Chapter 1: Anatomy and Physiology of the Vascular System

Question 1

Integumentary System

Answer 1

skin

• first organ affected in IV access
• protects the body from the environment
• natural barrier to external forces`

Question 2

The Skin is Made up of What?

Answer 2

• Epidermis
• Dermis
• Superficial Fascia`

Question 3

Epidermis

Answer 3

• uppermost layer
• provides a protective covering for the dermis
• thickness varies w/ anatomical location and age

Question 4

Dermis

Answer 4

• under layer

- contains many capillaries and thousands of nerve fibers

Question 5

Superficial Fascia (subcutaneous areolar connective tissue)

Answer 5

• lies below the epidermis and dermis layers of the skin
• superficial veins used for venipuncture are located in this fascia, which varies in thickness and elasticity
• great care and meticulous aseptic technique must be observed since an infection in this area spreads easily causing cellulitis

Question 6

Vessels are made of the following layers (in order)

Answer 6

• Tunica Intima
• Tunica Media
• Tunica Adventitia

Question 7

Vessel Layer: Tunica Intima

Answer 7

inner layer

• smooth layer of flat cells (endothelial lining); smooth surface allows cells and platelets to flow freely
• care must be taken when inserting/removing IV catheters to avoid roughening this smooth surface; any trauma that roughens the endothelial lining encourages aggregation of cells and platelets forming a thrombus; a thrombus could obstruct blood flow or break off creating an embolus

Question 8

Valves

Answer 8

• many veins contain valves that are semilunar folds of endothelium
• found in larger veins
• keep blood flowing toward the heart and often occur at points of branching, causing noticeable bulge in the vein

Question 9

Vessel Layer: Tunica Media

Answer 9

middle layer

• muscular and elastic tissue
• contains nerve fibers, vasoconstrictors, and vasodilators
• receives impulses from vasoconstrictor center in the medulla; keeps vessels in a state of clonus
• stimulates both arteries and veins to contract (vasoconstrict) or relax (vasodilate)
• not as strong/stiff in veins as in arteries; veins collapse or distend as pressure within falls or rises; arteries do NOT collapse

Question 10

Causes of Vessel Spasms

Answer 10

1. Temperature changes
2. Chemical irritation
3. Mechanical irritation

Question 11

How can Vessel Spasms be relieved?

Answer 11

application of heat to the vein which results in vasodilation that improves the flow of blood

Question 12

Vessel Layer: Tunica Adventitia

Answer 12

Outer layer

• areolar connective tissue
• surrounds and supports vessels
• in arteries, layer is thicker than in veins b/c arteries are subjected to greater pressure from the force of blood within
• arteries pulsate, veins do NOT

Question 13

Veins

Answer 13

• carry unoxygenated blood to the heart
• have valves
• will collapse
• located close to the surface
• do NOT pulsate

Question 14

Arteries

Answer 14

• carry oxygenated blood from the heart to the body
• do NOT have valves
• will NOT collapse
• located deep in tissue, protected by muscle
• DO pulsate

Question 15

Aberrant Artery

Answer 15

an artery that is located superficially in an unusual place
-avoid mistaking an aberrant artery for a vein; when a chemical irritation causes a spasm in this artery, permanent damage may result

Question 16

Availability of Veins: Peripheral Venous Anatomy (Upper Extremities)

Answer 16

• veins are usually found in same places in most individuals
• certain situations affect the ability to use the veins most frequently united to venipuncture
• ex: extra body fat, extensive burns, or frequent intravenous drug use; may make it difficult, if not impossible, to cannulate peripheral veins

Question 17

INS Standard for Vein Selection and Placement

Answer 17

• smallest-gauge peripheral catheter that will accommodate the prescribed therapy and patient need while maintaining peripheral vein preservation
• using the forearm to increase dwell time, decrease pain during dwell time, promote self-care, and prevent accidental removal and occlusions
• “steel winged devices are for single dose administrations and are NOT to be left in place”

Question 18

Veins of the Hand

Answer 18

• Digital Veins
• Metacarpal Veins
• Dorsal Venous Arch

Question 19

Veins of the Hand: Digital Veins

Answer 19

• flow along the lateral portions of the fingers; joined to each other by communicating branches
• available for last resort for fluid administration; only isotonic solutions w/o additives
• 21 Gauge scalp needle (well taped) or 20 to 22G catheter

Question 20

Veins of the Hands: Metacarpal Vein

Answer 20

• 3 metacarpal veins are formed by the union of the digital veins on the dorsal of the hand between the knuckles
• position makes them suitable for IV use; saves the veins in the arm if used early in IV therapy
• perform venipuncture for IV therapy at the distal end of the extremity early in the course of therapy; enables nurse to initiate each successive venipuncture above the previous site
• avoid using if infusing antibiotics, potassium chloride, or chemotherapeutic agents
• 20 to 22, 3/4-1 inch in length over-the-needle catheter or 21 to 25G steel needle

Question 21

Veins of the Hand: Dorsal Venous Arch

Answer 21

-formed where the metacarpal veins join the cephalic vein

Question 22

Veins of the Forearm

Answer 22

• Cephalic Vein
• Basilic Vein
• Median Cubital Vein
• Median Ante-brachial Vein

Question 23

Veins of the Forearm: Cephalic Vein

Answer 23

• flows along the radial border/thumb side of the arm
• part of the radial artery runs under a section of the cephalic vein; take care during IV cannulation to avoid puncturing this artery
• b/c of size + position, excellent route for infusing chemically irritating medications and blood transfusion
• 18 to 22G

Question 24

Accessory Cephalic Vein

Answer 24

• joins the cephalic vein below the elbow
• excellent route for blood administration; accommodate large IV cannula; 18 to 22G
• may be difficult to palpate w/ large amount of adipose tissue
• short periods of infusing

Question 25

Veins of the Forearm: Basilic Vein

Answer 25

• located on the ulnar aspect (pinky)
• when other veins have been exhausted, this is still available
• by flexing the elbow and bending the arm up, this vein can be visualized
• brachial artery and ulnar artery run under the basilica vein at various places; take care during IV cannulation to avoid puncturing
• area of the basilica vein outside the antecubital fossa on the ulnar curve of the arm is NOT desirable for venipuncture d/t an increased risk of hematoma formation; if site is used, nurse discontinuing the IV must be sure to apply direct pressure on the site and NOT flex the elbow to stop the bleeding
• 18 to 22G

Question 26

Veins of the Forearm: Median Cubital Vein

Answer 26

• located just below the elbow bend
• connects the cephalic and basilica veins
• 16 to 18G

Question 27

Veins of the Forearm: Median Ante-brachial Vein

Answer 27

• extends along the ulnar portion of the from of the forearm (ventral surface)
• empties into the median cubital vein
• infiltration can occur easily
• 18 to 22G

Question 28

Systemic Veins

Answer 28

1. Superficial/cutaneous
2. Deep veins
3. Venous sinuses

Question 29

Systemic Veins: Superficial/Cutaneous Veins

Answer 29

• superficial or cutaneous veins are used in venipuncture
• located just beneath the skin in the superficial fascia
• can unite in lower extremities; leg veins not used for venipuncture

Question 30

Systemic Veins: Deep Veins

Answer 30

• enclosed in the same sheath with the arteries
• arteriovenous anastomosis may occur as a result of past penetrating injury of the vein and adjacent artery; veins large and torturous; b/c of trauma, the blood flows directly from the artery into the vein
• recognition of an arteriovenous fistula may prevent pain, complication, and loss of time resulting from repeated unsuccessful venipuncture attempts