Pseudohyponatremia: Mechanism, Diagnosis, Clinical Associations and Management.

Pseudohyponatremia remains a problem for clinical laboratories. In this study, we analyzed the mechanisms, diagnosis, clinical consequences, and conditions associated with pseudohyponatremia, and future developments for its elimination. The two methods involved assess the serum sodium concentration ([Na]S) using sodium ion-specific electrodes: (a) a direct ion-specific electrode (ISE), and (b) an indirect ISE. A direct ISE does not require dilution of a sample prior to its measurement, whereas an indirect ISE needs pre-measurement sample dilution. [Na]S measurements using an indirect ISE are influenced by abnormal concentrations of serum proteins or lipids. Pseudohyponatremia occurs when the [Na]S is measured with an indirect ISE and the serum solid content concentrations are elevated, resulting in reciprocal depressions in serum water and [Na]S values. Pseudonormonatremia or pseudohypernatremia are encountered in hypoproteinemic patients who have a decreased plasma solids content. Three mechanisms are responsible for pseudohyponatremia: (a) a reduction in the [Na]S due to lower serum water and sodium concentrations, the electrolyte exclusion effect; (b) an increase in the measured sample's water concentration post-dilution to a greater extent when compared to normal serum, lowering the [Na] in this sample; (c) when serum hyperviscosity reduces serum delivery to the device that apportions serum and diluent. Patients with pseudohyponatremia and a normal [Na]S do not develop water movement across cell membranes and clinical manifestations of hypotonic hyponatremia. Pseudohyponatremia does not require treatment to address the [Na]S, making any inadvertent correction treatment potentially detrimental.

Dialysis disequilibrium syndrome (DDS) in pediatric patients on dialysis: systematic review and clinical practice recommendations.

BACKGROUND AND OBJECTIVES: Dialysis disequilibrium syndrome (DDS) is a rare neurological complication, most commonly affecting patients undergoing new initiation of hemodialysis (HD), but can also be seen in patients receiving chronic dialysis who miss regular treatments, patients having acute kidney injury (AKI), and in those treated with continuous kidney replacement therapy (CKRT) or peritoneal dialysis (PD). Although the pathogenesis is not well understood, DDS is likely a result of multiple physiological abnormalities. In this systematic review, we provide a synopsis of the data available on DDS that allow for a clear picture of its pathogenesis, preventive measures, and focus on effective management strategies. METHODS: We conducted a literature search on PubMed/Medline and Embase from January 1960 to January 2021. Studies were included if the patient developed DDS irrespective of age and gender. A summary table was used to summarize the data from individual studies and included study type, population group, age group, sample size, patient characteristics, blood and dialysate flow rate, and overall outcome. A descriptive analysis calculating the frequency of population size, symptoms, and various treatments was performed using R software version 3.1.0. RESULTS: A total of 49 studies (321 samples) were identified and analyzed. Out of the included 49 studies, a total of 48 studies reported the presence of DSS among patients (1 study reported based on number of dialysis and therefore was not considered for analysis). Among these 48 studies, 74.3% (226/304) patients were reported to have DSS. The most common symptoms were nausea (25.2%), headache (24.8%), vomiting (23.9%), muscle cramps (18.1%), affected level of consciousness (8.8%), confusion (4.4%), and seizure (4.9%) among the 226 DDS patients. Furthermore, 12 studies decided to switch from HD to alternative dialysis modalities including continuous venovenous hemofiltration/hemodiafiltration (CVVH/CVVHDF) or PD which reported no DDS symptoms. CONCLUSION: Early recognition and timely prevention are crucial for DDS patients. We have provided comprehensive clinical practice points for pediatric, adolescent, and young adult populations. However, it is essential to recognize that DDS was reported more frequently in the early dialysis era, as there was a lack of advanced dialysis technology and limited resources.

Flummoxed by flux: the indeterminate principles of haemodialysis.

In haemodialysis (HD), unwanted substances (uraemic retention solutes or 'uraemic toxins') that accumulate in uraemia are removed from blood by transport across the semipermeable membrane. Like all membrane separation processes, the transport requires driving forces to facilitate the transfer of molecules across the membrane. The magnitude of the transport is quantified by the phenomenon of 'flux', a finite parameter defined as the volume of fluid (or permeate) transferred per unit area of membrane surface per unit time. In HD, as transmembrane pressure is applied to facilitate fluid flow or flux across the membrane to enhance solute removal, flux is defined by the ultrafiltration coefficient (KUF; mL/h/mmHg) reflecting the hydraulic permeability of the membrane. However, in HD, the designation of flux has come to be used in a much broader sense and the term is commonly used interchangeably and erroneously with other measures of membrane separation processes, resulting in considerable confusion. Increased flux is perceived to reflect more 'porous' membranes having 'larger' pores, even though other membrane and therapy attributes determine the magnitude of flux achieved during HD. Adjectival designations of flux (low-, mid-, high-, super-, ultra-) have found indiscriminate usage in the scientific literature to qualify a parameter that influences clinical decision making and prescription of therapy modalities (low-flux or high-flux HD). Over the years the concept and definition of flux has undergone arbitrary and periodic adjustment and redefinition by authors in publications, regulatory bodies (US Food and Drug Administration) and professional association guidelines (European Renal Association, Kidney Disease Outcomes Quality Initiative), with little consensus. Industry has stretched the boundaries of flux to derive marketing advantages, justify increased reimbursement or contrive new classes of therapy modalities when in fact flux is just one of several specifications that determine membrane or dialyser performance. Membranes considered as high-flux previously are today at the lower end of the flux spectrum. Further, additional parameters unrelated to the rate of diffusive or convective transport (flux) are used in conjunction with or in place of KUF to allude to flux: clearance (mL/min, e.g. of ß2-microglobulin) or sieving coefficients (dimensionless). Considering that clinical trials in nephrology, designed to make therapy recommendations and guide policy with economic repercussions, are based on the parameter flux they merit clarification-by regulatory authorities and scientists alike-to avoid further misappropriation.

Home Dialysis in the Coronavirus Disease 2019 Era.

The coronavirus disease 2019 pandemic has had a significant impact on patients with end-stage kidney disease and their care, especially given the potential for severe coronavirus disease 2019 in those with a depressed immune status. Patients receiving in-center hemodialysis have been particularly affected by this pandemic because of their need to travel multiple times a week to receive treatment. Although patients on home dialysis are able to avoid such exposure, they face their own unique challenges. In this review, we will discuss the challenges posed by the coronavirus disease 2019 pandemic for patients on home dialysis, the impact of coronavirus disease 2019 on various aspects of their care, and the resultant rapid adaptations in policy/health-care delivery mechanisms with implications for the future care of patients on home dialysis.

Refractory orthostatic hypotension after creation of a brachio-basilic arteriovenous fistula.

Arteriovenous fistulas (AVFs) are preferred vascular access in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). However, AVFs, can occasionally lead to clinically significant complications. Of these, cardiovascular complications have been well described in the literature. In this report, we describe a case of a 78-year-old Caucasian male with ESRD who presented with severe debilitating dizziness and orthostatic hypotension that started soon after the creation of left brachiobasilic AVF. The patient had no significant cardiovascular history apart from essential hypertension. His symptoms persisted despite extensive evaluation and interventions, and abated only after banding of the AVF. This report describes the timeline of the patient's clinical course beginning from the day of creation of his AVF, through the course of his hospitalization leading to AVF banding and ending with postoperative recovery phase with resolution of symptoms. We will also review the pathophysiologic effects of AVF on cardiovascular system, as well as the potential causes of our patient's clinical presentation.

Transition Between Different Renal Replacement Modalities: Gaps in Knowledge and Care-The Integrated Research Initiative.

Patients with end-stage kidney disease (ESKD) have different options to replace the function of their failing kidneys. The "integrated care" model considers treatment pathways rather than individual renal replacement therapy (RRT) techniques. In such a paradigm, the optimal strategy to plan and enact transitions between the different modalities is very relevant, but so far, only limited data on transitions have been published. Perspectives of patients, caregivers, and health professionals on the process of transitioning are even less well documented. Available literature suggests that poor coordination causes significant morbidity and mortality.This review briefly provides the background, development, and scope of the INTErnational Group Research Assessing Transition Effects in Dialysis (INTEGRATED) initiative. We summarize the literature on the transition between different RRT modalities. Further, we present an international research plan to quantify the epidemiology and to assess the qualitative aspects of transition between different modalities.

Historical Milestones in Peritoneal Dialysis.

Two and a half centuries have passed since the therapeutic use of peritoneal cavity for the treatment of ascites by peritoneal lavage was reported. George Ganter was the first to describe the use of peritoneal dialysis (PD) in humans. This chapter will describe the various milestones in the field of PD achieved over the years. These include the understanding of solute and water transport across the peritoneal membrane, developments in PD technique and technology, progress in the prevention and treatment of infections, and other important milestones.

A need for a paradigm shift in focus: From Kt/Vurea to appropriate removal of sodium (the ignored uremic toxin).

Hemodialysis for chronic renal failure was introduced and developed in Seattle, WA, in the 1960s. Using Kiil dialyzers, weekly dialysis time and frequency were established to be about 30 hours on 3 time weekly dialysis. This dialysis time and frequency was associated with 10% yearly mortality in the United States in 1970s. Later in 1970s, newer and more efficient dialyzers were developed and it was felt that dialysis time could be shortened. An additional incentive to shorten dialysis was felt to be lower cost and higher convenience. Additional support for shortening dialysis time was provided by a randomized prospective trial performed by National Cooperative Dialysis Study (NCDS). This study committed a Type II statistical error rejecting the time of dialysis as an important factor in determining the quality of dialysis. This study also provided the basis for the establishment of the Kt/Vurea index as a measure of dialysis adequacy. This index having been established in a sacrosanct randomized controlled trial (RCT), was readily accepted by the HD community, and led to shorter dialysis, and higher mortality in the United States. Kt/Vurea is a poor measure of dialysis quality because it combines three unrelated variables into a single formula. These variables influence the clinical status of the patient independent of each other. It is impossible to compensate short dialysis duration (t) with the increased clearance of urea (K), because the tolerance of ultrafiltration depends on the plasma-refilling rate, which has nothing in common with urea clearance. Later, another RCT (the HEMO study) committed a Type III statistical error by asking the wrong research question, thus not yielding any valuable results. Fortunately, it did not lead to deterioration of dialysis outcomes in the United States. The third RCT in this field ("in-center hemodialysis 6 times per week versus 3 times per week") did not bring forth any valuable results, but at least confirmed what was already known. The fourth such trial ("The effects of frequent nocturnal home hemodialysis") too did not show any positive results primarily due to significant subject recruitment issues leading to inappropriate selection of patients. Comparison of the value of peritoneal dialysis and HD in RCTs could not be completed because of recruitment problems. Randomized controlled trials have therefore failed to yield any meaningful information in the area of dose and or frequency of hemodialysis.

A case of hypothermia on CRRT.

A 64-year-old Asian man, with past medical history of hypertension, hypothyroidism, and hyperlipidemia, presented with 3 days history of fever associated with cough and worsening shortness of breath. Subsequent clinical course was complicated by acute lung injury leading to acute respiratory distress syndrome requiring positive pressure ventilation, septic shock requiring inotropic support, and acute kidney injury requiring continuous renal replacement therapy (CRRT). On day 3 of CRRT, the patient developed significant hypothermia (temporal temperature 27.5°C), which was successfully managed. Continuous renal replacement therapy was subsequently discontinued as renal function recovered and the patient was discharged home after a prolonged hospital stay. He currently remains off dialysis and is being followed as an outpatient for chronic kidney disease. In this article, we examine various aspects of pathophysiology and management of hypothermia on CRRT and review relevant literature in this field.

Development, Validation, and Implementation of a Clinic Nurse Staffing Guideline.

Ensuring that the level of nurse staffing used to care for patients is appropriate to the setting and service intensity is essential for high-quality and cost-effective care. This article describes the development, validation, and implementation of the clinic technical skills permission list developed specifically to guide nurse staffing decisions in physician clinics of an academic medical center. Results and lessons learned in using this staffing guideline are presented.

Ethical issues in dialysis therapy.

Treatment for end-stage kidney disease is a major economic challenge and a public health concern worldwide. Renal-replacement therapy poses several practical and ethical dilemmas of global relevance for patients, clinicians, and policy makers. These include how to: promote patients' best interests; increase access to dialysis while maintaining procedural and distributive justice; minimise the influence of financial incentives and competing interests; ensure quality of care in service delivery and access to non-dialytic supportive care when needed; minimise the financial burden on patients and health-care system; and protect the interests of vulnerable groups during crisis situations. These issues have received comparatively little attention, and there is scant ethical analysis and guidance available to decision makers. In this Health Policy, we provide an overview of the major ethical issues related to dialysis provision worldwide, identify priorities for further investigation and management, and present preliminary recommendations to guide practice and policy.

Diagnostic Dilemma: A Case of Endogenous Peritonitis.

Endogenous peritonitis resulting from inflammation or perforation of an abdominal viscus-a result, for example, of diverticulitis, cholecystitis, or acute appendicitis-can be a complication in patients undergoing peritoneal dialysis (PD), with significant morbidity and a high incidence of catheter loss.Here, we describe an end-stage renal disease patient on PD who presented with acute abdominal pain and who was diagnosed with uncomplicated PD peritonitis. His clinical course was complicated by development of eosinophilic peritonitis because of an allergy to vancomycin. Subsequently, when he failed to show clinical improvement, abdominal and pelvic imaging revealed severe appendicitis, which necessitated emergent surgical intervention.

Pro: Higher serum bicarbonate in dialysis patients is protective.

Chronic metabolic acidosis is common in dialysis patients. Bicarbonate administration via the dialysate helps maintain the acid-base balance in these patients. Serum bicarbonate level in dialysis patients is determined by several factors that include dietary protein intake, nutritional status and dialysis prescription, etc. Additionally, a meaningful interpretation of serum bicarbonate in dialysis patients requires an understanding of complexities involving its measurement. Both very low as well very high levels of serum bicarbonate have been associated with adverse outcomes in observational studies. However, recent observational data, when adjusted for the confounding effects of nutritional status, do not associate higher predialysis serum bicarbonate with adverse consequences. At this time, there are no prospective studies available that have examined the association of serum bicarbonate with hard outcomes in dialysis patients. The ideal level of serum bicarbonate in dialysis patients is therefore unknown. This article examines the available data with regard to the benefits of higher predialysis serum bicarbonate.