Ultrafiltration rates and intradialytic hypotension: A case-control sampling of pooled haemodialysis data.

BACKGROUND: Intradialytic hypotension (IDH) is one of the most critical adverse events during maintenance haemodialysis. Previous studies reported the association of fluid removal rate with the occurrence of IDH. OBJECTIVE: We aimed to identify the optimal threshold of ultrafiltration rate to prevent the occurrence of IDH events. DESIGN, PARTICIPANTS AND MEASUREMENTS: Prognostic factor research with a retrospective case-control design was conducted. Patient data were gathered from four haemodialysis units from January to December 2017. All the haemodialysis records were independently justified, whether IDH occurred or not, based on the standard definition. A total of 10 haemodialysis sessions were sampled from each patient's pool based on the incidence of events. The association of ultrafiltration rates and IDH events was explored by multivariable multilevel logistic regression. RESULTS: A total of 1080 haemodialysis sessions from 108 patients were included: 149 (13.8%) with IDH and 931 (86.2%) without IDH. After adjusting for all pre-specified risk factors and imbalance baselines, the odds ratio of IDH were 1.22 (95% confidence interval [CI]: 0.59, 2.52) for rate 10-12 ml/kg/h; 2.52 (95% CI: 1.20, 5.29) for rate 12-14 ml/kg/h; 4.02 (95% CI: 1.61, 10.03) for rate 14-16 ml/kg/h; and 7.41 (95% CI: 2.53, 21.68) for rate >16 ml/kg/h comparing to the referent rate of <10 ml/kg/h. CONCLUSION: The ultrafiltration rate should be limited to 12 ml/kg/h. If a higher rate of fluid removal was indicated, it should not exceed 16 ml/kg/h to avoid the occurrence of IDH.

Automated Remote Monitoring for Peritoneal Dialysis and Its Impact on Blood Pressure.

INTRODUCTION: Peritoneal dialysis (PD) provides a safe, home-based continuous renal replacement therapy for patients. The adherence of the patients to the prescribed dialysis fluids cannot always be monitored by physicians. Remote monitoring automated peritoneal dialysis (RM-APD) can affect patients' compliance with treatment and, thus, clinical outcomes. OBJECTIVE: We aimed to evaluate the clinical outcomes of patients with a remote access program. METHODS: This was an observational study. We analyzed the effect of RM-APD on treatment adherence, dialysis adequacy, and change in blood pressure control, sleep quality, and health-related quality of life during the 6 months of follow-up. RESULTS: A total of 15 patients were enrolled in this study. It was found that there was a significant decrease (99 ± 19 vs. 89 ± 11 mm Hg) in mean arterial blood pressure of patients, and a considerable increase in Kt/V was observed in the sixth month after the RM-APD switch (2.11 ± 0.4 vs. 2.25 ± 0.5). A significant increase was found when comparing the 3-month and 6-month ultrafiltration amounts before RM-APD and the ultrafiltration amount within 6 months after RM-APD (800 mL [500-1,000] and 752 mL [490-986] vs. 824 mL [537-1,183]). The daily antihypertensive pill need (4 [0-7] vs. 2 [0-6]) and alarms received from the device decreased (from 4 [3-8] to 2 [0-3]) at the sixth month of the switch. There was no significant change in sleep quality and health-related quality of life within 6 months. CONCLUSION: This study showed that treatment adherence and ultrafiltration amounts of patients increased with the use of RM-APD, as well as better blood pressure control with fewer antihypertensive drugs.

Hemodynamic and Laboratory Changes during Incremental Transition from Twice to Thrice-Weekly Hemodialysis.

OBJECTIVE: Incremental hemodialysis (HD) is a strategy utilized to gradually intensify dialysis among patients with incident end-stage renal disease. However, there are scarce data about which patients' clinic status changes by increasing treatment frequency. METHODS: We retrospectively examined statistically de-identified data from 569 patients who successfully transitioned from twice- to thrice-weekly HD (2007-2011) and compared the differences in monthly-averaged values of hemodynamic and laboratory indices during the 3 months before and after the transition with the values at 1 month prior to transition serving as the reference. RESULTS: At 3 months after transitioning from twice- to thrice-weekly HD, ultrafiltration volume decreased by 0.5 (95% CI 0.3-0.6) L/session among 189 patients (33%) with weekly interdialytic weight gain (IDWG) ≥5.4 kg/week, and increased by 0.4 (95% CI 0.3-0.5) L/session among 186 patients (33%) with weekly IDWG <3.3 kg/week. Weekly IDWG consistently increased after the transition irrespective of baseline values (1.7 [95% CI 1.5-1.9] kg/week). Pre-HD systolic blood pressure (SBP) decreased by 12 (95% CI 9-14) mm Hg among 177 patients (31%) with baseline pre-HD SBP ≥160 mm Hg, which coincided with a decreasing trend in post-HD body weight (1.3 [95% CI 0.8-1.7] kg). DISCUSSION: In conclusion, patients who increased HD frequency from twice to thrice weekly treatment experienced increased weekly IDWG and better pre-HD SBP control with lower post-HD body weight.

Ultrafiltration Rate, Residual Kidney Function, and Survival Among Patients Treated With Reduced-Frequency Hemodialysis.

RATIONALE & OBJECTIVE: Patients receiving twice-weekly or less-frequent hemodialysis (HD) may need to undergo higher ultrafiltration rates (UFRs) to maintain acceptable fluid balance. We hypothesized that higher UFRs are associated with faster decline in residual kidney function (RKF) and a higher rate of mortality. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 1,524 patients with kidney failure who initiated maintenance HD at a frequency of twice or less per week for at least 6 consecutive weeks at some time between 2007 and 2011 and for whom baseline data for UFR and renal urea clearance were available. PREDICTOR: Average UFR during the first patient-quarter during less-frequent HD (<6, 6-<10, 10-<13, and≥13mL/h/kg). OUTCOME: Time to all-cause and cardiovascular death, slope of decline in RKF during the first year after initiation of less-frequent HD (with slopes above the median categorized as rapid decline). ANALYTICAL APPROACH: Cox proportional hazards regression for time to death and logistic regression for the analysis of rapid decline in RKF. RESULTS: Among 1,524 patients, higher UFR was associated with higher all-cause mortality; HRs were 1.43 (95% CI, 1.09-1.88), 1.51 (95% CI, 1.08-2.10), and 1.76 (95% CI, 1.23-2.53) for UFR of 6 to<10, 10 to<13, and≥13mL/h/kg, respectively (reference: UFR < 6mL/h/kg). Higher UFR was also associated with higher cardiovascular mortality. Baseline RKF modified the association between UFR and mortality; the association was attenuated among patients with renal urea clearance≥5mL/min/1.73m2. Higher UFR had a graded association with rapid decline in RKF; ORs were 1.73 (95% CI, 1.18-2.55), 1.89 (95% CI, 1.12-3.17), and 2.75 (95% CI, 1.46-5.18) at UFRs of 6 to<10, 10 to<13, and≥13mL/h/kg, respectively (reference: UFR < 6mL/h/kg). LIMITATIONS: Residual confounding from unobserved differences across exposure categories. CONCLUSIONS: Higher UFR was associated with worse outcomes, including shorter survival and more rapid loss of RKF, among patients receiving regular HD treatments at a frequency of twice or less per week.

Automated peritoneal dialysis could rapidly improve left heart failure by increasing peritoneal dialysis ultrafiltration: a single-center observational clinical study
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Ultrafiltration failure (UFF) is a major cause of water retention, left heart failure (LHF), and peritoneal dialysis (PD) failure. Automated peritoneal dialysis (APD) might have better ultrafiltration (UF) than continuous ambulatory peritoneal dialysis (CAPD). Here, we have studied whether short-term APD could increase UF and improve LHF. 47 patients were included in this study from December 1, 2015, to January 1, 2017. All patients had been treated with CAPD before they came to our center and were treated with APD in the hospital. 24-hour peritoneal UF volume, 24-hour urine volume, body weight, blood pressure, LHF class, serum creatinine, blood urea nitrogen, albumin, potassium, hemoglobin, and glucose were collected and compared before and after receiving short-time APD. A total of 47 patients (31 men, mean age 46.8 ± 16.2 years, mean duration 26 months (2 - 195 months)) were enrolled in this study. Of the 47 patients, peritoneal dialysis UF was significantly increased when receiving short-term APD compared to CAPD (1,261.9 ± 329.6 mL vs. 706.2 ± 222.3 mL, p < 0.001), and body weights had significantly decreased 3 days after treatment with APD (57.73 ± 10.5 vs. 59.81 ± 10.8, p < 0.001). LHF class was significantly decreased 3 days after receiving APD (1.7 ± 0.8 vs. 2.4 ± 1.0, p < 0.001). Blood pressure was well controlled 3 days after treatment with APD (146.6 ± 14.4 vs. 162.5 ± 23.8 of SBP, p = 0.007, and 85.6 ± 11.1 vs. 95.6 ± 14.7 of DBP, p = 0.001). In conclusion, short-term APD could significantly increase ultrafiltration, rapidly alleviate edema and improve LHF, and might be an effective method to treat UFF and LHF in PD patients.
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Association between intradialytic central venous oxygen saturation and ultrafiltration volume in chronic hemodialysis patients.

Background: Cardiac disease is highly prevalent in hemodialysis (HD) patients. Decreased tissue perfusion, including cardiac, due to high ultrafiltration volumes (UFVs) is considered to be one of the drivers of cardiac dysfunction. While central venous oxygen saturation (ScvO2) is frequently used as an indicator of cardiac output in non-uremic populations, the relationship of ScvO2 and UFV in HD patients remains unclear. Our aim was to determine how intradialytic ScvO2 changes associate with UFV. Methods: We conducted a 6-month retrospective cohort study in maintenance HD patients with central venous catheters as vascular access. Intradialytic ScvO2 was measured with the Critline monitor. We computed treatment-level slopes of intradialytic ScvO2 over time (ScvO2 trend) and applied linear mixed effects models to assess the association between patient-level ScvO2 trends and UFV corrected for body weight (cUFV). Results: We studied 6042 dialysis sessions in 232 patients. In about 62.4% of treatments, ScvO2 decreased. We observed in nearly 80% of patients an inverse relationship between cUFV and ScvO2 trend, indicating that higher cUFV is associated with steeper decline in ScvO2 during dialysis. Conclusions: In most patients, higher cUFV volumes are associated with steeper intradialytic ScvO2 drops. We hypothesize that in a majority of patients the intradialytic cardiac function is fluid dependent, so that in the face of high ultrafiltration rates or volume, cardiac pre-load and consequently cardiac output decreases. Direct measurements of cardiac hemodynamics are warranted to further test this hypothesis.

Predicting of ultrafiltration performances by advanced data analysis.

In order to optimize drinking water production operation, membrane users can use several analytical tools that help membrane fouling prediction and alleviate fouling by a proper feed water resource selection. However, during strong fouling event, membrane decision-makers still face short-term deadline to decide between different options (e.g. optimization of pretreatment or change in feed water quality). Hence, statistical approach might help to better select the most relevant analytical parameter related to fouling potential of a specific resource in order to speed-up decision taking. In this study, the physical and chemical properties and the filtration performances (at lab-scale) of five ground water resources, selected as potential resources of a large drinking production site of Paris (France), was evaluated through one year. Principal component analysis emphasizes the strong link between waters' organic matrix and fouling propensity. Cluster analysis of filtration performances allowed classifying the water samples into three groups exhibiting strong, low and intermediate fouling. Finally, multiple linear regressions performed on all collected data indicated that strong fouling events were related to a combined increase of carbon content and protein like-substances while intermediate fouling might only be anticipated by an increase of fluorescence signal associated to protein like-substances. This study demonstrates that advanced data analysis might be a powerful tool to better manage water resources selection used for drinking water production and to forecast filtration performances in a context of water quality degradation.

Ultrafiltration Rate and Mortality in Maintenance Hemodialysis Patients.

BACKGROUND: Observational data have demonstrated an association between higher ultrafiltration rates and greater mortality among hemodialysis patients. Prior studies were small and did not consider potential differences in the association across body sizes and other related subgroups. No study has investigated ultrafiltration rates normalized to anthropometric measures beyond body weight. Also, potential methodological shortcomings in prior studies have led to questions about the veracity of the ultrafiltration rate-mortality association. STUDY DESIGN: Retrospective cohort. SETTING & PARTICIPANTS: 118,394 hemodialysis patients dialyzing in a large dialysis organization, 2008 to 2012. PREDICTORS: Mean 30-day ultrafiltration rates were dichotomized at 13 and 10mL/h/kg, separately and categorized using various cutoff points. Ultrafiltration rates normalized to body weight, body mass index, and body surface area were investigated. OUTCOMES: All-cause mortality. MEASUREMENTS: Multivariable survival models were used to estimate the association between ultrafiltration rate and all-cause mortality. RESULTS: At baseline, 21,735 (18.4%) individuals had ultrafiltration rates > 13mL/h/kg and 48,529 (41.0%) had ultrafiltration rates > 10mL/h/kg. Median follow-up was 2.3 years, and the mortality rate was 15.3 deaths/100 patient-years. Compared with ultrafiltration rates ≤ 13mL/h/kg, ultrafiltration rates > 13mL/h/kg were associated with greater mortality (adjusted HR, 1.31; 95% CI, 1.28-1.34). Compared with ultrafiltration rates ≤ 10mL/h/kg, ultrafiltration rates > 10mL/h/kg were associated with greater mortality (adjusted HR, 1.22; 95% CI, 1.20-1.24). Findings were consistent across subgroups of sex, race, dialysis vintage, session duration, and body size. Higher ultrafiltration rates were associated with greater mortality when normalized to body weight, body mass index, and body surface area. LIMITATIONS: Residual confounding cannot be excluded given the observational study design. CONCLUSIONS: Regardless of the threshold implemented, higher ultrafiltration rate was associated with greater mortality in the overall study population and across key subgroups. Randomized controlled trials are needed to investigate whether ultrafiltration rate reduction improves clinical outcomes.

Ultrafiltration Rate Thresholds in Maintenance Hemodialysis: An NKF-KDOQI Controversies Report.

High hemodialysis ultrafiltration rate (UFR) is increasingly recognized as an important and modifiable risk factor for mortality among patients receiving maintenance hemodialysis. Recently, the Kidney Care Quality Alliance (KCQA) developed a UFR measure to assess dialysis unit care quality. The UFR measure was defined as UFR≥13mL/kg/h for patients with dialysis session length less than 240 minutes and was endorsed by the National Quality Forum as a quality measure in December 2015. Despite this, implementation of a UFR threshold remains controversial. In this NKF-KDOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) Controversies Report, we discuss the concept of the UFR, which is governed by patients' interdialytic weight gain, body weight, and dialysis treatment time. We also examine the potential benefits and pitfalls of adopting a UFR threshold as a clinical performance measure and outline several aspects of UFR thresholds that require further research.

Historical Perspective: What Constitutes Discovery (of a New Virus)?

A historic review of the discovery of new viruses leads to reminders of traditions that have evolved over 118 years. One such tradition gives credit for the discovery of a virus to the investigator(s) who not only carried out the seminal experiments but also correctly interpreted the findings (within the technological context of the day). Early on, ultrafiltration played a unique role in "proving" that an infectious agent was a virus, as did a failure to find any microscopically visible agent, failure to show replication of the agent in the absence of viable cells, thermolability of the agent, and demonstration of a specific immune response to the agent so as to rule out duplicates and close variants. More difficult was "proving" that the new virus was the etiologic agent of the disease ("proof of causation")-for good reasons this matter has been revisited several times over the years as technologies and perspectives have changed. One tradition is that the discoverers get to name their discovery, their new virus (unless some grievous convention has been broken)-the stability of these virus names has been a way to honor the discoverer(s) over the long term. Several vignettes have been chosen to illustrate several difficulties in holding to the traditions (vignettes chosen include vaccinia and variola viruses, yellow fever virus, and influenza viruses. Crimean-Congo hemorrhagic fever virus, Murray Valley encephalitis virus, human immunodeficiency virus 1, Sin Nombre virus, and Ebola virus). Each suggests lessons for the future. One way to assure that discoveries are forever linked with discoverers would be a permanent archive in one of the universal virus databases that have been constructed for other purposes. However, no current database seems ideal-perhaps members of the global community of virologists will have an ideal solution.

Pediatric perfusion in Japan: 2010 practice survey.

We report here Japan's first pediatric perfusion survey. It covers practices from January 2007 through December 2009. Of the 70 congenital heart centers contacted, 53 (76%) completed the survey. They reported performing 3,379 pediatric cardiopulmonary bypass (CPB) procedures in 2009, 3,408 in 2008, and 3,358 in 2007.Twenty-eight percent of all centers used CPB circuits with a priming volume between 151-200 ml. All centers used pre-bypass ultrafiltration and only 6% used retrograde autologous priming. A biomaterial-coated circuit was used by 78% of the centers, a roller pump as the arterial pump by 91%, vacuum-assisted venous drainage by 39%, dilutional ultrafiltration by 48%, and modified ultrafiltration at the end of the procedure by 30%. A regional oxygen saturation monitor was used by 69% of the centers and high flow (150-200 ml/kg/min) management with alpha-stat blood gas control was standard during moderate to normothermic CPBs. Crystalloid cardioplegia solution was used as myocardial protection by 56% of the centers, electronic recording of monitoring data by 51%. The centers performed 98 pediatric extracorporeal membrane oxygenation procedures in 2007, 109 in 2008, and 119 in 2009; 58% of the centers used a centrifugal pump. This survey provides a description of the current practice in Japan. Future surveys will identify trends and rate of change in practice.

Perfil peptídico de hidrolisados enzimáticos do concentrado proteico do soro de leite, obtidos pela ação da pancreatina e da papaína / Peptide profile of enzymatic hydrolysates from whey protein concentrate obtained by action of pancreatin and papain

The aim of this study was to obtain enzymatic hydrolysates from whey protein concentrate with high oligopeptide, especially di- and tripeptides, and free amino acid contents, besides small amounts of large peptides. Different parameters were evaluated such as type of enzyme (pancreatin and papain), enzyme:substrate ratio (0.5:100, 1:100, 2:100 and 3:100), and the use of ultrafi ltration. The peptide profi les of the hydrolysates were characterized by using a fractionation method by size-exclusion HPLC followed by a rapid Corrected Fraction Area method for quantifying the components of the chromatographic fractions. The results showed that, in terms of number of analyzed samples, the pancreatin action was more advantageous than papain. However, the best peptide profile was obtained by papain, reaching 15.29% of di- and tripeptides, 47.83% of free amino acids and 25.73% of large peptides. The use of the smallest enzyme:substrate ratio (0.5:100) was beneficial in some cases for both enzymes, while the lack of ultrafiltration was favorable just for pancreatin.

El objetivo de este trabajo fue obtener hidrolizados enzimáticos a partir de concentrado proteico de suero lácteo con elevados contenidos de oligopéptidos, especialmente di y tri péptidos, y aminoácidos libres, además de reducida cantidad de grandes péptidos. Para eso fueron evaluados algunos parámetros como el tipo de enzima (pancreatina o papaína), la relación enzima:substrato (0,5:100, 1:100, 2:100 y 3:100)y el empleo de ultrafiltración. Para evaluar el perfil peptídico, los hidrolizados se sometieron a fraccionamiento en cromatografía líquida de alta eficiencia de exclusión molecular (SE-HPLC) y para la cuantificación de los componentes de las fracciones de la cromatografía fue utilizado el método del Área Corregida de la Fracción (ACF). Los resultados indican que el uso de pancreatina fue más ventajoso que el de papaína, así como la menor relación enzima:substrato (0,5:100). Por otro lado, el mejor perfil peptídico (15,29% de di y tripéptidos, 47,83% de aminoácidos libresy 25,73% de grandes péptidos) fue conseguido con el empleo de papaína. La menor relación enzima:substrato (0,5:100) fue favorable en algunos casos para las dos enzimas. La ausencia de ultrafiltración favoreció los hidrolizados producidos con pancreatina.

O presente trabalho teve como objetivo a obtenção de hidrolisados enzimáticos do concentrado proteico do soro de leite com elevado teor de oligopeptídeos, principalmente di- e tripeptídeos, e de aminoácidos livres, além de quantidade reduzida de grandes peptídeos. Para tal, foram avaliados diferentes parâmetros, como tipo de enzima (pancreatina e papaína), relação enzima:substrato (0,5:100, 1:100, 2:100 e 3:100) e o emprego da ultrafiltração. Caracterizou-se o perfil peptídico pelo fracionamento dos hidrolisados por cromatografia líquida de alta eficiência de exclusão molecular e, para a quantificação dos componentes das frações cromatográficas, empregou-se o método rápido da Área Corrigida da Fração. Os resultados obtidos indicaram que, em termos de número de casos analisados, a ação da pancreatina foi mais vantajosa do que a da papaína. Entretanto, o melhor perfil peptídico foi obtido pela açãoda papaína, dando origem a 15,29% de di- e tripeptídeos, 47,83% de aminoácidos livres e 25,73% de grandes peptídeos. A utilização da menor relação enzima:substrato (0,5:100) foi benéfica em alguns casos para ambas as enzimas, enquanto que a ausência da ultrafiltração mostrou-se favorável apenas para a pancreatina.

Ultrafiltration does not affect certain predictors of outcome in heart failure.

Ultrafiltration as a therapeutic option for heart failure has been of more recent interest due to a proposed physiologic basis for its mechanism of action and the development of newer technology. Several studies have so far demonstrated its efficacy in rapid removal of fluid and improvement in congestive symptoms. However, there is currently no data on its impact on long-term outcomes of patients with heart failure. Moreover, evidence extracted from available studies does not support any beneficial impact on established predictors of mortality in this setting (i.e. blood urea nitrogen and serum sodium levels). This observation coupled with previous data indicating lack of expected beneficial effect on renal function highlights the emergent need for robust long-term outcome studies prior to expansion of the implementation of this complicated and costly therapy.

Effects of age and symptom status on silent ischemic lesions after carotid stenting with and without the use of distal filter devices.

BACKGROUND AND PURPOSE: The routine use of distal filter devices during carotid angioplasty and stent placement (CAS) is controversial. The aim of this study was to analyze their effects on the incidence of new diffusion-weighted imaging (DWI) lesions as surrogate markers for stroke in important subgroups. MATERIALS AND METHODS: DWI was performed immediately before and after CAS in 68 patients with and 175 without protection, and patients were further subdivided according to their age or symptom status. RESULTS: The proportion of patients with new ipsilateral DWI lesion(s) was significantly lower after protected versus unprotected CAS (52% versus 68%), as well as in symptomatic patients (56% versus 74%) or those at or younger than 75 years of age (46% versus 67%; all P < .05). Similarly, the total number of lesions was significantly lower after protected versus unprotected CAS (median, 1; interquartile range [IQR], 0-2; versus median, 1; IQR 0-4.75) and in symptomatic patients (median, 1; IQR, 0-3; versus median, 2; IQR, 0-6) or those at or younger than 75 years of age (median, 0; IQR, 0-2; versus median, 1; IQR, 0-4; all P < .05). In contrast, for asymptomatic patients (48% versus 52%; P = .8; median, 0; IQR, 0-2; versus median, 1; IQR, 0-2.5; P = .6) or those older than 75 years of age (73% versus 69%; P = .7; median, 1; IQR, 0-4; versus median, 1.5; IQR, 0-5.75; P = .6), the proportion of patients with new lesion(s) and the total number of these lesions were not significantly different between protected and unprotected CAS. CONCLUSIONS: The use of distal filter devices generally reduces the incidence of new DWI lesions; however, this beneficial effect might not necessarily pertain to older and asymptomatic patients.

Compared time profiles of ultrafiltration, sodium removal, and renal function in incident CAPD and automated peritoneal dialysis patients.

BACKGROUND: Fluid and sodium removal rates may not be equivalent in patients undergoing automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD). This may influence compared cardiovascular outcomes in both groups. METHODS: The authors compared prospectively the time courses of ultrafiltration, sodium removal, and residual renal function (RRF) in a group of incident patients treated with CAPD (n = 53) or APD (n = 51) for at least 1 year (mean follow-up, 28.9 months; range, 13 to 62). The authors analyzed potential effects of these factors on blood pressure (BP) control and cardiovascular morbidity and mortality. RESULTS: Ultrafiltration and sodium removal rates were consistently lower in APD patients (mean differences, 236 mL/d; P = 0.012, and 36 mmol/d; P = 0.018, respectively, end of first year). Moreover, univariate and multivariate analysis indicated that APD therapy results in a moderate, but significantly faster decline of RRF than CAPD therapy. Analysis of clinical outcomes showed that CAPD (versus APD) therapy or higher ultrafiltration or sodium removal rates were associated with a better time course of systolic, but not diastolic, BP. We were unable to identify PD modality, ultrafiltration, or sodium removal rates as independent predictors of cardiovascular morbidity and mortality. CONCLUSION: Ultrafiltration and sodium removal rates are consistently lower in incident APD patients than in their counterparts undergoing CAPD. Moreover, RRF declines faster during APD than during CAPD therapy, although this difference may be partially counteracted by a detrimental effect of ultrafiltration on RRF. Aside from a better control of systolic BP in CAPD patients, these differences do not portend significant cardiovascular consequences during the first years of PD therapy.

A leak quantification method using sulfur hexafluoride as tracer gas.

Filter holders and continuous air monitors are used extensively in the nuclear industry. It is important to minimize leakage in these devices, and, in recognition of this consideration, a limit on leakage for sampling systems is specified in; however, the protocol given in the standard is really germane to measurement of significant leakage, e.g., several percent of the sampling flow rate. In the present study, we developed a technique for quantifying leakage and used that approach to measure the sealing integrity of a continuous air monitor and two kinds of filter holders. The methodology involves use of sulfur hexafluoride as a tracer gas with the device being tested operated under dynamic flow conditions. The leak rates in these devices were determined in the pressure range from 2.49 kPa (10 inches H2O) vacuum to 2.49 kPa (10 inches H2O) pressure at a flow rate of 56.6 L min-1 (2 cfm). For the two filter holders, the leak rates were less than 0.007% of the nominal flow rate. The leak rate in the continuous air monitors was less than 0.2% of the nominal flow rate. These values are well within the limit prescribed in the ANSI standard, which is 5% of the nominal flow rate. We suggest that the limit listed in the ANSI standard should be reconsidered as lower values can be achieved, and the methodology presented herein can be used to quantify lower leakage values in sample collectors and analyzers.