title: How does adding and removing liquid from socket bladders affect residual-limb fluid volume?
abstract: Adding and removing liquid from socket bladders is a means for people with limb loss to accommodate residual-limb volume change. We fit 19 people with transtibial amputation using their regular prosthetic socket with fluid bladders on the inside socket surface to undergo cycles of bladder liquid addition and removal. In each cycle, subjects sat, stood, and walked for 90 s with bladder liquid added, and then sat, stood, and walked for 90 s again with the bladder liquid removed. The amount of bladder liquid added was increased in each cycle. We used bioimpedance analysis to measure residual-limb fluid volume. Results showed that the preferred bladder liquid volume was 16.8 +/- 8.4 mL (mean +/- standard deviation), corresponding with 1.7% +/- 0.8% of the average socket volume between the bioimpedance voltage-sensing electrodes. Residual-limb fluid volume driven out of the residual limb when bladder liquid was added was typically not recovered upon subsequent bladder liquid removal. Of the 19 subjects, 15 experienced a gradual residual-limb fluid volume loss over the test session. Care should be taken when implementing adjustable socket technologies in people with limb loss. Reducing socket volume may accentuate residual-limb fluid volume loss.
authors.affiliation: University of Washington, 3720 15th Ave NE, Seattle, WA 98195. jsanders@u.washington.edu.
authors.forename: Joan E
authors.initials: JE
authors.lastname: Sanders
authors.forename: John C
authors.initials: JC
authors.lastname: Cagle
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Harrison
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Myers
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Allyn
mesh_terms: D000328:Adult; D000672:Amputation Stumps / Q000033:anatomy & histology* / Q000503:physiopathology*; D001186:Artificial Limbs; D017097:Electric Impedance; D045604:Extracellular Fluid / Q000502:physiology; D005260:Female; D018495:Fluid Shifts; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000502:physiology; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D013977:Tibia / Q000601:surgery