The journal article may be accessed at reseachgate.net at this link:
https://www.researchgate.net/profile/Roger_Kamm/publication/12681713_The_Effects_of_External_Compression_on_Venous_Blood_Flow_and_Tissue_Deformation_in_the_Lower_Leg/links/0fcfd51236d6adf190000000.pdf
The article uses FEA (finite element analysis) to model venous flow and vein collapse when symmetric and asymmetric compression is applied.
A few important points that I have identified are the following:
1. The elastic modulus of skin is 2 x 10^6 Pa. The elastic modulus of the fascia is 3.4 x 10^8 Pa. Elastic modulus is the material's resistance to deformation (not permanent deformation). This means that skin is much more easily deformed than fascia.
2. Asymmetric compression more effectively narrows the vein diameter than symmetric circumferential compression.
From Fig. 4 of the article, for the same amount of compression, for example, 30 mmHg, asymmetric compression (designated as Anterior-Posterior Compression) effectively collapses the vein whereas circumferentially-uniform compression at 30 mmHg leaves the vein relatively open.
3. Because asymmetric compression more effectively narrows the vein diameter, the blood flow velocity is higher with asymmetric compression.
From Fig. 7 of the article, asymmetric compression causes a higher flow velocity peak than symmetric compression (as determined at the thigh location). The article also looks at single versus two-compartment graded-sequential compression (Fig. 7 bottom plot). There also, asymmetric compression shows a higher flow velocity. Surprisingly, the two-compartment, graded-sequential pressure application does not show a higher flow velocity than a single chamber pressure application. This suggests single-chamber compression devices are adequate.
The article suggests that an effective compression device should deliver asymmetric (not uniform circumferential) compression and multi/gradient compression chambers may not be necessary.
Lymphedema is also called lymphatic obstruction, is swelling of tissues due to the collection excess fluid called lymph in tissues.
ReplyDeleteThe lymphatic system is a part of the circulatory system and Lymphedema disease is caused by a blockage of this circulatory system. Lymphedema commonly affects one of the arms, legs or both arms, both legs may be affected. Some patients might suffer swelling in the head, genitals, or chest. Absorption of fats, Infections, swelling, heavy or skin tightened at the diseased area, aching or tingling pain, illness is the symptoms of Lymphedema. Surgery treatment and diagnosis are available are at Vascular Care Center, Hyderabad by skilled surgeons.
Vascular Surgeon in Hyderabad