Practical ST-504 guide
What changes when the question is leg swelling or edema?
“Leg swelling therapy” and “edema therapy legs” sound like product questions. They may actually be health questions. A page about the ST-504 can explain the device. It cannot identify why a leg is swollen or choose a set

Before the session
Prepare the controller, sleeve, cable, and treatment area.
During use
Stay awake, seated, and within the stated product scope.
After the session
Check comfort and follow the care instructions.
What changes when the question is leg swelling or edema?
“Leg swelling therapy” and “edema therapy legs” sound like product questions. They may actually be health questions. A page about the ST-504 can explain the device. It cannot identify why a leg is swollen or choose a setting for a diagnosis.
The first useful distinction is context. New, one-sided, painful, warm, red, rapidly worsening, or unexplained swelling needs more attention than an ordinary comfort question. Do not use a stronger pressure setting to test what the swelling means.
Separate an equipment question from a body question
An equipment question sounds like this: Is the sleeve connected? Is the controller charged? Does the selected mode run as described? Those questions belong to the ST-504 setup guide and the instruction for use.
A body question sounds different: Why is the swelling new? Why is one leg larger? Why is the skin warm or painful? A product page cannot answer those questions. Use the ST-504 safety and contraindications guide and seek appropriate professional guidance.
What a reader can observe safely
If the device is being used within its manual limits, record only concrete details. Note the selected mode. Note the pressure label. Check sleeve position, tubing, battery state, session time, and skin appearance. These notes describe the device and the session.
They do not measure circulation. They do not diagnose edema. They do not show that compression is treating the cause of swelling.
When to stop the device question
Stop for pain, increasing numbness, a new skin color or temperature change, worsening symptoms, unusual heat, visible damage, smoke, or unexpected operation. Do not restart at a higher pressure. Do not change several controls at once.
Sudden or severe symptoms should not be handled as product troubleshooting. Follow local emergency guidance when the person may be acutely unwell. Keep the device off while the concern is assessed.
What this page can and cannot promise
This page can help a reader decide whether the next step is equipment checking or safety guidance. It cannot promise edema relief. It cannot prevent a clot. It cannot replace a clinician’s assessment of swelling, medication, circulation, a wound, or a recent procedure.
For the related medical context, see venous stasis and compression. That page also keeps diagnosis and product information separate.
For general device terminology, consult the FDA medical device information. It provides regulatory context, not individualized permission to use the device.