Anesthesia for vascular surgery 1 Flashcards
Coexisting diseases with vascular disease include
Diabetes hypertension renal impairment pulmonary disease systemic atherosclerosis coronary artery disease
______ is the leading cause of perioperative mortality at the time of vascular surery
Coronary artery disease*****
________ occur in 23% to 28% of vascular patients
Unrecognized or silent MI’s
Atherosclerosis potentially compromises blood flow to all the
organs and extremities leading to MI, stroke, & gangrene
Atherosclerosis is a generalized, progressive, chronic
inflammatory disorder of the arterial tree with development of plaque
Describe atherosclerosis progression
Stage 1: fatty streak- endothelial damage
Stage II: fibrous plaque- blood flow reduction
Stage III: advanced lesion- complete occlusion possible
The most common sites for atherosclerotic lesions include
aortoiliac peripheral
coronary
arch branches
Three types of atherosclerosis morbidity include:
- enlarged plaque reduces lumen of blood vessel- supply vs. demand problem, “delayed” peri-op MI
- plaque rupture/ulceration, embolization, and thrombus formation- acute occlusion, “early” peri-op MI
- atrophy of media with arterial wall weakening (aneurysm dilation)
The goal of the American college of cardiology & american heart association preoperative evaluation guidelines includes:
information obtained should be used for both the peri-operative period and to inform the long-term treatment plan*
ACC & AHA preoperative evaluation guidelines include
clinical history- clinical risk factors, exercise tolerance
supplemental evaluation
perioperative therapy
surgical procedure- low risk, intermediate risk, high risk
Drug regimens can effect surgical and anesthetic management but
many should be continued**
Drug regimens may include
aspirin plavix statins ace inhibitors diuretics Ca+ channel blockers hypoglycemic drugs beta blockers
Concerns with aspirin include
inhibit platelets–> potential for increased bleeding and decreased GFR
Concerns with plavix include
inhibits platelets–> potential for increased bleeding
Concerns with statins include
effects liver function
Concerns with ACE-inhibitors include
induction hypotension, coughing
Concerns with diuretics include
hypovolemia, electrolyte imbalance
Concerns with Ca+ channel blockers include
hypotension
Concerns with hypoglycemic drugs include
hypoglycemia, lactic acidosis with metformin
Concerns with beta blockers include
bronchospasm, decreased blood press, & HR
*** if you think pt could benefit from them start them at least 3-4 days prior to surgery
Medical management of the patients prior to surgery includes
cessation of smoking
weight loss
exercise
After coronary stenting, post stenting _____ is required
dual-antiplatelet therapy with aspirin & plavix
The critical period to endothelialize after a coronary stent is
6 weeks***
If dual anti-platelet therapy is stopped too soon after coronary stenting, there is a greater risk for
MI
- bare metal stent (do not want to stop antiplatelet therapy <1 month)
- drug eluting stent (do not want to stop antiplatelet therapy <6 months)
The risk of stent thrombosis if the dual antiplatelet therapy is discontinued must be balanced with
the risk of increased intraoperative bleeding if DAPT is continued
-newer generation drug eluting stents require shorter durations of DAPT (3 to 6 months)***
Perioperative MI’s are the result of
culprit lesions demand ischemia (likely predominant cause of periop MI)
Culprit lesions are often located in
coronary vessels without critical stenosis (vulnerable plaques with high likelihood of thrombotic complications
Assessment of cardiac function includes
exercise/pharmacologic stress test
Echo
duplex imaging of carotid arteries or angiography
assessment of myocardial ischemia, previous MI, valvular dysfunction, and heart failure
Advanced cardiac testing is used to determine if coronary intervention is needed prior to
vascular surgery OR to determine if aggressive intraop and postop management is needed
The most important pulmonary complications are
atelectasis, pneumonia, respiratory failure, and exacerbation of underlying chronic disease
There is a high prevalence of _______ related to pulmonary function in vascular patients
cigarette smoking, COPD, and chronic bronchitis
Tests to assess for pulmonary function include
PFTs, ABGs, chest XRs
For patients with reduced pulmonary function consider
incentive spirometry, steroids, regional anesthesia, antibiotics, and CPAP
Chronic renal disease strongly predicts
long-term mortality* in patents with symptomatic lower extremity arterial occlusive disease
-CV disease is independently associated with a decline in renal function and the development of kidney disease
Tests for assessment of renal function include
serum creatinine, creatinine clearance
For renal function consider the use of
contract dye use, beta-blockers, statins, volume status, & perfusion pressures
Lower extremity peripheral artery disease is defined as
insufficiency in lower extremities presenting with acute or chronic limb ischemia with occlusions distal to the inguinal ligament
______ is indicated for peripheral artery disease or atherosclerotic occlusive disease of lower extremities
lower extremity revascularization
There is a risk for _______ with peripheral artery disease
amputation, stroke, MI, and death
probably atherosclerosis in other beds (cardiac, cerebrovascular)
DM at extra higher risk
Patients presenting for lower extremity revascularization are often taking
anti-platelets and anticoagulants which makes it challenging in the periop period
Peripheral revascularization indications include
acute ischemia
chronic ischemia
Acute ischemia can be due to
emboli
thrombus
pseudoaneurysm postop from femoral arterial line
Chronic ischemia can be due to
atherosclerotic plaque progressively narrowing vessel- claudication with eventual thrombosis of vessel
Peripheral revascularization surgery is indicated when
severe disabling claudication
critical limb ischemia (limb salvage)
Irreversible ischemic damage occurs in 4-6 hours and requires
urgent thrombolytic therapy &/or angioplasty
arteriography
surgical intervention
For peripheral occlusions, the traditional surgical approach includes the unobstructed blood flow source (donor)
artery is exposed
-typically the common femoral, superficial femoral, or deep femoral
target distal artery (recipient) is exposed at or below the knee- typically the dorsalis pedis or posterior tibial arteries
After exposure of the donor and recipient arteries for the traditional surgical approach of peripheral revascularization, the following steps occur:
a tunnel is created & graft is passed graft may be saphenous vein or prosthesis heparin IV given anastomosis are constructed arteriogram to confirm adequate flow heparin is not likely to be reversed
Anesthetic management for peripheral revascularization includes
preop beta blockers and/or other chronic medication
intraop-arterial line
continuous EKG monitoring & ST analysis
monitor intravascular volume by foley catheter- +/- CVP or PA catheter
minimal blood loss & 3rd space
For emergency surgery of peripheral revascularization, anesthetic management includes
carefully watching K+ levels, myoglobinemia, fasciotomy may be required, coagulation status, ECG ischemia, etc.
Describe considerations for regional vs. general for peripheral revascularization.
assess for coagulopathy or anticoagulation therapy
epidural>spinal
most studies have shown no difference between RA & GA in terms of cardiopulmonary*** complications
There is a significant difference in complication rate in terms of
GRAFT occlusion with REGIONAL being superior
Graft occlusion is significant with GA in the postop period because of
hypercoagulable state with GA as opposed to RA
fibrinolysis decreased after GA, therefore, fibrinogen not broken down and clots form
Epi, norepi, & cortisol release increased after GA compared to RA
patency of graft maintained with RA secondary to increased blood flow with sympathectomy
________ drugs should be avoided with revascularization procedures.
VASOPRESSORS**- keep feet warm
If performing RA for revascularization, the following dermatomes must be achieved
L1-L4 dermatomes (T10 level adequate)
epidural dosing is usually 9-12 mL
General anesthetic implications with revascularization include
balanced anesthetic with opioids, inhalation agent, nitrous oxide, neuromuscular blocker
- minimal opioids to facilitate extubation
- deepen anesthetic level during the tunneling phase
- avoid hemodynamic extremes- Beta blockers intraop often necessary
Postoperative anesthetic management for revascularization includes
control pain & anxiety- high risk for MI in this period- stress reduction essential! avoid anemia (Hgb <9.0 g/dL) control heart rate & blood pressure frequent checks of peripheral pulses continuous EKG monitoring & ST analysis
Lower extremity endovascular treatment includes (anesthetic type)
GA, neuraxial, or MAC
percutaneous procedures so often MAC
open access- e.g. femoral stenosis–> consider GA
