Bedside Evaluation of Edema: A simple technique for quantitative evaluation of an important clinical sign

Abstract Background: Edema is a cardinal clinical manifestation. Most clinicians measure edema semi-quantitatively, which is susceptible to subjective and non-reproducible intra- and inter-observer variation. A quick and reliable quantitative method is needed for more accurate measurement. Objective: To demonstrate the reliability of a new clinical examination technique, verified against a novel edema measuring device. Design: A convenience sample enrolled in one day at a community hospital. Patients: Seventeen adult patients with various clinical conditions. One patient was not examined by request and was excluded from analysis. Interventions: Clinical and device estimation of pit depth of edema created by manual pressure at a standard location on 27 limbs. Key Results: Clinical and device measurements were precisely the same 50% of the time; differences in measurements never exceeded 1 mm. The 95% confidence interval was 0.21 with an R2 statistic of 0.87 for all depths of edema, using either clinical or device measurement as the criterion standard, demonstrating excellent correlation between clinical examination and use of the device. Conclusions: Clinical evaluation can estimate edema pit depth in millimeters very accurately. A novel edema measuring device confirms these measurements independently and objectively. It is hypothesized that this new technique will help standardize the teaching of the clinical examination of edema, increase the utility of edema depth measurement over time, and increase intra- and inter-observer reliability of edema evaluation. There is no longer a justification for semi-quantitative determination of edema. NIH trial registry number: NCT03296085