title: Relationship between medical compression and intramuscular pressure as an explanation of a compression paradox.
abstract: BACKGROUND
  Using standing magnetic resonance imaging (MRI), we recently showed that medical compression, providing an interface pressure (IP) of 22 mmHg, significantly compressed the deep veins of the leg but not, paradoxically, superficial varicose veins.
  
  
  OBJECTIVE
  To provide an explanation for this compression paradox by studying the correlation between the IP exerted by medical compression and intramuscular pressure (IMP).
  
  
  METHODS
  In 10 legs of five healthy subjects, we studied the effects of different IPs on the IMP of the medial gastrocnemius muscle. The IP produced by a cuff manometer was verified by a Picopress® device. The IMP was measured with a 21G needle connected to a manometer. Pressure data were recorded in the prone and standing positions with cuff manometer pressures from 0 to 50 mmHg.
  
  
  RESULTS
  In the prone position, an IP of less than 20 did not significantly change the IMP. On the contrary, a perfect linear correlation with the IMP (r = 0.99) was observed with an IP from 20 to 50 mmHg. We found the same correlation in the standing position.
  
  
  CONCLUSIONS
  We found that an IP of 22 mmHg produced a significant IMP increase from 32 to 54 mmHg, in the standing position. At the same time, the subcutaneous pressure is only provided by the compression device, on healthy subjects. In other words, the subcutaneous pressure plus the IP is only a little higher than 22 mmHg-a pressure which is too low to reduce the caliber of the superficial veins. This is in accordance with our standing MRI 3D anatomical study which showed that, paradoxically, when applying low pressures (IP), the deep veins are compressed while the superficial veins are not.
authors.affiliation: URDIA research unit, EA 4465, Paris Descartes University, France jeanfrancois.uhl@gmail.com.
authors.forename: J-F
authors.initials: JF
authors.lastname: Uhl
authors.affiliation: HIA Begin, St Mandé, France.
authors.forename: J-P
authors.initials: JP
authors.lastname: Benigni
authors.affiliation: Hôpital Saint Antoine, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Cornu-Thenard
authors.affiliation: Zola Orthopédie, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Fournier
authors.affiliation: HIA Begin, St Mandé, France.
authors.forename: E
authors.initials: E
authors.lastname: Blin
mesh_terms: D000368:Aged; D001794:Blood Pressure; D005260:Female; D006801:Humans; D048228:Intermittent Pneumatic Compression Devices; D007866:Leg / Q000098:blood supply* / Q000000981:diagnostic imaging; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011859:Radiography; D014648:Varicose Veins / Q000000981:diagnostic imaging* / Q000503:physiopathology*
keywords: Medical compression; interface pressure; intramuscular pressure; leg vein anatomy; three-dimensional modeling