2 - Compression

Compression

A mechanical force that inc external pressure on the body or a body part

Hydrostatic pressure

Pressure exerted by a fluid

How does compression work?

• Compression applies pressure to the fluid in the interstitial space (more than the pressure in the vessels), and this pressure limits or reverses the outflow of fluid from blood vessels and lymphatics

• Simplified explanation: forces the fluid back into the vessels, causes it to circulate rather than accumulate in the interstitial space

Why might intermittent compression be more effective than static compression?

Because it varies the amount of pressure and “milks” the fluid from the distal to the proximal vessels

Compression can be used to limit the shape and size of new tissue formation.

True

What are the clinical uses for compression bandages or garments?

• Residual limb shaping after amputation

• Burn damaged skin

How does compression affect tissue temp?

• Inc superficial tissue temp ) b/c of insulation of the area)

• Inc in tissue temp inc activity of temp-sensitive enzymes, which breaks down collagen

What are the indications for compression used to treat edema? (VERY IMPORTANT)

Edema caused by:

• Injury

• Nutritional imbalance

• Venous insufficiency

• Lymphatic obstruction

• Airline travel

• Pregnancy

• Physical activity

What causes edema?

An imbalance between hydrostatic pressure (pushes fluid out of the vessels) and osmotic pressure pushes fluid into vessels

(VERY IMPORTANT) Compression should not be used for edema caused by…

• CHF

• Cirrhosis

• Acute renal disease

• Diabetic glomerulonephritis

• Malnutrition

• Radiation

Why is compression used for DVT?

• Inc venous return and reduces chance of thrombus formation

• Especially important in sedentary patients and for people who travel a lot on planes

Why is compression used for venous stasis ulcers?

Reduces risk of ulcer formation and speed healing of present ulcers

Intermittent or static compression may be used to shape a residual limb after amputation to prepare a patient for a prosthetic?

True

Although it can be used for shape a limb after amputation, what specific precaution should be taken when using compression for this?

Do not place compression over a bony prominence

How can DVT be prevented?

Compression socks and light compression, but do NOT use compression if someone already has it

What are other uses for compression?

• DVT prevention - stockings, light compression

• Venous statis ulcers - stockings

• Residual limb shaping after amputation to prepare for an prosthetic - intermittent or static compression but avoid excessive pressure on bony parts

• Control hypertrophic scarring - at least 23 hrs with 20-30 mm Hg for 12 months of longer

What are contraindications for compression?

• Heart failure or pulmonary edema

• Recent or acute DVT, thrombophlebitis, or pulmonary edema

• Total obstruction of lymphatic or venous return

• Severe peripheral arterial disease or ulcers resulting from arterial insufficiency - will overload the arteries

• Acute local skin infection

• Significant hypoproteinemia

• Acute trauma or fracture

• Arterial revascularization

What are the precautions for compression?

• Impaired sensation or mentation

• Uncontrolled HTN

• Cancer

• Stroke or significant cerebrovascular insufficiency

• Superficial peripheral nerves

How is ABA (ankle-brachial index) calculated?

Ankle systolic pressure/brachial stystolic pressure

What is resting pressure?

Pressure exerted by elastic when it is put on stretch - think short/long stretch bandage

What is work pressure?

Pressure produced by active measures pushing against an inelastic bandage

What compression garment pressure is used to prevent DVTs?

16-18 mmHg

What compression garment pressure is used for scar tissue control (including hypertrophic)?

20-30 mmHg

What compression garment pressure is used for edema control?

30-40 mmHg

What are intermittent pneumatic compression pumps used for?

Edema, venous stasis or DVT prevention OR residual limb reduction

What are the inflation and deflation times for intermittent pneumatic compression for edema, venous stasis ulcers, or DVT?

Inflation 80-100 sec, deflation 25-50 sec

What are the inflation and deflation times for intermittent pneumatic compression for residual limb reduction?

Inflation 40-60 sec, 10-15 sec (3:1 ratio)

What are the pressure limitations for intermittent compression?

• UE - 60mmHg (the one we will use)

• LE - 80 mmHg (the one we will use)

What are the potential adverse effects external compression?

• Aggravation of physiological problems causing edema (heart, kidney, liver failure

• Impaired arterial compression (acts like a tourniquet)

• Inc edema

• Inc BP

Which of the following is NOT a direct indication for the use of compression?

Pain relief

Which of the following is believed to be MOST effective for improving circulation?

sequential multichamber compression

What determines hydrostatic pressure?

blood pressure and the effects of gravity

What is the relationship between trauma, vascular permeability and edema?

Trauma can result in acute inflammation which increases vascular permeability and results in edema.

Edema caused by _____ should not be treated with compression because it may worsen the overall health of the patient.

cirrhosis

Compression is the commonly used treatment for _______________.

venous stasis ulcers

If the ABI (ankle-brachial index) is more than 0.6, all forms of static compression are contraindicated.

False

Which of the following can be applied after acute trauma to an area?

Static compression

What type of bandage produces low resting pressure, but can cause high working pressure during muscle activity?

short-stretch

How many hours a day is compression applied for controlling hypertrophic scarring?

23 hrs

Arterial insufficiency is a(n) __________ for intermittent compression

contraindication