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34 Cards in this Set
- Front
- Back
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What are the goals of Abdominal Aortic Aneurysm Surgery?
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Minimize patent morbidity, and maximize surgical benefit.
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What is the prevalence of AAA:
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200,000 newly diag annually
5% of pop older than 50. 15,000 annual deaths |
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What is the primary cause of AAA's in more than 90% of population?
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atherosclerosis
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What segment of the aorta is most common for aneurysm development?
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T12 (diaphragmatic hiatus)
to L4 (common iliac bifurcation) |
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Criteria for Nonsurgical treatments of AAA?
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Size <5.0
Overall status of patient Avg growth rate 0.2-0.5cm per year Treatments: Serial ultrasound Q6-12 mo and Beta-blocker Therapy. |
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What are the 2 AAA Surgical approaches w/ Open technique?
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1. Transperitoneal (midline)
Adv: Good control of all vessels disadv: Inc post-op pain, ileus and resp compl. 2. Retroperitoneal (flank) adv: Less EBL, Good exposure, shorter hospital stay Disadv: Can't view contralateral vessels . |
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What are the 4 categories of etiology of AAA development?
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1. Degenerative (atherosclosis)
2. Inflammatory Arteritis (Giant Cell, Temporal, thromb obliterans) 3. Embolic, traumatic (Trauma) 4. Heredofamilial (15-19% inc of incidence if relative) Marfan and osteoimperfecti |
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What is the most frequent site of AAA?
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Aortoiliac Bifurcation
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What is the typical nonsurgical treatment of AAA?
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Beta blockers and serial Ultrasound (if <5cm) and health
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What is the average growth of an AAA?
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2-5mm/yr (0.2-0.5cm)
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What Law of physics governs the risk of a AAA >5cm?
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La Place Law (T = P x R) Inc surface tension with increases in radius = inc risk of rupture
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What are the surgical stages of AAA Reconstruction (general)?
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1. Exposure
2. Heparin 3. Cross Clamping 4. Tube graft 5. Unclamping 6. Closure |
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What are some of the goals of Induction for a AAA repair?
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1. Stress free induction
2. Minimize CV effect 3. tight hemodynamic control 4. Euvolemia or Mild hypovolemia |
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What is the role of the anesthetist for cross clamp preparation?
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1. Monitor CV stimulation
2. Deepen anesthesia 3. Give Vasodilators(nipride/fenoldopam) 4. Add 15cm of peep 5. assess renal fx and maintain U/O |
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What are the effects of Cross clamping on hemodynamics?
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Hypertension above the clamp
Hypotension below the clamp Increased afterload (Inc Myocardial wall tension) Increased MAP, SVR Increased EDV Dec LVEF |
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What are the effects of Release of Clamp on hemodynamics?
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Inc LVEF
Dec MAP Dec EDV Dec MAP, SVR |
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What are the unpaired branches off the anterior aorta?
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Celiac
Superior mesenteric Artery Inferior mesenteric artery |
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What are the paired branches off the lateral aorta?
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Suprarenal
Renal Gonadal |
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What are the branches off the posterior aorta?
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Inferior phrenic
Lumbar arteries |
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What is Mesenteric traction syndrome?
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Traction on the mesentery used to expose the aorta causes
dec in bp dec in svr inc HR inc CO **facial flushing |
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what are the mediators of the neuroendocrine response related to major surgical stress?
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Cytokines such as IL-1B,
IL-6, and TNF, plasma catecholamines, and cortisol. (causes Inc Temp, HR, RR, WBC and fluid retention). |
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describe Declamping Shock Syndrome?
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When the cross-clamp is released--- causes dec MAP, dec SVR, dec PAOP, CO dec (or no change)
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What should be done prior to unclamping to help prevent Declamping Shock Syndrome?
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1. Volume load
2. Neo for VASOCONSTRICTION 3. CaCL (300-500mg) 4. Bicarb (to offset the acidosis) |
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What is the most important indicators to renal perfusion?
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Cross-clamp level.
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What is fenaldopam?
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D1 Dopamine receptor agonist
it is a rapid-acting vasodilator that increases RBF significantly (dose: 0.05-0.1 mcg/kg/min) |
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What are some of the strategies for neuroprotection?
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1. limit cross clamp time
2. support distal circulation 3. hypothermia 4. maintain prox BP 5.. avoid post-op HOTN 6. enhanced monitoring |
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What is the approach to fluid administration with elective AAA?
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1. Prehydrate prior to induction
2. Keep map w/i 20 % of normal 3. sl hypovolemia- precross clam 4. replace blood loss with colloids. |
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What factors require CABG prior to AAA repair?
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LM disease
EF < 35% TVD |
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What should be done prior to cross-clamp removal?
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Decrease SNP, and/or lightening anesthesia
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HOTN > 4 min after cross-clamp release may be caused by what problems?
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excessive anesthesia
vasodilators still on myocardial dysfunction bleeding |
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What is the #1 post-op morbidity reason?
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MI
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Superior spinal cord perfusion comes from what areas?
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1. upper thoracic & cervical
2. S.c. and vertebral blood supply |
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What is the mst popular surgical approach for AAA repair?
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Transperitoneal
(adv: good control of vessels,) |
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What are the symptoms of AAA Rupture?
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Abd discomfort
pulsitile mass Severe back pain Dec peripheral pulses HOTN |
