The choice of dialysate bicarbonate: do different concentrations make a difference?

Metabolic acidosis is a common complication of chronic kidney disease; it is typically caused by the accumulation of sulfate, phosphorus, and organic anions. Metabolic acidosis is correlated with several adverse outcomes, such as morbidity, hospitalization, and mortality. Thus, correction of metabolic acidosis is fundamental for the adequate management of many systemic complications of chronic kidney disease. In patients undergoing hemodialysis, acid-base homeostasis depends on many factors including the following: net acid production, amount of alkali given by the dialysate bath, duration of the interdialytic period, and residual diuresis, if any. Recent literature data suggest that the development of metabolic alkalosis after dialysis may contribute to adverse clinical outcomes. Our review is focused on the potential effects of different dialysate bicarbonate concentrations on hard outcomes such as mortality. Unfortunately, no randomized studies exist about this issue. Acid-base equilibrium is a complex and vital system whose regulation is impaired in chronic kidney disease. We await further studies to assess the extent to which acid-base status is a major determinant of overall survival in patients undergoing hemodialysis. For the present, the clinician should understand that target values for predialysis serum bicarbonate concentration have been established primarily based on observational studies and expert opinion. Based on this, we should keep the predialysis serum bicarbonate level at least at 22 mmol/l. Furthermore, a specific focus should be addressed by the attending nephrologist to the clinical and nutritional status of the major outliers on both the acid and alkaline sides of the curve.

Risk assessment of physico-chemical contaminants in groundwater of Pettavaithalai area, Tiruchirappalli, Tamilnadu - India.

A study was carried out in Pettavaithalai area to evaluate the current status of physico-chemical contaminants and their sources in groundwater. Groundwater samples collected from pettavaithalai area in 15 different stations were analyzed every alternative months over a period of two years from August 2000 to June 2002. A sugar mill is situated at the heart of the study area. Three profiles (profile A, B and C) were selected based on the direction in which the sugar mill effluent flows. In each profile five samples were collected from five different station at a regular distance of about 1 Km. The physico-chemical parameters such as pH, EC TDS, TH, NO3, SO4, PO4, Na, K, Ca, Mg, DO, BOD and COD have been analyzed. The results showed that among the three profiles, many of the estimated physico-chemical parameters of profile C were very high when compared to profile B and A which indicates the poor quality of the groundwater around this area.

Ground water contamination in the area adjoining zinc smelter effluent stream.

A preliminary survey of the area adjoining to zinc smelter effluent stream was undertaken to assess ground water contamination. Twenty-five ground water samples from the wells located in the study area were collected and grouped into nine groups based on their lateral and longitudinal position from the stream carrying the effluent discharged from zinc smelter, Debari- Udaipur. The study indicate that waters of wells situated in the vicinity of effluent stream (255m radius) were of medium salinity having higher levels of Ca and Mg and lower values of pH as compared to the waters of the reference wells situated far away from the effluent stream. The Fe, Zn, Cd, Cl, F and SO4 contents ofthe water from the wells located within 80m vicinity of the effluent stream were above the permissible limits for drinking purposes. Furthermore the Zn, Cl and SO4 levels in these waters were so high that they were even not suitable for irrigation, indicating a gradual encroachment of effluent into the native ground water.

[Bacteriologic studies of bicarbonate dialysate and suitable initial solutions]. / Bakteriologische Untersuchungen von Bicarbonatdialysat und entsprechenden Ausgangslösungen.

Dialysates for the haemodialysis are produced unsterile and usually contain bacteria. Own investigations of bicarbonate dialysate and adequate initial solutions comprised sterility tests, determinations of the germ count and germ tolerance experiments. Only the "acid concentrate" was sterile. In the other solutions Corynebacteria, Acinetobacter and Pseudomonas bacteria dominated as typical water germs. In the fresh reverse osmosis water and the bicarbonate dialysate as well as in the recently produced 35-mmolar and 1-molar NaHCO3-solution the germ count was in each case about 10(5)/l and did not change itself essentially at room temperature within 6 hours. The "acid concentrate" and at a lower level also the 1-molar NaHCO3-concentrate have an antibacterial effect. The reverse osmosis water is the main contamination source for the bicarbonate dialysate, the application of which within 6 hours seems worth being used on account of the low germ count.

Evaluation of the efficacy of Alka-Seltzer Effervescent in gastric acid neutralization.

A commercially available antacid, a mixture of sodium and potassium bicarbonates and citric acid (Alka-Seltzer Effervescent), was evaluated experimentally and clinically for its efficacy in neutralizing 0.1 N HCl and gastric contents. In an in vitro titration study, Alka-Seltzer Effervescent buffered 5-30 times the volume of HCl with a pH between 1.0 and 2.0 to above a pH of 2.5. In an isolated canine pulmonary lobe model, aspiration of the antacid or acid-antacid mixture caused only a mild increase in lobe weight and did not increase intrapulmonary shunting. In the clinical study, when the antacid was given 5-40 min before administration of general anesthesia in a group of patients for emergency surgery, the pH of the gastric contents in each patient was increased to above 4.0. This contrasts with the control group of patients, which showed 50% (P less than 0.05) of the patients were at risk when no antacid was administered. Preoperative administration of Alka-Seltzer effectively increases the pH of the gastric contents in patients undergoing emergency surgery.