Bioimpedance spectroscopy: Is a picture worth a thousand words?

Volume status can be difficult to assess in dialysis patients. Peripheral edema, elevated venous pressure, lung crackles, and hypertension are taught as signs of fluid overload, but sensitivity and specificity are poor. Bioimpedance technology has evolved from early single frequency to multifrequency machines which apply spectroscopic analysis (BIS), modeling data to physics-based mixture theory. Bioimpedance plots can aid the evaluation of hydration status and body composition. The challenge remains how to use this information to manage dialysis populations, particularly as interventions to improve over hydration, sarcopenia, and adiposity are not without side effects. It is therefore of no surprise that validation studies for BIS use in peritoneal dialysis patients are limited, and results from clinical trials are inconsistent and conflicting. Despite these limitations, BIS has clinical utility with potential to accurately evaluate small changes in body tissue components. This article explains the information a BIS plot ("picture") can provide and how it can contribute to the overall clinical assessment of a patient. However, it remains the role of the clinician to integrate information and devise treatment strategies to optimize competing patient risks, fluid and nutrition status, effects of high glucose PD fluids on membrane function, and quality of life issues.

Tackling Dialysis Burden around the World: A Global Challenge.

CKD is a global problem that causes significant burden to the healthcare system and the economy in addition to its impact on morbidity and mortality of patients. Around the world, in both developing and developed economies, the nephrologists and governments face the challenges of the need to provide a quality and cost-effective kidney replacement therapy for CKD patients when their kidneys fail. In December 2019, the 3rd International Congress of Chinese Nephrologists was held in Nanjing, China, and in the meeting, a symposium and roundtable discussion on how to deal with this CKD burden was held with opinion leaders from countries and regions around the world, including Australia, Canada, China, Hong Kong, Singapore, Taiwan, the UK, and the USA. The participants concluded that an integrated approach with early detection of CKD, prompt treatment to slow down progression, promotion of home-based dialysis therapy like peritoneal dialysis and home HD, together with promotion of kidney transplantation, are possible effective ways to combat this ongoing worldwide challenge.

Relationship between sodium removal, hydration and outcomes in peritoneal dialysis patients.

BACKGROUND: Fluid overload (FO) in peritoneal dialysis (PD) patients is associated with mortality. We explore if low daily sodium removal is an independent risk factor for mortality. We examined severely FO PD patients established for >1 year in expectation that PD prescription would have been optimized for solute clearance and ultrafiltration. We also wish to determine the relationship between kt/v and sodium removal. METHODS: Retrospective analysis of 231 PD patients with FO ≥2.0 L and compared with 218 PD patients who were euvolaemic throughout their PD treatment. Patients were followed up until death censored for transplantation. RESULTS: Mean daily sodium removal in overhydrated patients was only 75 mmoles (=1.7 g). CAPD usage was more common in patients with the highest sodium removal. Achievement of UK guidelines for solute clearance and daily fluid removal were not independent predictors of mortality. Markers of sarcopenia (low serum albumin and high CRP) were associated with increased mortality, but these parameters were not independent predictors in a model that included functional assessment (Karnofsky score). Daily sodium removal was not predictive of mortality but the imprecision of clinically used sodium assay should be noted. The correlation between Na and kt/v is statistically significant but R2 was weak at .07. CONCLUSION: While diabetic males were more likely to become overhydrated, these factors did not increase mortality further. Traditional targets of 'dialysis adequacy' did not predict survival. Kt/v is not a good indicator of sodium removal which can be surprisingly low. Measuring sodium clearance may help clinicians optimize PD modality (CAPD vs. APD).

Polymerase chain reaction/electrospray ionization-mass spectrometry (PCR/ESI-MS) is not suitable for rapid bacterial identification in peritoneal dialysis effluent.

BACKGROUND: Peritoneal dialysis (PD)-related peritonitis is a serious complication of PD, but routine microbiological culture is slow and could not identify the organism in 15% cases. We examine the accuracy of polymerase chain reaction/electrospray ionization-mass spectrometry (PCR/ESI-MS), a PCR-based method developed for the direct detection of bacteria in blood, for rapid identification of microorganisms from PD effluent. METHODS: We recruited 73 consecutive patients with PD-related peritonitis. Dialysis effluent was collected for routine bacterial culture, PCR/ESI-MS, and bacterial DNA quantification before initiation of antibiotic therapy. RESULTS: By digital PCR with universal bacterial primers, bacterial DNA was detectable in all PD effluent specimens. For the entire cohort, taking standard bacterial culture as the gold standard, the PCR/ESI-MS assay correctly identified 34.3% of the causative organisms, failed to identify any organism in 52.1% cases, and identified a different organism in 8.2% cases. For the 14 episodes of peritonitis that were culture negative by conventional bacterial culture, the PCR/ESI-MS assay identified an organism in only four cases. The detection rate of the IRIDICA BAC BSI assay was not affected by the use of biocompatible PD solution or concomitant exit-site infection. CONCLUSIONS: The PCR/ESI-MS assay could not identify the causative organism in over 50% of the PD effluent samples in patients with PD-related peritonitis and should be not used for such purpose. The reason for the poor performance needs further investigation.

HEROIC: a 5-year observational cohort study aimed at identifying novel factors that drive diabetic kidney disease: rationale and study protocol.

INTRODUCTION: Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease worldwide and a major cause of premature mortality in diabetes mellitus (DM). While improvements in care have reduced the incidence of kidney disease among those with DM, the increasing prevalence of DM means that the number of patients worldwide with DKD is increasing. Improved understanding of the biology of DKD and identification of novel therapeutic targets may lead to new treatments. A major challenge to progress has been the heterogeneity of the DKD phenotype and renal progression. To investigate the heterogeneity of DKD we have set up The East and North London Diabetes Cohort (HEROIC) Study, a secondary care-based, multiethnic observational study of patients with biopsy-proven DKD. Our primary objective is to identify histological features of DKD associated with kidney endpoints in a cohort of patients diagnosed with type 1 and type 2 DM, proteinuria and kidney impairment. METHODS AND ANALYSIS: HEROIC is a longitudinal observational study that aims to recruit 500 patients with DKD at high-risk of renal and cardiovascular events. Demographic, clinical and laboratory data will be collected and assessed annually for 5 years. Renal biopsy tissue will be collected and archived at recruitment. Blood and urine samples will be collected at baseline and during annual follow-up visits. Measured glomerular filtration rate (GFR), echocardiography, retinal optical coherence tomography angiography and kidney and cardiac MRI will be performed at baseline and twice more during follow-up. The study is 90% powered to detect an association between key histological and imaging parameters and a composite of death, renal replacement therapy or a 30% decline in estimated GFR. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the Bloomsbury Research Ethics Committee (REC 18-LO-1921). Any patient identifiable data will be stored on a password-protected National Health Services N3 network with full audit trail. Anonymised imaging data will be stored in a ISO27001-certificated data warehouse.Results will be reported through peer-reviewed manuscripts and conferences and disseminated to participants, patients and the public using web-based and social media engagement tools as well as through public events.

Clinical Value of Screening Peritoneal Dialysis Patients for Bacterial Colonization or Contamination.

INTRODUCTION: The adoption of the International Society for Peritoneal Dialysis guideline of using mupirocin ointment has been limited by fear of developing mupirocin-resistant organisms. We performed a surveillance program of a large peritoneal dialysis (PD) unit. METHODS: We performed 1,175 surveillance swabs from anterior nares, PD catheter exit site, groin, and axilla, from 240 patients. The mean interval between swabs was 3.3 months. RESULTS: Colonization by Staphylococcus aureus (S. aureus) or Pseudomonas species was 9.5% and 10.9%, respectively. Despite adopting a universal policy of applying mupirocin to PD catheter exit sites in 2001, no instances of mupirocin-resistant S. aureus were identified. Moreover, patients who grew S. aureus from surveillance swabs did not experience higher peritonitis rates than those with "no growth." This was in contrast to patients who grew Pseudomonas or enteric organisms. There were no differences in patient demographics for those who grew S. aureus, Pseudomonas, or enteric organisms (compared with "no-growth" patients). CONCLUSION: Our results suggest that the application of mupirocin ointment appeared to minimize peritonitis of patients colonized with S. aureus. The use of mupirocin in this patient cohort has not led to mupirocin resistance. The increased peritonitis rate of patients who grew Pseudomonas or enteric organisms is of interest. We propose that greater attention to hygiene and catheter care in these patients is warranted. The increasing use of paid healthcare workers attending patients daily to help perform PD (assisted PD) gives an opportunity for us to address these wider issues.

Clinical value of body composition monitor to evaluate lean and fat tissue mass in peritoneal dialysis.

BACKGROUND/OBJECTIVES: Bioimpedance analysis is often routinely performed in any dialysis unit to guide fluid management but can provide a reproduceable assessment of fat and muscle mass. We wished to determine the clinical significance of low muscle or high fat mass and the determinants that influence their change. SUBJECTS/METHODS: We performed retrospective analysis of 824 patients on peritoneal dialysis who underwent routine repeated bioimpedance analysis measurements using the body composition monitor (BCM). RESULTS: Lean tissue index (LTI) was an independent predictor of mortality when sex, age, PD vintage and diabetes status were included in the models (HR 0.93; 95% CI 0.86-1.00, p < 0.05) and when baseline serum albumin was included in a separate model (HR 0.86; 95% CI: 0.79-0.93, p < 0.001). High fat tissue index (FTI) was an independent predictor of mortality when demographic factors were included (HR 0.87; 95% CI: 0.78-0.97, p < 0.02), but not with the addition biochemical parameters. Changes in body composition of 206 patients over a 2-year follow-up period could not be predicted by baseline demographics, functional or biochemical assessments. However, there was a strong inverse relationship between changes in LTI and FTI. There were no associations between changes in body composition with prescribed dialysate glucose. CONCLUSIONS: We showed body composition changes are common and complex. LTI was an independent predictor of survival. Changes in LTI and FTI could not be predicted by baseline parameters. BCM may be a sensitive and accurate tool to monitor changes in body composition during dialysis treatment.

Peritoneal dialysis in patients with failed kidney transplant: Single centre experience.

AIM: To determine if patients with failing kidney transplants who opt to have peritoneal dialysis (PD) have poor short-term PD technique survival and increased rates of peritonitis. METHODS: We performed a retrospective analysis comparing 50 consecutive patients starting PD after a failed kidney transplant to 93 incident patients starting PD (matching for age, gender, diabetes causing renal failure, ethnicity and year of starting PD). RESULTS: The mean follow-up period was 26 months. PD technique survival was lower for the post-transplant cohort. However, this did not appear to be related to PD peritonitis risk; infection rate was lower in the post-transplant group albeit not statistically significant (1 in 23.6 patient months vs 1 in 22.5 patient months). There were no differences in the proportion of Gram positive: Gran negative: Culture Negative infections. The only fungal peritonitis occurred in a Control patient. Results of baseline Peritoneal Equilibration Tests were not different; D/Pcr was 0.69 for post-TP versus 0.64 for Control (P = ns), and net UF was 250 mL for post-TP versus 310 mL for Control (P = ns). PET results after 12 months were also similar. CONCLUSION: Our study found a small but significantly higher rate of PD technique failure in the post-transplant cohort, but this did not appear to be related to peritonitis rates or peritoneal membrane function. Further studies are required to explore reasons for PD technique failure in patients who have had kidney transplant, but our study supports the use of PD in selected patient from this cohort.

Renal Association Clinical Practice Guideline on peritoneal dialysis in adults and children.

These guidelines cover all aspects of the care of patients who are treated with peritoneal dialysis. This includes equipment and resources, preparation for peritoneal dialysis, and adequacy of dialysis (both in terms of removing waste products and fluid), preventing and treating infections. There is also a section on diagnosis and treatment of encapsulating peritoneal sclerosis, a rare but serious complication of peritoneal dialysis where fibrotic (scar) tissue forms around the intestine. The guidelines include recommendations for infants and children, for whom peritoneal dialysis is recommended over haemodialysis.Immediately after the introduction there is a statement of all the recommendations. These recommendations are written in a language that we think should be understandable by many patients, relatives, carers and other interested people. Consequently we have not reworded or restated them in this lay summary. They are graded 1 or 2 depending on the strength of the recommendation by the authors, and A-D depending on the quality of the evidence that the recommendation is based on.

Addressing the burden of dialysis around the world: A summary of the roundtable discussion on dialysis economics at the First International Congress of Chinese Nephrologists 2015.

To address the issue of heavy dialysis burden due to the rising prevalence of end-stage renal disease around the world, a roundtable discussion on the sustainability of managing dialysis burden around the world was held in Hong Kong during the First International Congress of Chinese Nephrologists in December 2015. The roundtable discussion was attended by experts from Hong Kong, China, Canada, England, Malaysia, Singapore, Taiwan and United States. Potential solutions to cope with the heavy burden on dialysis include the prevention and retardation of the progression of CKD; wider use of home-based dialysis therapy, particularly PD; promotion of kidney transplantation; and the use of renal palliative care service.

Comparison of Change in Peritoneal Function in Patients on Continuous Ambulatory PD vs Automated PD.

BACKGROUND: Patients on automated peritoneal dialysis (APD) may have greater exposure to glucose in the PD fluid than those on continuous ambulatory PD (CAPD). If this causes long-term damage to the peritoneal membrane, it will have implications for a patient's choice of modality. METHODS: Membrane function of long-term APD or CAPD patients was followed prospectively. The data were collected from electronic patient records in our unit from 2000 to 2014. The rate of change in membrane transport status (D/Pcr) and ultrafiltration (UF4) for each patient was calculated using the least square regression line equation. RESULTS: We identified 106 APD and 123 CAPD patients who had a mean of 8.4 peritoneal equilibration test (PET) over 5.6 years. No differences were found in the rate of changes in D/Pcr or UF4. Baseline solute clearance (Kt/V) was lower in APD patients (1.66 vs 1.76, p = 0.04). However, APD patients experienced incremental changes to dialysis prescription that resulted in a greater increase in Kt/V compared with CAPD patients. CONCLUSION: This is the largest study comparing the long-term effect of APD vs CAPD prescriptions. Despite more glucose being prescribed, there were no differences in the evolution of peritoneal membrane transport characteristics. The lower baseline Kt/V of APD patients might be explained by our aggressive use of incremental APD (tidal with dry day). Despite greater glucose prescriptions, initiating patients on APD based on patient preference appears to be safe for the long-term integrity of the peritoneal membrane.

Could metformin be used in patients with diabetes and advanced chronic kidney disease?

Diabetes is an important cause of end stage renal failure worldwide. As renal impairment progresses, managing hyperglycaemia can prove increasingly challenging, as many medications are contra-indicated in moderate to severe renal impairment. Whilst evidence for tight glycaemic control reducing progression to renal failure in patients with established renal disease is limited, poor glycaemic control is not desirable, and is likely to lead to progressive complications. Metformin is a first-line therapy in patients with Type 2 diabetes, as it appears to be effective in reducing diabetes related end points and mortality in overweight patients. Cessation of metformin in patients with progressive renal disease may not only lead to deterioration in glucose control, but also to loss of protection from cardiovascular disease in a cohort of patients at particularly high risk. We advocate the need for further study to determine the role of metformin in patients with severe renal disease (chronic kidney disease stage 4-5), as well as patients on dialysis, or pre-/peri-renal transplantation. We explore possible roles of metformin in these circumstances, and suggest potential key areas for further study.

Is overhydration in peritoneal dialysis patients associated with cardiac mortality that might be reversible?

AIM: To study the relationship between overhydration (OH) in peritoneal dialysis (PD) patients and cardiac mortality. METHODS: OH, as measured by body composition monitor (BCM), is associated with increased mortality in dialysis patients. BCM has been used to guide treatment on the assumption that correcting OH will improve cardiac morbidity and mortality although data demonstrating causality that is reversible is limited. We wished to determine if OH in PD patients predicted cardiac mortality, and if there was a correlation between OH and cardiac troponin-T (cTnT) levels. Finally, we wished to determine if improving OH values would lead to a decrement in cTnT. All prevalent PD patients over the study period of 57 mo who had contemporaneous BCM and cTnT measurements were followed irrespective of transplantation or PD technique failure. We also studied a cohort of patients with who had severe OH (> +2L). The Fresenius Body Composition Monitor was used to obtain hydration parameters. cTnT levels were done as part of routine clinical care. Data was analysed using SPSS version 20.0. RESULTS: There were 48 deaths in the 336 patients. The patients that died from cardiac or non-cardiac causes were similar with respect to their age, incidence of diabetes mellitus, gender, ethnicity and cause of renal failure. However, the patients with cardiac causes of death had significantly shorter dialysis vintage (10.3 mo vs 37.0 mo, P < 0.0001) and were significantly more overhydrated by BCM measurement (2.95 L vs 1.35 L, P < 0.05). The mean (standard error of the means) hydration status of the 336 patients was +1.15 (0.12) L and the median [interquartile range (IQR)] cTnT level was 43.5 (20-90) ng/L. The cTnT results were not normally distributed and were therefore transformed logarithmically. There was a statistically significant correlation between Log (cTnT) with the OH value (Spearman r value 0.425, P < 0.0001). We identified a sub-group of patients that were severely overhydrated; median (IQR) hydration at baseline was +2.7 (2.3 to 3.7) L. They were followed up for a minimum of 6 mo. Reduction in OH values in these patients over 6 mo correlated with lowering of cTnT levels (Spearman r value 0.29, P < 0.02). CONCLUSION: Patients that were overhydrated had higher cTnT, and had deaths that were more likely to be cardiac related. Reduction in OH correlated with lowering of cTnT.

Use of Continuous Glucose Monitoring in Patients with Diabetes Mellitus on Peritoneal Dialysis: Correlation with Glycated Hemoglobin and Detection of High Incidence of Unaware Hypoglycemia.

INTRODUCTION: Glycated hemoglobin is used to assess diabetic control although its accuracy in dialysis has been questioned. How does it compare to the Continuous Glucose Monitoring System (CGMS) in peritoneal dialysis (PD) patients? METHODS: We conducted a retrospective analysis of 60 insulin-treated diabetic patients on PD. We determined the mean interstitial glucose concentration and the proportion of patients with hypoglycemia (<4 mmol/l) or hyperglycemia (>11 mmol/l). RESULTS: The correlation between HbA1c and glucose was 0.48, p < 0.0001. Three of 15 patients with HbA1c >75 mmol/mol experienced significant hypoglycemia (14-144 min per day). The patients with frequent episodes of hypoglycemia could not be differentiated from those with frequent hyperglycemia by demographics or PD prescription. CONCLUSION: HbA1c and average glucose levels measured by the CGMS are only weakly correlated. On its own, HbA1c as an indicator of glycemic control in patients with diabetes on PD appears inadequate. We suggest that the CGMS technology should be more widely adopted.

Hydration status measured by BCM: A potential modifiable risk factor for peritonitis in patients on peritoneal dialysis.

AIM: Peritoneal dialysis peritonitis and fluid overhydration (OH) are frequent problems in peritoneal dialysis. The latter can cause gut wall oedema or be associated with malnutrition. Both may lead to increased peritonitis risk. We wished to determine if OH is an independent risk factor for peritonitis (caused by enteric organisms). METHODS: Retrospectively study of patients with >2 bioimpedance assessments (Body Composition Monitor). We compared peritonitis rates of patients with above or below the median time-averaged hydration parameter (OH/extracellular water, OH/ECW). Multivariate analysis was performed to determine independent risk factors for peritonitis by enteric organism. RESULTS: We studied 580 patients. Peritonitis was experienced by 28% patients (followed up for an average of 17 months). The overall peritonitis rate was 1:34 patient months. Patients with low OH/ECW values had significantly lower rates of peritonitis from enteric organisms than overhydrated patients (incident rate ratio 1.53, 95% confidence interval 1.38-1.70, P < 0.001). Hydration remained an independent predictor of peritonitis from enteric organisms when multivariate model included demographic parameters (odds ratio for a 1% increment of OH/ECW was 1.05; 95% confidence interval 1.01-1.10, P < 0.02). However, including biochemical parameters of malnutrition reduced the predictive power of overhydration. CONCLUSION: We found an association between overhydration and increased rates of peritonitis. While this may partly be due to the high co-morbidity of patients (advanced age and diabetes), on multivariate analysis, only inclusion of nutritional parameters reduced this association. It remains to be determined if overhydration will prove to be a modifiable risk factor for peritonitis or whether malnutrition will prove to be more important.

Can Bioimpedance Measurements of Lean and Fat Tissue Mass Replace Subjective Global Assessments in Peritoneal Dialysis Patients?

OBJECTIVE: Malnutrition and protein energy wasting (PEW) determined by Subjective Global Assessment (SGA) is associated with increased mortality. There is an inverse relationship between body mass and overhydration in dialysis patients. Is the predictive accuracy of SGA (for death) independent of hydration status? Can bioimpedance spectroscopy analysis of lean tissue index (LTI) and fat tissue index (FTI) accurately identify dialysis patients with protein energy wasting and increased mortality? METHODS: We report an observational study of 455 peritoneal dialysis (PD) patients. RESULTS: We found that 96 patients (21%) were malnourished (SGA score between 1 and 5), and 192 (42%) had LTI values below 10th centile (age, gender adjusted). FTI was significantly lower in the SGA-defined malnourished cohort. By contrast, there was an inverse relationship between LTI and FTI. Malnourished (by SGA) patients were significantly more overhydrated (P < .0001), but SGA remained highly predictive of survival in multivariate analysis that included hydration status (hazard ratio: 3.12, 95% confidence interval 1.86-5.23, P < .0001). Obesity (patients with the highest 20% FTI) predicted survival (hazard ratio of death was 0.47, 95% confidence interval 0.16-0.85, P < .02) on univariate but not multivariate analysis. CONCLUSIONS: We have confirmed that SGA is an accurate predictor of mortality in PD patients, and its predictive value is independent of the hydration status. Predictive power of SGA was not affected when LTI and FTI were included in multivariate analysis. Patients with low LTI were different from patients with low SGA (associated with high FTI). Sensitivity and specificity of Body Composition Monitor to diagnose patients with low SGA readings were poor (area under the curve for receiver operator characteristics analysis 0.66). The phenomenon of reverse epidemiology (high FTI predicting a survival advantage) was found in our PD cohort.

Practical aspects of volume control in chronic kidney disease using whole body bioimpedance.

BACKGROUND: Fluid status is an independent predictor of mortality in dialysis patients. Current methods of fluid assessment have several limitations. SUMMARY: An ideal method should be cheap, portable, easy to perform without extensive training, reproducible and determines patients' excess or deficit of total body water. Bioimpedance analysis (BIA) fulfils many of these criteria and can give additional information on fat and lean tissue composition. The accuracy and precision of BIA has been shown to be equivalent to the 'gold standard' direct estimation techniques. KEY MESSAGES: Although there remains some concern about its validity in dialysis patients, fluid overload determined by BIA has been shown to predict mortality. BIA-guided fluid management appears superior to conventional fluid management in achieving clinically important outcomes such as reduction in blood pressure, left ventricular mass index, and arterial stiffness. Accurate setting of dry weight might also help preserve residual renal function by limiting episodes of dehydration. Nevertheless, as with all new technologies, there are issues that still need to be resolved. This will be achieved only with larger prospective interventional studies to explore its specific roles in dialysis cohorts.

Increasing the use of biocompatible, glucose-free peritoneal dialysis solutions.

A major concern inhibiting some clinicians from embracing peritoneal dialysis (PD) as the preferred first modality of dialysis is the effects of PD solutions on the peritoneal membrane. These anatomical and functional changes predispose to complications like peritonitis, encapsulating peritoneal sclerosis and ultrafiltration failure. In recent years, "biocompatible" and glucose-sparing PD regimens have been developed to minimize damage to the peritoneal membrane. Can the use of these more expensive solutions be justified on current evidence? In this review of the literature, we explore how we may individualize the prescription of biocompatible PD fluid.

Comparing lung ultrasound with bioimpedance spectroscopy for evaluating hydration in peritoneal dialysis patients.

BACKGROUND: Bioimpedance spectroscopy (BIS), ultrasound lung comets (ULC) and serum biomarkers (N-terminal pro-brain natriuretic peptide, NT-proBNP) have all been used to assist clinicians to determine hydration status in dialysis patients. METHODS: We performed simultaneous BIS, ULC and NT-proBNP measurements in 27 peritoneal dialysis patients to determine the concordance of the three methods. RESULTS: Patients with evidence of increasing lung congestion (as determined by ultrasound) were more likely to be diabetic, have systolic hypertension and have higher NT-proBNP (r = 0.65, P < 0.0005). Although there was a trend for patients with high ULC to be overhydrated as determined by BIS, this did not reach statistical significance. Moreover, the correlation between BIS and NT-proBNP (though statistically significant at r = 0.47, P < 0.02) appeared to be weaker. CONCLUSION: BIS and ULC may be complementary, providing different information, whereas BIS may be more specific to hydration. ULC and NT-proBNP may indicate left ventricular failure coexisting with overhydration.