Conductivity variations and changes in serum sodium concentration during dialysis related to monitor switching

INTRODUCTION

The sodium gradient during hemodialysis sessions is one of the key factors in sodium balance in patients with dialysis-dependent chronic kidney disease; however, until the appearance of the new monitors with sodium modules, the differences between prescribed and measured sodium have been understudied. The present study aimed to compare the impact on the measured conductivity and the initial and final plasma sodium after changing the 5008 Cordiax to the new 6008 Cordiax monitor.

MATERIAL AND METHODS

106 patients on hemodialysis were included. Each patient underwent 2 dialysis sessions in which only the monitor was varied. The variables collected were dialysate, sodium and bicarbonate prescribed, real conductivity, initial and final plasma sodium measured, and the calculated sodium gradient (ΔPNa).

RESULTS

The change of dialysis monitor showed small but statistically significant differences in the initial (138.14mmol/L with 5008 vs. 138.81mmol/L with 6008) and final plasma sodium (139.58mmol/L vs. 140.97mmol/L), as well as in the actual conductivity obtained (13.97 vs. 14.1mS/cm). The ΔPNa also increased significantly.

CONCLUSION

The change from 5008 to 6008 monitor is associated with increased conductivity, leading the patient to end the sessions with higher plasma sodium and ΔPNa. Knowing and confirming this change will allow us to individualize the sodium prescription and avoid possible undesirable effects. It could be the preliminary study to explore the new sodium biosensor incorporated into the new generation of monitors.

[Correlations between dietary salt intake and 24-h urine sodium excretion in a sample of the urban population of Cáceres]

OBJECTIVE

Excessive salt intake is associated with higher levels of AHT and prevalence of cardiovascular diseases. WHO recommends consuming less than 5 g/day of salt (equivalent to 2 g Na⁺/day). Identifying foods and behaviours with greater contribution to excess intake would facilitate preventive dietary advice.

DESIGN

Observational study. SITE: Urban Health Center in Cáceres.

MAIN MEASUREMENTS

We estimated salt consumption using two food consumption frequency (FFQ) questionnaires, one generic and one with high Na+ content, and a 24 h follow-up survey. We use the Evalfinut program for nutritional evaluation of the diet. We analyzed correlations between estimated salt intake and 24-h urine sodium elimination (gold standard).

RESULTS

92% of the population had consumption higher than the recommendations with intakes equivalent to 9.5 g/day of salt (3.7 g/d of Na⁺). When sodium intake is determined by the Na⁺/K⁺ ratio, 79.54% have high intakes. Sodium elimination follows a slightly increasing trend with BMI. The perception of salt consumption is low, 56.3% consider it "adequate". 32.4% add salt to food once served. FFQ underestimate Na⁺ intake and targeted surveys provide higher values. The correlation between FFQ and Na⁺ urinary elimination is weak.

CONCLUSION

We must reduce salt intake by increasing the perception of consumption, improving knowledge about the salt content in food and identifying target patients of the health council.

Syndrome of inappropriate antidiuretic hormone secretion

Hyponatremia is the most frequent electrolytic disorder in hospitalized patients, and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), the most frequent cause of hiponatremia with clinically normal extracellular volume. It consists of a disorder of the regulation of body water that obeys to different causes, mainly cancer, pulmonary illnesses, disorders of the central nervous system and diverse drugs. As in any hiponatremia it a physiological knowledge of the regulation of body water and sodium is essential as well as the application of precise diagnostic criteria in order to manage the problem with an effective treatment. The available data until the moment show that the clinical diagnosis of SIADH made by professionals is mainly not supported on the established criteria drawn by experts and this lack of accuracy probably hits in the therapeutic result. The basis of the treatment of the SIADH is to correct its cause, water restriction, solutes (sodium chloride) and the use of vaptans in case of failure of the previous measures.

Clinical experience with Tolvaptan outpatient use. Cost and effectiveness in 9 cases

Introduction

Tolvaptan introduction has constituted the main therapeutic novelty in the management of hyponatremia in recent years.

Objective

To describe the experience with this drug at Complejo Asistencial Universitario de León, Spain.

Method

Retrospective, observational study of tolvaptan outpatient use in a tertiary care hospital from March 2014 to August 2017.

Results

A total of 9 patients were treated with tolvaptan in the outpatient setting. Eunatremia was reached in 24 h by 23.1%. After tolvaptan administration, a reduction in days of hospitalization was recorded (361 vs. 70; p = 0.007), especially in those days of hospitalization that were attributable to hyponatremia (306 vs. 49; p = 0.009).

Conclusions

Long-term use of tolvaptan appears to be safe and is associated with a decrease in days of hospitalization.

[Basal renal function in paediatric patients: correlation of methods that depend on a 24h urine collection with simpler methods that do not require a timed urine]

INTRODUCTION

In daily clinical practice a quick, easy and accessible method is needed to adequately assess renal function. The objectives of this study were: 1. To quantify the relationship and concordance of the glomerular filtration rate (GF) calculated by the clearance of creatinine in 24h urine (CCr) and the original and modified Schwartz equation (SE); and 2. To correlate urine elimination of substances that depends on the volume of excreted urine in a unit of time with other parameters that are calculated measuring the concentration of these substances in blood and urine.

MATERIAL AND METHODS

The study included 401 healthy children with ages between 3 to 14 years (187 male and 214 female). The analysis between the variables was carried out using Pearson's correlation coefficient and the intraclass correlation coefficient (ICC).

RESULTS

The correlation between values of CCr and the original SE (non-standardised creatinine measurement) was r=0.58 (P<0.001) and the concordance, ICC=0.74. The correlation between CCr values and the modified SE (standardised creatinine measurement) was r=0.68 (P<.001), and the concordance ICC=0.78. There was a very significant correlation between the elimination of sodium in a 24h urine (mEq/kg/24h) and the Na-Fractional-Excretion (EFNa): r=0.8 (P<.001). There was a correlation between the potassium elimination in 24h (mEq/kg/24h) and EFK: r=0.85 (P<.001). Between volume/min/1.73m² and the urine volume percent of GF was: r=0.88 (P<.001).

CONCLUSIONS

These equations provide valuable information of the state of the basal renal function without having to use a timed urine.

Concordance of the ions and GAP anion obtained by gasometry vs standard laboratory in critical care

OBJECTIVE

To evaluate the differences observed in ion and GAP anion determinations obtained by point-of-care (POC) blood gas versus laboratory biochemical testing, and to analyze the possible errors according to the limits of normality.

MATERIAL AND METHODS

A descriptive, cross-sectional retrospective study was made to assess concordance between two diagnostic tests in patients admitted to the Critical Care Unit of Ourense University Hospital Complex (Spain), between July and November 2015, involving at least one coinciding biochemical test and POC determination. Patients under 18years of age were excluded.

RESULTS

A total of 1,073 samples were analyzed. Lin's concordance correlation coefficients for sodium, potassium and chlorine were 0.87, 0.84 and 0.72, respectively. Kappa concordance of the normality limits for sodium, potassium and chlorine was 0.63, 0.74 and 0.32. The results indicated poor correlation of the anion GAP and null concordance between POC and biochemical testing, including the value corrected for albumin.

CONCLUSIONS

Poor concordance was observed between the ion values as determined by biochemistry and blood gases; the two methods are therefore not interchangeable. Kappa agreement with normality limits was good for sodium and potassium, and weak for chlorine. Possible validity was noted in orienting the classification within the ion limits, with the exception of chlorine. No agreement was recorded in relation to the anion GAP, even that corrected for albumin.

[How does salt intake influence blood pressure? Associated aetiopathogenic mechanisms]

Abundant evidence from epidemiological and experimental studies has established a link between salt and blood pressure. However, there is heterogeneity in the blood pressure responses of humans to changes in sodium intake. Those individuals in whom a severe, abrupt change in salt intake causes the least change in arterial pressure and are termed salt-resistant, whereas in those in whom this leads to large changes in blood pressure, are called salt sensitive. Classically, Guyton's theory of the pressure-natriuresis phenomenon has been accepted to explain the pressor effect of salt, as well as the fundamental role played by the different protein sodium transporters of the renal tubules. In recent years, new theories have emerged pointing to the possible role of the immune system and the existence of a third sodium store in the body as aetiopathogenic factors.