Kapitel 19 - Bandages and drains

Question 1

What is the function of the Contact (primary) layer of a bandage?

Answer 1

• barrier between the wound and external contaminants
• absorbing or transferring exudate to the secondary layer
• and maintaining a moist wound environment

Question 2

How should dressings with an adhesive perimeter be used?

Answer 2

Only on periwound skin that is healthy and dry

Question 3

Give example of highly abortive dressings

Answer 3

Hypertonic saline

• Calcium alginate
• Dry polyurethane foam dressings

Question 4

How often should you change a non-infected would in inflammatory/debridement phase?

Answer 4

every 2 to 3 days

and then every 4 to 7 days as the repair phase progresses

Question 5

When is Polyurethane foams changed?

Answer 5

When absorbed fluid comes within 1 inch (2,5 cm) of the foam edge

Question 6

When should calcium alginate be removed?

Answer 6

When it has turned into a gel (which takes 1 or more days)

because the nongelled form may adhere to the wound, causing damage when removed

Question 7

Why is application of nonhydrophilic dressings (such as gauze) that adhere to the wound is no longer recommended?

Answer 7

Because they damage the wound bed when removed and may leave foreign material behind, delaying healing and causing chronic inflammation

Question 8

How should the circumferential (secondary and tertiary layer) be applied?

Answer 8

with each new wrap overlapping the previous one by 50%

And the last layer should end proximally

Question 9

What is Laplace’s law?

Answer 9

the pressure applied at each point under a bandage is proportional to (N × T)/(R × W),

where N is the number of bandage layers, T is the bandage tension, R is the radius of curvature of the body part being bandaged, and W is the width of the bandage material under tension

(Because limb circumference and thus the radius of curvature (R) generally increase in a distal-to-proximal direction, the pressure gradient under an evenly applied bandage naturally decreases proximally)

Question 10

What’s is the initial pressure under a Robert Jones bandage?

Answer 10

50 to 60 mm Hg.

This pressure declines during the first 15 minutes

Question 11

Whos layer establishes the subbandage pressure?

Answer 11

tertiary layer

Question 12

What materials are preferred for the tertiary layer?

Answer 12

Porous materials so that fluid absorbed by the intermediate layer can evaporate, avoiding maceration and decreasing the risk for bacterial growth in the bandage

Question 13

Give examples of pressure relief can be obtained

Answer 13

• doughnut bandages
• bandage windows
• splints.

Question 14

When is ischemic injury caused by bandages most reported?

Answer 14

Within 24 to 48 hours of bandage application

Question 15

What is the surface temperatur of the would and how long after a bandage change does it take to regain its original temperature?

Answer 15

16°C below normal body temperature. and the wound can take 40 minutes to regain its original temperature when rebandaged

Question 16

Which drain material causes the most inflammatory response?

Answer 16

Red rubber and latex

Question 17

Why is it not recommended to have both ends of a Penrose drain exit the skin?

Answer 17

• it is unlikely to increase drainage (which will occur primarily through the more dependent exit point)
• It limits the ability to have a portion of the drain in the deepest aspect of the affected tissue.
• creates an additional entry site for bacteria or other contaminants

Question 18

What does Poiseuille’s law describe?

Answer 18

Laminar flow through a drain

(F = dPπr4/8nL, where F is the flow of fluid through the drain lumen, dP is the pressure difference between the two ends of the drain, r is the radius of the tube, n is the viscosity of the fluid, and L is the drain length)