What are the physiological functions of blood vessels? (3)
Regulation of blood to tissues
Synthesis/secretion of vasoactive/antithrombic substances
Delivery of immune cells
What are the measurement of the aorta in cm?
~3cm from the origin
~5-6 cm long
What are the 3 branches off the arch of the aorta from left to right?
Left common carotid
What are the layers of the aorta?
Intima (innermost)--endothelial cells
Media--smooth muscle cells, elastic/collagen fibers 2:1
Adventitia--collagen (strength), vaso vasorum (vasculature that perfuses the outer layer)
What factors constitute an AAA? (3)
50% increased localized diameter
>4 cm in thoracic aorta
>3 cm in abdominal aorta
Define a true aneurysm.
Involves all 3 vessel layers
2 types: fusiform, saccular
Define a pseudoaneurysm.
Only involves the inner 2 layers: intima and media.
Pseudoaneurysms are more unstable. True or false?
False affects the intima and media and is contained in the adventitia.
Label the types of aneurysms.
________ is the origin of 90% of aneurysm cases.
Note: Usually occurs in males > 50 y/o.
What are cofactors leading to the cause of aneurysms? (4)
Loss of elastin
Men are ___ times more likely to have an aneurysm than women.
Abdominal aneurysms are often asymptomatic. True or false?
What are the clinical presentations of an aneurysm in the following areas:
Compression of esophagus/trachea
Recurrent laryngeal nerve
Dilation of aortic ring
Compression of esophagus: Wheezing, coughing, dyspnea, difficulty swallowing
RLN stretching: hoarseness
Aortic ring: Pt presents with aortic regurge
What are classic signs of an aortic aneurysm rupture?
Low back pain
Pulsative abdominal mass
Note: Only 1/2 pts present with these signs.
What is the gold standard for treating AAA?
What is the treatment for less severe ones?
surgical repair with prosthetic graft
When is surgical repair of a AAA considered? (Think of diameter.)
> 4.5 - 5 cm in diameter
What other co-existing conditions with pts with AAA have? (5)
Ischemic heart disease
What kind of access do we need prior to surgery?
What important factors do we need to consider intra-op?
Smooth induction to prevent cardiovascular swings.
Major blood loss may occur.
Hemodynamic changes that can occur during clamping/unclamping.
What hemodynamic changes occur during cross clamping?
Increased afterload--> increased BP
Decreased perfusion distal to the clamp
Note: Depending on where the clamp is placed, renal perfusion can be compromised.
What hemodynamic changes occur during unclamping? (3)
Sudden decreased afterload --> decreased BP
**need vasoconstrictor to anticipate the change
What is an aortic dissection?
The splitting of the intima from the adventitia along the length of the vessel.
What are the 2 types of aortic dissection?
What is a "Type A" aortic dissection? (3)
Involves the proximal, ascending aorta
Represents 2/3 of dissections
High risk of extruding into coronary and arch vessels
What is a "Type B" aortic dissection?
Distal dissection limited to the thoracic and abdominal aorta
What is the pathogenesis of aortic dissection? (4)
Connective tissue disorder like Marfan's
What type of aortic dissection presents as:
sudden, severe pain with ripping/tearing in anterior chest
What type of aortic dissection presents as:
sudden severe pain between scapulae
What other catastrophic events can occur from a dissecting aorta? (4)
Loss of pulse in extremities
Note: All occur as a result of occlusion of the propagating hematoma.
What are complications of aortic dissection?
Occlusion of aortic branch vessels
Distortion of the aortic annulus
What does the rupture of aortic dissection result in?
What does occlusion of the aortic vessels result in?
How do we treat an aortic dissection intra-operatively?
Stop progression of the dissection by:
decreasing BP --> Beta Blockers
decreasing LV contraction --> Sodium Nitroprusside
Symptomatic pts with >____% blockage yield the greatest benefit from an endarterectomy.
Pts who have already suffered a stroke will yield the most benefit to a carotid endarterectomy. True or false?
False, yields minimum benefit.
What do you consider during a carotid endarterectomy pre-op evaluation?
Effect of changes in head position
What is the anesthetic technique for carotid endarterectomies?
Regional: Cervical Plexus Block allows trial occlusion of carotid to evaluate neuro changes. Pt is awake.
GA: Infer neuro changes from EEG
What are the cons to performing a cervical plexus block for a carotid endarterectomy?
no cerebral protection
What are the benefits to GA for a carotid endarterectomy?
ability to regulate PO2, PCO2
What are the drugs of choice for induction for a carotid endarterectomy? (2)
Note: Because they lower CMRO2 and redistribute blood flow to potentially ischemic areas.
Etomidate for hemodynamically unstable pts.
What are anesthetic considerations intraoperatively for carotid endarterectomies?
PROMPT emergence to assess neuro function
What are post-operative concerns for carotid endarterectomies? (5)
HTN (carotid sinus activation) / Hyptension (baroreceptor reactivation)
MI/Infarction (MI is leading cause post-op complications)
Nerve injury (hypoglossal, RLN, SLN)
In what time frame does a carotid endarterectomy incident occur?
8-12 hours post op
Peripheral disease may result from: (3)
70% of pts > 75 y/o are affectedby peripheral atherosclerosis. True or false?
What are the clinical presentations of peripheral atherosclerosis? (4
Decreased arterial pulses
How do we pharmacologically treat peripheral atherosclerosis? (4)
What are causes of acute arterial occlusions? (4)
Thrombi originating from:
vasospasm of digital arteries with cold/stress
tricolor phasic response- white/blue/red
Affects women 20-40 y/o
What medications alleviate symptoms of Raynauds? (2)
Calcium channel blockers
Avoid EPI in local anesthetics when treating pts with Raynaud's. True or false?
Where do DVTs normally occur and what is a considerable risk of a DVT?
Calf veins or more proximally
What are the clinical symptoms of a 2º DVT, or, pulmonary embolism? (4)
What are DVT risk factors? (5)
Stasis of blood flow