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PubMed1977

[Influence of bicarbonate on the content of 2,3-DPG (bisdihydroglycerophosphate) in preserved erythrocytes].

Both whole blood in ACD-adenine-guanosine solution (PCV about 36%) and resuspensions of erythrocytes from EDTA-blood (PCV about 80%) were stored at 4 degrees C with an admixture of sodium bicarbonate. To the resuspensions simultaneously were added xylitol and inorganic phosphate. The erythrocyte concentration of 2,3-disphosphoglycerate in whole blood will be preserved the longer the more bicarbonate is added. Compared with whole blood in resuspensions of erythrocytes the preservation of 2,3-DPG is significantly prolonged, probably because xylitol was added. From these results and from literature data it is concluded that bicarbonate is fixed to metabolites of the pentose metabolism. The products of the fixation of bicarbonate may influence the 2,3-DPG metabolism of the erythrocytes.

Bicarbonates↗
PubMed1987

Bicarbonate versus acetate hemodialysis in ventilated patients.

Hemodynamic tolerance to bicarbonate versus acetate hemodialysis was studied in seven ventilated, critically ill patients, suffering from acute renal failure. Both kinds of hemodialysis were carried out with a recirculating dialysate delivery system and a relatively low blood flow (180 ml/min). Each patient underwent two hemodialysis procedures, one with bicarbonate and one with acetate, lasting for four hours. Ultrafiltration rates were kept below 250 ml/h and only biocompatible membranes with a relatively small surface area (Biospal 2400, Hospal, France) were used. Despite the mild hemodialysis conditions, hypotensive episodes with a mean blood pressure below 70 mmHg were observed in 3 out of 7 bicarbonate sessions and 4 out of 7 acetate sessions. Thus, we could not demonstrate a hemodynamic advantage of bicarbonate hemodialysis in this group of ventilated patients. This contrasts with other studies conducted in non-ventilated patients. Prevention of hypoxemia by mechanical ventilation and control of vascular tone by the use of vasoactive drugs may be of more clinical relevance than the kind of hemodialysis procedure that is used.

Acetates↗
PubMed1987

Failure of the serum CO2 determined by automation to estimate the plasma bicarbonate.

In the daily care of pulmonary disease patients, we have often encountered large differences in the bicarbonate value calculated from blood gas determination pCO2 and pH, and the serum CO2 obtained from the Dupont Automatic Clinical Analyzer (ACA). Realizing that many clinicians utilize the automated measurement of serum CO2 ([CO2]s) in place of blood gas determinations, we felt it necessary to analyze paired sets of ACA [CO2]s and blood gas bicarbonate values ([HCO3-]p) for variations which might lead to clinically significant differences in interpretation. A study of 1,841 patient samples, matched by date and within +/- 2 hours of sampling, and supported by a thorough chart review of 100 randomly selected patients, indicates that a statistically significant difference, which is unrelated to apparent changes in the patient clinical status, does exist. Evaluation of pK changes due to temperature failed to correct these differences in serum CO2 and plasma bicarbonate. Based on the limited information available in the literature, as well as the strict quality control measures utilized in the measuring of [CO2]s using the ACA method and the measurement of bicarbonate by blood gas determination, we have concluded that the differences in the [CO2]s and [HCO3-]p can only be related to erroneous assumptions about the method of measuring [CO2]s by the ACA or other automated methods as well as manual techniques of back titration.

Acid-Base Equilibrium↗
PubMed1988

Influence of sodium bicarbonate on sprint performance: relationship to dosage.

The purpose of this investigation was to determine the minimum oral dosage of bicarbonate needed to significantly elevate blood bicarbonate and the influence of induced alkalosis on performance in high-intensity, short-duration exercise. Nine endurance-trained cyclists performed four 2-min sprints on separate occasions using an isokinetic cycle ergometer (Fitron, Cybex, Inc.). One hour before each test, the cyclists consumed either a placebo (A), a solution of 0.10 g NaHCO3.kg-1 body weight (B), a solution of 0.15 g NaHCO3.kg-1 body weight (C), or a solution of 0.20 g NaHCO3.kg-1 body weight (D) in random order. Arterialized venous blood was taken before (PRE) and after (POST) ingestion, and 1, 3, 5, 10, and 15 min following the 2-min bike sprint. The results showed a significant increase in POST blood bicarbonate, and the elevation was incrementally related to the dosage. There was, however, no significant improvement in performance. Total work (mean +/- SE) for each treatment (N.m per 2 min) were: A, 47,267 (+/- 2,472); B, 47,004 (+/- 3,094); C, 46,312 (+/- 2,964); and D, 47,190 (+/- 2,621). The results of this study show that incremental doses of NaHCO3 of 0.20 g.kg-1 and below produce incremental elevations in blood bicarbonate but do not produce improvements in performance for a sprint bout lasting 2 min.

Acid-Base Equilibrium↗
PubMed1988

Determination of plasma bicarbonate of neonates in intensive care.

Most modern blood-gas analyzers are programmed to use the Henderson-Hasselbalch equation to calculate a value for plasma bicarbonate. It has been suggested, however, that among acutely ill patients, including newborns, these calculated values may be at variance with measured total CO2. To assess the clinical significance of such errors, we compared calculated bicarbonate with measured total CO2 in 79 blood samples from 40 babies in intensive care. The calculated bicarbonate values consistently exceeded the measured values by about 1.5 mmol/L. Of the errors, 94% were within the range -10% to +20%. When the systematic bias was removed, calculated and measured bicarbonate values agreed within +/- 3.30 mmol/L in 95% of cases. Because calculated values can be obtained much more quickly and frequently than laboratory measurements, we believe that these limits are clinically acceptable.

Bicarbonates↗
PubMed1987

Effect of sucralfate on gastroduodenal bicarbonate secretion and mucosal prostaglandin E2 metabolism.

The effect of sucralfate on gastroduodenal bicarbonate secretion has been examined using isolated amphibian mucosa. Significant increases in gastric bicarbonate secretory rate were seen following addition of 0.5 milligram sucralfate to the luminal solution. Duodenal alkali secretion was stimulated only by a higher concentration of 1 milligram. Pretreatment with indomethacin prevented the increases in gastric and duodenal bicarbonate secretion observed after sucralfate. Other experiments indicated that sucralfate caused stimulation of prostaglandin E2 formation by mucosal homogenates. These studies demonstrate that sucralfate is a potent stimulant of gastroduodenal bicarbonate secretion and that the action is dependent on mucosal prostaglandin formation. These effects are likely to play an important role in the mode of action of the drug.

Animals↗
PubMed1986

Acetate in predilution in bicarbonate.

Acetate in predilution in bicarbonate dialysis with AN69 S. The purpose of this work was to assess whether bicarbonate dialysis, with infusion of acetate in predilution, using an AN69-S filter, offered some advantage over bicarbonate and acetate dialysis. In a period of 16 months we analysed 11 patients with this method, comparing them with one group of 7 patients in bicarbonate dialysis and another of 11 in acetate dialysis. The following parameters were investigated: acid-basic balance, HCT, weight and the intradialytic symptoms. There was some improvement in both objective and subjective parameters in patients treated by this method compared to patients in the control groups and the results were lasting.

Acetates↗
PubMed1985

Effect of acetate and bicarbonate dialysis on cardiac performance and transmural myocardial perfusion in patients with renal failure.

The object of the present study was to assess the haemodynamic changes measured by impedance cardiography during acetate and bicarbonate dialysis in uraemic patients without cardiovascular diseases. It was demonstrated that the cardiac output increased significantly after 60 minutes during acetate dialysis compared with bicarbonate dialysis while the peripheral resistance decreased significantly during acetate dialysis. As estimated by the diastolic systolic pressure time index ratio myocardial perfusion fell significantly following acetate dialysis as compared to bicarbonate dialysis. It is concluded that the work of the heart increases during acetate dialysis. This involves risk of myocardial hypoperfusion. It is therefore recommended that bicarbonate dialysis is the choice for patients with unstable circulation and/or ischaemic heart disease.

Acetates↗
PubMed1985

Comparison of high and low sodium bicarbonate and acetate dialysis in stable chronic hemodialysis patients.

Eight stable center dialysis patients completed four, 10-week study periods in which either acetate or bicarbonate dialysis was used, each with high or low sodium concentration. During high sodium dialysis, blood pressure was better controlled, weight loss more easily tolerated and dialysis was most satisfactory from the patient's point-of-view with regard to dialysis-associated symptoms. Low sodium dialysis, whether with acetate or bicarbonate, was less satisfactory. In contrast to the beneficial effect of an increased sodium concentration, the use of bicarbonate instead of acetate appeared to make little difference either to the patient's symptoms, to the control of blood pressure or to changes in blood gases or biochemistry. Careful choice of dialysate sodium concentration appears to be important in lessening dialysis side-effects. Substitution of bicarbonate for acetate in chronic stable dialysis patients has comparatively little benefit and the choice can legitimately be made on the basis of cost and technical considerations.

Acetates↗
PubMed1985

[Secretin and bicarbonate secretion in probands and ulcer patients following bolus administration of hydrochloric acid into the duodenum].

Various amounts of hydrochloric acid (50, 100 and 200 ml) of two different concentrations (70- and 140 mmol/l) were rapidly instilled into the duodenum of eight healthy subjects and five duodenal ulcer patients. Secretin, gastrin and bicarbonate output were measured. Secretin release and bicarbonate secretion are dependent on acid load and not on acid concentration. There is a linear correlation between the amount of acid instilled into the duodenum and pancreatic bicarbonate output. After duodenal acidification duodenal ulcer patients released equal amounts of secretin and secreted as much bicarbonate as healthy subjects.

Adult↗
PubMed1979

Dialysance of acetate and bicarbonate: effect of ultrafiltration.

The dialysance of acetate and bicarbonate measured using a 1.8 M2 hollow fiber artificial kidney was quantitated both in vivo and in vitro. The diffusional transfers of acetate and bicarbonate were similar as would be expected from their almost identical ionic weights. However, ultrafiltration increased bicarbonate loss and decreased acetate uptake and at a TMP of 300 mm Hg the dialysance of bicarbonate was significantly greater than the dialysance of acetate. Therefore, ultrafiltration reduces the transfer of net base to the patient which impairs the correction of acidosis, and may contribute to clinical problems associated with ultrafiltration during hemodialysis.

Acetates↗
PubMed1984

Effect of long-term fasting of obese patients on pancreatic exocrine function, gastrointestinal hormones and bicarbonate concentration in plasma.

The CCK- and secretin stimulated pancreatic volume, bicarbonate and enzyme secretion was investigated before and during fasting for 20 days in 12 obese subjects. Pancreatic function tests were performed at the start of the fasting period and on the 10th and 20th day. In an additional and comparable group of 8 obese patients plasma concentrations of cholecystokinin (CCK), gastrin and insulin as well as metabolic parameters (bicarbonate, beta-OH-butyrate and free fatty acids) have been measured before and during total fasting. During three weeks of total fasting the average overweight of the patients undergoing pancreatic function tests was reduced from 49 to 31% (-11.5 +/- 1,5 kg). A significant reduction of volume, bicarbonate, trypsin and amylase secretion occurred already after 10 days of total fasting. After 20 days these parameters were further significantly reduced compared to the 10th day. All mentioned parameters were found at the lower limit of the normal range at the end of the fasting period at 20 days. The only exception being lipase secretion; the decrease of this enzyme was not significant at the 5% level. No significant reduction of basal plasma concentrations could be observed for CCK and gastrin during the course of total fasting. The plasma insulin levels were significantly reduced after 7 days whereas at 10 and 20 days insulin concentration was not significantly lowered compared to day 1. A small but significant decrease in the blood bicarbonate concentration could be observed after 7 days of fasting which remained constant up to the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxybutyric Acid↗
PubMed1983

[Bicarbonate hemodialysis. Pharmaceutical aspects].

Specific problems during fabrication of concentrated hemodialysis solutions containing bicarbonate arise because of the low solubility of sodium bicarbonate in water and the risk or precipitation of calcium, magnesium carbonates. These problems have been solved by the Pharmacie centrale by making 2 different concentrated solutions, the first one brinding the major essential elements, at the exclusion of bicarbonate, the second less concentrated, with bicarbonate and potassium gluconate, the latter complexing iron and so preventing precipitates of ferric carbonate. The various pharmaceutical steps are described in this paper: formulation, choice of raw materials and manufacturing processes, quality control.

Bicarbonates↗
PubMed1983

[Respiratory response and acid-base equilibrium in acetate dialysis and bicarbonate dialysis].

In order to elucidate the mechanisms responsible for the hypoxemia observed during acetate dialysis, but not found during bicarbonate dialysis, the authors studied ventilation, blood gases and their exchanges in the lungs and across the dialyzer on 9 patients. Oxygen consumption was similar both in acetate and bicarbonate dialysis. At the beginning of acetate dialysis, hypocapnia, due to CO2 losses through the dialyzer, causes hypoventilation and hypoxemia; afterwards, the worsening of acidosis (due to bicarbonate losses) stimulates ventilation, thus correcting the initial imbalance. Authors also hypothesize a pulmonary mechanism for CO2 "sparing" contributing to compensate CO2 losses through the dialyzer. The absence of hypoxemia during bicarbonate dialysis would be due to the absence of CO2 losses through the dialyzer.

Acetates↗
PubMed1980

Stability of carmustine in the presence of sodium bicarbonate.

The stability of carmustine in 5% dextrose injection and 0.9% sodium chloride injection, with and without added sodium bicarbonate, was studied at room temperature. Solutions of carmustine (0.1 mg/ml) in dextrose or saline with and without added sodium bicarbonate (1 meq/ml) were prepared. After 0, 15, 30, 60, and 90 minutes, aliquots of each test solution were analyzed for carmustine using the Bratton-Marshall test with absorbance at 540 nm. There was no significant decomposition of carmustine in dextrose or saline alone. However, the addition of sodium bicarbonate increased carmustine degradation; after 90 minutes, approximately 73% of the active drug remained. It is recommended that carmustine be neither admixed with nor administered piggyback with parenteral infusion solutions containing sodium bicarbonate.

Bicarbonates↗
PubMed1980

Effect of sodium bicarbonate and ammonium chloride ingestion in experimental gentamicin nephrotoxicity in rats.

To examine the possibility that gentamicin binding to renal tubular epithelium is electrostatic, the effect of sodium bicarbonate-induced alkaline diuresis and ammonium chloride administration on the course of gentamicin nephrotoxicity in male Fischer 344 rats was examined. After 14 days of gentamicin, sodium bicarbonate drinking animals did not differ significantly from tap water drinking controls in the degree of nephrotoxicity as determined by serum creatinine, in vitro para-aminohippurate and N-methylnicotinamide uptake, histology and renal cortical gentamicin concentrations. However, 7/10 sodium bicarbonate drinking animals had extensive intratubular renal calcifications as compared to 0/29 tap water drinkers. Ammonium chloride drinking animals had more severe toxicity than tap water drinking controls. We conclude that in our model, sodium bicarbonate administration does not reduce experimental gentamicin toxicity and is associated with intratubular calcification. Ammonium chloride potentiates gentamicin nephrotoxicity.

Ammonium Chloride↗
PubMed1980

Short term reversible modulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity in isolated epithelial cells from rat ileum. Regulation of phosphorylation dephosphorylation by bicarbonate.

In ileal epithelial cells isolated through incubation of gut loops in phosphate-buffered saline containing EDTA, 3-hydroxy-3-methylglutaryl coenzyme A reductase was found to exist prdominantly in an active (dephosphorylated) form. However, in cells obtained by scraping the intestine, the enzyme was mostly inactive (phosphorylated) and could be activated several-fold on incubation with a crude phosphatase preparation. Reductase activity in microsomes from ileal epithelial cells could be inactivated extensively by incubation with Mg . ATP in the absence of any exogenous factors. When cells isolated in phosphate-buffered saline were incubated in bicarbonate-containing buffers, there was a time-dependent decrease in the apparent activity of 3-hydroxy-3-methylglutaryl CoA reductase with little change in the total activity of the enzyme. On transferring the cells to a buffer without bicarbonate, the decrease in the apparent activity of the enzyme was fully reversed. There was no change in both the apparent and the total activities of reductase when cells were incubated in buffers lacking bicarbonate. Sterol synthetic rates in isolated intestinal cells were reflective of the fraction of reductase in the active form. These results strongly suggest the operation of a phosphorylation-dephosphorylation mechanism for short term modulation of 3-hydroxy-3-methylglutaryl CoA reductase activity in the intact mucosal cell. The bicarbonate anion appears to function as an activator of this modulation system.

Animals↗
PubMed1995

Treatment of Helicobacter pylori infection with omeprazole-amoxicillin combination therapy versus ranitidine/sodium bicarbonate-amoxicillin.

OBJECTIVES: Simpler, effective therapies to treat Helicobacter pylori infection are greatly needed. Omeprazole co-therapy apparently enhances effectiveness of some antimicrobials. Our objective in this study was to determine whether the apparent additional benefit provided by omeprazole to amoxicillin therapy could be equaled by a high dose of ranitidine plus sodium bicarbonate. METHODS: In a prospective randomized trial, we tested 1 g amoxicillin b.i.d. with either omeprazole 20 mg b.i.d., or high dose ranitidine (900 and 1800 mg) plus sodium bicarbonate tablets 650 t.i.d. (with meals) for 14 day. RESULTS: Fifty-two patients with documented H. pylori infection and peptic ulcer completed therapy. The cure rate with omeprazole and amoxicillin was poor (46%), with the 95% confidence interval (CI) = 25-67%. Ranitidine plus sodium bicarbonate was also poor (39% cure) with the 95% CI = 21.5-59% (p > 0.57). Average compliance was more than 92% for all three groups. Side effects were experienced in only two patients (stomatitis and mild diarrhea). CONCLUSION: Neither the omeprazole nor ranitidine plus bicarbonate plus amoxicillin therapies used here can be recommended for treatment of H. pylori infection.

Amoxicillin↗