlace

Question 3

law of Laplace equation (& what do each stand for?)

Answer 3

T = P x r
T = wall tension
P = transmural pressure
r = vessel radius

Question 4

As _____ of vessel increases, ____ _____ increases (LAPLACE STUFF)

Answer 4

RADIUS, WALL TENSION

Question 5

IN GENERAL, aneurysms >____cms require surgery.

Answer 5

4-5cm

Question 6

Preoperatively, what is the most important techniques to enhance cardiac function during AAA repair?

Answer 6

preop fluid loading & restoration of intravascular volumes

Question 7

what is better PA catheter monitoring or central venous monitoring?

Answer 7

neither, randomized controlled studies show no difference

Question 8

Aortic cross clamping causes release of ____ ___ derivatives and the synthesis of _____ __ .

Answer 8

Arachidonic acid derivatives, thromboxane A2 synthesis

Question 9

traction of mesentery has been associated w/ high concentrations of _-____________ __ which can cause ______ (multiple factors).

Answer 9

6-ketoPROSTAGLANDIN F1, Decreases in blood pressure and SVR, tachycardia, increased cardiac output, and facial flushing are common responses to mesenteric traction. (nagelhout)

Question 10

Aortic cross clamp end organ concerns? 50-90% of patients having aneurysmectomies have ___ ___ ____.

Answer 10

renal insufficiency, acute renal failure

Question 11

interruption of blood flow to what artery causes paraplegia? (two names) Originates where on spinal column

Answer 11

greater radicular artery AKA, artery of Adamkiewicz… b/t T8 and L2

Question 12

Name 2 types of (neuro)monitoring used for spinal cord ischemia?

Answer 12

SSEP, MEP

Question 13

SSEP is ?

Answer 13

SomatoSensory Evoked Potentials and reflects DORSAL (sensory) spinal cord function (NOT MOTOR).

Question 14

MEP

Answer 14

Motor Evoked Potentials and reflects ANTERIOR (ventral) cord function

Question 15

Colonic bloodflow is determined by which artery?

Answer 15

inferior mesenteric artery

Question 16

AORTIC CROSS CLAMP releases serum ______, causing ______ and ______ _____. This is manifested by _______ in SVR.

Answer 16

serum LACTATE, vasodilation and vasomotor paralysis. DECREASED SVR

Question 17

AA reconstruction APPROACH? Advantages? Disadvantages?

Answer 17

TRANSPERITONEAL INCISION. Advantages: exposure of infrarenal and iliac vessels, visible intraabdominal organs, rapid closure… Disadvantages: fluid losses, prolonged ileus, post-op incisional pain & pulmonary complications.

Question 18

50% of patients who req. AA reconstruction have ___ (dx) and it is the biggest risk factor for long-term survivability.

Answer 18

CAD

Question 19

_______ _______ testing is perhaps one of the most reliable methods for evaluating the extent of myocardial dysfunction associated with CAD and for predicting coronary events after vascular surgery.

Answer 19

Dipyridamole thallium

Question 20

Dipyridamole thallium is key b/c it does not rely on _______ to detect areas of myocardial hypoperfusion.

Answer 20

EXERCISE

Question 21

What anesthetic technique is ideal for AAA reconstruction? Why?

Answer 21

The McDizzle technique… A balanced technique using a combination of high-dose narcotics with nitrous oxide can be used as the anesthetic for major vascular surgery. Why? B/C of the CV stability provided by opioids and B/C IAA depress myocardium and cause hemodynamic instabilty.

Question 22

Best induction agent for patients w/ poor cardiac function/limited cardiac reserve?

Answer 22

etomidate

Question 23

In CAD patients, increases in PAOP and decreases in CO are treated w/ NG. Why?

Answer 23

decreases PRELOAD and decreases myocardial O2 DEMAND

Question 24

The more proximal the cross clamp is place on aorta, the _________ the severity of hemodynamic responses.

Answer 24

GREATER

Question 25

what do you expect when cross clamp is released? Prevented by doing what just before release?

Answer 25

declamping shock syndrome (severe hypotension and reduction in CO)... preventing via VOLUME LOADING to raise CVP 3-5mmHg or raising PAOP 3-4mmHg. Give HCO3 w/ acidosis.

Question 26

What does Mannitol do for renal function vs. CPB priming agent?

Answer 26

Renal: preserves renal function via osmotic effect (incapable of being reabsorbed from the renal tubule, resulting in decreased water and Na+ reabsorption/excretion thus lowering ECF) CPB: the solution prevents the swelling of endothelial cells in the kidney, which may have otherwise reduced blood flow to this area and resulted in cell damage (also preserving renal blood flow)

Question 27

Renal cooling is suggested for ischemic periods >____minutes. What is it?

Answer 27

flushing kidneys w/ iced electrolyte perfusate (contains heparin and glucose)

Question 28

3 layers of arterial wall?

Answer 28

tunica adventia, tunica media, tunica intima

Question 29

dissection vs. aneurysm

Answer 29

``` dissection = intima tear only w/ blood flowing along aorta's longitudinal axis aneurysm = all 3 layers of arterial wall ```

Question 30

which type of lesions (aneurysm) is more likely to rupture and thus require surgical intervention? *A or B*

Answer 30

A, B is managed medically w/ arterial dilators and beta blockers

Question 31

why would a complete neurologic assessment be important prior to thoracic aorta surgery?

Answer 31

paraplegia d/t poor arterial flow... hoarseness secondary to RLN damage (wraps around aorta remember)

Question 32

For any kind of aorta surgery, what special arterial monitoring is preferred?

Answer 32

R radial arterial b/c L SC bloodflow may be compromised during surgery... femoral arterial lines allow monitoring of lower extremity perfusion (in conjunction w/ R radial)

Question 33

spinal cord injury risk increases ____ minutes after aortic cross clamping

Answer 33

45

Question 34

one method that is proven to prevent spinal cord ischemia is

Answer 34

CSF drainage

Question 35

formula for spinal cord perfusion pressure

Answer 35

arterial pressure minus CSF pressure

Question 36

renal protection agents like mannitol and LASIX should be given __ minutes prior to clamping?

Answer 36

20-30

Question 37

one-lung ventilation is specific to which aortic surgical procedure

Answer 37

thoracic

Question 38

EVAR stands for? Procedure? Benefits?

Answer 38

endovascular aortic aneursym repair... EVAR involves deployment of an endovascular stent graft within the aortic lumen. The graft restricts blood flow to the portion or the aorta where the aneurysm exists... potential explanations for the absence of spinal cord complications are (1) no thoracic aortic cross-clamping and (2) no prolonged periods of extreme hypotension

Question 39

EVAR anesthetic considerations

Answer 39

GA and be prepared to convert to an open procedure