Compartment pressure is measured to assist in diagnosing compartment syndrome. Measurement of compartment pressure is a hospital-based procedure that requires considerable technical skill; an orthopedic or general surgeon is typically consulted.
Compartment pressures can be measured in the 4 compartments of the lower leg (anterior, deep posterior, lateral, and superficial posterior).
The Stryker® system, a commercially available instrument, is used here. Know what equipment is available at your particular institution.
(See also Compartment Syndrome.)
Indications for Measuring Lower Leg Compartment Pressure
Suspected compartment syndrome
Compartment syndrome is suggested by worsening pain of the lower leg that is disproportionate to the severity of the apparent injury and exacerbated by passive stretching of compartment muscles. On palpation, the compartment may be swollen and tense.
Contraindications to Measuring Lower Leg Compartment Pressure
Absolute contraindications
None
Relative contraindications
Infection of skin or deeper tissues at the anticipated site of needle insertion: If possible, use an alternate, uninfected site.
Bleeding diathesis, which may need to be corrected before compartment pressure measurement
Complications of Measuring Lower Leg Compartment Pressure
Erroneously high or low pressure measurements may be due to poorly placed or obstructed needles, faulty or inaccurately calibrated devices, patient agitation, or excess test saline injected into the compartment. These measurement errors can lead to incorrect treatment.
Infection, bleeding, or tissue damage resulting from needle insertion may occur.
Equipment for Measuring Lower Leg Compartment Pressure
Sterile gowns, gloves, and drapes
Sterile gauze
The Stryker® system, containing a needle, tubing, and transducer
25-gauge needle
About a 3-mL or larger syringe for local anesthetic injection
Sterile dressings
pulse oximetry, and capnometry if available
Additional Considerations for Measuring Lower Leg Compartment Pressure
Sterile technique is required to prevent microbial contamination of the compartment tissues.
Maintain a low threshold for measuring compartment pressure in at-risk patients because deep compartments may not feel tense or grossly swollen, pain is nonspecific, and, in obtunded patients, symptoms may be absent.
Diagnosis must be made and treatment started before pallor or pulselessness develops.
Relevant Anatomy for Measuring Lower Leg Compartment Pressure
The lower leg has 4 compartments:
Anterior compartment: Includes the tibialis anterior, extensor hallucis longus, and extensor digitorum longus muscles, the deep peroneal nerve, and the anterior tibial artery
Deep posterior compartment: Includes the tibialis posterior, flexor hallucis longus, and flexor digitorum longus muscles, the tibial nerve, and the posterior tibial and peroneal arteries
Lateral compartment: Includes the peroneus longus and peroneus brevis muscles and the superficial peroneal nerve
Superficial posterior compartment: Includes the gastrocnemius and soleus muscles
The anterior compartment and deep posterior compartment are most commonly affected by compartment syndrome.
Positioning for Measuring Lower Leg Compartment Pressure
Position the patient with the affected leg at heart level and so that the needle can enter the skin at an angle perpendicular to the compartment being measured.
Step-by-Step Description for Measuring Lower Leg Compartment Pressure
Prepare the equipment
Open the Stryker® system and remove the contents onto a sterile field.
Place the needle firmly onto the tapered stem of the diaphragm chamber. Remove the cap on the pre-filled syringe and attach it to the stem on the opposite side.
Open the cover of the monitor and place the chamber into the pressure monitor with the black surface down. Carefully push it until it is seated in place. Snap the cover of the monitor closed.
Hold the needle at a 45° angle upward and depress the plunger to purge the system of air. Do not allow saline to trickle down the needle into the transducer well.
Turn on the monitor and check for a numeric reading to appear in the display window.
Calibrate the device: Hold the device at the intended angle of insertion. Press the "zero" button and ensure that, after a few seconds, the display reads “00.” The display must read “00” before continuing. For each additional measurement, the unit must be recalibrated to “00.”
General steps for all compartments
Do a pre-procedure neurovascular examination of the affected lower leg.
Using a 25-gauge needle, place a wheal of local anesthetic over the needle entry site. Avoid injecting anesthetic into the deeper tissues of the muscle and fascia. Doing so may falsely elevate the compartment pressure measurement.
Hold the assembled and calibrated pressure monitor perpendicular to the compartment being measured and insert the needle as gently as possible through the skin to a depth appropriate for the target compartment.
Slowly inject 0.3 mL of saline into the compartment.
Wait for the display window to show that equilibrium has been reached and record the resultant pressure.
For each additional measurement, recalibrate the unit to "00" and repeat the process.
A measured pressure of more than about 30 mm Hg or within about 30 mm Hg of diastolic blood pressure supports the diagnosis of compartment syndrome and indicates consideration for immediate fasciotomy.
Compartment syndrome is possible even if compartment pressure is not elevated; if suspected based on clinical findings, the diagnosis should be presumed and compartment pressures should be measured serially.
Specific steps for the anterior compartment
Position the patient supine.
Palpate the anterior border of the tibia at the junction of the proximal and middle thirds of the lower leg.
Insert the needle 1 cm lateral to the anterior border of the tibia (the most lateral part of the tibia), perpendicular to the skin.
Advance the needle to a depth that allows a rise in pressure when you press with your finger over the anterior compartment just proximal or distal to the needle insertion site, or with plantarflexion of the foot or dorsiflexion of the foot.
Specific steps for the deep posterior compartment
Position the patient supine with the lower leg slightly elevated if the clinical situation permits.
Palpate the medial border of the tibia at the junction of the proximal and middle thirds of the lower leg.
Insert the needle just posterior to the medial border of the tibia.
Advance the needle perpendicularly to the skin toward the posterior border of the fibula to a depth of 2 to 4 cm.
Confirm proper needle placement by observing a rise in pressure during toe extension and ankle eversion.
Specific steps for the lateral compartment
Position the patient, usually supine, on the stretcher. Elevate the lower leg slightly.
Palpate the posterior border of the fibula at the junction of the proximal and middle thirds of the lower leg.
Insert the needle just anterior to the posterior border of the fibula, on the lateral aspect of the leg.
Advance the needle perpendicularly to the skin and direct it toward the fibula to a depth of 1 to 1.5 cm. If the needle contacts bone, withdraw it 0.5 cm.
Confirm proper needle placement by observing a rise in pressure when you press with your finger over the lateral compartment just inferior or superior to the needle entry site and with inversion of the foot and ankle.
Specific steps for the superficial posterior compartment
Position the patient prone.
Visualize a transverse line at the level of the junction between the proximal and the middle thirds of the lower leg.
Insert the needle at this level, 3 to 5 cm on either side of the anatomic midline of the lower leg.
Advance the needle perpendicular to the skin and direct it toward the center of the lower leg to a depth of 2 to 4 cm.
Confirm proper needle placement by observing a rise in pressure when you press with your finger over the posterior compartment just inferior or superior to the needle insertion point and with dorsiflexion of the foot.
Aftercare for Measuring Lower Leg Compartment Pressure
Apply sterile dressings to all needle entry sites.
Repeat the neurovascular examination of the leg.
Warnings and Common Errors for Measuring Lower Leg Compartment Pressure
Compartment syndrome is a clinical, often difficult, diagnosis to make. Early consultation with an orthopedist or general surgeon is recommended.
Presence of distal pulses and capillary refill and even normal compartment pressures do not rule out compartment syndrome.
Measure pressures for all possibly affected compartments in the involved extremity.
Tips and Tricks for Measuring Lower Leg Compartment Pressure
To maximize accuracy, measure pressure at sites of trauma or maximum palpable tension.
