Use Of Bioimpedance Spectroscopy Research Articles

Use of Bioimpedance Spectroscopy for Postoperative Fluid Management in Patients Undergoing Cardiac Surgery with Cardiopulmonary Bypass

ObjectiveTo assess whether bioimpedance spectroscopy analysis (BIA) can be used as a potential tool to guide postoperative fluid management in patients who undergo cardiac surgery. DesignAn observational study. SettingA single, tertiary hospital. ParticipantsPatients who underwent cardiac surgery with cardiopulmonary bypass between June to November 2023 who were able to undergo BIA measurements. InterventionsNone. Measurements and Main ResultsCorrelations between BIA measurements of extracellular fluid (ECF) and total body water (TBW) volumes and daily changes in weight and 24-hour net intake and output (I/O) of fluids were assessed. Correlations between pre-discharge ECF volume as a percentage of TBW volume (ECF%TBW) and pre-discharge Pro-BNP (Pro-BNP) levels and readmissions were analyzed. Changes in daily ECF volume significantly correlated with daily weight changes (p<0.01) and 24-hr I/O (p<0.01). TBW volume significantly correlated with daily weight changes (p<0.01) and with 24-hr I/O (p=0.04). Daily weight changes did not correlate with 24-hr I/O (p=0.06). The patients with pre-discharge ECF%TBW(%) greater than or equal to 51 had significantly higher pre-discharge Pro-BNP than those with ECF%TBW(%) less than 51 (p<0.01). Patients who had heart failure revisits or admissions after discharge had a higher pre-discharge ECF%TBW(%) on index admission compared to patients that did not have heart failure readmissions (p=0.01). ConclusionsUtilization of BIA measurements in postoperative cardiac surgery patients may be a valuable tool to quantitatively determine fluid status to help guide fluid management in this patient population. Further studies validating the use of BIA for postoperative care in this population are warranted.

Advances in Evaluating Fluid Levels: Bioimpedance in Patients with Kidney Failure

This study delves deeply into the various facets of bioimpedance analysis as it relates to the development of chronic kidney disease (CKD). The use of bioimpedance spectroscopy (BIS) to evaluate the effectiveness of peritoneal dialysis (PD) and determine dialysis adequacy using variables like volume (V) and Kt/V is at the heart of this compilation. The investigations closely look at how important water distribution is for the advancement of CKD and how that affects patient outcomes. Evaluation of several body composition measurement methods is emphasized, especially the combination of the bioelectrical impedance analysis (BIA) ratio and the dry mass index (DMI). By applying the BIA TBW Watson ratio, these approaches provide important insights into the relationships between fluid volume and physiological indicators, such as body mass index (BMI) and total body water (TBW). The study emphasizes the differences in fluid overload diagnosis between conventional clinical assessments and sophisticated bioimpedance techniques, particularly in older patients with chronic kidney disease (CKD), underscoring the need for proper monitoring and intervention. Bioimpedance analysis is crucial to understanding chronic renal disease and associated cardiac complications, as shown in the assembled study. Bioimpedance analysis, used in devices like the Body Composition Monitor (BCM), is highlighted in this study collection to monitor hydration and improve dialysis adequacy. Bioimpedance analysis improves illness treatment, giving chronic renal failure and heart failure patients a more precise and nuanced grasp of fluid management, according to the literature.

Technologies of Bioimpedance Spectroscopy in Decision Support Systems for the Diagnosis of Socially Significant Diseases

The purpose of the research is to develop methods for the synthesis of hybrid classifiers to assess the risk of socially significant diseases using bioimpedance analysis.Methods. We developed a descriptor approach using impedance spectroscopy results, generating four amplitudephase-frequency responses from four quasi-orthogonal leads. They create the feature spaces necessary for our hybrid classifier in the diagnosis of pancreatic diseases, the autonomous intelligent agents of which are built on various paradigms: probabilistic neural networks, fuzzy logical inference, fully connected feedforward neural networks. We also presented a device structure for creating an informative feature space.Results. Experimental studies of the proposed methods and means of classifying medical rice were carried out on diagnostic tasks according to the classes "acute destructive pancreatitis" – "no acute destructive pancreatitis" and differential diagnosis tasks according to the classes "prostate cancer" ‒ "chronic pancreatitis". They showed that incorporating multi-frequency sensing into neural network-based classifiers allows the development of clinical decision support systems for disease diagnosis that are comparable in performance to existing clinical diagnostic methods. The results were confirmed in groups of male and female patients at different stages of cancer aged 25 to 80 years using a variety of diagnostic methods, including history, physical examination, assessment of comorbidities, laboratory tests, ultrasound, laparoscopy, intraoperative exploration and computed tomography.Conclusion. The use of bioimpedance spectroscopy and hybrid classifier models opens up new opportunities for accessible and objective diagnosis of pancreatic diseases, expanding the capabilities of intelligent medical decision support systems.

Abstract P3-05-29: Use of Bioimpedance Spectroscopy as a Surrogate for Bone Mineral Content in Oncology Patients: Practical Application of the SOZO Device

Abstract Background: Many cancer patients, particularly those with breast or prostate cancer, receive hormonal manipulation therapies that can significantly impact their bone mineral content (BMC), potentially leading to osteoporotic associated life-threatening fractures, particularly given the median age of patients diagnosed with these malignancies. Bioimpedance spectroscopy (BIS) is a non-invasive tool that measures fluid and body composition values including skeletal muscle mass (SMM) and fat free mass (FFM). BIS devices can be used easily and quickly at point-of-care at the time of vital signs, with the patient standing on the device placing their hands and feet on metal electrodes and a reading obtained in less than a minute. Multiple previous studies have shown strong correlation between SMM and BMC, suggesting that a BIS reading can provide a reproducible, simple and quick estimate of BMC. To that end, we present initial findings correlating BIS readings obtained with a SOZO device (ImpediMed) with dual x-ray absorptiometry (DXA) to determine if BIS readings can be applied as an accurate point of care surrogate measure of BMC. Materials and Methods: Concurrent BIS measures and DXA scans, were performed in 75 healthy volunteers and 93 cancer patients (during and after cancer treatment) Group 1: 75 healthy volunteers (32 male, 43 female), mean age 27.4 (18-66 years); Group 2: 44 patients undergoing cancer treatment (11 male, 33 female; 18 breast, 7 lung, 4 endometrial, 4 colorectal, 4 prostate, 7 other), mean age 61.3 (38-79 years); and Group 3: 49 patients participating in a 12-week exercise program after cancer treatment (15 males, 34 females; 22 breast, 6 prostate, 3 colorectal, 3 endometrial, 2 lung, 13 other), mean age 57.8 (19-79 years). The healthy volunteers in Group 1 were further randomized into two subsets. Group A was used to develop a BIS predicted BMC algorithm and Group B was used to validate the algorithm. Results: The Pearson correlation coefficients (R) for DXA BMC and SOZO SMM were strong for all 3 groups (R=0.92, 0.85, and 0.80 for Groups 1, 2, and 3, respectively). Stepwise multiple linear regression for BMC was performed for Group A based on BIS parameters. For Group A, SMM resulted in a multiple correlation coefficient of 0.94 (P&amp;lt; 0.0001). The correlation coefficient between the BIS predicted BMC and DXA BMC of Group B was 0.87 (P&amp;lt; 0.0001, 95%CI 0.78-0.93). For Groups 2 and 3 combined, the correlation coefficient between the BIS predicted BMC and DXA BMC was 0.82 (P&amp;lt; 0.0001, 95%CI 0.73-0.87). Conclusions: Concurrent measures of SMM obtained with BIS using SOZO correlated strongly with DXA BMC, demonstrating that SOZO SMM may be a useful surrogate in the clinic to provide a quick, easy, and reproducible indicator of change in BMC, particularly for those patients undergoing treatments that may affect BMC. Tracking SMM during or after cancer treatment with SOZO may provide an estimate of changes in BMC allowing clinicians to obtain additional diagnostic testing and/or consider treatment modifications. Citation Format: Frank Vicini, Chirag Shah. Use of Bioimpedance Spectroscopy as a Surrogate for Bone Mineral Content in Oncology Patients: Practical Application of the SOZO Device [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-29.

MO671: Should We Undergo Peritoneal Dialysis in Malnourished Chronic Kidney Disease Patients?

Abstract BACKGROUND AND AIMS The implementation of peritoneal dialysis (PD) in end-stage renal disease has been associated with various long-term pathophysiologic changes, which result in adverse consequences, such as malnutrition, occurring in 30–50% of patients. Specific factors to PD might be associated with poor oral intake as continuous absorption of glucose from PD solutions and abdominal fullness induced by the dialysate can suppress appetite. There are several accepted strategies for stratifying malnutrition in PD, such as laboratory markers [serum albumin and normalized protein catabolic ratio (nPCR)] and the recent use of bioimpedance spectroscopy (BIS) (with low lean tissue index). We aimed to evaluate if PD patients with a poor nutritional status at the beginning of the technique had worse outcomes (peritonitis, PD failure, hospitalizations, and death). METHOD We studied a cohort of incident patients from a single PD unit between 1 July 2011 and 31 August 2021, who had one BIS measurement and a peritoneal equilibration test in the first 3 months after the start of PD. We also collect laboratory data within 6 months from the BIS evaluation (serum albumin). Besides demographic parameters, we evaluated established endpoints (peritonitis, PD failure, hospitalizations and death). RESULTS There were included 91 PD patients. The mean age of patients was 65.40 $ \pm $ 13.88 years with a median dialysis vintage of 24 (IQR 14–31.61) months; 59.3% were male and 28% had diabetes. During the follow-up period, 5.5% of the cohort died, 56% were hospitalized and 47.3% had at least one episode of peritonitis. Furthermore, the transfer to hemodialysis occurred in 18 cases (19.8%) and 15 (16.5%) received a renal transplant. There was no difference in nutritional markers median in patients that had clinical endpoints versus those who had not (Table 1). In a multivariable analysis, neither nPCR, nor albumin nor lean tissue index were predictors of peritonitis, PD failure or hospital admissions. CONCLUSION In this study, we found that malnourished patients, prevalent in PD, did not have worse clinical endpoints (higher rate of infections, hospital admissions and PD failure). Although adequate nutrition has been deemed vital to the success of PD, this modality of renal replacement therapy did not result in worse outcomes, despite the malnutrition markers at the beginning of PD. Further studies are warranted to evaluate the positive impact of PD in nutrition status.

MO689: Relationship between Peritoneal/Renal Function and Nutritional Status in Peritoneal Dialysis Patients

Abstract BACKGROUND AND AIMS The positive impact of nutritional status on the health and treatment adequacy of peritoneal dialysis (PD) patients has been well established. There are several accepted strategies for stratifying malnutrition in PD, such as laboratory markers [serum albumin and normalized protein catabolic ratio (nPCR)] and the recent use of bioimpedance spectroscopy (BIS). The aim of this study was to assess the nutritional status of PD patients upon the start of the therapy. We also aimed to establish a potential relationship between peritoneal/renal function, obtained by a peritoneal equilibration test (PET), and nutritional markers. METHOD We studied a cohort of patients from a single PD unit between 1 July 2011 and 31 August 2021, who had one BIS measurement and a PET in the first 3 months after the beginning of PD. We also collect laboratory data within 6 months from the BIS reading (albumin, C-reactive protein and phosphorus). Demographic parameters (age, dialysis vintage, presence or absence of diabetes mellitus) and body mass index were also evaluated. RESULTS The study included 91 incident PD patients. The mean age of patients was 65.40 $ \pm $ 13.88 years, 59.3% were male and 28% had diabetes. Regarding baseline renal and peritoneal parameters, weekly total kt/v median was 1.99 (IQR 0.99–2.59) residual renal function (eGFR) median 3.2 (IQR 2.12–7.75) mL/min/1.73 m2 daily diuresis median 1500 (IQR 1000–2100), fluid removal (FR) median 2.23 (IQR 1.86–2.65) L/day and 41.8% had a dialysate/plasma (D/P) creatinine higher than 0.77. Lean tissue index was low in 36.3% and fat tissue index was high in 52.2%. Serum albumin median was 3.7 (IQR 3.3–4) g/dL and nPCR median 0.84 (IQR 0.72–1.04) g/kg/day. Hypervolemic patients had significantly lower lean tissue index (13.77 ± 3.25 versus 16.87 ± 3.82, P = 0.003). In a univariate analysis, patients with nPCR &amp;lt; 1.2 g/kg/day (79.1% from the complete cohort with no age difference) had lower baseline weekly total kt/v (2.17 ± 0.43 versus 6.62 ± 4.45, P &amp;lt; 0.001, lower daily diuresis (1261 ± 753 versus 1687 ± 958, P = 0.047), lower FR (2.05 ± 0.57 versus 2.40 ± 0.80, P = 0.043), and also significantly lower D/P creatinine (0.74 ± 0.1 versus 0.97 ± 0.27, P &amp;lt; 0.001). Furthermore, patients with serum albumin &amp;lt;3.8 g/dL had a lower ultrafiltration proof (326 ± 192 versus 511 ± 267, P = 0.028) and those with low lean tissue index had a lower daily diuresis (1405 ± 825 versus 1823 ± 1025, P = 0.045). In a multivariate analysis, patients with nPCR &amp;lt; 1.2 g/kg/day were older [exp (B) 0.19, 95% CI 0.8–0.9, P = 0.012] and had lower weekly total kt/v [exp (B) 0.18, 95% CI 0.6–0.9, P = 0.017]. CONCLUSION This study showed some relationships between kidney/peritoneal function parameters and body composition parameters. The level of nPCR, a measure of nutritional status, was significantly and positively associated with indicators of dialysis adequacy (kt/v), daily diuresis and, also with transport type. Further research regarding nutrition must be undertaken to help improve health outcomes in PD patients.

Role of technology in a prospective surveillance and early intervention model for preventing lymphedema: The RE-AIM framework.

e14005 Background: Translation of research derived technology into busy clinical practice can be difficult. The effectiveness of technology translation can be assessed by applying the Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) evaluation framework. Methods: The RE-AIM evaluation framework was applied to the use of bioimpedance spectroscopy (BIS) in the prospective surveillance and early intervention model of care for breast cancer survivors at risk of arm lymphedema. Data was obtained during an interim analysis from four hospital sites (public and private settings) in Australia who were participating in the PREVENT international study. Women with breast cancer were monitored for lymphedema from a pre-treatment baseline and at regular intervals for a minimum of 12-months. Results: Each of the RE-AIM framework components were evaluated at patient, practitioner and institutional levels. Patients in both public (n = 50) and private settings (n = 61) were Reached with BIS technology which demonstrated Effectiveness of early surveillance with 16 participants being identified for an early prevention intervention. Each of the four sites Adopted the use of BIS technology using various Implemented strategies like education of all stakeholders and development of referral and care pathways. Adherence rates for mandatory study visits was 88. 48% for the prospective surveillance and the early intervention model of care group and were Maintained for a minimum 12 months following completion of the recruitment phase of the study. Conclusions: The effectiveness of using a technology such as BIS in a prospective surveillance and early intervention model of care in breast cancer in both public and private settings has been demonstrated using the RE-AIM framework. The translation of research into clinical practice has been successfully achieved with the PREVENT study. Clinical trial information: NCT02167659.

Diagnosing Male Unilateral Upper Limb Lymphedema: Determination of Normatively Determined Thresholds Using Bioimpedance Spectroscopy.

Background: The use of bioimpedance spectroscopy (BIS) for the detection of unilateral upper limb lymphedema is growing. Currently, normatively determined diagnostic thresholds using bioimpedance are available for females only. It is unclear if they are suitable for males at risk of unilateral upper limb lymphedema. The aim of the present study was to determine normatively based bioimpedance thresholds for male unilateral upper limb lymphedema. Methods and Results: Impedance values (R0) for the upper limbs of 60 healthy adult male participants were assessed using BIS. As has been found in females, dominance was found to significantly impact on R0 values (p = 0.002); therefore, two diagnostic thresholds are required depending on the at-risk limb. Interlimb impedance thresholds were calculated, set at both two standard deviations (2SD) and three standard deviations (3SD) above the mean. The 3SD threshold for unilateral lymphedema in the upper limbs of males is 1.127 for the dominant at-risk limb and 1.094 for the nondominant at-risk limb. The 2SD threshold is 1.090 for the dominant at-risk limb and 1.058 for the nondominant at-risk limb. These differ from what has previously been found for females. Conclusions: This study is the first to establish normatively determined bioimpedance thresholds for male unilateral upper limb lymphedema. These thresholds should now be used to improve early detection of male unilateral upper limb lymphedema.

The use of bioimpedance spectroscopy to guide fluid management in patients receiving dialysis.

To summarize the findings of recent trials and meta-analyses designed to determine whether bioimpedance spectroscopy adds value to the clinical assessment of fluid status in dialysis patients so as to achieve a normally hydrated weight and put these in a contemporary context. Eight trials (published 2010-2018) and two meta-analyses (2017) are reviewed. Both haemodialysis and peritoneal dialysis modalities are represented. Despite considerable heterogeneity in intervention, all are open-label randomized comparisons of a bioimpedance intervention with normal clinical practice in which clinicians were blinded to bioimpedance data. In a total of 1443 patients studied, no significant differences in mortality, cardiovascular or adverse events between groups were observed. Bioimpedance use was associated with a reduction in overhydration, especially when residual kidney function was not present and a greater reduction in blood pressure. A modest correlation in the change in fluid status and fall in systolic blood pressure was seen compared to baseline. A more rapid fall in urine volume was seen in the two studies with the greatest change in fluid status, with significantly higher risk of anuria in one. How bioimpedance was integrated with the complex process of decision making by clinicians was variable and not always explained. The usefulness of bioimpedance spectroscopy in guiding fluid management in dialysis patients is not yet clear. Bioimpedance can drive clinical decisions that lead to significant changes in fluid status but the best way to apply this in clinical practice requires further studies.

Validating the use of bioimpedance spectroscopy for assessment of fluid status in children

BackgroundBioimpedance spectroscopy (BIS) with a whole-body model to distinguish excess fluid from major body tissue hydration can provide objective assessment of fluid status. BIS is integrated into the Body Composition Monitor (BCM) and is validated in adults, but not children. This study aimed to (1) assess agreement between BCM-measured total body water (TBW) and a gold standard technique in healthy children, (2) compare TBW_BCM with TBW from Urea Kinetic Modelling (UKM) in haemodialysis children and (3) investigate systematic deviation from zero in measured excess fluid in healthy children across paediatric age range.MethodsTBW_BCM and excess fluid was determined from standard wrist-to-ankle BCM measurement. TBW_D2O was determined from deuterium concentration decline in serial urine samples over 5 days in healthy children. UKM was used to measure body water in children receiving haemodialysis. Agreement between methods was analysed using paired t test and Bland-Altman method comparison.ResultsIn 61 healthy children (6–14 years, 32 male), mean TBW_BCM and TBW_D2O were 21.1 ± 5.6 and 20.5 ± 5.8 L respectively. There was good agreement between TBW_BCM and TBW_D2O (R2 = 0.97). In six haemodialysis children (4–13 years, 4 male), 45 concomitant measurements over 8 months showed good TBW_BCM and TBW_UKM agreement (mean difference − 0.4 L, 2SD = ± 3.0 L). In 634 healthy children (2–17 years, 300 male), BCM-measured overhydration was − 0.1 ± 0.7 L (10–90th percentile − 0.8 to + 0.6 L). There was no correlation between age and OH (p = 0.28).ConclusionsThese results suggest BCM can be used in children as young as 2 years to measure normally hydrated weight and assess fluid status.

Utilization of bioimpedance spectroscopy (BIS) to reduce rates of breast cancer related lymphedema (BCRL) in extremely high-risk patients.

e22112Background: We evaluated the use of bioimpedance spectroscopy (BIS) as part of a structured surveillance program for the development of breast cancer-related lymphedema (BCRL) in very high ri...

Reducing chronic breast cancer-related lymphedema utilizing a program of prospective surveillance with bioimpedance spectroscopy.

This single-institution experience evaluated the use of bioimpedance spectroscopy to facilitate early detection and treatment of breast cancer-related lymphedema (BCRL) in a cohort of 596 patients (79.6% high risk). Seventy-three patients (12%) developed an elevated L-Dex score with axillary lymph node dissection (P<.001), taxane chemotherapy (P=.008), and regional nodal irradiation (P<.001) associated. At last follow-up, only 18 patients (3%) had unresolved clinically significant BCRL requiring complete decongestive physiotherapy. This rate of BCRL is lower than reported in contemporary studies, supporting recent NCCN guidelines promoting prospective screening, education and intervention for BCRL.

Reducing chronic breast cancer related lymphedema utilizing a program of prospective surveillance with bioimpedance spectroscopy (BIS).

10117 Background: Breast cancer related lymphedema (BCRL) represents a major side effect that can significantly impact quality of life. Current guidelines support prospective surveillance to allow for early diagnosis and treatment of BCRL at a subclinical, reversible stage. This current large, single institution experience evaluated the use of bioimpedance spectroscopy (BIS) to monitor patients for the development and treatment of BCRL. Methods: From April 2010 through Nov 2016, 596 patients (79.6% with high-risk features) were evaluated with BIS.Patients received a pre-operative baseline L-Dex measurement and post-operatively at regular intervals. Elevated L-Dex scores were defined as an increase of ≥10 points above baseline (considered subclinical BCRL). Intervention then consisted of applying an over the counter (OTC) sleeve for 4 weeks followed by re-evaluation. The need for complete decongestive physiotherapy (CDP) represented a surrogate for the development of clinically significant, chronic BCRL. Results: Median follow-up for all patients was 17 months. Seventy-three patients (12%) developed an elevated L-Dex score with axillary lymph node dissection (ALND) (p &lt; 0.001), taxanes (p = 0.008), and (regional nodal irradiation (RNI) (p &lt; 0.001) associated. At last follow-up, only 18 patients (3%) had unresolved clinically significant BCRL requiring CDP. Mastectomy (p = 0.02), ALND (p &lt; 0.001), taxanes (p = 0.05), and RNI (p &lt; 0.001) were associated with requiring CDP. Conclusions: Our results demonstrate that prospective monitoring using BIS, with intervention (using a simple OTC sleeve for 4 weeks) triggered by a ≥10-point L-Dex elevation, resulted in only a 3% rate of chronic, clinically significant BCRL. These results are lower than reported in contemporary studies and validate recent guidelines supporting prospective screening and intervention for BCRL.

Does Routine Bioimpedance-Guided Fluid Management Provide Additional Benefit to Non-Anuric Peritoneal Dialysis Patients? Results from COMPASS Clinical Trial.

In peritoneal dialysis (PD) patients, volume overload is related to cardiac dysfunction and mortality, while intravascular volume depletion is associated with a rapid decline in the residual renal function (RRF). This study sought to determine the clinical usefulness of bioimpedance spectroscopy (BIS)-guided fluid management for preserving RRF and cardiac function in PD patients. This is a multicenter, prospective, open-label study that was conducted over a 1-year period (NCT01887262). Non-anuric (urine volume > 500 mL/day) subjects on PD were enrolled. Subjects in the control group received fluid management based on the clinical information alone. Those in the BIS group received BIS-guided fluid management along with clinical information. The subjects (N = 137, mean age 51.3 ± 12.8 years, 54% male) were randomly assigned to the BIS group (n = 67) or to the control group (n = 70). There were no significant differences between the 2 groups with regard to age, sex ratio, cause of kidney failure, duration of PD, baseline comorbidity, RRF, PD method, or peritoneal transport type. At baseline, the 2 groups were not different in terms of RRF (glomerular filtration rate [GFR], 5.1 ± 2.9 vs 5.5 ± 3.7 mL/min/1.73 m2). After follow-up, changes in the GFR between the 2 groups were not different (-1.5 ± 2.4 vs -1.3 ± 2.6 mL/min/1.73 m2, p = 0.593). Over the 1-year study period, both groups maintained stability of various fluid status parameters. Between the 2 groups, there were no differences in the net change of various fluid status parameters such as overhydration (OH) and extracellular water/total body water (ECW/TBW). A net change in ECW over 1 year was slightly but significantly higher in the control group (net increase, 0.57 ± 1.27 vs 0.05 ± 1.63 L, p = 0.047). However, this difference was not translated into an improvement in RRF in the BIS group. There were no differences in echocardiographic parameters or arterial stiffness at the end of follow-up. Routine BIS-guided fluid management in non-anuric PD patients did not provide additional benefit in volume control, RRF preservation, or cardiovascular (CV) parameters. However, our study cannot be generalized to the whole PD population. Further research is warranted in order to investigate the subpopulation of PD patients who may benefit from routine BIS-guided fluid management.

Comparison of bioimpedance spectroscopy and the Watson formula for measuring body volume in patients on peritoneal dialysis

IntroductionKnowing total body volume (V) is crucial in patients on peritoneal dialysis (PD). It is usually calculated by the Watson anthropometric formula, although the use of bioimpedance spectroscopy (BIS) is becoming increasingly widespread. Measuring V with both methods can at times produce quite different results. ObjectiveWe aimed to identify differences between the 2 forms of measuring volume in a PD unit and determine which clinical factors are associated with these differences. MethodsOurs is an observational study of 74 patients on PD. We measured V using BIS (Vbis) and the Watson formula (Vw); 271 measurements were made with each method. We calculated the difference between Vbis and Vw in each patient and classified them into 2 groups: Difference between volumes ≥10% or <10% Vbis. We assessed the presence of several clinical parameters in our patients.We assessed whether there were any differences between Vbis and Vw (Student t-test). We determined whether there was any association between the difference in volumes and the presence of the clinical parameters analyzed (chi square test). ResultsV was 2.15 l higher measured by the Watson formula than with BIS (p<0.01). In 58.67% of the measurements, the difference between Vbis and Vw was ≥10%.Significant differences were found when comparing the presence of difference between volumes and the presence or not of diabetes mellitus (DM) (p=0.03), hypertension (HTN) (p=0.036), hypoalbuminemia (p<0.01), hypoprealbuminemia (p<0.01), low phase angle at 50Hz (p<0.01), high C reactive protein (p<0.01), obesity (p=0.027), E/I ratio (ratio between extracellular and intracellular water) ≥1 (p<0.01) and residual diuresis (p=0.029). ConclusionsThere are significant differences in the V of PD Unit patients when obtained by Watson formula or by BIS. A difference between the measurements is associated with the presence of DM, HTN, hypoalbuminaemia, obesity, malnutrition, inflammation, E/I ratio ≥1 and the absence of residual diuresis.

Comparación entre bioimpedancia espectroscópica y fórmula de Watson para medición de volumen corporal en pacientes en diálisis peritoneal

IntroductionKnowing total body volume (V) is crucial in patients on peritoneal dialysis (PD). It is usually calculated by the Watson anthropometric formula, although the use of bioimpedance spectroscopy (BIS) is becoming increasingly widespread. Measuring V with both methods can at times produce quite different results. ObjectiveWe aimed to identify differences between the 2 forms of measuring volume in a PD unit and determine which clinical factors are associated with these differences. MethodsOurs is an observational study of 74 patients on PD. We measured V using BIS (Vbis) and the Watson formula (Vw); 271 measurements were made with each method. We calculated the difference between Vbis and Vw in each patient and classified them into 2 groups: Difference between volumes ≥10% or <10% Vbis. We assessed the presence of several clinical parameters in our patients.We assessed whether there were any differences between Vbis and Vw (Student t-test). We determined whether there was any association between the difference in volumes and the presence of the clinical parameters analysed (chi square test). ResultsV was 2.15 l higher measured by the Watson formula than with BIS (P<.01). In 58.67% of the measurements, the difference between Vbis and Vw was ≥10%.Significant differences were found when comparing the presence of difference between volumes and the presence or not of diabetes mellitus (DM) (p=0,03), hypertension (HTN) (p=0,036), hypoalbuminemia (p<0,01), hypoprealbuminemia (p<0,01), low phase angle at 50 Hz (p<0,01), high C reactive protein (p<0,01), obesity (p=0,027), E/I ratio (ratio between extracellular and intracellular water) ≥1 (p<0.01) and residual diuresis (p=0.029). ConclusionsThere are significant differences in the V of PD Unit patients when obtained by Watson formula or by BIS. A difference between the measurements is associated with the presence of DM, HTN, hypoalbuminaemia, obesity, malnutrition, inflammation, E/I ratio ≥1 and the absence of residual diuresis.

Usefulness of bioimpedance spectroscopy for detection of hypotensive episode during dialysis.

Using statistical methods, this study investigates whether bioimpedance spectroscopy (BIS) and plasma electrolytes can be used to identify risk of intradialytic hypotension (IDH) based on information obtained during the first half of the dialysis treatment only. Data obtained from 40 patients included information on blood pressure, parameters defined from BIS, plasma electrolytes, and relevant clinical data. Patients were divided into three groups based on their intradialytic decrease in systolic blood pressure (SysBP) and associated symptoms and interventions: (1) Stable SysBP, (2) Asymptomatic unstable SysBP, and (3) symptomatic unstable SysBP. Retrospective analysis showed a significant reduction in extracellular fluid of 0.64 ± 0.62 L and potassium (K) concentration of 0.24 ± 1.67 mM in parallel with a decrease in SysBP of ≥25 mm Hg/hr. Data analysis using mixed-model procedure revealed that unstable patients compared with stable patients were characterized by higher extracellular resistance (p = 0.014) and K concentration (p = 0.009). Discriminant analysis using relative changes in extracellular resistance, potassium, and pH resulted in correct identification of 85% of the patients at risk. This study indicates that combining BIS and plasma electrolytes analysis may be a promising method to provide more accurate monitoring of IDH.

The Use of Bioimpedance Spectroscopy to Monitor Therapeutic Intervention in Patients Treated for Breast Cancer-Related Lymphedema

The Use of Bioimpedance Spectroscopy to Monitor Therapeutic Intervention in Patients Treated for Breast Cancer-Related Lymphedema

The use of bioimpedance spectroscopy to monitor response to treatment interventions with breast cancer-related lymphedema.

138 Background: Currently, limited tools are available to assess response to therapy in patients with breast cancer related lymphedema (BCRL). The purpose of this study was to perform an exploratory analysis to determine if, in clinical settings, bioimpedance spectroscopy (BIS) can detect changes in extracellular fluid volume in response to treatment of BCRL. Methods: Three centers that had experience with BIS (L-Dex U400, ImpediMed Limited, Brisbane, Australia) provided retrospective data on 50 patients with breast cancer who were evaluated with BIS at baseline and following loco-regional procedures. Patients had a pre-surgical L-Dex measurement as well as at least 2 post-surgical measurements (before and after BCRL intervention). Decisions regarding intervention were made by physicians with no L-Dex score cut-off utilized. An analysis was performed comparing changes in L-Dex scores for those patients undergoing treatment for BCRL (n=13) versus those not undergoing intervention (n=37). A second analysis was also performed on all patients with elevated L-Dex scores compared to baseline prior to intervention (n=32). Results: The mean age was 54 years old. Fifty four percent of patients underwent SLN biopsy with a mean of 7.9 nodes removed. The mean change in L-Dex score from baseline (pre-treatment) to the first post-surgical L-Dex score measurement was 3.3 +/- 6.8. When comparing the cohort treated for BCRL to those not treated, L-Dex scores were significantly reduced (-4.3 v. 0.1, p=0.005) following intervention. For the subset of patients with elevated L-Dex scores post-surgery, the change in L-Dex score following BCRL intervention was significantly reduced (-5.8 v. 0.1, p=0.001) compared with those observed. Conclusions: These results confirm that BIS can detect increases in L-Dex scores following breast surgery and can also detect reductions in L-Dex scores following intervention for early onset lymphedema. These results demonstrate that BIS has significant clinical utility as it can be used to monitor patients with early BCRL who undergo intervention and to follow these patients (through serial measurements) to document their short and long-term response to these treatments.

Comparison of Diagnostic Accuracy of Clinical Measures of Breast Cancer–Related Lymphedema: Area Under the Curve

Smoot BJ, Wong JF, Dodd MJ. Comparison of diagnostic accuracy of clinical measures of breast cancer–related lymphedema: area under the curve. Objective To compare diagnostic accuracy of measures of breast cancer–related lymphedema (BCRL). Design Cross-sectional design comparing clinical measures with the criterion standard of previous diagnosis of BCRL. Setting University of California San Francisco Translational Science Clinical Research Center. Participants Women older than 18 years and more than 6 months posttreatment for breast cancer (n=141; 70 with BCRL, 71 without BCRL). Interventions Not applicable. Main Outcome Measures Sensitivity, specificity, receiver operator characteristic curve, and area under the curve (AUC) were used to evaluate accuracy. Results A total of 141 women were categorized as having (n=70) or not having (n=71) BCRL based on past diagnosis by a health care provider, which was used as the reference standard. Analyses of ROC curves for the continuous outcomes yielded AUC of .68 to .88 ( P<.001); of the physical measures bioimpedance spectroscopy yielded the highest accuracy with an AUC of .88 (95% confidence interval, .80–.96) for women whose dominant arm was the affected arm. The lowest accuracy was found using the 2-cm diagnostic cutoff score to identify previously diagnosed BCRL (AUC, .54–.65). Conclusions Our findings support the use of bioimpedance spectroscopy in the assessment of existing BCRL. Refining diagnostic cutoff values may improve accuracy of diagnosis and warrant further investigation.