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At least 199 records · Page 11Linked to original sources
PubMed1985

Effect of selective PEEP on pulmonary blood flow following unilateral hydrochloric acid aspiration in the dog.

We investigated the effect of unilateral or bilateral positive end-expiratory pressure (PEEP) on pulmonary perfusion in 12 dogs with a hydrochloric acid aspiration injury of the left lung. The lungs were ventilated separately and PEEP was applied to the left lung at 10 cmH2O (1.0 kPa) in six and at 15 cmH2O (1.5 kPa) in six others. Measurements of the right and left pulmonary arterial blood flows (QR and QL) and venous admixture were made before, during and after PEEP. After this study, 5 and 10 cmH2O (0.5 and 1.0 kPa) PEEP were applied to both lungs in six dogs and measurements were repeated. Following the application of PEEP to the left lung, a significant decrease in QL and increase in QR were observed. However, the application of PEEP to both lungs was followed by significant decreases in both QL and QR. The cardiac output decreased slightly during unilateral PEEP and markedly during bilateral PEEP. The venous admixture decreased significantly during PEEP in all the groups. These findings indicate that selective PEEP causes a transfer of pulmonary blood flow from the injured lung to the normal lung, improving ventilation-perfusion inequality, and improves gas exchange without impeding oxygen delivery.

Animals↗
PubMed1975

A study of the effectiveness of calcined magnesite as a neutralizing agent for hydrochloric acid in the diet of sheep.

1. Five experimental diets were offered ad lib. for 21 d to five sheep in a 5 x 5 Latin-square design experiment as follows: pelleted grass meal alone (control); pelleted grass meal plus hydrochloric acid (470 mmol/kg dry matter (OM); pelleted grass meal plus 470 mmol HCl/kg DM and either an equivalent amount of calcined magnesite (MgO) (235 mmol/kg DM) or twice the amount (470 mmol MgO/kg DM); pelleted grass meal plus 470 mmol MgO/kg DM. 2. MgO supplementation partly prevented the reduction in food intake caused by HCl, being more effective at the low than at the high level. When fed alone, the high level of MgO had a slight adverse effect on food intake. 3. There was no significant treatment effect on either the pH or volatile fatty acid concentrations of rumen fluid. MgO supplementation was only slightly effective in preventing the metabolic acidosis caused by HCl supplementation, as indicated by blood and urine acid-base measurements. 4. With the MgO-supplemented diets, values for the faecal and urinary excretion of magnesium were approximately 70 and 10% respectively of Mg intake and were not significantly affected by HCl supplementation. For rumen fluid, the water-soluble Mg concentration as a percentage of the total Mg concentration was similar for each treatment, approximately 90%. For faeces, the corresponding value was also similar for each treatment, approximately 30%. 5. MgO supplementation altered the effect of dietary HCl on faecal calcium excretion and on the balance of Ca, but did not alter its effect on urinary Ca excretion. 6. It is concluded that the beneficial effect of MgO supplementation on the intake of the HCl-treated diet was related more to its influence on dietary pH than on conditions in the rumen or the acid-base balance of the sheep.

Acidosis↗
PubMed1986

Cholinergic influence on duodenal bicarbonate response to hydrochloric acid perfusion in the conscious rat.

Present information suggests that endogenous prostaglandins, hormonal factors, and neuropeptides participate in the regulation of duodenal bicarbonate secretion in response to luminal hydrochloric acid. The purpose of this study was to examine the effects of cholinergic antagonists and agonists on basal and acid-stimulated bicarbonate secretion in the proximal duodenum of the conscious rat. The basal bicarbonate secretion, 9 mumol X cm-1 X h-1, increased to 21 +/- 3 mumol X cm-1 X h-1 after 5 min of exposure to 150 mM HCl and remained significantly elevated for more than 3.5 h. The muscarinic blocker atropine, 0.5 mg X kg-1, reduced the acid-stimulated bicarbonate response by a third, and higher doses did not increase the inhibition. The ganglionic blocker hexamethonium, 10-20 mg X kg-1, suppressed in a dose-related manner the alkaline response by maximally one half. The opioid inhibitor naloxone was also an effective inhibitor. Hexamethonium, but not atropine, inhibited the basal duodenal bicarbonate secretion, which was unaffected by graded doses of the cholinergic agonists bethanechol and carbachol. We conclude that cholinergic nicotinic activity participates in maintaining basal duodenal bicarbonate secretion in the conscious rat. The bicarbonate response to luminal 150 mM HCl is partially dependent on cholinergic sites, but activation of such sites is not a single final step, since cholinergic agonists failed to elevate bicarbonate secretion from basal.

Animals↗
PubMed2004

[Chewing gum Dirol effect upon the status of oral cavity and gastric acid secretion in patients with hypersecretion of hydrochloric acid].

The purpose of our research was to learn the efficacy of the Dirol chewing gum upon the condition of the oral cavity and the stomach acidity in patients with hyperchlorhydratic type of secretion. It has been estimated that correct usage of chewing gum by patients with hyperacidity of the stomach in a month after its administration decreases the level of gastric acidity to a normal one. Thus, it has been proved that the Dirol chewing gum favorably changes the condition of oral cavity both from hygienic point of view, acido-alkaline balance and saliva condition.

Adolescent↗
PubMed2006

Sequential soil washing techniques using hydrochloric acid and sodium hydroxide for remediating arsenic-contaminated soils in abandoned iron-ore mines.

Sequential washing techniques using single or dual agents [sodium hydroxide (NaOH) and hydrochloric acid (HCl) solutions] were applied to arsenic-contaminated soils in an abandoned iron-ore mine area. We investigated the best remediation strategies to maximize arsenic removal efficiency for both soils and arsenic-containing washing solution through conducting a series of batch experiments. Based on the results of a sequential extraction procedure, most arsenic prevails in Fe-As precipitates or coprecipitates, and iron exists mostly in the crystalline forms of iron oxide. Soil washing by use of a single agent was not effective in remediating arsenic-contaminated soils because arsenic extractions determined by the Korean standard test (KST) methods for washed soils were not lower than 6mg kg(-1) in all experimental conditions. The results of X-ray diffraction (XRD) indicated that iron-ore fines produced mobile colloids through coagulation and flocculation in water contacting the soils, containing dissolved arsenic and fine particles of ferric arsenate-coprecipitated silicate. The first washing step using 0.2M HCl was mostly effective in increasing the cationic hydrolysis of amorphous ferrihydrite, inducing high removal of arsenic. Thus, the removal step of arsenic-containing flocs can lower arsenic extractions (KST methods) of washed soils. Among several washing trials, alternative sequential washing using 0.2M HCl followed by 1M HCl (second step) and 1M NaOH solution (third step) showed reliable and lower values of arsenic extractions (KST methods) of washed soils. This washing method can satisfy the arsenic regulation of washed soil for reuse or safe disposal application. The kinetic data of washing tests revealed that dissolved arsenic was easily readsorbed into remaining soils at a low pH. This result might have occurred due to dominant species of positively charged crystalline iron oxides characterized through the sequential extraction procedure. However, alkaline extraction using NaOH was effective in removing arsenic readsorbed onto the surface of crystalline minerals. This is because of the ligand displacement reaction of hydroxyl ions with arsenic species and high pH conditions that can prevent readsorption of arsenic.

Arsenic↗
PubMed1998

Survival of Escherichia coli O157:H7 in synthetic gastric fluid after cold and acid habituation in apple juice or trypticase soy broth acidified with hydrochloric acid or organic acids.

Extreme acid tolerance of Escherichia coli O157:H7 has raised doubts about the safety of acidic foods. This study examined whether prior storage in acidic and/or cold conditions enhanced survival of E. coli O157:H7 in synthetic gastric fluid (SGF). Three E. coli O157:H7 strains were stored in trypticase soy broth (TSB; acidified with HCl, malic acid, citric acid, or lactic acid) or pH 3.5 and 6.5 (nonacidic control) apple juice at 4 and 21 degrees C for < or = 7 days and then were incubated in pH 2.5 SGF at 37 degrees C for 4 h. Cells survived better in apple juice than in TSB containing organic acids, suggesting that juice constituents other than organic acids protect E. coli O157:H7. Refrigeration combined with low pH best protected cells in apple juice and acidified TSB, but, compared to the nonacidic control, only acidified TSB enhanced subsequent survival in pH 2.5 SGF. Equal survival in SGF occurred after storage in pH 3.5 or 6.5 apple juice at 4 degrees C, suggesting that low temperature alone in apple juice enhanced acid tolerance. Two strains stored at 4 degrees C in TSB containing malic or citric acid subsequently survived better in SGF than cells stored in nonacidified TSB but poorer than cells stored in the presence of HCl. These differences reflect the higher pKa of these organic acids. However, subsequent survival of these strains in SGF was poorer after refrigerated storage in apple juice than in TSB containing citric or malic acids. Cells stored in lactic acid were most likely to be completely eliminated upon transfer to SGF. Differences in survival in storage media or SGF related to strain, storage conditions, or acidifier were consistent and often statistically significant (P < 0.05). Although the survival of E. coli O157:H7 in refrigerated acidic beverages may not be affected by the type of acidifier used, the subsequent survival in SGF of this pathogen may be critically dependent on this factor.

Beverages↗
PubMed2001

Intraluminal modulation of gastric sensitivity to distension: effects of hydrochloric acid and meal.

Conscious sensations in response to gut distensions may be modulated by temporospatial interactions among different stimuli. This study investigated whether symptoms induced by gastric distension may be modified by hydrochloric acid (HCl) gastric infusion and meal ingestion. In nine healthy subjects, fixed pressure (isobaric) and fixed volume (isovolumetric) distensions were performed during continuous (4 ml/min) intragastric saline or HCl infusion, during fasting and after meal ingestion, until the maximal distension step defined as discomfort or a predefined maximal volume. During fasting isobaric distensions, the maximal distension step was significantly decreased during HCl compared with saline. The intragastric volumes were not significantly different, but the wall tension was significantly lower during HCl than saline. HCl increased gastric compliance. Meal ingestion relaxed the stomach and decreased the pressure at the maximal distension step during saline, but HCl did not further decrease it compared with fasting. During isovolumetric distensions, HCl also increased gastric compliance, but in both fasted and fed states it did not modify the maximal distension steps. In conclusion, sensations in response to gastric isobaric distensions, but not to isovolumetric distensions, are influenced by gastric acid infusion and meal ingestion. The effects of HCl might be related to a sensitization of mucosal mechanoreceptors.

Adult↗
PubMed1991

[Effect of superimposed high frequency oscillation on pulmonary edema induced by intrapulmonary injection of hydrochloric acid in dogs].

Effect of superimposed high frequency oscillatory ventilation on pulmonary gas exchange was investigated in seven anesthetized and paralyzed dogs with pulmonary edema induced by intrapulmonary injection of hydrochloric acid. Efficacy of the ventilatory modes (HFO:6 Hz and 12 Hz) was evaluated observing changes in ventilation-perfusion mismatch, which was demonstrated by using six inert gas elimination method. The ventilation with 6 Hz HFO had no significant effect on PaO2, true shunt, and perfusion distribution. With 12 Hz HFO, PaO2 showed a tendency to increase from 57 +/- 18 mmHg at IPPV to 144 +/- 117 mmHg (0.05 less than P less than .01), and the true shunt decreased from 42.2 +/- 29.0% at IPPV to 16.6 +/- 25.8% (P less than 0.05). However, no change appeared in the perfusion distribution. During the ventilation with 12 Hz HFO increased mean airway pressure produces a PEEP-like effect, which may improve the pulmonary gas exchange by opening small airways, namely a decrease in the true shunt rather than an improvement in the ventilation-perfusion maldistribution.

Animals↗
PubMed1985

Action of hydrochloric acid on aluminum hydroxide-magnesium hydroxide gels and magaldrate: 27Al NMR and pH-stat studies.

Neutralization of mixtures of aluminum hydroxide-magnesium hydroxide gels and of magaldrate by hydrochloric acid were studied by 27Al NMR under conditions of both equilibrium and kinetic control. Under conditions where equilibrium has been attained, an aluminum NMR signal is detectable for suspensions of the mixed gels and magaldrate only after enough acid has been added to exhaust the acid-neutralizing capacity of the magnesium hydroxide. Mixed gels seem to form several soluble aluminum-containing species as neutralization proceeds. Under the conditions of the modified Beekman neutralization procedure, in which the species concentrations reflect neutralization kinetics, mixed gels show a sharp burst of the hexaaquoaluminum cation as acid is added followed by a slow loss of that cation from solution and an accompanying slow rise in pH. Magaldrate shows a steady increase in the hexaaquoaluminum cation with added acid. Differences between magaldrate and mixed gels are also apparent in pH-stat titrations in which magaldrate displays a biphasic response, contrasting to the two burst phases with an intervening lag phase observed for mixed gels. The results of the 27Al NMR and pH-stat titrations are consistent with the hypotheses that magaldrate is a homogeneous substance with a hydrotalcite-like structure and that mixed gels consist of a magnesium hydroxide core surrounded by aluminum hydroxide.

Aluminum↗
PubMed1989

Hydrochloric acid infusion for treatment of metabolic alkalosis associated with respiratory acidosis.

Hypercapnia due to respiratory failure can be more severe when accompanied by coexistent metabolic alkalosis. We therefore tested the hypothesis that hydrochloric acid (HCl) infusion could improve PaCO2 in 15 critically ill patients admitted with mixed respiratory acidosis and metabolic alkalosis, and a pH of between 7.35 and 7.45. HCl was infused at a constant rate of 25 mmol/h until the bicarbonate concentration decreased less than 26 mmol/L, or until the pH decreased less than 7.35 (initial pH greater than 7.40) or 7.30 (initial pH less than 7.40). Administration of 170 +/- 53 mmol of HCl decreased the bicarbonate concentration from 34 +/- 3 to 25 +/- 2 mmol/L (p less than .001), the pH from 7.41 +/- 0.03 to 7.33 +/- 0.02 (p less than .001), and the PaCO2 from 54 +/- 8 to 48 +/- 8 torr (p less than .001). Postinfusion PaCO2 could be predicted accurately from the initial status of the patients (r = .95, p less than .001) except in one patient with fixed hypercapnia. PaCO2 increased from 77 +/- 19 to 94 +/- 24 torr (p less than .001) and PaO2/PAO2 increased from 59 +/- 17 to 66 +/- 17% (p less than .001). The effects of HCl were still present 12 h after the end of the infusion. No complications related to the acid infusion were noted. These results indicate that, even in the absence of alkalemia, active correction of metabolic alkalosis by HCl infusion can improve CO2 and oxygen exchange in critically ill patients with mixed respiratory acidosis and metabolic alkalosis.

Acidosis, Respiratory↗
PubMed1989

[Effect of endotracheal instillation of hydrochloric acid on the contents of alveolar surfactant in rats].

Aspiration of gastric contents to the lung is a cause of Adult Respiration Distress syndrome. We studied the effects of endotracheal instillation of hydrochloric acid (2 ml/kg, 0.1 N solution) in anesthetized rats who were sacrificed 4 or 48 hr later. A control group received 0.9% saline solution instead. Total protein, phospholipids, disaturated phosphatidylcholine (DSPC) and number of cells were determined in the bronchoalveolar lavage fluid. Histologic studies were performed in one rat in each group. HCl caused edema and inflammatory reaction characterized by a rise in protein and cells in the bronchoalveolar fluid 48 hr after endotracheal instillation. This was associated with an increase in total phospholipid and in DSPC. Therefore, the inflammatory response to HCl is associated to an increase in alveolar surfactant 48 hr after instillation.

Animals↗
PubMedDate not supplied

Treatment of central venous catheter occlusions with ethanol and hydrochloric acid.

BACKGROUND: Occluded central venous lines (CVLs) is a major problem in pediatric patients. METHODS: To relieve obstructed catheters, infusions of ethanol (up to 3 mL of a 70% solution) for presumed lipid occlusions and hydrochloric acid (HCl, 0.1 N, up to 3 mL) for presumed mineral and drug precipitates were given in an attempt to relieve obstructed catheters. RESULTS: Patency was restored in 34 of 39 occluded catheters over an 18-month period. CONCLUSIONS: Clearing occluded CVLs with ethanol and HCl is not only beneficial to the patient but also offers considerable cost savings compared to CVL replacement.

Catheterization, Central Venous↗