bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of maturity of reverse logistics as a strategy to sustainable solid waste management
Authors: Peña-Montoya Claudia C , Bouzon Marina , Torres-Lozada Patricia , Vidal-Holguin Carlos Julio
Published: February 2020

Small- and medium-sized enterprises primarily focus on their operations and rarely pay attention to issues related to sustainable solid waste management that originate from their production processes. A suitable strategy to support sustainable solid waste management is reverse logistics. Through the use of maturity models, it is possible to determine the grade to which small- and medium-sized enterprises are prepared to perform this strategy. This study proposes an adapted maturity model to measure maturity levels of reverse logistics aspects at small- and medium-sized enterprises in regions from Colombia in order to contribute to sustainable solid waste management. The maturity model was applied to seven small- and medium-sized enterprises in the plastics sector in the central and southern regions of Colombia by adapting a maturity model that was previously correlated to suggested drivers and barriers in this sector. Results show that maturity levels range from naïve to immature owing to the incipient development of reverse logistics in Colombia. Therefore, it is necessary to establish a holistic vision of the organisation to improve the reverse logistics decision-making process to achieve sustainable solid waste management.
Universal Design for Learning Chemistry Instruction for Students With and Without Learning Disabilities
Authors: King-Sears Margaret E. , Johnson Todd M.
Published: February 2020

Students with and without learning disabilities in high school chemistry classes, either co-taught or self-contained, received instruction on calculating molar conversions using universal design for learning (UDL) or business-as-usual techniques. For Study 1, posttest scores of students with and without learning disabilities (LD) in co-taught classes who received the UDL treatment are compared with peers’ scores in the comparison group. For Study 2, posttest scores from students with LD who received UDL treatment in a self-contained special education class are reported. Students in the UDL treatment scored significantly higher on posttests than comparison group peers in Study 1. Mean scores for students with LD in Study 2 were similar to UDL students in Study 1. Social validity feedback on the UDL instruction was positive. Implications for UDL chemistry instruction and future research are described.
Dying in the Neurointensive Care Unit After Withdrawal of Life-Sustaining Therapy: Associations of Advance Directives and Health-Care Proxies With Timing and Treatment Intensity
Authors: Stachulski Frank , Siegerink Bob , Bösel Julian
Published: February 2020

Background and Purpose:

Critically ill patients require a careful approach for prognosis and decision-making. The German health legislation aims to strengthen the role of advance directives (ADs) and health-care proxies (HCPs). Their impact within a dedicated neurocritical care setting is unknown. This study aimed to assess the practice of withdrawal or withholding of life-sustaining therapy (WOLST) in a German neurointensive care unit (NICU) focusing on whether AD or HCP is associated with timing and treatment intensity.

Methods:

Data on patients who died after WOLST at a dedicated NICU of a German university hospital, from 2010 to 2013, were retrospectively analyzed.

Results:

Of 400 deceased patients, 310 (77.5%) died after initiation of WOLST. Among them, 68 (21.9%) were identified to have AD or HCP or both (AD + HCP). WOLST patients with AD, HCP, or AD + HCP were older than those without (median age: 77 vs 72 years, P < .001) but did not show any other distinct baseline features. There was no difference in the specific neurocritical care measures between the groups. Poisson regression analysis showed no significant difference in the probability of time-dependent WOLST initiation between those with and without AD/HCP, after adjusting for age and sex (adjusted incidence rate ratio, 1.10; 95% confidence interval, 0.94-1.28; P = .244).

Conclusions:

In this single-center study of mainly cerebrovascular NICU patients, AD or HCP was neither associated with an earlier WOLST nor associated with a difference in treatment intensity before WOLST. Further prospective studies should assess the emerging concept of advance care planning in neurocritical care.
The Impact of Forced Answering and Reactance on Answering Behavior in Online Surveys
Authors: Sischka Philipp E. , Décieux Jean Philippe , Mergener Alexandra , Neufang Kristina M. , Schmidt Alexander F.
Published: February 2020

Forced answering (FA) is a frequent answer format in online surveys that forces respondents to answer each question in order to proceed through the questionnaire. The underlying rationale is to decrease the amount of missing data. Despite its popularity, empirical research on the impact of FA on respondents’ answering behavior is scarce and has generated mixed findings. In fact, some quasi-experimental studies showed that FA has detrimental consequences such as increased survey dropout rates and faking behavior. Notably, a theoretical psychological process driving these effects has hitherto not been identified. Therefore, the aim of the present study was twofold: First, we sought to experimentally replicate detrimental effects of FA on online questionnaire data quality. Second, we tried to uncover an explanatory psychological mechanism. Specifically, we hypothesized that FA effects are mediated through reactance. Zero-order effects showed that FA increased state reactance and questionnaire dropout as well as reduced answer length in open-ended questions. Results of survival and mediation analyses corroborate negative FA effects on data quality and the proposed psychological process.
A Call to Arms: Economic Barriers to Optimal Dialysis Care
Authors: McFarlane Philip A. , Mendelssohn David C.
Published: February 2020

Epidemic growth rates and the enormous cost of dialysis pressure end-stage renal disease (ESRD) delivery systems around the world. Payers of dialysis services can constrain costs through ( 1 ) limiting access to dialysis, ( 2 ) reducing the quality of dialysis, and ( 3 ) placing constraints on modality distribution. In order to secure the necessary resources for ESRD care, we propose that the nephrology community consider the following suggestions: First, future leaders in dialysis should acquire additional advanced training in innovative pathways such as health care economics, business and health care administration, and health care policy. Second, the international nephrology community must strongly engage in ongoing advocacy for accessible, high quality, cost-effective care. Third, efforts should be made to better define and then implement optimal dialysis modality distributions that maximize patient outcomes but limit unnecessary costs. Fourth, industry should be encouraged to lower the unit cost of dialysis, allowing for improved access to dialysis, especially in developing countries. Fifth, research should be encouraged that seeks to identify measures that will reduce dialysis costs but will not impair quality of care. Finally, early referral of patients with progressive renal disease to nephrology clinics, empowerment of informed patient choice of dialysis modality, and proper and timely access creation should be encouraged and can be expected to help limit overall expenditures. Ongoing efforts in these areas by the nephrology community will be essential if we are to overcome the challenges of ESRD growth in this new decade.
Influence of Plasticizer-Free CAPD Bags and Tubings on Serum, Urine, and Dialysate Levels of Phthalic Acid Esters in CAPD Patients
Authors: Mettang Thomas , Pauli–Magnus Christiane , Alscher Dominik Mark , Kirchgessner Judith , Wodarz Roman , Rettenmeier Albert W. , Kuhlmann Ulrich
Published: February 2020

Objectives

To evaluate the impact of a plasticizer-free device on exposure to di-(2-ethylhexyl) phthalate (DEHP) and its major metabolites in patients on continuous ambulatory peritoneal dialysis (CAPD). DEHP is the most commonly used plasticizer in polyvinyl chloride (PVC) products; it is added to CAPD bags in order to improve the flexibility of the material. Since DEHP leaches out of the plastic matrix, patients on CAPD are exposed to considerable amounts of DEHP and its metabolites.

Design

A prospective cross-over study.

Setting

Department of nephrology in a teaching hospital.

Participants

Six patients (4 female, 2 male) stable on peritoneal dialysis (PD) for at least 6 months.

Interventions

Patients were switched from a plasticizer-containing PVC CAPD system (A.N.D.Y. Plus, Fresenius Medical Care, Bad Homburg, Germany) to a polyolefine-made plasticizer-free system (stay-safe, Fresenius).

Main Outcome Measures

Prior to and 42 days after the switch, 24-hour effluent dialysate and urine collections were performed and 10 mL blood was drawn. Concentrations of DEHP, mono-(2-ethylhexyl) phthalate (MEHP), phthalic acid (PA), and 2-ethylhexanol (2-EH) in urine, dialysate, and serum were determined using gas chromatography/mass spectrometry.

Results

Complete data were obtained from 5 patients. Serum levels of PA decreased significantly during the study period (0.137 ± 0.078 mg/L vs 0.124 ± 0.049 mg/L, p = 0.04), and the respective levels of DEHP decreased insignificantly (0.097 ± 0.076 mg/L vs 0.069 ± 0.046 mg/L, p = 0.07), whereas the concentrations of MEHP and 2-EH remained unchanged. Urine concentrations of PA were high (0.81 ± 0.69 mg/L) but did not change substantially (0.70 ± 0.50 mg/L). Effluent dialysate concentrations of MEHP and PA decreased significantly (0.0176 ± 0.004 mg/L vs 0.0040 ± 0.0007 mg/L, p = 0.043 and 0.158 ± 0.056 mg/L vs 0.111 ± 0.051 mg/L, p = 0.043, respectively).

Conclusions

Although PD patients seem to be exposed to other sources of phthalates in addition to dialysis, use of plasticizer-free devices may help to reduce potentially immunosuppressive exposure to phthalate esters.
Peritoneal Kinetics and Mesothelial Markers in CCPD Using Icodextrin for Daytime Dwell for Two Years
Authors: Posthuma Nynke , Verbrugh Henri A. , Donker Ab J.M. , Van Dorp Wim , Dekker Hubertina A.Th. , Peers Elizabeth M. , Oe Po L. , Ter Wee Pieter M.
Published: February 2020

Objective

To evaluate the safety, efficacy, and biocompatibility of icodextrin (Ico), continuous cycling peritoneal dialysis (CCPD) patients were treated for 2 years with either Ico- or glucose (Glu)-containing dialysis fluid for their daytime dwell (14 – 15 hours). Prior to entry into the study, all patients used standard Glu solutions (Dianeal, Baxter BV, Utrecht, The Netherlands).

Design

Open, randomized, prospective two-center study.

Setting

University hospital and teaching hospital.

Patients

Both established patients and patients new to CCPD were included. A life expectancy of more than 2 years, a stable clinical condition, and written informed consent were necessary before entry. Patients aged under 18 years or with peritonitis in the previous month, and women of childbearing potential unless taking adequate contraceptive precautions, were excluded. Thirty-eight patients entered the study (19 Glu, 19 Ico).

Main Outcome Measures

Daytime dwell peritoneal effluents were collected every 3 months in combination with other study variables (clinical data, laboratory measurements, dialysis-related data, and urine collection). Peritoneal transport studies were carried out every 6 months.

Results

In Glu- and Ico-treated patients, peritoneal transport of low molecular weight solutes and protein clearances neither changed during follow-up nor differed between the two groups. Peritoneal membrane markers (CA125, interleukin-8, carboxyterminal propeptide of type I procollagen, and aminoterminal propeptide of type III procollagen) measured in effluents did not differ between the groups and did not change over time. All these markers showed a dialysate/plasma ratio of more than 1, suggesting local production. Residual renal function remained stable during follow-up and adverse clinical effects were not observed.

Conclusions

Peritoneal membrane transport kinetics and markers remained stable in both groups over a 2-year follow-up period. Membrane markers were higher in effluents than in serum, suggesting local production. No clinical side effects were demonstrated. Icodextrin was a well-tolerated effective treatment.
Relationship between Fill Volume, Intraperitoneal Pressure, Body Size, and Subjective Discomfort Perception in CAPD Patients
Authors: De Jesús Ventura María , Amato Dante , Correa–Rotter Ricardo , Paniagua Ramón ,   Mexican Nephrology Collaborative Study Group
Published: February 2020

Objective

To determine changes in intraperitoneal pressure (IPP) when dialysate fill volume is increased from 2.0 L to 2.5 L to 3.0 L per exchange, and to evaluate the relationship with subjective discomfort perception.

Design

Cross-sectional survey.

Setting

Seven Mexican hospital-based dialysis centers.

Patients

Eighty-one adult patients on continuous ambulatory peritoneal dialysis (CAPD) without restriction criteria for age, gender, or time on dialysis, were studied. Patients seropositive for HIV or hepatitis B, and those with cancer or receiving immunosuppressive drugs were excluded. Participants were studied as outpatients.

Main Measures

Blindly and in random order, 2.0-, 2.5-, and 3.0-L volumes of dialysate were infused consecutively. Body surface area (BSA) was calculated from patient height and weight. IPP was assessed with the patient lying supine, measuring the height of the dialysate column inside the peritoneal dialysis bag tubing. Blood pressure and subjective discomfort perception (using a visual analog scale of 0 – -100 mm) were also evaluated and registered after each of the three exchanges.

Results

The IPP rose with each increase of dialysate volume and was higher in males than in females for each fill volume level. For males IPP was 18.9 ± 6.9, 20.8 ± 7.1, and 22.9 ± 7.5 cm H2O; and for females it was 16.5 ± 5.7, 18.4 ± 5.5, and 19.7 ± 6.2 cm H2O for 2.0-, 2.5-, and 3.0-L fill volumes respectively ( p < 0.01 among fill volumes and between genders). Intraperitoneal pressure showed significant negative correlation with the fill volume corrected for patient body size as reflected by the dialysate volume/ BSA ratio ( r = –0.393, p < 0.01; r = 0.319, p < 0.01; and r = –0.274, p < 0.02 for 2.0-, 2.5-, and 3.0-L fill volumes respectively). Discomfort score rose as fill volume rose, with a median of 0, 2.5, and 13.0 for 2.0-, 2.5-, and 3.0-L fill volumes respectively ( p < 0.001). It is interesting, however, that with 2.5-L and 3.0-L dialysate infusion volumes, 64% and 44% of the patients, respectively, had no discomfort at all.

Conclusion

Dialysate volume increase is associated with higher IPP, which is modulated by the gender and body size of the patients. Although the mean discomfort score was higher with larger dialysate volumes, there was no significant correlation between discomfort and IPP or the dialysate volume/BSA ratio. Many patients had no discomfort with 2.5-L or even with 3.0-L dialysate infusions; theoretically, they can be treated with larger volumes.
Exit-Site Care with Ciprofloxacin Otologic Solution Prevents Polyurethane Catheter Infection in Peritoneal Dialysis Patients
Authors: Montenegro Jesús , Saracho Ramón , Aguirre Román , Martínez Isabel , Iribar Izakun , Ocharán Julián
Published: February 2020

Objective

Mupirocin ointment and antiseptics are standard cleansing agents in routine exit-site care of peritoneal dialysis (PD) catheters, but these agents have a deleterious effect on polyurethane devices. We assessed the effectiveness of topical use of ciprofloxacin otologic solution for preventing exit-site infection (ESI) in PD patients with polyurethane catheters.

Design

Prospective study.

Setting

Service of Nephrology of an acute-care teaching hospital in Galdácano, Bizkaia, Spain.

Patients

A total of 164 patients with polyurethane catheters inserted was studied from start of continuous ambulatory PD to the end of a 24-month period. Patients were divided into two groups according to exit-site treatment protocols.

Intervention

Patients in group 1 ( n = 86) were instructed on daily exit-site care with soap and water only; whereas patients in group 2 ( n = 78) cleansed with soap and water, followed by application of a single-dose vial of 0.5 mL ciprofloxacin (1 mg) for application around the insertion site.

Main Outcome Measures

Episodes of ESI and peritonitis.

Results

There were 67 episodes of ESI among patients in group 1 versus 9 episodes among patients in group 2 ( p < 0.05), resulting in a rate of 0.41 and 0.06 episodes per patient-year of exposure, respectively ( p < 0.001). Staphylococcus aureus ESI rate was 0.34 in group 1 versus 0.06 in group 2 ( p = 0.001). Infections caused by Pseudomonas aeruginosa and other pathogens occurred in 11 patients in group 1 and in no patients in group 2 ( p = 0.05). Peritonitis due to S. aureus ESI was significantly less frequent among patients treated with ciprofloxacin (1 vs 9 cases, p = 0.001). Removal of the catheter was necessary in 5 patients in group 1 and in no patients in group 2 ( p < 0.05).

Conclusion

Daily application of ciprofloxacin otologic solution at the exit site of PD patients with polyurethane catheters inserted significantly reduces the rate of ESI caused by S. aureus and other organisms, particularly P. aeruginosa.
Pharmacokinetics of Intraperitoneal Piperacillin/Tazobactam in Patients on Peritoneal Dialysis with and without Pseudomonas Peritonitis
Authors: Zaidenstein Ronit , Weissgarten Joshua , Dishi Victor , Koren Maya , Soback Stefan , Gips Marina , Averbuch Zhan , Simantov Roman , Assulin Etty , Golik Ahuva
Published: February 2020

Objective

The objective of this study was to assess the pharmacokinetics of intraperitoneal (IP) administration of the antibiotic combination piperacillin/tazobactam (PIP/TAZ) to patients on chronic ambulatory peritoneal dialysis (CAPD) with and without pseudomonas peritonitis.

Design

Open-labeled study.

Setting

The study was carried out in the CAPD unit of Assaf Harofeh Medical Center, Zerifin, Israel.

Patients and Methods

Six patients participated in the study, 4 had pseudomonas peritonitis, all were given an IP loading dose of 4 g/0.5 g PIP/TAZ. Twenty-four hours after the initial dose, a maintenance dose of 0.5 g/0.0625 g PIP/TAZ was administered with each dialysate exchange for a period of 1 week. The patients without peritonitis received only the loading dose. High performance liquid chromatography was used to determine the concentrations of PIP/TAZ in plasma obtained at 0, 30, 60, 90, 120, 360, 480, 600, 720, and 1440 minutes after administration. Samples of the dialysate fluid for determination of PIP/TAZ concentration were collected at 6, 10, 14, 24, and 72, 120, and 168 hours.

Results

After the loading dose, the highest plasma PIP concentration (Cmax) was 51.6 ± 21.25 μg/mL and appeared at 1.5 ± 0.45 hours (tmax). During the maintenance period plasma PIP concentration was 5.2 ± 4.75 μg/mL. Tazobactam was detected in the plasma of 1 patient only. The concentration of TAZ in the dialysate fluid during the maintenance period was 2.3 ± 0.5 μg/mL.

Conclusions

Piperacillin administered IP at 4 g reached plasma concentrations comparable to intravenous administration and considered therapeutic (above the MIC90 for Pseudomonas aeruginosa) in CAPD patients with or without peritonitis. The maintenance dose, however, should be augmented. Tazobactam could not be detected in the plasma of most patients and the therapeutic implications of IP administration of TAZ cannot be directly correlated to intravenous administration.
Reduced Oxidative Stress in Hypoalbuminemic CAPD Patients
Authors: Kim Soon Bae , Yang Won Seok , Min Won Ki , Lee Sang Koo , Park Jung Sik
Published: February 2020

Objective

Albumin is one of the plasma antioxidants. The higher incidence of cardiovascular disease in dialysis patients with hypoalbuminemia may be related to decreased antioxidant capacity resulting from low serum albumin. We evaluated malondialdehyde (MDA), a marker of oxidative stress, and total antioxidant capacity (TAC) in relation to serum albumin in continuous ambulatory peritoneal dialysis (CAPD) patients.

Patients and Methods

In this cross-sectional study, we measured MDA, TAC, albumin, uric acid (another important plasma antioxidant), prealbumin, and C-reactive protein (CRP) in the blood of 66 CAPD patients and 30 normal controls. Twenty-two CAPD patients with albumin less than or equal to 3.5 g/dL were divided into two groups: In the experimental group ( n = 11), MDA, TAC, and CRP were measured before and after repeated infusion of 20% albumin 100 mL daily for 7 days. In the control group ( n = 11), the same parameters were measured without albumin infusion.

Results

CAPD patients had lower albumin and higher MDA, TAC, and uric acid than normal controls. There were positive correlations between albumin and TAC or uric acid in CAPD patients. Contrary to our expectation, there was also positive correlation between albumin and MDA in CAPD patients ( r = 0.37, p = 0.004). MDA showed a positive correlation with TAC. Uric acid was correlated with TAC. It did not, however, show correlation with MDA. Log CRP was negatively correlated with albumin, but did not show correlation with MDA or TAC. Prealbumin was correlated with MDA, TAC, albumin, and uric acid. Serum albumin in the experimental group increased from 2.5 ± 0.3 g/dL to 3.6 ± 0.2 g/dL ( p < 0.001) at the end of repeated infusions. No changes were seen in MDA, TAC, and CRP in either group.

Conclusions

The present study suggests that lipid peroxidation is increased in CAPD patients and that this is not due to weakening of antioxidant defenses of plasma. Increased TAC was mainly caused by a higher level of uric acid. Reduced, rather than increased, MDA in hypoalbuminemic patients and lack of effects of albumin infusion on levels of MDA suggest that the frequent occurrence of cardiovascular disease in dialysis patients with hypoalbuminemia is not due to the decrease in antioxidant capacity resulting from low serum albumin.
Peritonitis Prevention in CAPD: To Mask or Not?
Authors: Prowant Barbara F. , Bernardini Judith Y. , Kelman Betty , Figueiredo Ana E. , de Figueiredo Carlos E. Poli , d'Avila Domingos O.
Published: February 2020

Objective

To assess the efficacy of wearing a face mask to prevent peritonitis during continuous ambulatory peritoneal dialysis (CAPD) bag exchange.

Setting

Renal unit at a university hospital.

Patients

Two groups of patients on CAPD were compared: those performing bag exchange with ( n = 24) and those without a face mask ( n = 40).

Outcomes

Occurrence of first episode of peritonitis and total number of episodes.

Results

No difference was found between groups with respect to probability of developing the first episode of peritonitis ( p = 0.757). Patients holding university degrees had evidence of protection, with borderline significance [relative risk (RR) 0.52; confidence interval (CI) 95%, 0.23 – 1.18; p = 0.109]. Cox's proportional hazard regression analysis also demonstrated a significant protective factor for patients with university level education (RR 0.42; CI 95%, 0.18 – 0.98; p = 0.04). Incidence of peritonitis was not significantly different between groups: with-mask group had 1.0 episode/year, and without-mask group had 0.94 episodes/year. Staphylococcus epidermidis was the most commonly identified agent. Staphylococcus aureus was found more frequently in the with-mask group ( p = 0.003). Peritonitis due to Streptococcus viridans and Enterococci were detected only in the without-mask group.

Conclusion

The current study suggests that routine use of face masks during CAPD bag exchanges may be unnecessary and could be discontinued.
Rate of Decline of Residual Renal Function in Patients on Continuous Peritoneal Dialysis and Factors Affecting It
Authors: Singhal Manoj K. , Bhaskaran Shaunmukhum , Vidgen Edward , Bargman Joanne M. , Vas Stephen I. , Oreopoulos Dimitrios G.
Published: February 2020

Objective

We analyzed residual renal function (RRF) in a large number of new peritoneal dialysis (PD) patients to prospectively define the time course of decline of RRF and to evaluate the risk factors assumed to be associated with faster decline.

Study Design

Single-center, prospective cohort study.

Setting

Home PD unit of a tertiary care University Hospital.

Patients

The study included 242 patients starting continuous PD between January 1994 and December 1997, with a minimum follow-up of 6 months and at least three measurements of RRF.

Measurement

All patients had data on demographic and laboratory variables, episodes of peritonitis and the use of aminoglycoside (AG) antibiotics, temporary hemodialysis, and number of radiocontrast studies. Adequacy of PD was measured from 24-hour urine and dialysate collection and peritoneal equilibration test using standard methodology. Further data on RRF was collected every 3 to 4 months until the patient became anuric (urine volume < 100 mL/day or creatinine clearance < 1.0 mL/min) or until the end of study in December 1998.

Outcome Measure

The slope of the decline of residual glomerular filtration rate (GFR) (an average of renal urea and creatinine clearance) was the main outcome measure. Risk factors associated with faster decline were evaluated by a comparative analysis between patients in the highest and the lowest quartiles of the slopes of GFR, and a multivariate analysis using a stepwise option within linear regression and general linear models.

Results

There was a gradual deterioration of residual GFR with time on PD, with 40% of patients developing anuria at a mean of 20 months after the initiation of PD. On multivariate analysis, use of a larger volume of dialysate ( p = 0.0001), higher rate of peritonitis ( p = 0.0005), higher use of AG ( p = 0.0006), presence of diabetes mellitus ( p = 0.005), larger body mass index (BMI) ( p = 0.01), and no use of antihypertensive medications ( p = 0.04) independently predicted the steep slope of residual GFR. Male gender, higher grades of left ventricular dysfunction, and higher 24-hour proteinuria were associated with faster decline on univariate analysis only.

Conclusion

Faster decline of residual GFR corresponds with male gender, large BMI, presence of diabetes mellitus, higher grades of congestive heart failure, and higher 24-hour proteinuria. Higher rate of peritonitis and use of AG for the treatment of peritonitis is also associated independently with faster decline of residual GFR. Whether the type of PD (CAPD vs CCPD/NIPD) is associated with faster decline of residual GFR remains speculative.
Long-Term Peritoneal Dialysis is a Risk Factor of Sclerosing Encapsulating Peritonitis for Children
Authors: Araki Yoshinori , Hataya Hiroshi , Tanaka Yuriko , Fukuzawa Ryuji , Ikeda Masahiro , Kawamura Ken , Honda Masataka
Published: February 2020

Objective

Sclerosing encapsulating peritonitis (SEP) is a clinical syndrome with a high mortality rate and is a serious complication of peritoneal dialysis (PD). Peritoneal sclerosis (PS) is a histological diagnosis. PS is usually observed in the peritoneal specimens of patients with SEP. Avoiding SEP is considered to be extremely important for pediatric patients who may require long-term PD. In this study, the characteristics of patients with PS were investigated to determine when to perform peritoneal biopsies and how long PD can be performed safely.

Design

A retrospective single-center study.

Setting

Tokyo Metropolitan Kiyose Children's Hospital.

Patients

A total of 109 children younger than 16 years have received chronic PD in our unit since 1981. Among these children, 16 patients had been on PD for more than 5 years (mean 7.4 ± 2.5 years) from May 1992 to March 1999. Peritoneal biopsies were performed in 14 of the 16 patients, who were divided into two groups based on the histological diagnoses: a PS and a peritoneal fibrosis (PF) group.

Results

The 14 patients were on PD for a mean of 7.8 ± 2.5 years. There were 8 patients with PS and 6 patients with PF. SEP was observed in 2 patients in the PS group. The risk of PS increased with the duration of PD: 57% (8/14) > 5 years, 80% (4/5) > 8 years, and 100% (3/3) > 10 years. All patients in the PS group showed both peritoneal calcifications on abdominal CT scan and poor ultra-filtration at the time of diagnoses.

Conclusion

Long-term PD was the important risk factor of SEP. If both peritoneal calcification on abdominal CT scan and poor ultrafiltration are observed in a patient on PD more than 5 years, a peritoneal biopsy should be performed. If PS is detected, PD should be discontinued.
Role of Surfactant in Peritoneal Dialysis
Authors: Hills Brian A.
Published: February 2020

Evidence is reviewed that demonstrates how the mesothelial cell in the normal peritoneum and comparable serosal cavities secretes surface-active phospholipid (SAPL) as a means of protecting itself and the membrane it forms with its neighbors. It is shown how SAPL, if adsorbed (reversibly bound) to mesothelium, can impart excellent lubricity, antiwear and release (antistick) properties, while impeding surgical adhesion formation. More-speculative benefits include acting as a deterrent to fibrosis and as a barrier to both protein leakage and pathogen invasion by spanning cell junctions. Such spanning would also “pin down” cell corners, impeding peeling as the first step in exfoliation encountered in prolonged continuous ambulatory peritoneal dialysis (CAPD). The molecular mechanism underlying each of these possible functions is adsorption. Morphological and hydrophobicity studies are discussed as validation for such an adsorbed lining and how it can be fortified by administering exogenous SAPL.

Any role for SAPL in ultrafiltration is much more controversial. However, a surfactant lining can explain the very high permeability of the membrane to lipid-soluble drugs, implying that it is a barrier to water-soluble solutes. The clinical and animal evidence is conflicting but would seem to be best explained by a role for the barrier in promoting semipermeability, and hence the osmotic driving force for water transmission. Thus, adsorption of exogenous SAPL in CAPD patients with low ultrafiltration seems to restore this barrier function. The future direction for surfactant in CAPD would seem to rest with the physical chemists in producing formulations that optimize adsorption, probably involving a compromise between water solubility and surface activity of the phospholipids selected. It might even warrant using the interdialytic interval for re-adsorbing SAPL without the problem of dilution by a large volume of dialysate.
A Long-Term Study of a Bicarbonate/Lactate-Based Peritoneal Dialysis Solution — Clinical Benefits
Authors:   for The Bicarbonate/Lactate Study Group, Tranæus Anders
Published: February 2020

Objective

A bicarbonate/lactate peritoneal dialysis solution (Bic/Lac) has been developed based on in vitro and ex vivo data showing better preservation of cell function and correction of pain on infusion.

Design

This was a randomized, prospective, controlled, open-label study comparing a new 25 mmol/L bicarbonate/15 mmol/L lactate with a standard 40 mmol/L lactate-buffered peritoneal dialysis solution (Lac) over a 12-month treatment period.

Setting

17 European nephrology centers.

Patients

106 (70 Bic/Lac and 36 Lac) well-dialyzed continuous ambulatory peritoneal dialysis (CAPD) patients.

Interventions

Dialysis adequacy and peritoneal equilibration test (PET, week –4, months 3, 6, and 12); 24-hour ultrafiltration (week –4, months 1, 3, and 6); blood biochemistry (week –2, day 0, months 1, 2, 3,6, 9, and 12); and a product acceptability questionnaire (months 1 and 6).

Results

88 patients completed the first 6 months, and 44 the full year. The solutions were shown to be therapeutically equivalent with respect to plasma bicarbonate and peritoneal urea and creatinine clearances. Ultrafiltration in the Bic/Lac group increased significantly from baseline by about 150 mL/day for the whole of the 6-month treatment period ( p < 0.05). The biochemistry profile, adverse events, and physical examination (except body weight where there was a statistically significant increase in the Bic/Lac group) results did not differ significantly between the two groups. Reduced pain/discomfort on infusion or an increased sense of well-being was reported by 41% of patients on the Bic/Lac fluid.

Conclusions

The Bic/Lac solution is safe and effective in correcting uremic acidosis, provides relief of inflow pain/discomfort, and improves ultrafiltration and body weight.
Relationship between Dialysis Adequacy and Quality of Life in Long-Term Peritoneal Dialysis Patients
Authors: Chen Yin-Cheng , Hung Kuan-Yu , Kao Tze-Wah , Tsai Tun-Jun , Chen Wan-Yu
Published: February 2020

Objective

The purpose of this study was to compare quality of life (QOL) between peritoneal dialysis (PD) patients with adequate and inadequate total solute clearance (TSC). We also tried to determine the relationship between QOL and TSC.

Design

A cross-sectional study design was used in which QOL was evaluated and compared between PD patients with adequate and inadequate TSC.

Setting

The PD unit of a university teaching hospital.

Patients

Sixty-seven patients were recruited, 38 on continuous ambulatory PD and 29 on continuous cycler-assisted PD.

Methods

Patients were divided into adequate and inadequate groups, based on the results of either total urea clearance (Kt/Vurea) or total creatinine clearance (weekly CCr). The demographic data, dialysis variables, and clinical parameters of these patients were all collected. QOL was evaluated using the SF-36 questionnaire, which contains eight domains and is a comprehensive and validated instrument for QOL evaluation. QOL of patients in adequate and inadequate groups was compared. The relationship between QOL and TSC was also examined.

Results

Among patients grouped by Kt/Vurea, patients in the adequate group had significantly higher scores in two domains of the SF-36, that is, physical and emotional role functioning, than did those in the inadequate group. The total SF-36 scores were positively correlated with Kt/Vurea when all patients were pooled together. However, among patients grouped by weekly CCr, there was no significant difference in any of the eight domains of the SF-36 between patients in the adequate and inadequate groups. No correlation was found between the total SF-36 scores and weekly CCr.

Conclusion

Our study had two important findings: First, PD patients with adequate total solute clearance, based on Kt/Vurea and not on weekly CCr, had a better QOL. Second, Kt/Vurea is better correlated with QOL than weekly CCr. These findings suggest that Kt/Vurea is a better parameter for the clinical evaluation of total solute clearance from the viewpoint of QOL.
What is the Optimal Frequency of Cycling in Automated Peritoneal Dialysis?
Authors: Perez Rafael A. , Blake Peter G. , McMurray Susan , Mupas Lou , Oreopoulos Dimitrios G.
Published: February 2020

Objective

The recent increase in the use of automated peritoneal dialysis (APD) has led to concerns about the adequacy of clearances delivered by this modality. Few clinical studies looking at the effects of varying the individual components of the APD prescription on delivered clearance have been done, and most published data are derived from computer modeling. Most controversial is the optimal frequency of exchanges per APD session. Many centers prescribe 4 to 6 cycles per night but it is unclear if this is optimal. The purpose of this study was to address at what point the beneficial effect of more frequent cycles is outweighed by the concomitant increase in the proportion of the total cycling time spent draining and filling.

Methods

A comparison was made between the urea and creatinine clearances (CCrs) achieved by 4 different APD prescriptions, used for 7 days each, in 18 patients. The prescriptions were for 9 hours each and were all based on 2-L dwell volumes, but differed in the frequency of exchanges. They were 5 x 2 L, 7 x 2 L, and 9 x 2 L, as well as a 50% tidal peritoneal dialysis (TPD) prescription using 14 L. Ultrafiltration, dwell time, glucose absorption, sodium and potassium removal, protein excretion, and relative cost were also compared. Clearances due to day dwells and residual renal function were not included in the calculation.

Results

Mean urea clearances were 7.5, 8.6, 9.1, and 8.3 L/night for the four prescriptions respectively. Urea clearance with 9 x 2 L was significantly greater than with the other three prescriptions ( p < 0 0.05). Urea clearance with 7 x 2 L and TPD were superior to 5 x 2 L ( p < 0.05). Mean CCr was 5.1, 6.1, 6.4, and 5.6 L/night, respectively. Compared to 5 x 2-L, the 7 x 2-L, 9 x 2-L, and TPD prescriptions achieved greater CCr ( p < 0.05). Taking both urea and CCr into account, 9 x 2 L was the optimal prescription in 12 of the 18 patients. Ultrafiltration and sodium and potassium removals were all significantly greater with the higher frequency prescriptions.

Conclusion

The 5 x 2-L prescription significantly underutilizes the potential of APD to deliver high clearances, and 7 x 2 L is a consistently superior prescription if 2-L dwells are being used. Although more costly, 9 x 2 L should be considered if higher clearances are required.
Intermittent Intravenous Piperacillin Pharmacokinetics in Automated Peritoneal Dialysis Patients
Authors: Manley Harold J. , Bailie George R. , Frye Reginald , McGoldrick M. Donald
Published: February 2020

Background

Use of intermittent antibiotic dosing is increasing in the treatment of peritoneal dialysis (PD)-related peritonitis. We studied the pharmacokinetics of intravenous (IV) piperacillin in automated PD patients.

Patients and Methods

Eight patients (3 males, 5 females) were recruited and received a single IV dose of piperacillin (35 mg/kg actual body weight). Blood and dialysate samples were collected at the beginning, middle, and end of dwells 1 – 3 (on cycler), and end of dwells 4 – 5 (off cycler) for a 24-hour period. Baseline and 24-hour urine samples (nonanuric patients, n = 7) were collected. Pharmacokinetic parameters were calculated assuming a one-compartment model. Glomerular filtration rate (GFR) and piperacillin clearance (CL) values were normalized to 1.73 m2.

Results

The patients were 49.5 ± 10.1 years of age (mean ± SD) and had been receiving PD for a median of 3 months (range 2 – 66 months). Dwell times were 2.25 ± 0.06 hours on cycler and 7.26 ± 0.14 hours off cycler. Piperacillin half-life was not statistically different on or off the cycler (on cycler 1.99 ± 0.39 hr, off cycler 4.39 ± 5.4 hr; p = 0.12) and remained insignificant, even accounting for an outlier (on cycler 2.01 ± 0.41 hr, off cycler 2.54 ± 1.48 hr; p = 0.19). Piperacillin total CL (CLT) was 31.29 ± 6.02 mL/minute. Renal CL (CLR) and PD CL (CLPD) accounted for 8.8% and 16.8% of CLT; CLR correlated well with GFR (CLR = 0.86 GFR + 0.1; p < 0.000 03). Mean piperacillin serum and dialysate end-of-dwell concentrations were above minimum inhibitory concentration of susceptible organisms (8 μg/mL) for the three cycler exchanges only. Serum and dialysate concentrations predicted using a one-compartment model suggest that IV piperacillin 4000 mg would provide adequate concentrations for susceptible organisms over a 12-hour period.

Conclusion

The current IV piperacillin dosing recommendations of 4000 mg every 12 hours for PD-related peritonitis are appropriate for patients on automated PD. Intermittent intraperitoneal piperacillin is not recommended.
Human Peritoneal Mesothelial Cells Produce Nitric Oxide: Induction by Cytokines
Authors: Chen Jinn-Yang , Chiu Jen-Hwey , Chen Hui-Ling , Chen Tzen-Wen , Yang Wu-Chang , Yang An-Hang
Published: February 2020

Objective

To investigate the induction of nitric oxide synthase type II (iNOS) in human peritoneal mesothelial cells (HPMC) using cytokines and bacterial lipopolysaccharide (LPS).

Design

Confluent monolayers of HPMC were exposed to cytokines [tumor necrosis factor alpha (TNFα), interleukin-1 beta (IL-1β), interferon gamma (IFNγ)] or LPS, individually or in various double and triple combinations, for 24 – 72 hours. Concentrations of nitrate and nitrite in the media were quantified using the Griess reaction and used as indirect indices of nitric oxide (NO) production. The expression of iNOS was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot.

Results

Neither single cytokines nor LPS was able to induce iNOS mRNA or NO production. Both double combinations of TNFα+ IFNγ and IL-1β + IFNγ were able to induce iNOS mRNA expression, but only TNFα + IFNγ induced significant NO production. The triple combination of TNFα + IFNγ + IL-1β induced even more NO production than TNFα + IFNγ. There was no constitutive NO synthase type III (eNOS) expression in HPMC.

Conclusions

Certain combinations of cytokines could stimulate cultured HPMC to produce NO, and HPMC might be a source of intraperitoneal NO production during peritonitis.
Uremic Anorexia: A Consequence of Persistently High Brain Serotonin Levels? The Tryptophan/Serotonin Disorder Hypothesis
Authors: Aguilera Abelardo , Selgas Rafael , Codoceo Rosa , Bajo Auxiliadora
Published: February 2020

Anorexia is a frequent part of uremic syndrome, contributing to malnutrition in dialysis patients. Many factors have been suggested as responsible for uremic anorexia.

In this paper we formulate a new hypothesis to explain the appetite disorders in dialysis patients: “the tryptophan/serotonin disorder hypothesis.” We review current knowledge of normal hunger–satiety cycle control and the disorders described in uremic patients. There are four phases in food intake regulation: ( 1 ) the gastric phase, during which food induces satiety through gastric distention and satiety peptide release; ( 2 ) the post absorptive phase, during which circulating compounds, including glucose and amino acids, cause satiety by hepatic receptors via the vagus nerve; ( 3 ) the hepatic phase, during which adenosine triphosphate (ATP) concentration is the main stimulus inducing hunger or satiety, with cytokines inhibiting ATP production; and ( 4 ) the central phase, during which appetite is regulated through peripheral (circulating plasma substances and neurotransmitters) and brain stimuli. Brain serotonin is the final target for peripheral mechanisms controlling appetite. High brain serotonin levels and a lower serotonin/ dopamine ratio cause anorexia. Plasma and brain amino acid concentrations are recognized factors involved in neurotransmitter synthesis and appetite control. Tryptophan is the substrate of serotonin synthesis. High plasma levels of anorectics such as tryptophan (plasma and brain), cholecystokinin, tumor necrosis factor alpha, interleukin-1, and leptin, and deficiencies of nitric oxide and neuropeptide Y have been described in uremia; all increase intracerebral serotonin.

We suggest that brain serotonin hyperproduction due to a uremic-dependent excess of tryptophan may be the final common pathway involved in the genesis of uremic anorexia. Various methods of ameliorating anorexia by decreasing the central effects of serotonin are proposed.
Effect of High Glucose on Peritoneal Mesothelial Cell Biology
Authors: Ha Hunjoo , Lee Hi Bahl
Published: February 2020

Objective

This study reviews evidence that implicates high glucose (HG) in the pathogenesis of peritoneal fibrosis and proposes mechanisms potentially involved in the HG-induced peritoneal fibrosis that is observed in long-term peritoneal dialysis (PD) patients.

Design

Selected Western literature is reviewed, examining the effect of HG on rat or human peritoneal mesothelial cell (HPMC) biology with particular reference to extracellular matrix (ECM) gene expression and protein synthesis.

Results

HG up-regulated the expression of monocyte chemotactic peptide–1 (MCP-1), transforming growth factor beta 1 (TGFβ1), and fibronectin messenger RNAs (mRNAs) and proteins. These HG-induced up-regulations were effectively blocked by the inhibition of protein kinase C (PKC). In addition, cytosolic reactive oxygen species (ROS) rapidly increased in HPMC cultured under HG, and treatment with antioxidant effectively inhibited HG-induced fibronectin protein synthesis by HPMC.

Conclusion

Continuous exposure of the peritoneal membrane to HG may induce changes in HPMC biology, leading to excessive deposition of ECM and peritoneal injury. HG-induced activation of diacylglycerol PKC (DAG–PKC) plays a major role in up-regulation of MCP-1, TGFβ1, and fibronectin synthesis by HPMC cultured under HG. In addition, ROS, recently recognized as signalling molecules, are rapidly generated in HPMC as a result of increased glucose metabolism and may prove to be an important mediator of HG-induced peritoneal injury.
Urea is the Best Molecule to Target Adequacy of Peritoneal Dialysis
Authors: Gotch Frank A.
Published: February 2020

For hemodialysis, a large base of data shows the validity of modelling the dialysis dose and reliably estimating protein intake from equilibrated Kt/V urea (eKt/VU), the total dialyzer urea clearance provided during each treatment divided by the urea distribution volume. An eKt/VU of 1.05 thrice weekly is judged adequate, but is still under study.

In continuous ambulatory peritoneal dialysis (CAPD), two dosage criteria are widely recognized: continuous (“standard”) Kt/VU (stdKt/VU = 2.0 weekly), and total creatinine (Cr) clearance normalized to body surface area (KCrT = 70 L/week/1.73 m2). The CANUSA study concluded that a stdKt/VU of 2.1 and a KCrT of 70 L/week/1.73 m2 gave equivalent clinical outcomes. The Dialysis Outcomes Quality Initiative (DOQI) recommends values of 2.0 and 60 L/ week/1.73 m2 respectively.

An analysis of these two parameters for males and females over a wide range of body surface areas (BSAs) was done and the analysis showed: ( 1 ) The U and Cr dose criteria are incommensurable—that is, they can virtually never be achieved simultaneously in anephric patients. ( 2 ) The Cr criterion varies widely with the sex of the patient and with the BSA-dependent variation in stdKt/VU over a range of 2.1 to 3.0. ( 3 ) The U criterion always produces a KCrT < 60 L/week/1.73 m2 in females and 60 – 70 L/ week/1.73 m2 in males.

With respect to U and Cr, the CANUSA results were concluded to be valid in patients with substantial residual renal function, but probably not applicable to anephric patients where the doses are clearly incommensurable.