title: Upper-extremity volume measurements in women with lymphedema: a comparison of measurements obtained via water displacement with geometrically determined volume.
abstract: OBJECTIVE
  Upper-extremity (UE) swelling following breast cancer treatment is a frequent manifestation of lymphedema. In order to document outcomes from lymphedema treatments, reliable, valid, and practical measurements of UE swelling are necessary. The purpose of this study was to compare geometric methods of determining UE volumes with water displacement methods.
  
  
  METHODS
  The edematous hand, forearm, and upper arm of 50 women with UE swelling secondary to lymphedema were measured.
  
  
  METHODS
  Upper-extremity volumes were determined by water displacement using arm and hand volumeters. Displaced water was weighed to determine volume. Circumferential girth measurements were taken. Width and depth measurements of the hand were taken with a tension-controlled caliper. Geometric volume formulas for a cylinder, frustum, rectangular solid, and trapezoidal solid were used to calculate volumes of the arm and hand at different measurement intervals.
  
  
  RESULTS
  Intraclass correlation coefficients [2,1] for interrater and intrarater reliability of all water and geometric measurements of the arm and hand were.91 to.99 and.92 to.99, respectively. Water displacement correlated with geometric measurements in the arm (r=.97-.98) and in the hand (r=.81-.91). The limits of agreement (LOA) indicated that water and geometric measurements of arm volume differed by 479 to 655 mL. Scatterplots of the LOA data indicated in that geometric volumes were either larger or smaller than water volumes. The smallest standard error of measurement for the arm measurements was for the 6-cm frustum method at 115 mL; for the hand measurements, the smallest standard error of measurement was for the frustum method at 16 mL.
  
  
  CONCLUSIONS
  Volume of an edematous UE calculated by geometric formulas correlated strongly with volume determined by water displacement. Although strongly correlated, the measurements obtained by the 2 methods did not agree.
authors.affiliation: Department of Physical Therapy and Human Movement Sciences, The Feinberg School of Medicine, Northwestern University, 645 N Michigan Ave, Suite 1100, Chicago, IL 60611, USA. t-sander@northwestern.edu
authors.forename: Antoinette P
authors.initials: AP
authors.lastname: Sander
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Hajer
authors.forename: Kristie
authors.initials: K
authors.lastname: Hemenway
authors.forename: Amy C
authors.initials: AC
authors.lastname: Miller
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry / Q000379:methods*; D001132:Arm / Q000473:pathology*; D005260:Female; D006801:Humans; D008209:Lymphedema / Q000175:diagnosis*; D008875:Middle Aged