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.
B.
C.
D.
Low volume, low pressure
High volume, low pressure
Low volume, high pressure
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 the
Anterior 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!