Magnesium Is a Vital Ion in the Body-It Is Time to Consider Its Supplementation on a Routine Basis

The importance of maintaining proper magnesium intake and total body magnesium content in preserving human health remains underappreciated among medical professionals and laymen. This review aimed to show the importance of hypomagnesemia as a modifiable risk factor for developing disease processes. We searched the PubMed database and Google Scholar using the keywords 'magnesium', 'diabetes', 'cardiovascular disease', 'respiratory disease', 'immune system', 'inflammation', 'autoimmune disease', 'neurology', 'psychiatry', 'cognitive function', 'cancer', and 'vascular calcification'. In multiple contexts of the search terms, all reviews, animal experiments, and human observational data indicated that magnesium deficiency can lead to or contribute to developing many disease states. The conclusions of several in-depth reviews support our working hypothesis that magnesium and its supplementation are often undervalued and underutilized. Although much research has confirmed the importance of proper magnesium supply and tissue levels, simple and inexpensive magnesium supplementation has not yet been sufficiently recognized or promoted.

A bibliometric analysis of publications in Renal Failure in the last three decades

Publications in Renal Failure in Science Citation Index Expanded (SCI-EXPANDED) between 1992 and 2021 were analyzed. Six publication indicators: total, independent, collaborative, first author, corresponding author, and single author publications as well as their related citation indicators, were used to compare performances of countries, institutes, and authors. Comparison of the highly cited papers and journal's impact factor (IF) contributors was discussed. In addition, the main research topics in the journal were presented. Results show that China published the most total articles and reviews, as well as the first-author papers and corresponding-author papers in the journal. The Chang Gung Memorial Hospital in Taiwan ranked the top in five publication indicators: total, single-institution, inter-institutionally collaborative, first author, and corresponding-author papers. A low percentage of productive authors emerged as a journal IF contributor. Similarly, only a limited relationship between highly cited papers and IF contributing papers was found. Publications related to hemodialysis, chronic kidney disease, and acute kidney injury were the most popular topic, while meta-analysis was new focus in the last decade in the journal.

A Critical Reassessment of the Kidney Risk Caused by Tetrastarch Products in the Perioperative and Intensive Care Environments

Purpose: To reassess the results of former meta-analyses focusing on the relationship between novel HES preparations (130/0.4 and 130/0.42) and acute kidney injury. Previous meta-analyses are based on studies referring to partially or fully unpublished data or data from abstracts only. Methods: The studies included in the former meta-analyses were scrutinized by the authors independently. We completed a critical analysis of the literature, including the strengths, weaknesses and modifiers of the studies when assessing products, formulations and outcomes. Results: Both the published large studies and meta-analyses show significant bias in the context of the deleterious effect of 6% 130/0.4-0.42 HES. Without (1) detailed hemodynamic data, (2) the exclusion of other nephrotoxic events and (3) a properly performed evaluation of the dose-effect relationship, the AKI-inducing property of 6% HES 130/0.4 or 0.42 should not be considered as evidence. The administration of HES is safe and effective if the recommended dose is respected. Conclusions: Our review suggests that there is questionable evidence for the deteriorating renal effect of these products. Further well-designed, randomized and controlled trials are needed. Additionally, conclusions formulated for resource-rich environments should not be extended to more resource-scarce environments without proper qualifiers provided.

The Importance of the Nephrologist in the Treatment of the Diuretic-Resistant Heart Failure

Heart failure is not only a global problem but also significantly limits the life prospects of these patients. The epidemiology and presentation of heart failure are intensively researched topics in cardiology. The risk factors leading to heart failure are well known; however, the real challenge is to provide effective treatments. A vicious cycle develops in heart failure of all etiologies, sooner or later compromising both cardiac and kidney functions simultaneously. This can explain the repeated hospital admissions due to decompensation and the significantly reduced quality of life. Moreover, diuretic-refractory heart failure represents a distinct challenge due to repeated hospital admissions and increased mortality. In our narrative review, we wanted to draw attention to nephrology treatment options for severe diuretic-resistant heart failure. The incremental value of peritoneal dialysis in severe heart failure and the feasibility of percutaneous peritoneal dialysis catheter insertion have been well known for many years. In contrast, the science and narrative of acute peritoneal dialysis in diuretic-resistant heart failure remains underrepresented. We believe that nephrologists are uniquely positioned to help these patients by providing acute peritoneal dialysis to reduce hospitalization dependency and increase their quality of life.

Dialysis patients who smoke are more hypertensive, more fluid overloaded and take more antihypertensive medications than nonsmokers

Background

Smoking remains a powerful risk factor for death in end-stage renal disease (ESRD) and so is the presence of fluid overload. The relationship between smoking, blood pressure (BP) control and volume overload is insufficiently explored in patients on maintenance dialysis.

Methods

This is a retrospective cross-sectional cohort study, utilizing existing patients’ data generated during routine ESRD care, including bimonthly protocol bioimpedance fluid assessment of the volume status.

Results

We analyzed the data of 63 prevalent patients receiving thrice weekly maintenance hemodiafiltration treatments at one rural dialysis unit in Hungary. The cohort’s mean ± SD age was 61.5 ± 15.3 years; 65% male, 38% diabetic, with a mean arterial blood pressure (MAP) 99.5 ± 16.8 mmHg and Charlson score 3.79 ± 2.04. Of these, 38 patients were nonsmokers and 25 smokers. The nonsmokers’ MAP was 94.3 ± 14.0 versus smokers’ 105.9 ± 18.9 mmHg (p: .002); nonsmokers took an average 0.73 ± 0.92 antihypertensive medications vs. 1.73 ± 1.21 for smokers (p: .0001). The distribution of taking more antihypertensive medications is skewed toward a higher number among the smokers (2x5 chi square p: .004). By bioimpedance spectroscopy, nonsmokers had an average 10.93 ± 7.65 percent overhydration (OH) over the extracellular space compared to 17.63 ± 8.98 in smokers (p: .005).

Conclusions

Smoking may be a significant mediator of not only BP but also of chronic fluid overload in ESRD patents. Additional, larger studies are needed to explore the mechanistic link between smoking and volume overload.

Bedside placement of peritoneal dialysis catheters - a single-center experience from Hungary

Objectives: The successful implantation of peritoneal dialysis (PD) catheters is a critical skill procedure with the potential to impact both the short- and long-term success of renal replacement therapy and the patients’ survival.

Methods: We retrospectively reviewed our single-center experience with nephrologist-placed minimally invasive, double-cuffed PD catheters (PDCs).

Results: The recruitment period was March 2014 through December 2015. The follow-up period lasted until 2016. The mean age of the subjects was 60 ± 18 years and indications for the PD were diuretic resistant acutely decompensated chronic heart failure in seven patients (47%) and end-stage renal disease in eight (53%) patients. Comorbid conditions included diabetes (27%), ischemic heart disease (47%), advanced liver failure (27%), and a history of hypertension (73%). The cohort had a high mortality with five subjects only in severe heart failure group (33%) passing away during the index hospitalization; of the rest, two (13%) had heart transplantation, three (20%) changed modality to hemodialysis, and only five (33%) continued with maintenance PD beyond 1 month. Acute technical complications within the first month were infrequent: one catheter (6%) had drainage problems and one (6%) was lost due to extrusion. There were no serious complications (e.g., organ damage, peritonitis, etc.).

Conclusions: In selected cases, particularly in severe diuretic refractory heart failure, PDC placement placed by a nephrologist is feasible with a low rate of complications even in a low-volume center setting. The catheters we placed were all functioning with only minor complications and PD could be started immediately.

The association of overhydration with megafistulas in hemodialysis patients

Objectives: Diffuse enlargements of arteriovenous dialysis fistulas customarily attributed to either excessive arterial inflow or central outflow stenosis. The relationship between volume status and clinically enlarged (arteriovenous) fistula (CEF) formation in end-stage renal disease (ESRD) patients is not well understood.

Methods: We assessed the pre-dialysis bioimpedance spectroscopy-measured percentage of overhydration (OH%) in 13 prevalent dialysis patients with CEF development and negative angiography and compared the results with those of 52 control dialysis patients (CONTR). All patients were prevalent ESRD patients receiving thrice-weekly maintenance hemodiafiltration at an academic outpatient dialysis unit.

Results: 10/13 CEF patients had OH% ≥15% as compared to 20/52 control patients (Chi square p: .02). The degree of OH% was 20.2 ± 7.4% among the CEF vs. 14.4 ± 7.1% in the control group (Student’s t-test p: .01), representing 4.2 ± 3.2 vs. 2.8 ± 1.6 L of excess fluid pre-dialysis (p: .03). Patients with CEF development took an average of 1.7 ± 1.4 vs. 0.8 ± 0.8 (p: .002) antihypertensive medications compared to the CONTR patients, yet their blood pressure was higher: 156/91 vs. 141/78 mmHg (systolic/diastolic p: .03<.0001). We found no difference in fistula vintage, body mass index, age, diabetes status, or diuretic use. The odds ratio of having a CEF in patients with ≥15% OH status was 5.3 (95% CI: 1.3–21.7; p: .01), the Number Needed to Harm with overhydration was 4.

Conclusions: There is an association between bioimpedance spectroscopy-measured overhydrated clinical state and the presence of CEF; either as an increased volume capacitance or as a potential cause.

Diuretics and bioimpedance-measured fluid spaces in hypertensive patients

The authors examined the relationship between thiazide-type diuretics and fluid spaces in a cohort of hypertensive patients in a retrospective study of 60 stable hypertensive patients without renal abnormalities who underwent whole-body bioimpedance analysis. Overhydration was greater in the diuretic group, but only to a nonsignificant degree (5.9 vs. 2.9%; P=.21). The total body water did not differ in the two groups (41.8 L vs. 40.5 L; P=.64). Extracellular fluid volume (ECV) (19.7 L vs. 18.5 L; P=.35) and intracellular fluid volume (ICV) spaces (20.8 L vs. 21.3 L; P=.75) were also not significantly different in the two groups. The ratio of ICV:ECV, however, appeared different: 1.05 vs 1.15 (P=.017) and the effect was maintained in the linear regression-adjusted model (β coefficient: -0.143; P=.001). The diuretic-related distortion of ICV:ECV ratio indicates potential fluid redistribution in hypertensive patients, with ICV participating in the process.

Safety and efficacy of percutaneous renal biopsy by physicians-in-training in an academic teaching setting

OBJECTIVES

The safety and efficacy of percutaneous renal biopsy (PKB) are relatively little studied in a training setting. We sought to review our recent experience with bedside PKB in our training program.

METHODS

We performed a retrospective cohort review of our consecutive 2.5-year renal biopsy experience (May 2007-November 2009) at the University of Mississippi Nephrology Fellowship. All of the biopsies were performed exclusively by renal fellows using real-time ultrasound (US) visualization within the framework of a structured US-PKB training course.

RESULTS

A total of 64 patients underwent PKB during the index period; 50 (78.1%) of these procedures were performed on native kidneys. Participant age was 39.8 ± 13.7 years, blood pressures measured 140.1/85.3 ± 21.5/14.9 mm Hg, serum creatinine was 3.05 ± 3.15 mg/dL, and median random urine protein:creatinine ratio was 2.38 (25%-75% interquartile range 0.49-7.32). The biopsied kidneys measured 11.8 (±1.6) cm. We recovered 18.8 ± 11.5 glomeruli per procedure; two biopsies were unsuccessful. Focal glomerular sclerosis and lupus nephritis (22% and 25%, respectively) predominated among the specimens. Only three specimens returned with no diagnostic changes. There was a close correlation between preceding history and recovered diagnoses of diabetic changes and lupus nephritis (r 0.605 and 0.842; P < 0.0001 for both). Initial hemoglobin of 10.8 ± 1.8 g/dL dropped to 10.2 (1.9) g/dL after the procedure (P < 0.0001). Five (7.8%) patients needed transfusion; one patient experienced persistent urine leakage; however, none of the patients needed surgical or radiological intervention or died.

CONCLUSIONS

In the setting of a well-structured training environment, US-guided PKB is a reasonably safe and valuable component of renal fellowship training.

The safety and efficacy of bedside removal of tunneled hemodialysis catheters by nephrology trainees

BACKGROUND

Some nephrologists remove tunneled hemodialysis catheters (TDC) at the bedside, but this practice has never been formally studied. Our hypothesis was that bedside removal of TDC is a safe and effective procedure affording prompt removal, including in cases of suspected infection.

METHODS

We reviewed our consecutive 3-year experience (2007-2009) with bedside TDC removal at the University of Mississippi Renal Fellowship Program. Data were collected on multiple patients and procedure-related variables, success and complication rates. Association between clinical characteristics and biomarkers of inflammation and myocardial damage was examined using correlation coefficients.

RESULTS

Of 55 inpatient TDC removals (90.9% from internal jugular location), 50 (90.9%) were completed without hands-on assistance from faculty. Indications at the time of removal included bacteremia, fever or clinical sepsis with hemodynamic instability or respiratory failure. All procedures were successful, with no cuff retention noted; one patient experienced prolonged bleeding which was controlled with local pressure. Peak C-reactive protein (available in 63.6% of cohort) was 12.9 ± 8.4 mg/dL (reference range: <0.49) and median troponin-I (34% available) was 0.534 ng/mL (IQR 0.03-0.9) (reference range: <0.034) and they did not correlate with each other. Abnormal troponin-I was associated with proven bacteremia (p < 0.05) but not with systolic and diastolic BP or clinical sepsis.

CONCLUSION

Our results suggest that bedside removal of TDC remains a safe and effective procedure regardless of site or indications. Accordingly, TDC removal should be an integral part of competent Nephrology training.

The safety and efficacy of bedside removal of tunneled hemodialysis catheters by nephrology trainees

BACKGROUND

Some nephrologists remove tunneled hemodialysis catheters (TDC) at the bedside, but this practice has never been formally studied. Our hypothesis was that bedside removal of TDC is a safe and effective procedure affording prompt removal, including in cases of suspected infection.

METHODS

We reviewed our consecutive 3-year experience (2007-2009) with bedside TDC removal at the University of Mississippi Renal Fellowship Program. Data were collected on multiple patients and procedure-related variables, success and complication rates. Association between clinical characteristics and biomarkers of inflammation and myocardial damage was examined using correlation coefficients.

RESULTS

Of 55 inpatient TDC removals (90.9% from internal jugular location), 50 (90.9%) were completed without hands-on assistance from faculty. Indications at the time of removal included bacteremia, fever or clinical sepsis with hemodynamic instability or respiratory failure. All procedures were successful, with no cuff retention noted; one patient experienced prolonged bleeding which was controlled with local pressure. Peak C-reactive protein (available in 63.6% of cohort) was 12.9 ± 8.4 mg/dL (reference range: <0.49) and median troponin-I (34% available) was 0.534 ng/mL (IQR 0.03-0.9) (reference range: <0.034) and they did not correlate with each other. Abnormal troponin-I was associated with proven bacteremia (p < 0.05) but not with systolic and diastolic BP or clinical sepsis.

CONCLUSION

Our results suggest that bedside removal of TDC remains a safe and effective procedure regardless of site or indications. Accordingly, TDC removal should be an integral part of competent Nephrology training.

Volume estimation in dialysis patients: the concordance of brain-type natriuretic peptide measurements and bioimpedance values

Correct estimation of the dialysis patients' hydration status remains an important clinical challenge. Bioimpedance measurements have been validated by various physiological tests, and the use of brain-type natriuretic peptide (BNP) has been validated by inferior vena cava diameter measurements. This is an observational cohort study that evaluated the correspondence between bioimpedance-measured overhydration percentage (OH%) and BNP. We measured predialysis OH% by bioimpedance apparatus (Body Composition Monitor) and BNP by microparticle enzyme-linked immunoassay in 41 prevalent stable hemodialysis patients, 19 (46%) women, aged 58.9 ± 14.5 years. The cohort's average BNP was 2694 ± 3278 pg/mL and 10 (24.4%) of these 41 patients had BNP < 500 pg/mL (average 260.7 ± 108.5). The OH% was 8.5 ± 7.0% among those with a BNP < 500 pg/mL, while the rest of the population had an OH% of 21.4 ± 8.0%, corresponding to excess volumes of 1.6 ± 1.3 and 4.4 ± 3.8 L, respectively. The OH% vs. BNP relationship was best described by the exponential regression of y = 216.4e(0.097x) , predicting a BNP of 216.4 pg/mL at 0% overhydration status (r 0.61). Receiver-operating curves revealed an area under the curve of 0.885 for BNP when the OH% was set ≥15% of overhydration and an area under the curve of 0.918 for OH% when the BNP was set ≥500 pg/mL for being abnormal. We conclude that in our cohort there was a high degree of correspondence between these two tests with an exponential relationship between the measurements.

r.hu-erythropoietin (EPO) treatment of pre-ESRD patients slows the rate of progression of renal decline

BACKGROUND

As EPO treatment of chronic anemia of advanced renal disease is now the standard of care we examined if such treatment may slow the progression of renal function decline.

METHODS

Data of 18 pre-ESRD patients were analyzed retrospectively 12 months prior and prospectively 12 months after the initiation of EPO. Mean creatinine was 5.0 +/- 1.8 mg/dL (Mean +/- SEM) when starting EPO at a weekly dose of 5000 +/- 500 units once the hematocrit was below 30 %. EPO dose was titrated monthly for a hematocrit between 33.0% and 37.0%. Metabolic complications and hypertension were controlled.

RESULTS

At month_0 the average blood pressure was 148/76 +/- 5/4 mmHg and at month_12 it was 145/73 +/- 6/3 mmHg (p = 0.75 by 2 tailed paired Student's t test). 12/18 patients were on an ACE-i or ARB before month_0 and 14/18 were on it after (p = 0.71 by Fisher's 2 tailed exact test). The average hematocrit rose from 26.9% +/- 0.6 to 33.1 % +/- 0.1. When linear regression analysis was applied to pre- and post-EPO 1/creatinine data the mean rate of decline was -0.0140 +/- 0.0119 (mean +/- SD) and -0.0017 +/- 0.0090 (non-parametric Wilcoxon matched pairs signed rank sum test: Z value: -2.91; P = 0.004) respectively. 5/18 patients did not require dialysis 12 months after starting EPO (month_0).

CONCLUSION

Treatment of the anemia of chronic renal failure with erythropoietin, when instituted together with vigorous metabolic control may slow the rate of renal function decline.

Hemodialysis is as effective as hemoperfusion for drug removal in carbamazepine poisoning

Although most authors recommend charcoal hemoperfusion (CHP) for the removal of carbamazepine (CBZ) in acute CBZ poisoning, we present a case where we had the chance to compare CHP with hemodialysis (HD). A 50-year-old white man with normal renal function ingested an unknown quantity of CBZ with lithium. He was dialyzed for 3 h and his serum CBZ level was reduced by 27.7%. Four hours later he also had a 3-hour CHP which further reduced his CBZ level by 25.3%. Therefore we conclude that HD with high-flux dialyzers is at least as effective as CHP for the removal of CBZ from the blood after CBZ intoxication.

Lovastatin has direct renal hemodynamic effects in a rodent model

PURPOSE

Lovastatin, an HMG-CoA reductase inhibitor, has been shown to preserve renal function in models of chronic renal failure. We determined the effect of lovastatin on renal function and hemodynamics in normal nonpathologic kidneys in a rodent model.

MATERIALS AND METHODS

Renal function was measured in anesthetized (Inactin) control rats (n = 13) and lovastatin-treated rats (15 mg./kg./day, 3 weeks, orally, n = 17). Renal blood flow was measured with an ultrasonic flowprobe, and glomerular filtration rate was measured by inulin clearance. The effect of lovastatin on pre- and postglomerular vessel diameters was also observed in a hydronephrotic kidney preparation by videomicroscopy.

RESULTS

Lovastatin significantly increased (p < 0.05) renal blood flow and glomerular filtration rate by 17% (3.4 +/- 0.2 ml./min./gram kidney weight (gKW) versus 2.9 +/- 0.2 ml./min./gKW) and 49% (0.67 +/- 0.04 ml./min./gKW versus 0.45 +/- 0.06 ml./min./gKW). The increase in renal blood flow was mediated by preglomerular vasodilation (expressed as percent increase from baseline diameter, n = 20), 25% in the interlobular artery and 20% in the afferent arteriole (p < 0.05).

CONCLUSIONS

In addition to its known lipid-lowering properties, lovastatin has a direct renal hemodynamic effect, increasing renal blood flow and glomerular filtration rate in normal nonpathologic kidneys. Lovastatin's selective preglomerular vasodilation may account for the observed increase in renal blood flow and glomerular filtration rate. Accordingly, this additional hemodynamic effect may be useful in preserving renal function in models of chronic renal failure.

Bicarbonate dialysate for continuous renal replacement therapy in intensive care unit patients with acute renal failure

Lactate-buffered peritoneal solution traditionally has been used as dialysate for continuous renal replacement therapy (CRRT) in the United States because no bicarbonate solution is commercially available. Since 1994, the Cleveland Clinic Foundation Dialysis Unit has prepared a bicarbonate solution (sodium 144 +/- 3 mEq/L, HCO3 37 +/- 2 mEq/L, potassium 3 or 4 mEq/L, calcium 3.0 +/- 0.3 mEq/L, and magnesium 1.4 +/- 0.3 mg/dL) replicating the dialysate for chronic intermittent hemodialysis. No solute precipitation, as calcium or magnesium salts, were observed, and several cultures of the solution, performed at various time periods, remained negative. Fifty critically ill acute renal failure patients have been treated with bicarbonate-CRRT. All patients were in multiple organ failure and required mechanical ventilation; 37 were receiving vasopressors. Forty-four continuous venovenous hemodialysis sessions and eight continuous arteriovenous hemodialysis sessions were performed with a mean duration of 7.8 +/- 6.1 days. The mean inflow dialysate rate was 1,249 +/- 225 mL/hr and the mean outflow rate (dialysate plus ultrafiltration) was 1,399 +/- 237 mL/hr; the inflow rate was constantly kept lower or equal to the outflow rate to avoid an enhanced potential for backfiltration. No related fever spikes or sepsis episodes were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

What dialysis dose should be provided in acute renal failure? A review

Increased dialysis dose has been shown to improve morbidity and survival in chronic hemodialysis patients. Despite improvement in care and technological aspects of renal replacement therapy, mortality rates of acute renal failure (ARF) have remained essentially unchanged for over two decades, exceeding 50% in most studies. The occurrence of ARF in older patients with more complicated medical and surgical conditions has contributed to this lack of outcome amelioration, and death of ARF patients is now more frequently caused by underlying disease than ARF itself. A recent prospective survey at this institution found a mortality rate of 79.1% among a total of 363 ARF medical and surgical intensive care unit patients, with a mean age near 60 years and a mean admission APACHE II score of over 20, who were treated by intermittent hemodialysis and continuous renal replacement therapy (CRRT). Nonsurvivors had a mean of over four failed systems, in addition to the renal failure, compared with survivors who had less than four. The standards for dialysis adequacy in ARF are not currently defined. Increased catabolism seen in ARF patients in the intensive care unit may justify large dialysis dose delivery. An apparent influence of delivered dialysis dose on the outcome of ARF intensive care unit patients has been recently observed at our institution. Compared with nonsurvivors, survivors had received significantly higher dialysis dose, as assessed by Kt/V and urea reduction ratio. In ARF patients, the discrepancy between delivered versus prescribed dialysis dose may be particularly important and contributed to by the following: reduced blood flow rate and dialysis time consequent to patient intolerance; lower dialyzer in vivo clearances, particularly in heparin-free dialysis; blood recirculation when using temporary vascular access; and postdialysis urea rebound. Prolonging the course of renal failure is one of the risks attributed to frequent dialysis; hypotension and ultrafiltration combined with a deficient renal autoregulation can result in further renal damage. The detrimental effects of bioincompatible membranes have been demonstrated with an induced-delay of renal function recovery. A recent study has reported benefits of biocompatible membranes in terms of potential for renal recovery and maintenance of urine output during dialytic support when compared with bioincompatible membranes. CRRT offers many advantages over intermittent hemodialysis for ARF intensive care unit patients: better hemodynamic tolerance, avoidance of solute rebound, and removal of serum sepsis mediators. However, CRRT have not yet been firmly shown to improve survival rates. Recently, urea kinetics have been used to estimate dialysis dose provided by CRRT.(ABSTRACT TRUNCATED AT 400 WORDS)