Surgical versus percutaneous catheter placement for peritoneal dialysis: an updated systematic review and meta-analysis.

BACKGROUND: No consensus currently exists regarding the optimal approach for peritoneal dialysis catheter placement. We aimed to compare the outcomes of percutaneous and surgical peritoneal dialysis catheter placement. METHODS: A systematic review of the literature was performed using the MEDLINE, Cochrane Library, and Scopus databases (end-of-search date: August 29th, 2020). We included studies comparing percutaneous (blind, under fluoroscopic/ultrasound guidance, and "half-perc") and surgical peritoneal dialysis catheter placement (open and laparoscopic) in terms of their infectious complications (peritonitis, tunnel/exit-site infections), mechanical complications (leakage, inflow/outflow obstruction, migration, hemorrhage, hernia, bowel perforation) and long-term outcomes (malfunction, removal, replacement, surgery required, and mortality). RESULTS: Thirty-four studies were identified, including thirty-two observational studies (twenty-six retrospective and six prospective) and two randomized controlled trials. Percutaneous placement was associated with significantly lower rates of tunnel/exit-site infection [relative risk (RR) 0.72, 95% confidence interval (CI) 0.56-0.91], catheter migration (RR 0.68, 95% CI 0.49, 0.95), and catheter removal (RR 0.73, 95% CI 0.60-0.88). The 2-week and 4-week rates of early tunnel/exit-site infection were also lower in the percutaneous group (RR 0.45, 95% CI 0.22-0.93 and RR 0.41, 95% CI 0.27-0.63, respectively). No statistically significant difference was observed regarding other outcomes, including catheter survival and mechanical complications. CONCLUSION: Overall, the quality of published literature on the field of peritoneal dialysis catheter placement is poor, with a small percentage of studies being randomized clinical trials. Percutaneous peritoneal dialysis catheter placement is a safe procedure and may result in fewer complications, such as tunnel/exit-site infections, and catheter migration, compared to surgical placement. PROTOCOL REGISTRATION: PROSPERO CRD42020154951.

Diagnosis and Management of Disorders of Body Tonicity-Hyponatremia and Hypernatremia: Core Curriculum 2020.

Overall body fluid concentration is regulated within a narrow range by the concerted action of the hypothalamic-pituitary axis to influence water intake through thirst and water excretion via the effect of vasopressin, or antidiuretic hormone, on renal collecting duct water permeability. Sodium is the principal extracellular cation; abnormalities in overall effective body fluid concentration, or tonicity, manifest as disturbances in serum sodium concentration. Depending on its severity and chronicity, hyponatremia can lead to significant symptoms, primarily related to central nervous system function. Failure to correct hyponatremia can lead to permanent neurologic damage, as can over rapid correction. It is thus essential to stay within specific limits for correction, particularly for chronic hyponatremia. Hypernatremia also leads to central nervous system dysfunction, although goals for its correction rate are less well established. This Core Curriculum article discusses the normal regulation of tonicity and serum sodium concentration and the diagnosis and management of hypo- and hypernatremia.

Digital chalk-talk videos improve knowledge and satisfaction in renal physiology.

The authors began a curriculum reform project to improve the experience in a Renal Physiology course for first-year medical students. Taking into account both the variety of learning preferences among students and the benefits of student autonomy, the authors hypothesized that adding digital chalk-talk videos to lecture notes and live lectures would improve student knowledge, course satisfaction, and engagement. The authors measured performance on the renal physiology exam before (the traditional curriculum) and for 2 yr after implementation of the new curriculum. During the traditional and subsequent years, students took a Q-sort survey before and after the Renal Physiology course. Satisfaction was assessed based on ranked statements in the Q sort, as well as through qualitative analysis of student commentary. Compared with the traditional curriculum, mean scores on the renal physiology final exam were higher after implementation of the new curriculum: 65.3 vs. 74.4 ( P < 0.001) with year 1 and 65.3 vs. 79.4 ( P < 0.001) in the second year. After the new curriculum, students were more likely to agree with the statement, "I wish other courses were taught like this one." Qualitative analysis revealed how the video-based curriculum improved student engagement and satisfaction. Adding digital chalk-talk videos to a traditional Renal Physiology course that included active learning led to improved exam performance and high levels of student satisfaction. Other preclinical courses in medical school may benefit from such an intervention.

Medical student attitudes toward kidney physiology and nephrology: a qualitative study.

Interest in nephrology among trainees is waning in the USA. Early perceptions and attitudes to subject matter can be linked to the quality of pre-clinical curricula. We wanted to explore these attitudes in the setting of modern curriculum redesign. We utilized Q methodology to understand first-year medical student attitudes after an innovative kidney physiology curriculum redesign that focuses on blending multiple learning methods. First-year medical students were invited to take a Q sort survey at the conclusion of a kidney physiology course. Students prioritized statements related to their understanding of kidney physiology, learning preferences, preferred course characteristics, perceived clinical relevance of kidney physiology, and interest in nephrology as a career. Factor analysis was performed to identify different student viewpoints. At the conclusion of our modified course, all students (n = 108) were invited to take the survey and 44 (41%) Q sorts were returned. Two dominant viewpoints were defined according to interest in nephrology. The Potentials are students who understand kidney physiology, perceive kidney physiology as clinically relevant, attend class sessions, utilize videos, and are willing to shadow a nephrologist. The Uninterested are students who are less satisfied with their kidney physiology knowledge, prefer to study alone with a textbook, avoid lectures, and are not interested in learning about nephrology. In an updated renal physiology course, students that use multiple learning methods also have favorable attitudes toward learning kidney physiology. Thus, modern curriculum changes that accommodate a variety of learning styles may promote positive attitudes toward nephrology.

Exploring student preferences with a Q-sort: the development of an individualized renal physiology curriculum.

Medical education reform is underway, but the optimal course for change has yet to be seen. While planning for the redesign of a renal physiology course at the Duke School of Medicine, the authors used a Q-sort survey to assess students' attitudes and learning preferences to inform curricular change. The authors invited first-year medical students at the Duke School of Medicine to take a Q-sort survey on the first day of renal physiology. Students prioritized statements related to their understanding of renal physiology, learning preferences, preferred course characteristics, perceived clinical relevance of renal physiology, and interest in nephrology as a career. By-person factor analysis was performed using the centroid method. Three dominant factors were strongly defined by learning preferences: "readers" prefer using notes, a textbook, and avoid lectures; "social-auditory learners" prefer attending lectures, interactivity, and working with peers; and "visual learners" prefer studying images, diagrams, and viewing materials online. A smaller, fourth factor represented a small group of students with a strong predisposition against renal physiology and nephrology. In conclusion, the Q-sort survey identified and then described in detail the dominant viewpoints of our students. Learning style preferences better classified first-year students rather than any of the other domains. A more individualized curriculum would simultaneously cater to the different types of learners in the classroom.

Prescriptions for dietary sodium in patients with chronic kidney disease: how will this shake out?

Patients with chronic kidney disease (CKD) are at risk of exhibiting expanded extracellular volume, and low-sodium diets are often prescribed to limit clinical complications from this condition. Fan et al. performed a post hoc study from the database of the Modification of Diet in Renal Disease Study. Their article, as well as other recent observations, suggests that a low-sodium diet may not be as beneficial as previously thought in all CKD patients.

IgG4-related tubulointerstitial nephritis associated with chronic lymphocytic leukemia.

BACKGROUND: Tubulointerstitial nephritis (TIN) is typically seen in association with drug exposure and infection or in autoimmune diseases such as Sjogren's syndrome or systemic lupus erythematosis. The recently described IgG4-related systemic diseases can affect many organ systems including the kidney and typically respond to corticosteroid treatment. CASE: We present a case of IgG4-related TIN in a patient with concomitant chronic lymphocytic leukemia. To our knowledge, IgG4-related TIN has not been associated with any hematological disorder such as chronic lymphocytic leukemia.
 CONCLUSION: We propose that all kidney biopsies with significant plasma cell infiltrate should be stained for IgG4 as response to treatment is common.

Role of vaptans in the management of hyponatremia.

Hyponatremia, the most commonly encountered electrolyte abnormality, affects as many as 30% of hospitalized patients. It is a powerful predictor of poor outcomes, especially in patients with congestive heart failure or cirrhosis. The failure to excrete electrolyte-free water that results from persistent secretion of antidiuretic hormone despite low serum osmolality usually underlies the development of hyponatremia. Treatment depends on several factors, including the cause, overall volume status of the patient, severity of hyponatremic symptoms, and duration of hyponatremia at presentation. This review focuses on the role of the vasopressin receptor antagonists, or vaptans, in the treatment of hyponatremia. These recently introduced agents have the unique ability to induce an aquaresis, the excretion of electrolyte-free water without accompanying solutes. After a brief historical perspective and discussion of pharmacologic characteristics of vaptans, we review the accumulated experience with vaptans for the treatment of hyponatremia. Vaptans have been shown to increase serum sodium concentrations in patients with euvolemic or hypervolemic hyponatremia in a reproducible manner, but their safe use requires full understanding of their indications and contraindications.

Hyponatremia and the use of vasopressin receptor antagonists in critically ill patients.

Hyponatremia in critically ill patients is a common and challenging problem. Increased levels of arginine vasopressin almost always contribute to the etiology. Inhibition of the vasopressin receptor with a vasopressin receptor antagonist (vaptan) is a novel approach to the treatment of hyponatremia. Vaptans are well suited to the treatment of chronic hyponatremia associated with syndrome of inappropriate anti-diuretic hormone secretion (SIADH) and hypervolemic states like cirrhosis or congestive heart failure. No data are available on the use of vaptans in acute hyponatremia, and they are not indicated in hypovolemic hyponatremia. The focus of this review is the treatment of critically ill patients with hyponatremia with vaptans and other measures.

AT1 receptors in the collecting duct directly modulate the concentration of urine.

Mice lacking AT(1) angiotensin receptors have an impaired capacity to concentrate the urine, but the underlying mechanism is unknown. To determine whether direct actions of AT(1) receptors in epithelial cells of the collecting duct regulate water reabsorption, we used Cre-Loxp technology to specifically eliminate AT(1A) receptors from the collecting duct in mice (CD-KOs). Although levels of AT(1A) receptor mRNA in the inner medulla of CD-KO mice were significantly reduced, their kidneys appeared structurally normal. Under basal conditions, plasma and urine osmolalities and urine volumes were similar between CD-KO mice and controls. The increase in urine osmolality in response to water deprivation or vasopressin administration, however, was consistently attenuated in CD-KO mice. Similarly, levels of aquaporin-2 protein in inner and outer medulla after water deprivation were significantly lower in CD-KO mice compared with controls, despite its normal localization to the apical membrane. In summary, these results demonstrate that AT(1A) receptors in epithelial cells of the collecting duct directly modulate aquaporin-2 levels and contribute to the concentration of urine.

Modifiable risk factors associated with sudden cardiac arrest within hemodialysis clinics.

Sudden cardiac arrest is the most common cause of death among patients with end-stage kidney disease (ESKD) maintained on hemodialysis. Here we sought to identify dialysis-related factors associated with this increased risk in a case-control study encompassing 43,200 patients dialyzed in outpatient clinics of a large organization. Within this group, we compared the clinical and dialysis-specific data of 502 patients who experienced a sudden cardiac arrest with 1632 age- and dialysis-vintage-matched controls. There were 4.5 sudden cardiac arrest events per 100,000 dialysis treatments during the 3-year study period. These patients were significantly more likely to have been exposed to low potassium dialysate of less than 2 meq/l. These differences could not be explained by predialysis serum potassium levels. There was no evidence for a beneficial effect of low potassium dialysate even among those with higher predialysis serum potassium levels. Other factors strongly associated with sudden cardiac arrest by multivariable analysis included increased ultrafiltration volumes, exposure to low calcium dialysate, and predialysis serum creatinine levels. These relationships persisted after adjustment for covariates, but traditional risk factors such as history of coronary heart disease and congestive heart failure were not significantly influential. Hence, our study suggests that modifications of the hemodialysis prescription may improve the risk of sudden cardiac arrest in patients with ESKD.

When is it appropriate to use vasopressin receptor antagonists?

Hyponatremia is a common and challenging disorder. The mainstays of treatment until recently were water restriction and hypertonic saline. The first nonpeptide vasopressin receptor antagonist (VRA) is now approved by the US Food and Drug Administration for use in patients with euvolemic and hypervolemic hyponatremia. VRA induce urinary dilution with an aquaresis that leads to an increase in serum sodium concentration. In patients with heart failure, VRA modestly improve congestive symptoms but have no effect on short- or long-term mortality. Long-term effects have not been extensively studied, but serious adverse effects of VRA are rare, and the rate of rise in serum sodium that they produce seems unlikely to lead to osmotic demyelination. Beneficial effects beyond changing serum tonicity and alternative uses, such as in polycystic kidney disease, need further exploration. This commentary discusses the current and potential indications for use of VRA.

Predictors of survival after cardiac arrest in outpatient hemodialysis clinics.

Cardiac arrest (CA) is the most common cause of death in hemodialysis patients, and factors that improve survival after arrest are unknown. This study sought to identify modifiable factors that are associated with survival after CA in hemodialysis clinics. Patients who experienced in-center CA in the Gambro Healthcare System in the United States from 2002 to 2005 were identified. Patient characteristics at the time of arrest were compared between survivors and nonsurvivors at 24 h and 6 mo after CA. A total of 729 patients sustained in-clinic CA; 310 (42.5%) patients survived 24 h, and 80 (11%) patients survived 6 mo. Traditional risk factors, including cardiovascular comorbidities, diabetes, hemoglobin, and dialysis adequacy, did not predict survival at either time point. After adjustment for case-mix factors, presence of indwelling catheter, and concomitant medications, only use of beta blockers (BBL), calcium-channel blockers (CCB), and angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) remained significantly associated with survival (BBL odds ratio [OR] 0.32 [95% confidence interval (CI) 0.17 to 0.61]; CCB OR 0.42 [95% CI 0.23 to 0.76]; ACEI/ARB OR 0.51 [95% CI 0.28 to 0.95]). The beneficial effect of ACEI/ARB and BBL on survival increased sequentially with higher medication dosages. Prescription of BBL at the time of the event was the only predictive variable of survival at 24 h. Therefore, traditional cardiovascular risk factors were not associated with survival after CA in this hemodialysis cohort. The benefits that are associated with BBL, CCB, and ACEI/ARB suggest that these medications may improve the chances of survival after CA.

Automated external defibrillators and survival from cardiac arrest in the outpatient hemodialysis clinic.

Automated external defibrillators (AED) have been recommended for use in outpatient dialysis clinics to improve outcomes from cardiac arrest, the most common cause of death in patients with ESRD. The effectiveness of this policy is unknown. The study cohort consisted of 43,200 hemodialysis patients in the US Gambro Healthcare System from 2002 to 2005. Of these, 729 patients who sustained an in-center cardiac arrest were identified. Baseline characteristics at the time of the event were compared between patients who underwent hemodialysis in clinics with and without an AED on site. Unadjusted survival and survival adjusted for potential confounders was measured using Cox proportional hazards regression models. Unadjusted survival at 30 d was 19 versus 15% (P = 0.12) and 9.5 versus 7.8% at 1 yr (P = 0.39) in the AED-present and AED-absent groups, respectively. AED presence was not associated with outcome in unadjusted analysis (hazard ratio [HR] 0.91; 95% confidence interval [CI] 0.78 to 1.07; P = 0.26). Univariable analysis identified age (HR 1.07 per decade; 95% CI 1.01 to 1.13), serum albumin (HR 0.91 per 0.7-mg/dl increase; 95% CI 0.82 to 1.01), and indwelling dialysis catheters (HR 1.21; 95% CI 1.02 to 1.42) as potential confounders. Medications including angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, beta blockers, calcium channel blockers, other BP medications, aspirin, antibiotics, and antiarrhythmics were associated with survival and considered confounders. After controlling for case mix and confounders, AED presence was not associated with outcome (HR 0.98; 95% CI 0.82 to 1.18; P = 0.83). Presence of AED in the dialysis clinic is not sufficient by itself to improve the abysmal outcome from in-clinic cardiac arrest in hemodialysis patients in the United States.

Intravenous immunoglobulin and plasmapheresis in acute humoral rejection: experience in renal allograft transplantation.

Acute humoral rejection (AHR) in kidney transplantation is associated with higher rates of allograft loss when compared with acute cellular rejection (ACR). Treatment with intravenous immunoglobulin (IVIG) combined with plasmapheresis (PP) has been used recently in many centers. We report the incidence, clinical characteristics, and outcome of patients with AHR treated with IVIG and PP. All patients (n=519) at our institution who underwent kidney transplantation between January 1999 and August 2003 were retrospectively analyzed and classified according to biopsy results into three groups: AHR, ACR, and no rejection. AHR was diagnosed in 23 patients (4.5%) and ACR in 75 patients (15%). Mean follow-up was 844+/-23 days. Female sex, black race, and high panel-reactive antibody were risk factors for AHR. Most AHR patients (22 of 23) were treated with IVIG and PP. Two-year graft survival was numerically worse in patients with AHR versus ACR (78% vs. 85%, p=0.5) but the difference was not statistically significant. Graft survival after AHR treated with IVIG and PP is much better than it has been historically. IVIG in combination with PP is an effective treatment for AHR. Graft survival in this setting is similar to graft survival in patients with ACR.