anesthesia for vascular surgery mark welliver ms, crna

ANESTHESIA For VASCULAR SURGERY

Mark Welliver MS, CRNA

Significant contributions from original by Gwenn Randal MSN, CRNA

Outline• Introduction• Carotid endarterectomy (not covered)

• Peripheral vascular surgery– Bypass grafting– Embolectomy

• Abdominal aortic surgery

• Endovascular Surgery

• Thoracic aortic surgery

Vascular Surgery Patients• Coexisting diseases:

– CAD 40-80%– Htn– Diabetes – Smokers– CNS; carotid disease, stroke– Renal

• 50% of post op mortalities d/t MI

• If the surgical site is sclerotic so are other areas

Carotid Vascular surgery

• Consider carotid vascular disease coexisting

• CEA Covered next spring in trauma course

Peripheral Vascular Surgery

• Bypass grafting for occlusive disease or aneurysms

• Upper or lower extremities

• Endogenous vessels or synthetic (Gortex)

• Anesthesia options:– General– Regional

Peripheral Bypass

– Potential for blood loss; type and cross 2U– 2 large bore IV access (#18 minimal)– Consider central line; fluids and CVP (PA?)– Fluid warmers with blood tubing– Colloids available; Hespan, albumin– A-line for unstable or ASA 3,4– Heating blankets (burn risk)– Serial H&H, Abgs

Peripheral Bypass

• Femoral-popliteal and lower;– general, spinal, epidural

• Ileo-femoral and lower;– general, spinal, epidural

• Axillo-femoral;– General, regional, local

Peripheral Embolectomy

• Potential for significant blood loss

• Type and screen minimal

• Large bore IV access

• Often MAC with local

• Duration?

Abdominal Aortic Surgery

• Aorta below diaphragm

• Bypass grafting for occlusive disease or aneurysms

• Over sew or synthetic grafts (Gortex)

• Anesthesia option; General alone or with epidural catheter adjunct

Abdominal Aortic Aneurysm

Common in older adults >60 (5-7%) Appears to be a genetic link because this type

of aneurysm tends to run in families. Usually occurs in people with atherosclerosis. Symptoms: abdominal, groin, back pain,

syncope, flank mass, or paralysis Diagnosis: routine physical find, abdominal

ultrasound.

Abdominal Aortic AneurysmSociety of Vascular Surgery and the

International Society for Cardiovascular Surgery have characterized abdominal aneurysms as:

-suprarenal

-juxtarenal

-pararenal

-infrarenal

90-95% of AAAs involve the infrarenal abdominal aorta.

True aneurysmInvolves dilation of all 3 layers of the vessel wall:(outer) Tunica externa- fibrous connective tissue

(middle) Tunica Media- smooth muscle/elastic tissue(inner) Tunica interna- epithelial layer, squamous cells

False aneurysmCaused by disruption of 1 or more layers of the vessel wall.

Aneurysms

Abdominal Aortic Aneurysm

<4cm--- u/s q 6 months4-5cm– elective repair w/low operative risk

and good life expectancy.5-6 cm– need repair (mortality rate 0.9-

5%)6-7 cm– threshold for rupture (mortality as

high as 75%).

Overview

Large incision in the abdominal wall, just below your breastbone to top of the pubic bone

Aorta clamped Aneurysm cut open Plaque and clotted blood removed Aortic graft sewn in place- functions as a

conduit for blood flow

Management

– Potential for blood loss; type and cross 2U– large bore IV access (#18 minimal)– Central line; fluids and CVP (PA?)– Fluid warmers with blood tubing– Colloids available; Hespan, albumin– A-line– Vasodilator gtts and vasopressors– Clamping issues… – Heating blankets (burn risk)– Serial H&H, ABGs

Endosvascular Surgery

Performed under local, mac, ga, regional Radial a-line & IV’s in right arm Left arm & both groins used for surgical access Patients are discharged in 1-2 days post-op Approved September 2000 by FDA. Disadvantages:

Endoleaks- (failure to exclude the AAA) Require follow-up eval’s w/serial CT scans Demands more office visits than open

Endovascular grafting (EVR)

Catheter tip inserted through a groin artery into abdominal aorta using fluoroscopy

Catheter’s tip holds a deflated balloon. Balloon inflated, graft opens to span the length

and width of the artery. Devices at both ends of the graft secure it to the

inner wall of aorta to strengthen it and keep from rupturing

May not be available at all hospital facilities. ADV: much less invasive

Endovascular Stent Grafts Indications

Severe COPDSevere cardiac diseaseActive infectionMedical problems that preclude operative

intervention.1.5cm neck of aorta to pass graft between

the renal arteries and the aneurysmAnatomy/ braches/graft selection factors

Thoracic Aortic Surgery

• Aneurysms

• Dissection

• Occlusive disease• Trauma (covered in neuro/trauma)

• Coarctation (covered in Pediatrics)

Risks

• Most often requires CPB

• Large blood losses

• Hypertension pre-op, hypotension intra-op

• Myocardial ischemia

• Renal ischemia

• Spinal ischemia

• Death

Aneurysms

• Rupture-death #1 risk. >6cm 50% rupture w/in one year.

• Surgical repair 2-5% mortality risk

• Leaking = >50% mortality

• Thoracic aneurysms: tracheal &/or bronchial compression/deviation, Laryngeal nerve compression

Thoracic Aneurysm

• Ascending-between aortic valve & innominate

• Arch- between innominate & l. subclavian

• Descending- distal to l. subclavian

Classification of thoracic aneurysms

Anesthetic Management

• Ascending Aorta:

• Similar to cardiac surgery utilizing CPB– Consider fem-fem bypass(risk rupture w/sternotomy

• Special considerations:– Long aortic cross clamp times– Large blood loss– Right radial A-line (why?)

Anesthetic Management

• Aortic Arch: • Similar to cardiac surgery utilizing CPB

median sternotomy• Goal- cerebral protection

– Hypothermia– Thiopental infusion– Maintain flat EEG– Corticosteroids– Free radical scavengers

Anesthetic Management• Descending Aorta:• Usually without CPB• L. thoracotomy incision• One lung anesthesia• PA cath, A-line, Many large bore ivs, TEE, Cell saver, SSEP • Cross Clamping issues:

– ↑SVR, myocardial ischemia, CHF, ↓CO,– Limit fluids pre-clamping– ↑anesthetic depth– Ntg, nitroprusside gtts primed & ready

• Clamp Release issues:– SEVERE HYPOTENSION,↓SVR– Preload w/fluids(crystaloid,colloid) before release, vasodilators OFF– ABGs acidosis (bicarb, ↑min. vent.)– Paraplegia risk d/t thoracolumbar artery injury– Renal failure

Aortic Occlusive Disease

• Incorporates Aortobifem grafting with/without peripheral thromboendarterectomy

• Tx; same as above with focus on location

• Rarely a localized phenomena