A new miniature plethysmograph to measure volume changes in small circumscribed tissue areas

Abstract

With an ultrasonic method tissue layer thickness was measured in man in circumscribed superficial tissue areas where the underlaying bone provided good backwall echos. In a 5 mm tissue layer changes of +/- 0.2% could be reliably detected. Knowing the height of the tissue cylinder between the surface of the skin and the bone allowed to calculate the tissue volume. The ultrasonic probes could therefore serve as miniature plethysmograph. Several probes were attached in the frontal region, sternum, along the vertebral column and along the tibia simultaneously. Changes of the volume content of the superficial shell tissues were induced by orthostasis, water immersion and heat exposure. It was possible to assess quantitatively the volume shifts into or out of the superficial tissues. During orthostasis 166 ml of fluid left the superficial tissues of the cephalad parts of the body and 164 ml could be traced in the dependent parts. Heat exposure was followed by a pooling 140 ml in the tissues studied. The most pronounced tissue volume changes were observed in the forehead region during heat exposure.

Austrian Moderate Altitude Study (AMAS 2000) – fluid shifts, erythropoiesis, and angiogenesis in patients with metabolic syndrome at moderate altitude (≅1700 m)

“…The weight of the probe and the Teflon ring together was 6.5 g. The coupling of the equipment with the tissues induced a deformation from an undisturbed level of less than 2%, assuming a subcutaneous tissue thickness between 2 and 8 mm. This was experimentally tested (Kirsch et al 1980;Gunga et al 1994bGunga et al , 1995. Based on the alterations in tissue thickness, the volume increase or decrease at the respective body areas could be determined.…”

Methodological aspects of high‐frequency ultrasound of skin in children

“…The fLEP was not affected by exercise in neither anatomical location, which may indicate that the measure is not as precise or sensitive as measurement of the thickness of cutis or subcutis. Changes in skin thickness have previously been detected with high frequency ultrasound minutes after intravenous fluid infusion (25) and after fluid redistribution due to gravitational stress (26, 27). The increase in thickness of cutis and subcutis on the distal thigh was probably induced by fluid effusion due to higher blood flow in the legs.…”

Measurement of Fluid Volume Shifts during Hemodialysis by A-Mode Ultrasonography

“…Experimental conditions such as orthostasis, water immersion and heat exposure [12,17], effects of the microgravity environment on fluid shifts into and out of superficial tissues [18] could be accurately monitored noninvasively. These changes were established within a few minutes.…”

“…Aukland [11] reported that, among other factors like water intake and renal excretion of salt and water, plasma volume (PV) is regulated by transferring surplus volume to the interstitium or by mobilizing fluid from this space by regulation of the net capillary filtration pressure. Volume changes in this interesting fluid compartment can be measured by ultrasound as recently published by Kirsch et al [12] and Gunga et al [13]. The aim of our study was to evaluate the changes in fluid compartment volume due to plasma refill by measuring the forehead tissue thickness (TT) using a novel hand-held ultrasound device.…”