Distribution of Extracellular Fluid in Legs with Venous Edema and Lymphedema

Fluid Distribution Patterns in Early-Stage Upper Extremity Lymphedema

INTRODUCTION

Magnetic resonance imaging (MRI) stage 1 (early stage) upper extremity lymphedema is characterized by fluid infiltration in the subcutaneous tissues that does not exceed 50% of the extremity circumference at any level. The spatial fluid distribution in these cases has not been detailed and may be important to help determine the presence and location of compensatory lymphatic channels. The aim of this study is to determine whether there was a pattern of distribution of fluid infiltration in patients with early-stage lymphedema that could correspond to known lymphatic pathways in the upper extremity.

METHODS

A retrospective review identified all patients with MRI stage 1 upper extremity lymphedema who were evaluated at a single lymphatic center. Using a standardized scoring system, a radiologist graded the severity of fluid infiltration at 18 anatomical locations. A cumulative spatial histogram was then created to map out regions where fluid accumulation occurred most and least frequently.

RESULTS

Eleven patients with MRI stage 1 upper extremity lymphedema were identified between January 2017 and January 2022. The mean age was 58 years and the mean BMI was 30 m/kg2. One patient had primary lymphedema and the remaining 10 had secondary lymphedema. The forearm was affected in nine cases, and fluid infiltration was predominantly concentrated along the ulnar aspect, followed by the volar aspect, while the radial aspect was completely spared. Within the upper arm, fluid was primarily concentrated distally and posteriorly, and occasionally medially.

CONCLUSIONS

In patients with early-stage lymphedema, fluid infiltration is concentrated along the ulnar forearm and the posterior distal upper arm, which aligns with the tricipital lymphatic pathway. There is also sparing of fluid accumulation along the radial forearm in these patients, suggesting a more robust lymphatic drainage along this region, possibly due to a connection to the lateral upper arm pathway.

Tissue Dielectric Constant of the Lower Leg as an Index of Skin Water: Temporal Variations

Tissue dielectric constant (TDC) measurements are a convenient, reliable, and accurate way to noninvasively access local tissue water content and its change with time or treatment. The method has been widely used for upper extremity lymphedema assessments but less so for lower extremities. For lower extremity assessments, it would be useful to have an estimate of the expected inter-leg TDC differentials of normal non-affected legs to help interpret measured inter-leg differentials when such measurements are done in patients with lower extremity edema or lymphedema. The goals of this study were to determine normal inter-leg TDC differences, quantify TDC temporal changes during 60 minutes of supine lying in a group of 10 middle-aged women (42-57 years), and evaluate the change in TDC values as measured throughout the day from 0800 to 2000 hours in a group of 10 younger women (23-28 years). The overall findings indicate that TDC measurements, as an assessment parameter of lower extremity localized skin-to-fat tissue water, are only minimally dependent on potential confounding factors such as 60-minute supine lying or the time of day at which the measurements are made. If the small sample size of the present study is reflective of the larger population, an inter-leg TDC ratio exceeding a value of 1.2 is suggested as a threshold for judging unilateral lower extremity edema or lymphedema. This possibility needs assessment in women with these conditions.

Clinical Utility of Fluid Volume Assessment in Heart Failure Patients Using Bioimpedance Spectroscopy

Background: Bioimpedance spectroscopy (BIS) is a non-invasive method used to measure fluid volumes. In this report, we compare BIS measurements from patients with heart failure (HF) to those from healthy adults, and describe how these point-of-care fluid volume assessments may be applied to HF management.

Methods and results: Fluid volumes were measured in 64 patients with NYHA class II or III HF and 69 healthy control subjects. BIS parameters including extracellular fluid (ECF), intracellular fluid (ICF), total body water (TBW), and ECF as a percentage of TBW (ECF%TBW) were analyzed. ECF%TBW values for the HF and control populations differed significantly (49.2 ± 3.2% vs. 45.2 ± 2.1%, respectively; p < 0.001); both distributions satisfied criteria for normality. Interquartile ranges did not overlap (46.7–51.0% vs. 43.8–46.4%, respectively; p < 0.001). Subgroup analyses of HF patients who underwent transthoracic echocardiography showed that impedance measurements correlated with inferior vena cava size (Pearson correlation −0.73, p < 0.0001). A case study is presented for illustrative purposes.

Conclusions: BIS-measured ECF%TBW values were significantly higher in HF patients as compared to adults without HF. We describe three strata of ECF%TBW (normal, elevated, fluid overload) that may aid in clinical risk stratification and fluid volume monitoring of HF patients.

Clinical Trial Registration: COMPARE – www.ClinicalTrials.gov; IMPEL – www.ClinicalTrials.gov; Heart Failure at Home – www.ClinicalTrials.gov, identifier: NCT02939053; NCT02857231; NCT04013373.

Use of ultrasound imaging software to differentiate venous and lymphatic edema in lower limbs

BACKGROUND

Lower limb edema has both systemic and local causes. Using software to differentiate the origin of edema in ultrasound images is an innovation.

OBJECTIVE

To determine the parameters for using software to differentiate edema of venous and/or lymphatic origin in ultrasound images of the lower limbs.

METHOD

This is a cross-sectional, quantitative, analytical study with non-probabilistic sampling by convenience. Data were collected by patient interview, physical examination, ultrasound examination, and analysis of software for tissue characterization in ultrasound image by means of quantification of echogenicity and Gray Scale Median (GSM).

RESULTS

The sample comprised 42 lower limbs with venous edema, 35 with lymphatic edema, 14 with mixed edema, and 11 control limbs. The distributions of pixels in echogenicity intervals by group was as follows. In the venous edema group, 88.31% were distributed from hypoechogenic interval IV to echogenic interval III; in the lymphatic edema group 71.73% were from hypoechogenic interval II to echogenic interval I; in the mixed edema group 76.17% were from hypoechogenic interval III to echogenic interval II; and in the control group 84.87% were distributed from echogenic interval II to hyperechogenic interval I. Mean and standard deviation of GSM values showed statistical differences between groups.

CONCLUSION

The CATUS software enabled differentiation of the type of lower limb edema, facilitating diagnosis of edema type and, consequently, choice of the best therapeutic option.

Bioelectrical impedance analysis; a new method to evaluate lymphoedema, fluid status, and tissue damage after gynaecological surgery - A systematic review

The aim of this descriptive review is to summarise the current knowledge of non-invasive bioelectrical impedance analysis (BIA) used with gynaecological surgical patients in regard to postoperative development of lymphoedema and determination of perioperative fluid balance, and as a prognostic factor in cancer mortality and a predictor of postoperative complications. The databases PubMed, MEDLINE, Scopus Web of Science, the Cochrane Library, and reference lists of selected articles were searched for relevant articles published during the period January 2008-April 2018. Only papers published in English were retrieved. Thirty-seven articles were evaluated. Where gynaecological studies were lacking, studies with a study population from neighbouring clinical fields were used instead. Studies on the clinical use of BIA with gynaecological surgical patients were divided into three categories: the postoperative development of lower limb lymphoedema (n = 7), perioperative hydration measuring (n = 3), and the BIA parameter phase angle as a prognostic factor in cancer survival and as predictive for postoperative complications (n = 6). Of these 16 studies only three used a pure gynaecological study population. Three different methods of BIA were used in these articles: single frequency-BIA, multifrequency-BIA and bioimpedance spectroscopy. BIA was found to detect lymphoedema with a sensitivity of 73% and a specificity of 84%. Studies indicated that BIA was able to detect lower limb lymphoedema at an early stage even before it became clinically detectable. During postoperative hydration measurements, an increase in extracellular fluid volume and extracellular fluid volume in relation to total body fluid volume, as well as a decrease in phase angle, were associated with higher frequencies of postoperative complications. Moreover, low values for the phase angle have been associated with increased mortality in cancer patients. However, the number of studies in this field was limited. From our review, BIA seems to be a useful tool for use in the clinical setting of the gynaecological surgical patient. The theoretical approach of using bioelectrical impedance values to measure the fluid distribution in the body compartments offers wide opportunities in the clinical setting. However, so far, all studies have set up cut-off limits within the study population, and reference values for a general population need to be defined. There are also rather few studies on a gynaecological study population. Hence, there is a need for further studies within gynaecological surgery focusing on early detection of lower limb lymphoedema, perioperative fluid balance, and postoperative complications in order to establish the value of BIA in clinical praxis.

Prediction of hemodialysis vascular access failure using segmental bioimpedance analysis parameters

PURPOSE

Segmental bioimpedance analysis (BIA) can identify fluid volume changes in the arms of patients on hemodialysis (HD) after vascular access surgery. We investigated whether the difference in fluid volumes between the arms of the patients using segmental BIA is associated with vascular access outcome.

METHODS

Body composition measurements were taken for 127 patients on HD with segmental, multi-frequency BIA equipment (InBody 1.0, Biospace Co. Ltd, Seoul, Korea). The difference in fluid volume between the arms of the patients was calculated from the fluid volume of the arm with the vascular access minus that of the other. The primary outcome was the loss of vascular access patency within 3 months of BIA measurement.

RESULTS

The median absolute and relative inter-arm fluid volume differences were 150 ml [interquartile range (IQR) 90-250 ml] and 9.6% (IQR 4.9-14.4%), respectively. Within 3 months of BIA measurement, 38 patients (30.0%) experienced vascular access failure. When the patients were divided into three groups based on the tertiles of relative inter-arm fluid volume differences (lowest tertile: < 6.8%; middle tertile: 6.8-12.7%; highest tertile: > 12.7%), greater difference in relative inter-arm fluid volume differences was associated with higher vascular access failure rates (14 vs. 28 vs. 48%, p value for trend across tertiles = 0.003).

CONCLUSIONS

We conclude that segmental BIA may be used as a tool that can predict vascular access failure in patients on HD by calculating the relative difference in fluid volume between the arms of the patients with and without vascular access.

Local Echo-Free Space in a Limb with Lymphedema Represents Extracellular Fluid in the Entire Limb

BACKGROUND

We previously reported that local subcutaneous echo-free space (SEFS) in the leg was stirringly correlated with extracellular fluid (ECF) status in the same part of the leg when assessed using bioelectrical impedance analysis (BIA). In this study, we examined whether local SEFS represents the ECF status in the entire limb.

METHODS AND RESULTS

In 51 legs and 40 arms with lymphedema (LE), subcutaneous tissue ultrasonography was performed to determine SEFS severity (range, 0-2). BIA was also performed to calculate the L-Dex^® score (LDS), which is a BIA-derived parameter to represent ECF status, for the arm and modified LDS (mLDS) for the leg (the right arm was used as a reference instead of the contralateral leg). SEFS severity in any part of the leg showed good correlation with mLDS, but that in the lateral lower calf showed the strongest correlation (ρ = 0.86). In contrast, only SEFS severity in the medial forearm showed good correlation with LDS (ρ = 0.74).

CONCLUSIONS

Local SEFS may represent ECF status in the entire limb in both the leg and arm LE.

Correlation Between the Severity of Subcutaneous Echo-Free Space and the Amount of Extracellular Fluid Determined by Bioelectrical Impedance Analysis of Leg Edema

BACKGROUND

Both subcutaneous echo-free space (SEFS) observed by ultrasonography and the ratio of intracellular fluid resistance to extracellular fluid resistance (R_i/R_e) calculated from bioelectrical impedance analysis (BIA) represent extracellular edema status in the extremities. We tried to correlate these parameters.

METHODS AND RESULTS

In 70 legs with venous edema (VE) and 68 legs with lymphedema (LE), subcutaneous tissue ultrasonography to determine SEFS severity (range, 0-2) and BIA to calculate R_i/R_e were performed. In the calf, SEFS severity showed good linear correlation with R_i/R_e, particularly in the lower lateral calf where the mean R_i/R_e for LE (SEFS grade 0: 3.2 ± 0.8; SEFS grade 1: 4.0 ± 0.9; SEFS grade 2: 6.3 ± 3.6) and VE (SEFS grade 0: 3.6 ± 0.6; SEFS grade 1: 4.4 ± 1.6; SEFS grade 2: 5.3 ± 2.0) was similar. In the thigh, a mild correlation was confirmed only in LE.

CONCLUSIONS

It may be concluded that SEFS in the lower calf area well represents the local fluid status regardless of the type of edema, but not so in the thigh.