Vascular Flashcards
Preoperative management of patients with peripheral vascular disease should include:
Beta blockade
Statins
How long should a patient with peripheral vascular disease take beta blockers preop?
days to weeks before surgery, with a heart rate goal of 50-60
When should a statin be instituted in the preoperatively?
30 days prior to surgery
Should vascular patients continue to take or start taking aspirin preoperatively?
No. The data doesn’t show any benefit
The risk of rupture for AAA that are _____ cm in diameter are greater
greater than 5
surgery is recommended if greather than 5.5
What is the mortality from a ruptured AAA?
80-90%
Where do AAAs most frequently occur?
the infrarenal aorta
about 50% will also involved the iliac arteries
What is the most common cause of poor outcomes in patient undergoing AAA repair?
Perioperative MI
What is the most important technique to enhance cardiac function during a AAA repair?
Preop fluid loading and restoration of intravascular volume
Why are AAA repairs so challenging for anesthetists?
There is an extreme degree of hemodynamic instability during cross clamping and unclamping of the aorta
During aortic cross-clamping, _____ occurs above the cross clamp and _____ occurs below the cross clamp
Hypertension above
hypotension below
What happens in the body in response to cross clamping?
- Increase plasma levels of catecholamines, aldosterone, cortisol, prostaglandins and other stress hormones associated with SNS
- No blood flow distal
- MAP and SVR increase, which increases myocardial oxygen demand
What does it mean if your PAOP is increasing after cross clamp?
The left ventricle can’t tolerate the increased afterload
what is mesenteric traction syndrome?
Traction on the mesentery causes:
decreases in BP and SVR
Tachycardia
Increased CO
facial flushing
The neuroendocrine response to surgical stress is mediated by:
cytokines
TNF
Catecholamines
Cortisol
What has been proven to decrease the incidence of AKI following AAA repair?
balanced crystalloids and hyperchloremic solutions
aggressive hemodynamic stabilization
minimization of aortic cross clamp time
SSEP = _____ tract = ______ arteries =
dorsal column
posterior
MEP = _____ tract = _____ arteries
corticospinal tract
anterior arteries
The anterior spinal arteries supply _____% of blood flow to the spine
The posterior arteries supply _____ %
Posterior 20%
Anterior 80%
Cross clamping above which artery causes paraplegia following AAA repair?
Where does it orginate?
The radicular artery
It originates around T8-T12 but can be as low as L2
Why is the incidence of paraplegia after AAA so variable?
Because there’s extreme variability in where the radicular artery originates
MEP is more sensitive than SSEP for continuously assessing motor function. So why don’t we use it?
Because all these patients have NMBAs on board
What are some strategies to reduce paraplegia risk from AAA surgery?
Distal aortic prefusion
CSF drainage
Mild hypothermia
Maintaining SBP greater than 120
Releasing the cross clamp results in ____ afterload and _____ preload
Both are reduced
The hemodynamic instability that follows cross clamp release is called:
declamping shock syndrome
What is the single most significant risk factor for mortality from AAA?
underlying CAD
What parameters should fluid resuscitation be titrated to during a AAA repair?
normal cardiac filling pressures
normal cardiac output
Urine output of 1ml/kg/hr
What degree of carotid artery occlusion necessitates a CAE?
70% or greater
What is the most common consequence of CEA?
MI, not stroke
