Mod X: ANESTHESIA FOR PERIPHERAL VASCULAR DISEASE Flashcards
ANESTHESIA FOR PERIPHERAL VASCULAR DISEASE
OBJECTIVES
- Discuss the degenerative disease process associated with peripheral vascular disease
- Identify common risks associated with atherosclerosis
- Discuss surgical treatment options for peripheral vascular disease
- Discuss anesthetic management, including benefits of regional anesthesia in this patient population
- Discuss postoperative management of these patients
PERIPHERAL ARTERIAL DISEASE
Incidence:
Common condition
Affecting 10 million Americans
Incidence is rising
Most patients asymptomatic at the begining or they have symptoms other than the classical intermittent claudication, the actual prevalence of the dz is unknown
PERIPHERAL ARTERIAL DISEASE
Most common cause of PAD is:
Atherosclerosis
With the infrarenal and iliac arteries being the most common sites of chronic atherosclerosis (plaque build up), when compared to all other aortic atherosclerotic sites
PERIPHERAL ARTERIAL DISEASE
PVD is strong indicator of generalized arterial disease, including CAD and cerebral vascular disease - why?
Plaque is not usually comfined to the peripheral arterial tree
Patients with CAD and PVD have higher incidence of triple vessel CAD than patients with CAD only
More than 20% of patients with PVD have at least 70% stenosis of carotid arteries
PERIPHERAL ARTERIAL DISEASE
Pts with PVD should have testing prior to any ellective surgery - why?
PVD patients have higher incidence of cardiac M&M following surgery
Peripheral arterial disease = very strong marker of mortality
PERIPHERAL ARTERIAL DISEASE
Non Modifiable risk factors for PAD
Non Modifiable risk factors for PAD
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PERIPHERAL ARTERIAL DISEASE
Modifiable risk factors for PAD
Modifiable risk factors for PAD
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PERIPHERAL ARTERIAL DISEASE
Graphycal representation of the Natural History of Atherosclerotic Lowe Extremity PAD Syndromes
Graphycal representation of the Natural History of Atherosclerotic Lowe Extremity PAD Syndromes
Note the long history
5 years after diagnosis more pts w/ PVD die from cardiac causes than those who loose limbs
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PERIPHERAL ARTERIAL DISEASE
5 years after diagnosis more pts w/ PVD die from
A. cardiac causes
B. loss of limbs
A. cardiac causes
B. loss of limbs
ACUTE ARTERIAL OCCLUSION
ACUTE ARTERIAL OCCLUSION is Usually the result of:
an embolus or
a thrombus
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ACUTE ARTERIAL OCCLUSION
Emboli typically originate from? What are their most common causes?
The heart
Atrial fibrillation and MI are most common cause of emboli
Other causes: endocarditis, atrial myxoma, paradoxical venous emboli, rheumatic heart disease
Symptoms are more severe than with thrombotic occlusion
ACUTE ARTERIAL OCCLUSION
Thrombotic uutnumber embolic occurence by
6:1
ACUTE ARTERIAL OCCLUSION
Thrombi almost always occurs as a result of
Long standing atherosclerosis
Patients typically had chronic vessel occlusion
Associated with hypercoagulable states that disposes pts to thrombus formation
ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE
Clinical presentation is dependent on
subtotal obstruction that allows for the development of collateral circulation
In these pts, total occlusion will present with less symptoms
In pts w/o collateral circulation, the event has dramatic symptoms
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ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE
Symptoms of Sudden onset of acute extremity ischemia include:
Pulselessness
Pain
Pallor
Paresthesia
Paralysis
These are the 5 Ps a/w acute ischemia!!!
Acute Ischemia of an extremity is an Emergency
Irreversible tissue damage will occur if not reversed w/in 4 - 6 hrs
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ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE
Early manifestations of acute extremity ischemia:
Absence of pulses and pallor
ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE
Late manifestations of acute extremity ischemia:
Motor weakness and Paresthesia
ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE
Initial Management of acute ischemia:
Emergency
Requires Rapid evaluation and treatment
Immediate anticoagulation
<strong>T</strong>o prevent propagation of the thrombus => typically general anesthesia for this reason
Many will already taking an antiplatelet drug
Will still receive IV heparin upon arrival to the hospital
Immediate surgical revascularization
If thrombotic formation in non-atherosclerotic limb (No PVD but develop a thrombus) => femoral thromboembolectomy
Anticipate significant and acute blood loss with thrombectomy or embolectomy
If thrombotic formation in PVD limb (a thrombus forms in someone who has PVD) => arteriography to determine severity and anatomic location of the occlusion
Thrombolytic therapy in conjunction with both
ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE
Medical evaluation and cardiac testing warranted - why?
Perioperative M&M is high as most of these patients have several clinical risk factors
CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
Chronic PVD is caused by
atherosclerosis (plaque build up),
vessels become progressively narrowed by plaque
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CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
Once diameter of the vessel is significantly narrowed, what typically occurs?
Thrombotic occlusion
CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
symptoms are often not as dramatic, some patients are asymptomatic - why?
Slow progression
Development of collateral circulation
CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
Most common symptom
Intermittent claudication
This is pain, fatigue with exercise, that gets better w/ rest
Occurs in the muscle group distal to the arterial insufficiency
As disease becomes more severe => rest pain develops
CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
Claudication is a/w
High degree of mortality
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CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
standard test for diagnosis of PVD
Ankle-Brachial Index (ABI):
It is done by dividing the ankle SBP by the brachial SBP
Ankle SBP/Brachial SBP = ABI
Without PVD, Ankle SBP > Brachial SBP
Normal ABI = 1-1.1
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CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
Low ABI =
strong indicator of disease progression
<0.9 = significant for PVD
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CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
Claudication occurs at which ABI?
0.3 – 0.9
CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
Disabling claudication or rest pain at which ABI?
< 0.5
CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE
Gangrenous extremities at at which ABI?
<0.2
MEDICAL AND SURGICAL MANAGMENT
What should be attempted prior to offering a pt w/ intermittent claudication the option of any invasive revascularization therapy
Risk factor normalization
(Exercise, smoking cessation, management of blood pressure, lipids, and diabetes)
pharmacological risk reduction
(Antiplatelet therapy)
MEDICAL AND SURGICAL MANAGMENT
Invasive options
Percutaneous endovascular modalities
many performed in radiology suites under local anesthesia without anesthesia providers present
Intra-arterial thrombolytic therapy
Balloon catheter embolectomy
Transluminal balloon angioplasty
Intra-arterial stent placement
SURGICAL MANAGMENT
Choice of operative approach depends on
Location and Distribution of arterial occlusion
SURGICAL MANAGMENT
Attempt will be made to first use autologous graft - why?
Prosthetic grafts have high failure rates
SURGICAL MANAGMENT
What is often the procedure chosen for occlusions distal to the inguinal ligament?
Femoral-popliteal bypass
(w/ a saphenous vein harvest)
59% graft patency at 5 years, 38% at 10 years
This is a more demanding technique
Requires removal of valves from vein to allow adequate flow
May not be available in patients who have had previous CABG
Upper extremity veins can also be used
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SURGICAL MANAGMENT
Procedure chosen for pt w/ Aortoiliac disease w/ blockages in both iliac arteries
Axillo-femoral bypass or Femorofemoral bypass
Aortobiiliac/Aortobifemoral bypass
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ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE
According the AHA, Vascular surgery is classified as which type of operation
High risk operation!!!
Vascular pts have clinical variables that increase their risk of peri-op vardiac events
ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE
Medical management prior to elective surgical procedures
These pts tend to have PVD + CAD + Renal incufficiency + COPD + DM + Obesity in combination
Should have their comorbidities medically managed prior to elective surgery
If correction of CAD is required, it must be performed prior
ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE
Monitoring
Routine monitors +
arterial line, +/-
advanced lines depending on comorbidities
ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE
Good IV access:
Good IV access is important
If an arm vein will be harvested, the IV access should be placed on the opposite side
In this case, Arterial line should also be placed on the opposite side
ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE
Type and screen:
All patient should have type and screen (at minimum)
Blood loss w/ these procedures is not rapid
Slow continuous blood loss may occur for which transfusion may be needed, esp. in pts w/ CAD
GENERAL VS. REGIONAL ANESTHESIA
Choosing REMAINS CONTROVERSIAL - why?
Both methods have pros and cons
GENERAL VS. REGIONAL ANESTHESIA
REGIONAL anesthesia:
Should be avoided in patients who are demented, uncooperative, or unable to lie flat
Could be difficult in pts w/ osteoarthritis of their backs
Severe spine deformity may make placement difficult
Hemostasis-altering drugs may preclude the placement of spinals or epidurals
Peripheral nerve blocks shown beneficial
There is little clinical info available for the vascular surgical population
GENERAL VS. REGIONAL ANESTHESIA
GENERAL anesthesia:
Requires airway instrumentation, and the use of neuromuscular blockade
This makes it difficult in pulmonary pts
May be associated with increased hypercoagulable states and lower graft patency, when compared to regional anesthesia
Postoperative pain control may be more difficult after General anesthsia when compared to regional
GENERAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Ultimate goal:
Hemodynamic stability
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GENERAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Induction
Slow, gradual induction to maintain hemodynamic stability
Fentanyl & Propofol in incremental doses
Etomidate if poor LV fx
Muscle relaxant to facilitate intubation
(Not required for the procedure)
GENERAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Tracheal Extubation based on
Ability of the pt to pass the standard criteria
These are: adequate ventilation, return of reflexes, full reversal of muscle relaxation
GENERAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
BP control:
Appropriate control of BP
Vasodilators: NTG, SNP
Esmolol in incremental doses
REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Coagulation profile
Specific drugs used
Discontinuance of anticoagulants, for how long? consider the duration of the procedure
Concomitant administration of medications affecting hemostasis
REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Spinal anesthesia
Limited DOA with surgical procedures that have unpredictable durations of actions (some procedures can take hours to complete)
Should the procedure be discontinued if a bloody wet tap occur? This is controvertial
Studies show that Bloody wet tap were a/w a 50% increase of spinal headaches (from hematomas?!)
Less controllable levels
REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Epidural anesthesia
Most frequently used regional technique
The American Society of Regional Anesthesia and Pain Medicine recommends a one-hour interval between the time that the needle is placed and the time that the pt will be heparinized
Heparinization should also be dcd for 4-6hrs w/ confirmation of coagulation status prior to neuroaxial catheter manipulation or removal
REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Epidural anesthesia - Level of Lumbar catheter placement:
T10 level sufficient for lower extremity procedures
Epidural catheters should not be removed until anticoagulants dc’d
REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Peripheral nerve blocks
Associated w/ the least amount of systemic symptoms
Occasionally sciatic, femoral, ankle, or popliteal blocks may be adequate
However there is little clinical info in the vascular surgical population
REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY
Recommended Time Intervals Before and After Neuraxial Puncture or Catheter Removal
Recommended Time Intervals Before and After Neuraxial Puncture or Catheter Removal
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