Anaesthesia for lower limb

revascularizationPresented by:- Dr. Gopan. G

Date :- 27/04/ 2015

Introduction

Lower extremity arterial insufficiency, or

Peripheral artery disease (PAD) is a type of organic

PVD.

PVD manifests as insufficient tissue perfusion.

Peripheral vascular disease (PVD) is a marker for

severe multi-system atherosclerosis.

Classification

Acute - < 14 days ischemia

Acute on chronic – worsening of symptoms

& signs < 14 days

Chronic – ischemia stable for > 14 days.

Causes

Atherosclerosis.

Embolism, Thromboangiitis obliterans (Buerger

disease), Immune arteritis, Radiation arteritis,

Giant cell arteritis, Adventitial cystic disease,

Fibromuscular dysplasia, and Homocysteinemia.

Sites

Femoral artery

Popliteal artery

Any of the infrapopliteal arteries

Superficial femoral artery is the most common site

Acute limb ischemia

Pulselessness, pain, pallor, paresthesia, and

paralysis (the five Ps).

Embolism and thrombosis.

Trauma, iatrogenic (vascular interventions),

dissection of an arterial aneurysm.

Management

Immediate anticoagulation

Coexisting medical conditions - stabilized

Immediate surgical revascularization

Arteriography

Intra-arterial thrombolysis

Lower extremity bypass surgery

Implications for the anesthesiologist

Regional anesthesia is not an option.

Morbidity and mortality rates high.

Rapid sequence induction.

Severe reperfusion injuries.

Chronic arterial occlusion

Most patients are asymptomatic.

Mild intermittent claudication.

Severe disabling intermittent claudication or rest pain

Critical limb ischemia (CLI) is defined as chronic

ischemic rest pain, ulcers or gangrene attributable to

objectively proven arterial occlusive disease.

Ankle-brachial index (ABI)

Clinical standard

Ankle systolic pressure/ brachial systolic

pressure.

Normal value is between 1.0 and 1.1

Value < 0.9 indicates arterial disease.

Claudication 0.3 to 0.9.

Disabling claudication or rest pain < 0.5.

Gangrenous extremities < 0.2.

Treatment strategies Life style modification.

Cholesterol lowering therapy

Antiplatelet therapy

Optimum diabetic control

Blood pressure control <140/80 mm Hg

Non-surgical interventions.

Surgical revascularization- endarterectomy,

bypass grafting and amputation

Preoperative assessment

Cardiovascular symptoms.

Co-morbid conditions.

Functional capacity, assessed in terms of metabolic

equivalents (METs).

Full blood count, urea, electrolytes and glucose.

ECG and chest x-ray

Arterial blood gases and pulmonary function tests.

ACC/AHA clinical predictors of preoperative risk

MajorUnstable coronary syndromes (unstable angina/MI within 30 days)Decompensated congestive cardiac failureSignificant arrhythmiasSevere valvular disease

IntermediateMild angina pectorisPrevious MI ( >30 days earlier)Compensated or previous congestive cardiac failureDiabetes mellitusRenal insufficiency

MinorAdvanced age ( >70 yr)Abnormal ECGNon-sinus rhythmHistory of strokeUncontrolled systemic hypertension

ACC/AHA guidelines

Patients unable to meet a 4 MET and those with

intermediate clinical risk factors exercise stress

testing, dobutamine stress echocardiography (DSE), or

myocardial perfusion scanning.

Patients with acute or poorly controlled heart failure

Echo.

If Echo reveals MI coronary angiography and

revascularization.

ACC/AHA guidelines Coronary revascularization within the last 5 yrs and

have no cardiac symptoms further testing is not

necessary.

Symptoms have returned or revascularization was over

5 yrs ago coronary evaluation is recommended.

Peripheral vascular surgery should be delayed for at

least 4–6 weeks after balloon angioplasty, coronary

stenting or bypass surgery.

Preoperative management

Insulin therapy

Antihypertensive medication

Beta-blockers

a2-agonists

Statin therapy

Perioperative management

Ensure haemodynamic stability

Normothermia

Optimal perioperative hydration

Postoperative pain control

Peri-operative concerns

Tachycardia with hypertension or hypotension.

Hypothermia

Hypovolaemia

NTG infusion

Monitoring

Standard monitoring

Invasive arterial monitoring

Urinary catheterization

Central venous catheterization

Transoesophageal echocardiography

Pulmonary artery catheter

Anaesthetic techniques

Local anaesthesia with sedation

Regional anaesthesia

General anaesthesia (with or without regional

analgesic techniques)

REGIONAL Vs GENERAL ANESTHESIA

Choose the anesthetic and analgesic techniques

that are most familiar.

Optimization of perioperative care, rather than

anesthetic or analgesic selection, is the important

factor in improving outcome.

Anticoagulant and antiplatelet therapy often

precludes the use of spinal or epidural techniques.

REGIONAL Vs GENERAL ANESTHESIA

Use of regional techniques during intraoperative

systemic heparinization does not appear to

represent a significant risk.

Continuous catheter techniques preferable.

GA is preferred in patients who are unable to lie

still during lengthy surgery because of arthritis

or cardiorespiratory disease.

Peripheral nerve blocks

Sciatic, femoral, popliteal, and ankle.

Continuous catheter techniques can be used

Caution - when the neural structures are

deep or located in close proximity to vascular

structures

Theoretical advantages of RA

Attenuation of the stress response.

Improved postoperative respiratory function.

Improved graft flow and viability.

Attenuates the postoperative hypercoagulable

state.

Postoperative management

Epidural infusion

Patient-controlled analgesia

Normothermia

Oxygen supplementation is given for at least 24 h

Serial ECGs

Summary

PVS are associated with a high risk of cardiac

morbidity and mortality.

Preoperative cardiac risk assessment is

important and risk-reducing measures should be

started.

Quality of anaesthetic practice rather than

specific technique per se is important.

THANK YOU……