Endovascular Anesthesia Flashcards
(26 cards)
When can EVAR be used?
- As an alternative to a conventional open repair
- Alternative treatment for ruptured AAA
Anesthetic options for EVAR
- General
- Regional
- MAC with local anesthesia
Comparison of mortality for open repair vs EVAR
Basically short term mortality is significantly lower but long term survival is similar
Long term looked at because how they secure the graft in EVAR is a little less secure than in the open repair
Benefits of EVAR
- Reduced blood loss
- Reduced length of ICU and hospital stay
- Increased patients discharged home (aka didnt die)
Patient criteria for EVAR
- Femoral artery w/o significant disease or occlusion
- At least 8 mm in diameter without extreme tortusity
- Alternative: if Iliac artery also meets criteria from graft manufacturer
- Renal arteries > 1.5 cm from top of aneurysm
- Aortic bifurcation >1 cm away from distal end of aneurysm
Which is the most commonly used access site for EVAR?
alternative?
Femoral (80%)
Iliac (20%)
What all needs to be prepped in EVAR?
Both groins and entire abdomen
When and what level of heparinization required for EVAR?
why?
Anticoagulation maintained throughout procedure until cutdown is repaired and distal pulses verified
Heparinization with ACT >300 seconds
Balloon causes stagnant blood flow just like the cross clamp does in open
How is the abdominal aorta accessed in EVAR?
- most commonly femoral artery
- 12 French sheath inserted
- Guidewire is used to access abodminal aorta
- Under fluoro, stent is threaded
What to watch for when threading stent in abdominal aorta in EVAR?
Arrhythmias
How is the graft attached to the vessel in EVAR?
Inflatable balloon catheter is placed inside the proximal portion of the stent/graft which is the attachment system
Inflate balloon for 30-60 seconds to expand stent and attach it via hooks embedding into the normal arterial wall
Some systems are self deploying and dont require a balloon
What should BP be when stent is deployed in EVAR?
Reduced to 100 mm Hg
How to assess accuracy of stent placement in EVAR
Ultrasound
vessel related complications of endovascular repairs
Dissection or rupture of aorta
Ischemia distal to iliofemoral arteriotomy
What other complications can occur from EVAR besides injury to vessels?
- Embolization of plaque to distal vessel
- Reaction to radiographic contrast
- Displacement of stent/graft to occlude renal or mesenteric arteries (aortic) or subclavian (thoracic)
- Endoleak
What is endoleak?
Causes?
Persistance of blood flow outside the graft and aneurysmic vessel wall
Causes:
- Can be due to misplacement or poor sizing
- Device failure or fatigue
- Reaction between sac and graft
What type of endoleak is caused by flow through porous graft material?
Type IV
What type of endoleak is caused by retrograde flow into sac from a collateral vessel?
Type II
What type of endoleak is caused by tear or defect in graft or leak between two segments?
Type III
What type of endoleak is caused by inadequate seal at either proximal or distal?
Type I
Goals of Anesthetic for EVAR
(Basically the same goals we have for every other anesthetic)
- Maintain HD stability
- Oxygenation and ventilation - prevent respiratory depression
- Preserve organ function
- Maintain normothermia
- May be general, regional, or local
Challenges related to EVAR
- Patient must be perfectly still
- Fluoroscopy required positioning of stent
- Hemodynamic challenges
- Nephropathy related to radiographic contrast
- Well hydrate intraop and postop
Hemodynamic challenges related to EVAR
- Avoid tachycardia and hypertension
- MAP at 60 mm Hg during balloon inflation
- Vasopressors and inotropes available
Potential bleeding complications for EVAR
- Potential for hemorrhage and conversion to open procedure
- Blood loss may be hidden- around sheaths, retroperitoneal
- Check Hgb if patient becomes unstable
