Which area of sterile protective clothing is not considered sterile even before coming in contact with a nonsterile object?

a. front of gown above waist level

b. front of gown below waist level

c. sleeves

d. gloves

Arterial, Venous (and Lymphatic) Systems

Their Significance in Chronic Lower Extremity Wounds

Pain occurring when an extremity is elevated indicates:

A. Arterial disease

B. Venous disease

C. Lymphatic disease

When describing the benefits of your exercise program to your patient (to educate and also to improve compliance), you tell her that regeneration of the affected part of her circulatory system is possible.

Which part of the circulatory system would have been impaired for this to be true?

A. Arterial system

B. Venous system

C. Lymphatic system

The arterial system contains what percentage of total body blood volume?

A. 30%

B. 50%

C. 90%

The venous system is:

A. Low volume, low pressure

B. High volume, low pressure

C. Low volume, high pressure

D. High volume, high pressure

“. . .it is best to think of a wound not as a disease, but rather as a

manifestation of disease.”Joe McCulloch

In order to manage wounds effectively, it is essential to

appreciate the underlying cause.

Part I

A Brief Review of Structure and Function of

Vascular Structures

Overview of 3 Circulatory Systems

• Arterial

• Venous

• Lymphatic

Common Vessel Wall Layers or Coats (Tunics)

• Tunica intima - endothelial cells and basement membrane; uniformly smooth in all structures; (inner)

• Tunica media - smooth muscle and elastic tissue(middle)

• Tunica adventitia – collagen fibers plus blood vessels & nerves (outer)

Variations in Vessel Walls

The common theme of the three layers varies widely, depending on type, size, and location of the artery, vein, or lymph vessel.

Arterial System

• Conveys oxygenated blood to tissues

• Responds to sympathetic and humoral stimuli that maintain blood pressure

• Shunts blood from nonworking to working organs

• Contains 30% of blood volume

Artery Characteristics

• Aorta to arteriole

• Media: thick layers of muscular and elastic tissue

• Diameter responds to left ventricular pressure

• Lie on flexor side of major joints

Arterial Pressure

- normal systolic pressure< 140 mm Hg

- arterial capillary pressure 25 mm Hg

- high pressure/low volume system

Arteries of theAnterior Leg

Arteries of the Posterior Leg

Venous System

• Removes interstitial fluid from tissues

• Returns deoxygenated blood to right atrium

• Contains 70% of blood volume

Vein Characteristics

• Large, medium, and small

• Superficial, deep, and perforating veins

• Valves in medium and large veins formed by folds in intima

• Two large, major veins usually accompany each major artery on flexor side of joints

Venous Pressure

- wide variation (10-90 mm Hg)

- low pressure/high volume

- blood conveyed back to heart by:

muscle pump

respiratory “pump” (vacuum?)

valves

? Questions ?

• What 3 “factors” return venous blood to the heart?

• Bonus: What is one more factor not included in this program?

• What forms venous valves?

Superficial Veins, Posterior Leg

Superficial Veins, Anterior Leg

Lymphatic System

• removes interstitial fluid and large cells that cannot pass into capillary or venule

• has immunologic and phagocytic functions

• controls tone of precapillary arterioles

Characteristics of Lymphatics

• Very thin walls

• Many semilunar, paired valves in larger vessels

• No major direct link to artery or vein except the thoracic and right lymphatic ducts

Pressures in Lymphatics

• Very low pressure

• Lymph moved centrally by valves*, negative pressure in chest, muscle pump (like veins)

• *Lymphangion: lymph vessel segments with valves at either end—a “lymph pump”

Thoracic and Right Lymphatic Ducts

Normal: Equilibrium Between. . .

• Arterial Capillary

• Venous Capillary

• Initial Lymph Vessel

• Interstitial Tissue

Capillary Bed

- capillaries allow diffusion of O2 and nutrients to tissues, AND

- CO2 and other waste products diffuse out of tissues, WHILE

- Open-ended lymphatics move comparatively small amounts of fluid from the capillary bed, but handle large cells

Review: Equilibrium at the Capillary Bed

• Adequate Arterial Supply

• Functional Venous Return Structures

• Patent Lymphatic Structures

• Normal Interstitial “Space”

Part II

Vascular Diseases Producing Wounds in the Lower

Extremity

Classifications of Wounds in Lower Extremity

• Arterial

• Venous

• Mixed

Basis for Wounds of Arterial Origin

• Arteriosclerosis – “hardening of arteries”

-calcification of arteries of all sizes

- loss of elasticity of arterial walls

Atherosclerosis – fibrous “plaque”

- thickening of inner coat (intima)

- fatty degeneration of middle layer (media)

Events Producing Wounds of Arterial Origin

• Diminished arterial flow

• Thrombus or microembolus formation

• Blockage - most often at bifurcations

• Tissue hypoxia and cell death

Appearance of Limb in Arterial Disease – Trophic Changes

• Pale, cool skin

• Abnormal toenail growth

• Hair absent

• Muscle atrophy

• Edema

Trophic Skin Changes in Arterial Disease

Arterial Diseases associated with Wound Development

• Arteriosclerosis obliterans

• Other Examples

- Diabetes

- Vasculitis (RA)

- Sickle Cell Disease

• Thromboangiitis obliterans*

Arteriosclerosis obliterans

• Disease of large and medium sized arteries

• Associated with:– High blood pressure– Hyperlipidemia– Arterial occlusion particularly at bifurcations

Necrosis of Toe in Arteriosclerosis obliterans

Heel Ulcer in Arteriosclerosis Obliterans

Other Examples: Arterial

• Diabetes – hyperglycemia—”sticky blood” adds to development of atherosclerosis

• Vasculitis – inflammation blocks blood flow

• Sickle Cell Disease – clumps of misshapen red cells occlude small arteries

Thromboangiitis obliterans

• Also called Buerger’s Disease

• Affects adults under age 40

• *Veins also involved

• Unlike arteriosclerosis obliterans, may affect hands

• Primary cause: cigarette smoking!

Thromboangiitis obliterans - early

Thromboangiitis obliterans - late

Noninvasive Tests of Arterial Sufficiency

• Doppler ultrasound

• Skin temperature

• Arterial perfusion– Pulses #– Capillary refill test #– Venous filling time #– Rubor of dependency #

Rubor of Dependency in Arteriosclerosis obliterans

Pathology of Wounds associated with Venous Diseases

• Venous thrombosis (thrombophlebitis)– Deep vein (DVT)– Superficial vein

• Venous Stasis– Venous obstruction– Varicose veins

• Ulceration

Etiology of Venous Stasis Wounds

• Old theory: venous congestion (1917)

• insufficient oxygenation of tissues

• WRONG !!!

• Tissues have been shown to be adequately oxygenated.

Etiology of Venous Stasis Wounds, continued

• Arteriovenous fistula theory (1947)

• Fibrin cuff theory (1982)

• Leukocyte activation (1988)

ALL mostly discredited as causes of ulcers. . .

Question ???

• True or False

• Your patient was once told that the reason she developed ulcers at the ankles was that the swelling in her legs prevented adequate oxygen from reaching the tissues.

• How would you respond?

Present Theory of Etiology of Venous Stasis Wounds

• High pressure causes extravasation of macromolecules (e.g. fibrinogen) and red blood cells into dermal interstitium.

• Degradation of these molecules and cells attracts leukocytes, macrophages, mast cells (inflammation).

• Inflammation leads to tissue injury (breakdown) and wound development.

Venous Thrombosis

Varicose Veins

Varicose Veins

Venous Stasis Ulcer

Importance of the “Calf Pump” Normal Edema Present

Appearance of Limb in Venous Insufficiency (Early)

• Stasis dermatitis

• Erythema

• weeping blebs or vesicles

• edema

Stasis Dermatitis - Early

Appearance of Limb in Venous Insufficiency (Late)

• Induration of subcutaneous tissue

• Brawny (brownish) discoloration: “Hemosiderin” iron-containing pigment

• Edema

• Ulceration usually around medial malleolus

Stasis Dermatitis (Late)

Questions. . .

1. Your venous stasis wound patient asks specifically:

a. why she developed varicose veins

b. why her lower calf is discolored.

You would explain that. . .

Noninvasive Tests of Venous Sufficiency

• Doppler ultrasound

• Plethysmography

• Percussion test #

• Brodie-Trendelenburg test #

• Venous filling time #

Venous Filling Time

Tests for Deep Venous Thrombosis (DVT)

- cuff test #

- test for Homan’s sign #

Combined Pathologies

• Arterial and venous disease may coexist

• Venous disease can contribute to lymphatic dysfunction, and vice-versa

How is Lymphedema different from Edema?

• Edema: tissue fluid accumulated in the interstitial spaces secondary to many causes

• Lymphedema: protein rich fluid that accumulates in the tissue secondary to lymphatic blockage

Lymphedema itself not usually associated with wounds

• A complete discussion of lymphedema will be addressed in the oncology section of this course.

Combined Pathologies

• Thorough examination

• Teamwork

• Patient education

• General rule: treat most threatening aspect first (usually arterial insufficiency)

The End!