Peritoneal catheter insertion: combating barriers through policy change

Barriers to accessing home dialysis became a matter of life and death for many patients with kidney failure during the coronavirus disease 2019 (COVID-19) pandemic. Peritoneal dialysis (PD) is the more commonly used home therapy option. This article provides a comprehensive analysis of PD catheter insertion procedures as performed around the world today, barriers impacting timely access to the procedure, the impact of COVID-19 and a roadmap of potential policy solutions. To substantiate the analysis, the article includes a survey of institutions across the world, with questions designed to get a sense of the regulatory frameworks, barriers to conducting the procedure and impacts of the pandemic on capability and outcomes. Based on our research, we found that improving patient selection processes, determining and implementing correct insertion techniques, creating multidisciplinary teams, providing appropriate training and sharing decision making among stakeholders will improve access to PD catheter insertion and facilitate greater uptake of home dialysis. Additionally, on a policy level, we recommend efforts to improve the awareness and feasibility of PD among patients and the healthcare workforce, enhance and promulgate training for clinicians—both surgical and medical—to insert PD catheters and fund personnel, pathways and physical facilities for PD catheter insertion.

Expanding Utilization of Home Dialysis: An Action Agenda From the First International Home Dialysis Roundtable

In a groundbreaking meeting, leading global kidney disease organizations came together in the fall of 2020 as an International Home Dialysis Roundtable (IHDR) to address strategies to increase access to and uptake of home dialysis, both peritoneal dialysis and home hemodialysis. This challenge has become urgent in the wake of the coronavirus disease 2019 (COVID-19) pandemic, during which patients with advanced kidney disease, who are more susceptible to viral infections and severe complications, must be able to safely physically distance at home. To boost access to home dialysis on a global scale, IHDR members committed to collaborate, through the COVID-19 public health emergency and beyond, to promote uptake of home dialysis on a broad scale. Their commitments included increasing the reach and influence of key stakeholders with policy makers, building a cooperative of advocates and champions for home dialysis, working together to increase patient engagement and empowerment, and sharing intelligence about policy, education, and other programs so that such efforts can be operationalized globally. In the spirit of international cooperation, IHDR members agreed to document, amplify, and replicate established efforts shown to improve access to home dialysis and support new policies that facilitate access through procedures, innovation, and reimbursement.

A COVID-19 pandemic-specific, structured care process for peritoneal dialysis patients facilitated by telemedicine: Therapy continuity, prevention, and complications management

Coronavirus disease 2019 (COVID‐19) has been declared a pandemic. Peritoneal dialysis (PD), being a home therapy, allows for physical distancing measures and movement restrictions. In order to prevent COVID‐19 contagioun among the Dominican Republic National Health System PD program patients, a follow‐up virtual protocol for this group was developed. The aim of this study is to outline the protocol established by the PD program's healthcare team using telemedicine in order to avoid COVID‐19 transmission and to report initial results and outcomes of this initiative. This is an observational prospective longitudinal study with 946 patients being treated in seven centers distributed throughout the country between April 1 and June 30. The protocol was implemented focusing on the patient follow‐up; risk mitigation data were registered and collected from electronic records. During the follow‐up period, 95 catheters were implanted, 64 patients initiated PD, and the remaining were in training. A total of 9532 consultations were given by the different team specialists, with 8720 (91%) virtual and 812 (9%) face‐to‐face consultations. The transfer rate to hemodialysis was 0.29%, whereas the peritonitis rate was 0.11 episode per patient/year. Eighteen adults tested positive for COVID‐19. The implementation of the protocol and telemedicine utilization have ensured follow‐up and monitoring, preserved therapy, controlled complications, and PD lives protected.

The impact of body mass index (BMI) variation on mortality of incident elderly patients on peritoneal dialysis: a joint model analysis

INTRODUCTION

Data on impact of high body mass index (BMI) on mortality of patients on peritoneal dialysis (PD), especially among elderly, are inconsistent. Objective: To evaluate impact of BMI on cohort of incident elderly PD patients over time.

METHODS

Prospective multicenter cohort study (December / 2004-October/2007) with 674 patients. Socio-demographic and clinical data evaluated with patients followed until death, transfer to hemodialysis (HD), recovery of renal function, loss of follow-up or transplant. Patients were divided into incident on renal replacement therapy (RRT) for PD (PD first: 230) and transferred from hemodialysis (HD first: 444). Analysis was performed comparing these two groups using chi-square or Kruskal Wallis. Similar analysis was used to compare patients on automated peritoneal dialysis (APD) vs. continuous ambulatory peritoneal dialysis (CAPD). Data were compared between patients according to BMI by ANOVA, Kruskal Wallis or chi-square. For analysis of survival, Kaplan Meier method was used and to adjust confounding variables, Cox regression proportional hazard. Joint model for longitudinal and time-dependent data was conducted, assessing impact that a longitudinal variable displays on time of survival.

RESULTS

Malnourished patients (76.79 ± 7.53 years) were older (p < 0.0001) with higher percentage of death (44.6%, p = 0.001); diabetes mellitus showed high prevalence in obese patients (68%, p < 0.0001); higher blood pressure levels (p = 0.002) were present in obese and overweight patients.

CONCLUSIONS

Increased BMI variation over time proved to be a protective factor, with a decrease of about 1% in risk of death for every BMI unit earned.

Icodextrin reduces insulin resistance in non-diabetic patients undergoing automated peritoneal dialysis: results of a randomized controlled trial (STARCH)

BACKGROUND

Insulin resistance is a common risk factor in chronic kidney disease patients contributing to the high cardiovascular burden, even in the absence of diabetes. Glucose-based peritoneal dialysis (PD) solutions are thought to intensify insulin resistance due to the continuous glucose absorption from the peritoneal cavity. The aim of our study was to analyse the effect of the substitution of glucose for icodextrin on insulin resistance in non-diabetic PD patients in a multicentric randomized clinical trial.

METHODS

This was a multicenter, open-label study with balanced randomization (1:1) and two parallel-groups. Inclusion criteria were non-diabetic adult patients on automated peritoneal dialysis (APD) for at least 3 months on therapy prior to randomization. Patients assigned to the intervention group were treated with 2L of icodextrin 7.5%, and the control group with glucose 2.5% during the long dwell and, at night in the cycler, with a prescription of standard glucose-based PD solution only in both groups. The primary end-point was the change in insulin resistance measured by homeostatic model assessment (HOMA) index at 90 days.

RESULTS

Sixty patients were included in the intervention (n = 33) or the control (n = 27) groups. There was no difference between groups at baseline. After adjustment for pre-intervention HOMA index levels, the group treated with icodextrin had the lower post-intervention levels at 90 days in both intention to treat [1.49 (95% CI: 1.23-1.74) versus 1.89 (95% CI: 1.62-2.17)], (F = 4.643, P = 0.03, partial η(2) = 0.078); and the treated analysis [1.47 (95% CI: 1.01-1.84) versus 2.18 (95% CI: 1.81-2.55)], (F = 7.488, P = 0.01, partial η(2) = 0.195).

CONCLUSIONS

The substitution of glucose for icodextrin for the long dwell improved insulin resistance measured by HOMA index in non-diabetic APD patients.

Impact of baseline health-related quality of life scores on survival of incident patients on peritoneal dialysis: a cohort study

INTRODUCTION

In an attempt to decrease mortality in patients with end-stage renal disease, an increase in the lifetime of these patients without much focus on health-related quality of life (HRQOL) was pursued for a long period of time. However, lately, an improvement in the quality of this extended lifetime has focused on both the physical as well as the social and emotional aspects, as these parameters may be associated with clinical outcomes in end-stage renal disease patients.

AIM

To evaluate the impact of self-determined HRQOL at admission on survival of incident peritoneal dialysis (PD) patients.

PATIENTS AND METHODS

A total of 1,624 incident Brazilian PD patients participating in a multicenter prospective cohort study (BRAZPD) were evaluated. HRQOL was assessed using the SF-36, divided into mental and physical components. Cox proportional regression analysis was used to determine the influence of HRQOL (mental and physical components) on mortality. Multivariate Cox proportional hazards analyses were used to adjust gradually for more potential explanatory variables: first for demographic variables, followed by additional adjustment for socioeconomic, clinical and laboratory variables. The significance level in all analyses was set at p < 0.05. All analyses were carried out with SPSS 17.0.

RESULTS

Incident PD patients presented with low HRQOL scores on admission to therapy. Even after correction for sociodemographic variables, comorbidities, PD modality and laboratory parameters, HRQOL (both the mental and the physical components) remained a predictor [HR: 0.97 (CI: 0.95-0.98); HR: 0.97 (CI: 0.96-0.99), respectively] of survival.

CONCLUSION

On admission to therapy, patients presenting with low HRQOL scores for both the mental and the physical components were associated with a higher mortality. These results suggest that early and timely intervention measures to improve the QOL of these patients are important.

Longitudinal changes in health-related quality of life scores in Brazilian incident peritoneal dialysis patients (BRAZPD): socio-economic status not a barrier

BACKGROUND AND OBJECTIVES

A large proportion of the patients on peritoneal dialysis (PD) in Brazil have low levels of education and family income. The present study assessed whether education level and family income are associated with baseline and longitudinal changes in health-related quality of life (HRQOL) scores during the first year of PD therapy.

METHODS

We evaluated 1624 incident patients from the Brazilian Peritoneal Dialysis Multicenter Study (BRAZPD) at baseline, and 486 of them after 12 months. The SF-36 was used to determine HRQOL and the Karnofsky index (KI), physical performance.

RESULTS

At baseline, patients received high KI scores compared with scores on the SF-36. The means of the mental and physical components at baseline and after 12 months were 39.9 ± 10.5 compared with 38.7 ± 11.7 and 41.8 ± 9.6 compared with 40.7 ± 9.8 respectively, which were not statistically different. A multivariate regression analysis showed that age, sex, diabetes, and cardiovascular disease were predictors of the mental component (respectively, β = 0.12, p < 0.001; β = 0.11, p < 0.001; β = -0.08, β = 0.007; and β = -0.07, p = 0.007) and that age, sex, diabetes, cardiovascular disease, hemoglobin, glucose, and creatinine were predictors of the physical component (respectively, β = -0.28, p < 0.001; β = 0.06, p = 0.009; β = -0.09, p = 0.002; β = -0.09, p = 0.001; β = 0.07, p = 0.004; β = -0.05, p = 0.040; and β = 0.05, p = 0.040). Education level and family income were not significantly associated with HRQOL (mental and physical components) in the multivariate regression.

CONCLUSIONS

The results indicate that, as predictors, family income and education level have no impact on HRQOL, supporting the idea that socio-economic status should not be a barrier to the selection of PD as a treatment modality in Brazil.

Novel predictors of peritonitis-related outcomes in the BRAZPD cohort

INTRODUCTION

Peritonitis remains the main cause of peritoneal dialysis (PD) technique failure worldwide, despite significant reductions in infection rates observed over the past decades. Several studies have described risk factors for peritonitis, technique failure and mortality. However, there are scarce data regarding predictors of complications during and after a peritonitis episode. The aim of our study was to analyze predictors of peritonitis-related outcome in the Brazilian Peritoneal Dialysis study (BRAZPD) cohort.

METHODS

All adult incident patients recruited in the BRAZPD Study between December 2004 and October 2007, who remained at least 90 days on PD and presented their first peritonitis episode (n = 474 patients) were included in the study. The endpoints analyzed were non-resolution, death due to a peritonitis episode and long-term technique survival after a peritonitis episode.

RESULTS

In the multivariable regression, non-resolution was independently associated with older age (odds ratio (OR) 1.02; p < 0.01), collagenosis as the primary renal disease (OR 4.6; p < 0.05) and Pseudomonas spp as etiological agent (OR 2.9; p < 0.05). Patients who were transferred from APD to CAPD during peritonitis therapy presented a higher risk of non-response (OR 2.5; p < 0.05). The only factor associated with death during a peritonitis episode was older age (OR 1.04; p < 0.05). Exposure to vancomycin and male gender were the independent predictors of long-term technique failure (OR 2.2; p < 0.01).

CONCLUSION

Apart from confirming previous observations of the negative impact of older age and Pseudomonas spp peritonitis on outcomes, we observed that collagenosis may negatively impact response to treatment and exposure to vancomycin may possibly reduce long-term technique survival. It is important to emphasize that the association of vancomycin with technique failure does not prove causality. These findings shed light on new factors predicting outcome when peritonitis is diagnosed.

Association of ethnicity and survival in peritoneal dialysis: a cohort study of incident patients in Brazil

BACKGROUND

There are no available epidemiologic studies about the impact of ethnicity on outcomes of patients treated with peritoneal dialysis (PD) in South America. This study aims to assess the effect of ethnicity on the mortality of incident PD patients in Brazil.

STUDY DESIGN

Prospective observational cohort study of incident patients treated with PD.

SETTINGS & PARTICIPANTS

Patients 18 years or older who started PD therapy between December 2004 and October 2007 in 114 Brazilian dialysis centers.

PREDICTORS

Self-reported ethnicity defined by the Brazilian Institute of Geography and Statistics as black and brown versus white patients and baseline demographic, socioeconomic, clinical, and laboratory data were collected at baseline.

OUTCOME

Mortality, using cumulative mortality curves in which kidney transplantation and transfer to hemodialysis therapy were treated as competing end points. Multivariate Cox proportional hazards analysis was used to adjust for gradually more potential explanatory variables, censored for kidney transplantation and transfer to hemodialysis therapy. Analyses were performed for all patients, as well as stratified for elderly (aged ≥65 years) and nonelderly patients.

RESULTS

1,370 patients were white, 516 were brown, and 273 were black. The competing-risk model showed higher mortality in white patients compared with black and brown patients. With white patients as the reference, Cox proportional hazards analysis showed a crude HR for mortality of 0.77 (95% CI, 0.56-1.05) for black and 0.74 (95% CI, 0.59-0.94) for brown patients. After adjusting for potential explanatory factors, HRs were 0.67 (95% CI, 0.48-0.95) and 0.77 (95% CI, 0.43-1.01), respectively. The same results were observed in elderly and nonelderly patients.

LIMITATIONS

Ethnicity was self-determined and some misclassification might have occurred.

CONCLUSIONS

Black and brown Brazilian incident PD patients have a lower mortality risk compared with white patients.

Body size and longitudinal body weight changes do not increase mortality in incident peritoneal dialysis patients of the Brazilian peritoneal dialysis multicenter study

OBJECTIVES

To determine the roles of body size and longitudinal body weight changes in the survival of incident peritoneal dialysis patients.

PATIENTS AND METHODS

Patients (n = 1911) older than 18 years of age recruited from 114 dialysis centers (Dec/ 2004-Oct/2007) and participating in the Brazilian Peritoneal Dialysis Multicenter Cohort Study were included. Clinical and laboratory data were collected monthly (except if the patient received a transplant, recovered renal function, was transferred to hemodialysis, or died).

RESULTS

Survival analyses were performed using Kaplan-Meier survival curves and Cox proportional hazards. Total follow-up was 34 months. The mean age was 59 years (54% female). The weight category percentages were as follows: underweight: 8%; normal: 51%; overweight: 29%; and obese 12%. The multivariate model showed a higher risk of death for a body mass index <18.5 kg/m², a neutral risk between 25 and 29.9 kg/m² and a protective effect for an index >30 kg/m². Patients were divided into five categories according to quintiles of body weight changes during the first year of dialysis: <-3.1%, -3.1 to+0.12%, +0.12 to <+3.1% (reference category), +3.1 to +7.1% and >+7.1%. Patients in the lowest quintile had significantly higher mortality, whereas no negative impact was observed in the other quintiles.

CONCLUSION

These findings suggest that overweight/obesity and a positive body weight variation during the first year of peritoneal dialysis therapy do not increase mortality in incident dialysis patients in Brazil.

Increase in BMI over time is associated with fluid overload and signs of wasting in incident peritoneal dialysis patients

OBJECTIVES

Peritoneal dialysis (PD) patients may suffer changes in nutritional status after starting PD. Several markers can be used to evaluate these modifications, such as body mass index (BMI), serum albumin, and serum creatinine. Fluid overload should be considered because it can overestimate or underestimate nutritional status. The objective of this study was to evaluate the BMI changes over time in incident PD patients and identify interactions among BMI, signs of fluid overload, serum albumin, and serum creatinine.

DESIGN

The study included a cohort of 1,997 incident PD patients of the BRAZPD recruited from 2004 to 2007. Sociodemographic data and BMI classification were obtained at baseline. The evolutions of BMI and body weight were assessed over a period of 29 months. Changes in the evolution were analyzed when a patient presented with albumin < 3.8 g/dL, creatinine < 7.0 mg/dL, or the presence of edema. Data analysis was performed using linear mixed-effects regression models as the main statistical procedure.

RESULTS

BMI increased over time (29 months) by an average of 0.05 kg/m(2) per month, and body weight increased by 0.11 kg/month for a total increase of 3.08 kg. BMI decreased by 0.12 kg/m(2) in the presence of albumin < 3.8 g/dL and by 0.38 kg/m(2) in the presence of creatinine < 7.0 mg/dL. BMI increased by 0.61 kg/m(2) in the presence of edema. BMI increased in the presence of edema and albumin < 3.8 mg/dL or edema and creatinine < 7.0 mg/dL.

CONCLUSIONS

There is a mean increase in the BMI of incident PD patients over time, and these changes may be, at least partly, due to fluid overload, leading to distortions of body weight. When the patients presented with lower serum albumin or creatinine levels, the BMI values were reduced, suggesting that a reduction in lean mass and an increase in fat mass may be occurring in these patients.

Geography of peritoneal dialysis in Brazil: analysis of a cohort of 5,819 patients (BRAZPD)

INTRODUCTION

Brazil is a continental country with great diversity of population, social and cultural. This factor may determine different demographic, clinical and outcome presented by patients with chronic kidney disease on peritoneal dialysis (PD).

OBJECTIVE

To evaluate the clinical characteristics and outcomes presented by PD patients in different regions of Brazil, analyzing a cohort of patients (BRAZPD) in the period 12/2004 to 10/2007.

PATIENTS AND METHODS

Data were collected monthly and patients were followed until the outcome (death, renal transplantation, renal function recovery, transfer to hemodialysis or loss of follow-up).

RESULTS

We evaluated 5.819 patients incident and prevalent. Most patients performed renal replacement therapy (RRT) in the Southeast, where the average follow up time was longer (12.3 months) and there is a higher percentage of elderly (36.4%). The prevalence of diabetes is higher in Southeast and South (38.1% and 37%, respectively). Most patients in the North region had previously hemodialysis (66.2%). The mortality was higher in the Northern region (30.1%), as well as failure of the technique (22.3%).

CONCLUSION

The data shows different demographic, clinical, mortality and technique failure of PD reflecting the demographic and social peculiarities of Brazil. The geography of the DP in Brazil proves to be a mirror of the geography of Brazil. So health policies should take into account the characteristics of each region so we can improve patient survival and technique on peritoneal dialysis.

Are insulin-like growth factor and its binding proteins 1 and 3 clinically useful as markers of malnutrition, sarcopenia and inflammation in end-stage renal disease?

INTRODUCTION

Malnutrition is common in end-stage renal disease (ESRD) and affects both morbidity and mortality. The growth hormone-dependent insulin-like growth factor (IGF)-I may be a good marker of malnutrition because of its short half-life. In the present study, we investigate the influence of decreasing residual renal function as well as of chronic inflammation on the IGF system to assess its usefulness in this patient group.

PATIENTS AND METHODS

Cross-sectional analysis of 220 ESRD patients (140 males) with a mean age of 52+/-1 years. Biochemical analyses of insulin, IGF-I, IGFBP-1, IGFBP-3, IL-6, high sensitivity (hs)-CRP and other routine markers. Malnutrition status was recorded using subjective global assessment (SGA), body mass index, estimated protein intake from nitrogen appearance (nPNA), handgrip strength (HGS) and insulin resistance (HOMA-IR). Dual energy X-ray absorptiometry was used to assess body composition.

RESULTS

Both IGF-I and IGFBP-1 showed significant and opposite correlations with most markers of nutritional status, including SGA (rho=-0.29 and 0.27; P<0.001), nPNA (rho=0.18 and -0.22; P<0.05), S-creatinine (rho=0.19 and -0.19; P<0.01) and HGS (rho=0.21 and -0.25; P<0.01). IFG-I was strongly correlated with IGFBP-3 (rho=0.62; P<0.001) and inversely correlated with IGFBP-1 (rho=0.44; P<0.001). Both IGF-I and IGFBP-3, but not IGFBP-1, were significantly correlated with age (rho=-0.25 for IGF-I and -0.35 for IGFBP-3; P<0.001) and hsCRP (rho=-0.21 and -0.32; P<0.01). In multivariate analysis, SGA and s-albumin were independent predictors of both IGF-I and IGFBP-1.

CONCLUSION

Both IGF-I and IGFBP-1 appear to correlate well with markers of protein-energy malnutrition and sarcopenia. However, IGF-I is also influenced by age, whereas IGFBP-1 is influenced by glucose metabolism. IGFBP-3 does not correlate with nutritional status in ESRD, perhaps because of a strong association with inflammation.

Factors predicting malnutrition in hemodialysis patients: a cross-sectional study

Signs of protein-energy malnutrition are common in maintenance hemodialysis (HD) patients and are associated with increased morbidity and mortality. To evaluate the nutritional status and relationship between various parameters used for assessing malnutrition, we performed a cross-sectional study in 128 unselected patients treated with hemodialysis (HD) thrice weekly for at least two weeks. Global nutritional status was evaluated by the subjective global nutritional assessment (SGNA). Body weight, skinfold thicknesses converted into % body fat mass (BFM), mid-arm muscle circumference, hand-grip strength and several laboratory values, including serum albumin (SA1b), plasma insulin-like growth factor I (p-IGF-I), serum C-reactive protein (SCRP) and plasma free amino acids, were recorded. Dose of dialysis and protein equivalence of nitrogen appearance (nPNA) were evaluated by urea kinetic modeling. The patients were subdivided into three groups based on SGNA: group I, normal nutritional status (36%); group II, mild malnutrition (51%); and group III, moderate or (in 2 cases) severe malnutrition (13%). Clinical factors associated with malnutrition were: high age, presence of cardiovascular disease and diabetes mellitus. nPNA and Kt/V(urea) were similar in the three groups. However, when normalized to desirable body wt, both were lower in groups II and III than in group I. Anthropometric factors associated with malnutrition were low body wt, skinfold thickness, mid-arm muscle circumference (MAMC), and handgrip strength. Biochemical factors associated with malnutrition were low serum levels of albumin and creatinine and low plasma levels of insulin-like growth factor 1 (IGF-1) and branched-chain amino acids (isoleucine, leucine and valine). The serum albumin (SAlb) level was not only a predictor of nutritional status, but was independently influenced by age, sex and SCRP. Plasma IGF-1 levels also reflected the presence and severity of malnutrition and appeared to be more closely associated than SAlb with anthropometric and biochemical indices of somatic protein mass. Elevated SCRP (> 20 mg/liter), which mainly reflected the presence of infection/inflammation and was associated with hypoalbuminemia, was more common in malnourished patients than in patients with normal nutritional status, and also more common in elderly than in younger patients. Plasma amino acid levels, with the possible exception of the branched-chain amino acids (isoleucine, leucine, valine), seem to be poor predictors of nutritional status in hemodialysis patients.

Multifrequency bioimpedance in assessment of dry weight in haemodialysis

The use of multifrequency bioimpedance (MFB) for determination of dry weight (DW) in haemodialysis (HD) patients was evaluated in three studies. In Study 1, the fluid state [total body water (TBW) and extracellular volume (ECV)] was measured by MFB in 82 normotensive patients. 41 hypertensive patients and in 30 healthy subjects. TBW and ECV were expressed as per cent of body weight (BW). In Study 2, DW of five hypertensive HD patients was gradually decreased during 3 months and ECV (MFB) and blood pressure (48 h ambulatory blood pressure monitoring) were measured at the beginning and end of study. In Study 3, we measured the fluid status repeatedly by MFB and the diameter of the inferior vena cava (DIVC) by ultrasound before, during and 2 h post-HD. In Study 1, the hypertensive patients had significantly greater TBW (P < 0.05) than the normotensive patients before (50.3 +/- 6.5% vs 47.6 +/- 5.8%) and after HD (48.8 +/- 7.8% vs 45.7 +/- 6.4%) and ECV (P < 0.001) before (29.4 +/- 3.6% vs 26.8 +/- 3.5%) and after HD (27.0 +/- 4.0% vs 24.6 +/- 3.5%), Post-HD ECV in the normotensive patients was similar to that in the healthy subjects. In Study 2, more efficient ultrafiltration resulted in reduction of BW and ECV along with a decrease in blood pressure and need for antihypertensive medication. In Study 3, both ECV and DIVC decreased following the removal of fluid during HD. ECV maintained stable values during the post-HD period, unlike DIVC which increased significantly (P < 0.005) due to refilling from the interstitial space. We conclude that MFB is an appropriate non-invasive method for DW determination, which is highly reproducible and technically simple to use.