Evaluation of a Novel Water-Based Volumetric Device for Measuring Upper Limb Lymphedema: First Experience with Healthy Volunteers

Background: Lymphedema is a chronic, progressive disease consisting of tissue swelling resulting from excessive retention of lymphatic fluid. Measuring upper limb volume is crucial in patients to detect disease progression and to study the effects of treatment. The aim is to assess the validity and reliability of a newly developed system, Peracutus Aqua Meth, for measuring the upper limb volume compared with the gold standard water volumetry device. (In this study, the Bravometer was used). Methods and Results: Healthy volunteers were recruited in October 2017. Three measurements were performed per device. The obtained data were recorded per measurement, device, and researcher. Primary outcome was to determine the validity and reliability of the Peracutus Aqua Meth. Secondary outcomes were intra- and interrater reliability, measurement time, self-reported participant satisfaction, and influence of body mass index (BMI). Thirty-nine healthy volunteers were included. Mean differences in the validity in the Peracutus Aqua Meth and Bravometer were 47.26 and 78.16 mL, respectively (p = 0.04), with a Pearson's r of 0.99. Intra- and interrater reliability of the Peracutus Aqua Meth were both 0.99, in the Bravometer 0.96 and 0.97, respectively (p <0.01). The Peracutus Aqua Meth required more time to measure and obtained lower scores in the participant satisfaction questionnaire. BMI was statistically associated with the measurements (p <0.01). Conclusions: The first prototype of the Peracutus Aqua Meth is proven to be an accurate and reliable device for measuring the volume of the arm. Further improvements are needed in case of usability, time management, and participant satisfaction.