What Is a Compartment Pressure Measurement Test?

A compartment pressure measurement test is testing for compartment syndrome.

Compartment syndrome is a painful condition caused by excessive pressure building up within and between muscles. 

The muscles in your arms and legs are divided into groups by thick bands of tissue called fascia. The fascia has some openings or compartments which contain muscle tissue, nerves, and blood vessels. The fascia is non-expandable. 

Swelling due to the collection of fluids in the openings or compartments causes the fascia to be pushed against the muscles, nerves, or blood vessels within the arms and legs. This condition is called compartment syndrome.

The high pressure can damage muscles and nerves, which can decrease blood flow. Compartment syndromes may develop suddenly (acute compartment syndrome) or gradually over time (chronic compartment syndrome). 

In either case, compartment syndrome can lead to severe and permanent damage if left untreated. Compartment syndrome can happen at any site within the body. The leg, however, is most frequently affected. Other sites include 

• the forearm, 
• buttocks, 
• hand, 
• foot, 
• arm, 
• thigh and 
• back.

A compartment pressure measurement test is a method to determine the pressure within the muscle compartment. It is done to diagnose compartment syndrome, which is a condition of increased pressure in the non-stretchable space containing nerves, blood vessels, and muscles. 

This may result in damage to the structures within the compartment. If the test shows an increased pressure within the compartment, urgent surgery may be done to decompress and save the tissues from further damage.

Indications include:

• A severe injury such as a car crash
• Badly bruised muscle
• Fracture
• Crush injury
• Tight bandage or cast
• Steroid use

Symptoms suggestive of a compartment syndrome such as

• Excessive pain
• Pain that becomes severe when stretching muscles
• Pale skin
• Tingling or burning feeling in the skin
• Tightness or fullness in the muscle
• Numbness/weakness/paralysis
• Obvious muscle bulging
• Tightness felt when touching the muscle

During the compartment pressure measurement test:

• You will be comfortably positioned depending upon the part of the body where compartment pressure is to be measured.
• The doctor administers local anesthesia. 
• The doctor then inserts a needle into the muscle.
• The needle is attached to a machine that gives a compartment pressure reading. 
• The doctor may exert a little pressure on the affected part or ask you to move the limb or perform any activity that recreates the symptoms. Any rise in compartment pressure is recorded.

A compartment pressure measurement test can be painful. Local anesthesia reduces the pain to some extent. The discomfort caused by the test typically goes away once the test is completed.

The compartment pressure measurement test is relatively safe. The risks, although low, include:

• Infection
• Pain
• Bruising
• Bleeding 
• Nerve damage
• Muscle injury
• Development of acute compartment syndrome and the need for urgent surgery