Changes of interstitial fluid volume in superficial tissues detected by a miniature ultrasound device

We evaluated the changes of tissue layer thickness in circumscribed superfi cial tissue areas with a 10-MHz A-mode and a 20-MHz B-mode ultrasound devic e under alterations in body posture and plasma volume to detect fluid shift s between the different compartments. In 20 male volunteers, we measured ti ssue thickness by A mode and cerium and subcutis thickness by B mode at the forehead before and 30 min after three procedures: change from upright to supine position (P1); change from upright to 30 degrees head-down-tilt posi tion (P2); infusion of 10 ml/kg body wt of Ringer solution (P3). We found a significant correlation between baseline tissue thickness and the sum of c erium and subcutis thicknesses (r = 0.75, P < 0.01). The changes of body po sture and plasma volume resulted in significant increases of tissue thickne ss (P1, 2.9%; P2, 11.6%; P3, 5.8%) and cerium thickness (P1, 4.7%; P2, 8.1% ; P3, 9.1%) but not of the sum of chorium and subcutis thicknesses. The con clude that fluid shifts from the intravascular to the extravascular compart ment are detectible by evaluating corium thickness with a B-mode, or more e asily tissue thickness with an A-mode, ultrasound device.