ST-504 mechanism guide
How does the five-chamber sleeve layout affect a session?
Understand chamber order, fit, and observable movement without inferring a medical outcome.
Follow sections
The sleeve changes pressure through five areas.
Check fit
Twists and kinks change the sensation.
Write notes
Record order, position, and repeatability.
The ST-504 sleeve contains five inflatable sections. The controller sends air through the tubing and changes those sections in a programmed order. This is why the device feels different from a flat garment or a single inflatable cuff.
Think in sections, not one overall squeeze
One chamber may inflate while another releases. The pressure can move through the covered area as the program advances. A reader can observe the order, timing, and repeatability of that movement without making a medical conclusion.
Check the mechanism guide for the air path. Use the working modes guide when the question is about Sequence, Circulation, or Whole labels.
Fit changes what the chambers feel like
A twisted sleeve can create a sharp edge. A loose connector can prevent the expected inflation. A kinked tube can change the chamber pattern. Clothing and body position can also change the sensation.
Make the physical checks before changing pressure. Keep the controller within reach. The sleeve should remain secure without becoming painful or difficult to remove.
Why chamber notes are better than intensity words
Words such as strong, weak, or tight are hard to compare between sessions. A chamber note is clearer. Record which section inflated, whether the release followed, and whether the sleeve moved. Add the selected mode and pressure label. This gives the next person a physical detail to inspect instead of a conclusion about the body.
What to record
Write down which section inflated first, whether the pattern repeated, whether the sleeve moved, and whether the display matched the selected program. Note any visible skin change or equipment damage. These are useful product observations.
Stop for pain, marked numbness, unusual heat, visible damage, smoke, or unexpected behavior. The chamber layout explains operation. It does not establish suitability for a diagnosis.
The layout also explains why a single overall rating such as strong is incomplete. One chamber may feel different because of position, clothing, or programmed timing. Describe the location and sequence instead of assigning a medical meaning to the sensation. Add the selected mode, pressure label, session time, and battery state to the note.
When a chamber behaves differently, compare the physical path first. Check the sleeve fold, connector seating, tubing bend, and controller state. If the pattern remains unusual after those checks, stop and use the support route. Do not treat one chamber’s sensation as proof of a body-side problem or a device benefit.
Source boundary for chamber questions
The ST-504 instruction for use controls the sleeve layout. General FDA medical device information does not determine whether compression is suitable for a particular condition.