Mod X: ANESTHESIA FOR PERIPHERAL VASCULAR DISEASE

Question 1

_{ANESTHESIA FOR PERIPHERAL VASCULAR DISEASE}

OBJECTIVES

Answer 1

1. Discuss the degenerative disease process associated with peripheral vascular disease
2. Identify common risks associated with atherosclerosis
3. Discuss surgical treatment options for peripheral vascular disease
4. Discuss anesthetic management, including benefits of regional anesthesia in this patient population
5. Discuss postoperative management of these patients

Question 2

_{PERIPHERAL ARTERIAL DISEASE}

Incidence:

Answer 2

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

Question 3

_{PERIPHERAL ARTERIAL DISEASE}

Most common cause of PAD is:

Answer 3

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

Question 4

_{PERIPHERAL ARTERIAL DISEASE}

PVD is strong indicator of generalized arterial disease, including CAD and cerebral vascular disease - why?

Answer 4

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

Question 5

_{PERIPHERAL ARTERIAL DISEASE}

Pts with PVD should have testing prior to any ellective surgery - why?

Answer 5

PVD patients have higher incidence of cardiac M&M following surgery

Peripheral arterial disease = very strong marker of mortality

Question 6

_{PERIPHERAL ARTERIAL DISEASE}

Non Modifiable risk factors for PAD

Answer 6

Non Modifiable risk factors for PAD

Question 7

_{PERIPHERAL ARTERIAL DISEASE}

Modifiable risk factors for PAD

Answer 7

Modifiable risk factors for PAD

Question 8

_{PERIPHERAL ARTERIAL DISEASE}

Graphycal representation of the Natural History of Atherosclerotic Lowe Extremity PAD Syndromes

Answer 8

_{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

Question 9

_{PERIPHERAL ARTERIAL DISEASE}

5 years after diagnosis more pts w/ PVD die from

A. cardiac causes

B. loss of limbs

Answer 9

A. cardiac causes

B. loss of limbs

Question 10

_{ACUTE ARTERIAL OCCLUSION}

ACUTE ARTERIAL OCCLUSION is Usually the result of:

Answer 10

an embolus or

a thrombus

Question 11

_{ACUTE ARTERIAL OCCLUSION}

Emboli typically originate from? What are their most common causes?

Answer 11

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

Question 12

_{ACUTE ARTERIAL OCCLUSION}

Thrombotic uutnumber embolic occurence by

Answer 12

6:1

Question 13

_{ACUTE ARTERIAL OCCLUSION}

Thrombi almost always occurs as a result of

Answer 13

Long standing atherosclerosis

Patients typically had chronic vessel occlusion

Associated with hypercoagulable states that disposes pts to thrombus formation

Question 14

_{ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE}

Clinical presentation is dependent on

Answer 14

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

Question 15

_{ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE}

Symptoms of Sudden onset of acute extremity ischemia include:

Answer 15

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

Question 16

_{ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE}

Early manifestations of acute extremity ischemia:

Answer 16

Absence of pulses and pallor

Question 17

_{ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE}

Late manifestations of acute extremity ischemia:

Answer 17

Motor weakness and Paresthesia

Question 18

_{ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE}

Initial Management of acute ischemia:

Answer 18

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

Question 19

_{ACUTE ARTERIAL OCCLUSION: CLINICAL PICTURE}

Medical evaluation and cardiac testing warranted - why?

Answer 19

Perioperative M&M is high as most of these patients have several clinical risk factors

Question 20

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

Chronic PVD is caused by

Answer 20

atherosclerosis (plaque build up),

vessels become progressively narrowed by plaque

Question 21

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

Once diameter of the vessel is significantly narrowed, what typically occurs?

Answer 21

Thrombotic occlusion

Question 22

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

symptoms are often not as dramatic, some patients are asymptomatic - why?

Answer 22

Slow progression

Development of collateral circulation

Question 23

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

Most common symptom

Answer 23

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

Question 24

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

Claudication is a/w

Answer 24

High degree of mortality

Question 25

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

standard test for diagnosis of PVD

Answer 25

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

Question 26

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

Low ABI =

Answer 26

strong indicator of disease progression

<0.9 = significant for PVD

Question 27

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

Claudication occurs at which ABI?

Answer 27

0.3 – 0.9

Question 28

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

Disabling claudication or rest pain at which ABI?

Answer 28

< 0.5

Question 29

_{CHRONIC ARTERIAL OCCLUSION: CLINICAL PICTURE}

Gangrenous extremities at at which ABI?

Answer 29

<0.2

Question 30

_{MEDICAL AND SURGICAL MANAGMENT}

What should be attempted prior to offering a pt w/ intermittent claudication the option of any invasive revascularization therapy

Answer 30

Risk factor normalization

(Exercise, smoking cessation, management of blood pressure, lipids, and diabetes)

pharmacological risk reduction

(Antiplatelet therapy)

Question 31

_{MEDICAL AND SURGICAL MANAGMENT}

Invasive options

Answer 31

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}

Question 32

_{SURGICAL MANAGMENT}

Choice of operative approach depends on

Answer 32

Location and Distribution of arterial occlusion

Question 33

_{SURGICAL MANAGMENT}

Attempt will be made to first use autologous graft - why?

Answer 33

Prosthetic grafts have high failure rates

Question 34

_{SURGICAL MANAGMENT}

What is often the procedure chosen for occlusions distal to the inguinal ligament?

Answer 34

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

Question 35

_{SURGICAL MANAGMENT}

Procedure chosen for pt w/ Aortoiliac disease w/ blockages in both iliac arteries

Answer 35

Axillo-femoral bypass or Femorofemoral bypass

Aortobiiliac/Aortobifemoral bypass

Question 36

_{ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE}

According the AHA, Vascular surgery is classified as which type of operation

Answer 36

High risk operation!!!

Vascular pts have clinical variables that increase their risk of peri-op vardiac events

Question 37

_{ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE}

Medical management prior to elective surgical procedures

Answer 37

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

Question 38

_{ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE}

Monitoring

Answer 38

Routine monitors +

arterial line, +/-

advanced lines depending on comorbidities

Question 39

_{ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE}

Good IV access:

Answer 39

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

Question 40

_{ANESTHETIC MANAGEMENT FOR PERIPHERAL VASCULAR DISEASE}

Type and screen:

Answer 40

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

Question 41

_{GENERAL VS. REGIONAL ANESTHESIA}

Choosing REMAINS CONTROVERSIAL - why?

Answer 41

Both methods have pros and cons

Question 42

_{GENERAL VS. REGIONAL ANESTHESIA}

REGIONAL anesthesia:

Answer 42

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

Question 43

_{GENERAL VS. REGIONAL ANESTHESIA}

GENERAL anesthesia:

Answer 43

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

Question 44

_{GENERAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Ultimate goal:

Answer 44

Hemodynamic stability

Question 45

_{GENERAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Induction

Answer 45

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)}

Question 46

_{GENERAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Tracheal Extubation based on

Answer 46

Ability of the pt to pass the standard criteria

These are: adequate ventilation, return of reflexes, full reversal of muscle relaxation

Question 47

_{GENERAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

BP control:

Answer 47

Appropriate control of BP

Vasodilators: NTG, SNP

Esmolol in incremental doses

Question 48

_{REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Coagulation profile

Answer 48

Specific drugs used

Discontinuance of anticoagulants, for how long? consider the duration of the procedure

Concomitant administration of medications affecting hemostasis

Question 49

_{REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Spinal anesthesia

Answer 49

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

Question 50

_{REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Epidural anesthesia

Answer 50

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

Question 51

_{REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Epidural anesthesia - Level of Lumbar catheter placement:

Answer 51

T10 level sufficient for lower extremity procedures

Epidural catheters should not be removed until anticoagulants dc’d

Question 52

_{REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Peripheral nerve blocks

Answer 52

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

Question 53

_{REGIONAL ANESTHESIA FOR PERIPHERAL VASCULAR SURGERY}

Recommended Time Intervals Before and After Neuraxial Puncture or Catheter Removal

Answer 53

Recommended Time Intervals Before and After Neuraxial Puncture or Catheter Removal