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PubMed1992

Gastric tonometry in patients with sepsis. Effects of dobutamine infusions and packed red blood cell transfusions.

We wanted to determine the efficacy of dobutamine infusions and Prbc transfusions on splanchnic tissue oxygen utilization by measuring gastric pHi. Physiologic parameters and pHi measurements via the use of a gastric tonometer were obtained in 21 septic patients before and after the administration of a dobutamine infusion (5 micrograms/kg/min) or the transfusion of two units of Prbc. Subsets of measurements with normal (greater than 7.32) and with low (less than 7.32) pHi were separately analyzed for each intervention. In the dobutamine low pHi group, pHi increased significantly from 7.16 +/- 0.03 to 7.24 +/- 0.03 (n = 9, p less than 0.05). In contrast, pHi failed to increase in the Prbc low pHi subgroup (7.16 +/- 0.05 to 7.17 +/- 0.04 [n = 10, p greater than 0.80]). We conclude that dobutamine rather than Prbc transfusions should be administered to reverse gastric intramucosal acidosis.

Adult↗

PubMed1999

Tonometry to estimate intestinal perfusion in newborn piglets.

AIM: To determine the correlation between gastric intramucosal pH and superior mesenteric artery (SMA) flow in newborn piglets. METHODS: Fourteen newborn piglets were randomly assigned to either a control or to an epinephrine group which received 0,1,2,4,0 microg/kg/min of epinephrine for 60 minutes, each dose. Gastric tonometry was performed, SMA flow was measured, and intramucosal pH and the ratio of tonometer pCO(2) over arterial pCO(2) (rCO(2)) were calculated. RESULTS: Intramucosal pH decreased over time in both groups, but tended to be lower in the epinephrine group. With increasing dose of epinephrine, SMA flow decreased; this in turn increased rCO(2) (p = 0.04) with a tendency to decrease intramucosal pH (p = 0.06). CONCLUSIONS: Gastric tonometry may be useful in human neonates to evaluate gut ischaemia.

Animals↗

PubMed1976

The effect of long-term postoperative pentagastrin infusion on the maximal acid responses to pentagastrin in patients subjected to antrectomy.

Six duodenal ulcer patients subjected to antrectomy were given a continuous i.v. infusion of pentagastrin in a dose just below ED50 during 1 week in the immediate postoperative course. The peak acid output following stimulation with pentagastrin (PAOG) was determined preoperatively and 1 and 5 weeks postoperatively. PAOG was determined preoperatively and 1 week after antrectomy in a control group of 25 duodenal ulcer patients, and preoperatively and 5 weeks after antrectomy in another control group of 19 duodenal ulcer patients. One week post-antrectomy the PAOG was significantly less reduced (23%) in the pentagastrin infusion group than in the control group (46%). The reductions of PAOG 5 weeks post-antrectomy were not significantly different in the pentagastrin infusion group and the control group. The results show that the dysfunction of the parietal cells, reflected in a decreased capacity to secrete acid following antrectomy, can be partly reversed by continuous administration of pentagastrin in the immediate postoperative course. The results are interpreted as suggesting that antral gastrin in man, besides its property to stimulate acid secretion, also has a trophic effect on the parietal cells in analogy with the postulated trophic effect of antral gastrin in rats.

Adult↗

PubMed1975

A new hyrogen ion telemetry technique for evaluating gastroesophageal reflux.

A new pH capsule telemetry technique was used to measure the pH fluxes in the upper part of the gastrointestinal tract in normal volunteers, symptomatic patients and in those with hiatal herniorrhaphy during the preoperative and postoperative period. The Darvon-sized pH capsule is swallowed with ease and with minimal discomfort by a fasting patient. The pH of the surrounding media activates an FM radio transmitter within the capsule to emit a continuous radio signal which is converted by a receiver to a linear graph on a strip chart recorder. This pH capsule telemetry test is easy to perform on an ambulatory basis and allows an accurate and reproducible determination of the presence or absence of esophageal reflux in patients with and without a hiatal hernia. Its correlation with symptomatic reflux is higher than that found with a conventional gastrointestinal series examination. The technique allows a much clearer distinction to be made between those patients with real symptomatic esophagitis secondary to actual reflux and those with other esophageal, cardiac or pulmonary symptoms existing withour reflux. This study also reveals a consistently lower fasting gastric pH in patients with signs and symptoms of reflux than in normal individuals without reflux. The technique enabled a more accurate assessment of the efficacy of hiatal hernia repair and revealed a reduced degree of esophageal reflux in those patients who had undergone successful repair with fundic plication.

Clinical Trials as Topic↗

PubMed1989

Effect of diallyl sulfide on MNNG-induced nuclear aberrations and ornithine decarboxylase activity in the glandular stomach mucosa of the Wistar rat.

In previous investigations using models for gastrointestinal cancer, the anticarcinogenic effects of diallyl sulfide (DAS), an organosulfur compound present in garlic, was established. In this study, we conducted experiments to determine whether DAS modulates two biomarkers, nuclear aberrations (NA) and ornithine decarboxylase (ODC) activity, in the glandular stomach mucosa of the Wistar rat. N-methyl-N'-nitro-N-nitrosoguanidine (MN-NG) induced dose-related NA and ODC activity in the glandular stomach 24 h and 6 h, respectively, after oral intubation with the carcinogen. Either oral or parenteral pretreatment with DAS significantly reduced the MNNG induction of NA or ODC. Furthermore, the suppressions were observed to be dose dependent. These data suggest that DAS may potentially inhibit MNNG-induced gastric cancer. In view of recent epidemiologic evidence linking reduced risk for gastric cancer with increased consumption of allium vegetables, it is clear that DAS has pluripotent effects as an anticarcinogen, although studies addressing a mechanism of action have yet to be reported.

Allyl Compounds↗

PubMed1985

Prevention of acute stress bleeding with sucralfate, antacids, or cimetidine. A controlled study with pirenzepine as a basic medication.

In a prospective, controlled, randomized study of a prophylaxis for stress bleeding, 100 high-risk patients in an intensive care unit received, on a daily basis, 1 g of sucralfate every four hours, an antacid every two hours, or 2 g of cimetidine intravenously. All patients also received 50 mg of pirenzepine by intravenous infusion each day. Gastric pH was determined every eight hours. Bleeding was defined as macroscopically visible bleeding. The intragastric pH was less than 4 significantly more often in patients treated with sucralfate than in patients treated with the other agents, but stress bleeding occurred only in patients treated with cimetidine (n = 2) or antacids (n = 2). In the latter two treatment groups, the probability of bleeding correlated with the incidence of pH values below 4. No side effects of sucralfate therapy were observed. The results indicate that prophylactic treatment of stress bleeding with pirenzepine and sucralfate is at least as effective as combined treatment with pirenzepine and cimetidine or antacids.

Adult↗

PubMed1993

Application of dual radiotelemetric technique in studying drug-drug interaction between diclofenac sodium and ranitidine HCl in volunteers.

Drug-drug interaction between a commercial diclofenac sodium enteric-coated tablet (Voltaren; V) and a ranitidine HCl tablet (Zantac; Z) was evaluated using a dual radiotelemetric technique according to a randomized three-way Latin-Square crossover design balanced for carryover effects. V and Z were given either alone or in combination (Treatment V, Z, V/Z), with a 14-day washout period between treatments. Eighteen fasted subjects swallowed a tethered. Heidelberg pH capsule to provide continuous gastric pH. Then the assigned treatment drug and another Heidelberg pH capsule were given simultaneously. The free pH capsule provided information regarding gastric residence time (GRT). Serial blood samples were obtained for up to 12 hr after dosing and drug levels were determined by validated HPLC methods. Treatment effects on AUC, Cmax, Tmax, Tlag, Tmax-Tlag, and T1/2 were not significant except Cmax, which differed slightly for both V and Z when given in combination as compared to alone. Gastric residence times were 46, 33, and 51 min for Treatments V, Z, and V/Z, respectively. Gastric exposure of the enteric-coated tablet of diclofenac was estimated by pH values obtained from the tethered capsule. Median pH values at 3 and 15 min prior to gastric emptying were 3.8 and 4.9 for the combination treatment versus 2.1 and 2.7 for diclofenac alone. The results of this study indicated that there was minimal drug-drug interaction between diclofenac and ranitidine. The gastric pH range resulting from this study did not influence the oral absorption of enteric-coated diclofenac.

Adult↗

PubMed1994

Gastric alkalinization does not increase the risk of pneumonia in critically ill patients.

Nosocomial pneumonia remains an important determinant of hospital-acquired morbidity and mortality. Although therapy designed to prevent stress-induced gastritis has been effective at relieving upper gastrointestinal (GI) bleeding, the use of agents (histamine-2 receptor antagonists, antacids) that raise gastric pH have also been implicated as increasing the incidence of nosocomial pneumonia. Examination of two recently published meta-analyses investigating the role of gastric pH and nosocomial pneumonia and several individual studies show that raising gastric pH does not increase the incidence of nosocomial pneumonia. Importantly, those clinical trials that purport to show that raising gastric pH increases the incidence of nosocomial pneumonia have not been blinded studies and have failed to control for sites of enteral feeding and volume. Taken together, analysis of several clinical trials finds no compelling evidence for the concept that gastric alkalization increases the evidence of nosocomial pneumonia. Given the methodological flaws incurred in several previous studies, the optimal approach for preventing nosocomial pneumonia while preventing stress gastritis-induced upper (GI) bleeding remains to be identified.

Antacids↗

PubMed1997

Measurement of gastrointestinal intramucosal pH is a poor guide to tolerable levels of anemia during isovolemic hemodilution in a canine model of coronary stenosis.

OBJECTIVE: To determine the relationship between gastrointestinal intramucosal pH and myocardial oxygenation during isovolemic hemodilution in dogs with critical coronary artery stenoses. DESIGN: Prospective sequential evaluation of ileal intramucosal pH and regional myocardial function of a critically perfused area of myocardial tissue in a canine model of normovolemic hemodilution. SETTING: A research laboratory. SUBJECTS: Fifteen dogs. INTERVENTIONS: A micrometer snare was placed around a main coronary artery (8 left anterior descending artery, 7 right coronary artery). Three pairs of sonomicrometer crystals were placed in the heart to measure regional myocardial contraction. A gastrointestinal tonometer was placed in the ileum and used to measure luminal PCO2. This PCO2 value was used to calculate the ileal intramucosal pH. The animals underwent normovolemic hemodilution until myocardial ischemia occurred in the region supplied by the snared vessel. Measurements were continued for a further 40 minutes. MEASUREMENTS AND MAIN RESULTS: Following instrumentation, stabilization, and critical constriction of a coronary vessel, percentage changes in systolic shortening of myocardial tissue in the region of critical perfusion were determined every 20 minutes. Ileal intramucosal pH and commonly measured cardiovascular variables were determined at the same time points. Myocardial ischemia occurred after 80 minutes of hemodilution, when the mean (+/- SD) hemoglobin concentration had fallen from a baseline level of 123 +/- 18 g/L to 82 +/- 14 g/L (P < .01). From the start of hemodilution to 40 minutes after myocardial ischemia occurred, there were no significant changes in heart rate, cardiac output, oxygen consumption, arterial acid-base balance, or arterial PCO2. Oxygen delivery decreased by approximately 45% (5.99 +/- 1.66 to 3.41 +/- 0.90 mL/kg per minute; P < .01) but there were no changes in ileal intramucosal pH (7.31 +/- 0.08 to 7.30 +/- 0.08; P = .90). CONCLUSIONS: Myocardium compromised by coronary stenosis is more sensitive to normovolemic hemodilution-induced ischemia than the normally perfused gut mucosa. This limits the potential utilization of the measurement of gastrointestinal intramucosal pH as a guide to tolerable levels of anemia in critically ill patients.

Anemia↗

PubMed2001

Effect of coronary artery bypass grafting with gastroepiploic artery on gastric intramucosal pH and systemic inflammation.

BACKGROUND: The purpose of this study was to investigate the effect of coronary arterial bypass grafting (CABG) with gastroepiploic artery (GEA) on gastric intramucosal pH and systemic inflammation. METHODS DESIGN: retrospective study. SETTING: University hospital. PARTICIPANTS: 22 patients underwent CABG. INVESTIGATIONS: the GEA group (n=13) received CABG with the GEA graft. The non-GEA group (n=9) received conventional CABG without the GEA graft. MEASUREMENTS: gastric intramucosal pH (pHi) and carbon dioxide tension (PrCO(2)) were assessed by capnometric air tonometry. The difference between PrCO(2) and PaCO(2), PCO(2)-gap, was also determined. Systemic inflammatory responses were evaluated by serum interleukin-6 (IL-6) and leucocyte counts. Hemodynamics, oxygen delivery index (DO(2)I) and uptake index (VO(2)I) were monitored with catheters in the radial and pulmonary arteries (thermodilution). RESULTS: The duration of aortic cross-clamping and cardiopulmonary bypass was similar in both groups. Both groups did not show any significant difference in gastric pHi, PCO(2)-gap, systemic inflammation and hemodynamics. CONCLUSIONS: Our findings suggest that CABG using the GEA graft does not disturb gastric mucosal perfusion, and that laparotomy for the GEA graft does not aggravate systemic oxygen demand-supply imbalance or systemic inflammatory responses induced by hypothermic CPB. CABG with the GEA graft does not seem to pose an additional risk and is a safe technique compared with conventional CABG with regard to pHi and systemic inflammation.

Aged↗

PubMed1993

Gastric intramucosal acidosis in patients with chronic kidney failure.

BACKGROUND: Patients with chronic kidney failure have an increased incidence of gastrointestinal complications, particularly bleeding from the stomach. Diminished mucosal blood flow is thought to be an important etiologic factor for such bleeding. METHODS: Eleven patients with kidney failure on maintenance dialysis underwent placement of a gastric tonometer for the determination of gastric intramucosal pH (pHi) before and during dialysis. The arterial pH (pHa), calculated pHi, and pHa-pHi differences were compared with the results in a control group of seven normal volunteers. RESULTS: The patients with chronic kidney failure had a mean (+/- SD) pHa (7.36 +/- 0.04) similar to that found in seven control subjects (7.37 +/- 0.04). However, the gastric mucosal pH in the patients on dialysis (7.20 +/- 0.17) was lower than in the seven control subjects (7.38 +/- 0.06) (p < 0.01). A gastric mucosal pH thought to be predictive of either bleeding from stress ulceration (pHi < 7.32) or mucosal ischemia (pHi-pHa difference > 0.13) was found in nine (82%) of the patients with kidney failure and in only one (14%) of the control subjects (p < 0.001). CONCLUSIONS: This new preliminary finding suggests that the high incidence of gastric bleeding in chronic kidney failure may be related to mucosal ischemia.

Acidosis↗

PubMed1983

Effect of H2-receptor antagonists, cimetidine and YM-11170, on serum gastrin levels in lumen-perfused rats.

To determine whether cimetidine increases serum gastrin levels by elevation of intragastric pH or by other mechanisms, the effects of two different H2-receptor antagonists, cimetidine and YM-11170, on serum gastrin levels were compared in rats with controlled intragastric pH. When the intragastric pH was maintained between 4.5 and 5.5, 2-10 mumol/kg of cimetidine increased serum gastrin levels significantly, whereas no significant increase was observed after 0.02-0.1 mumol/kg of YM-11170. This occurred despite the same extent of inhibition of histamine-stimulated acid secretion as with cimetidine. When the intragastric pH was fixed at 5.5, the serum gastrin responses to cimetidine were significantly greater than to saline or YM-11170. Therefore, the increase in serum gastrin levels by cimetidine is due neither to the elevation of intragastric pH nor the result of H2-receptor blockade, but is probably due to a direct action to release gastrin.

Animals↗

PubMed1990

Ambulatory 24-hr pH monitoring of esophagus, fundus, and antrum. A new technique for simultaneous study of gastroesophageal and duodenogastric reflux.

A method for outpatient 24-hr simultaneous recording of pH in the distal esophagus, fundus, and antrum was developed in order to detect acid, alkaline, alkalacid gastroesophageal reflux, and duodenogastric reflux and to study these phenomena in patients complaining of gastroesophageal reflux and dyspepsia related symptoms. Two hundred ninety-four studies were performed in 42 healthy volunteers and 237 patients. Three-probe ambulatory 24-hr esophagogastric pH monitoring applicability, tolerability, and capability to determine a relationship between symptoms which occurred during the tests, gastroesophageal reflux, and duodenogastric reflux episodes were assessed. Eighty-nine percent of the three-probe esophagogastric pH studies were easily performed. The examination was tolerated well by 86.1% of the patients and poorly by 13.9%. A temporal correlation between symptoms and pH activities was recognized in 61.3% when the esophageal tracing was considered (acid gastroesophageal reflux recording) and in 95.6% when the three pH traces were simultaneously interpreted. Alkalacid gastroesophageal reflux and duodenogastric reflux total percentage times were significantly higher in patients complaining of dyspeptic symptoms than in patients only affected by typical gastroesophageal symptoms. Three-probe 24-hr ambulatory esophagogastric pH monitoring is a simple, well-tolerated test that should be routinely adopted for the study of patients complaining of unclear upper gastrointestinal tract symptomatology.

Adolescent↗

PubMed2006

Gastric longitudinal shortening may occur during gastric phase III activities in man.

BACKGROUND AND AIM: The aim of this study was to determine whether the gastric longitudinal shortening occurs during the gastric phase III in man. METHODS: Intragastric pH and gastroduodenal motility were simultaneously measured by means of a 24-h ambulatory recording system in 14 healthy volunteers. In nine subjects (group A), the catheter assembly was endoscopically clipped to the gastric mucosa with the middle transducer and the distal pH sensor in the antrum. In the remaining five subjects (group B), measurements were performed without securing the assembly. RESULTS: In 23 of the 25 gastrointestinal interdigestive migrating complexes in group A, the distal and middle transducers showed characteristic duodenal contractions (11-12 c.p.m.). Neutralization was noted at the distal pH sensor. Similar phenomena were observed during all 15 gastrointestinal interdigestive migrating complexes in group B. The catheter assemblies escaped into the duodenum despite the fact that they were secured to the stomach. This may be explained by gastric longitudinal shortening during gastric phase III activities. CONCLUSIONS: Studies of intragastric physiology with test catheters must take the effect of gastric longitudinal shortening during phase III into consideration.

Adult↗

PubMed1994

Gastric volume and pH in infants fed clear liquids and breast milk prior to surgery.

Recommendations for fasting intervals prior to anesthesia in pediatric patients have changed in recent years. There are few data concerning infants less than 1 yr of age fed clear liquids or breast milk before surgery. We performed a prospective, blinded study to determine residual gastric volumes and pH in this population. Approximately 2 h prior to surgery, 46 formula-fed infants ingested up to 8 oz of clear liquids and 24 breast-fed infants nursed as usual. After induction of general anesthesia and tracheal intubation, gastric fluid samples were aspirated by a blinded researcher who measured gastric volume and pH. Sufficient gastric fluid for analysis was obtained from 10 (22%) of the infants fed clear liquids and 8 (33%) of the breast-fed infants. For the group fed clear liquids, the residual gastric volume was 0.3 +/- 0.9 mL/kg and the pH was 2.1 +/- 1.4. Eight (17%) had gastric volumes > or = 0.4 mL/kg, 2 (4%) had gastric volumes > or = 1 mL/kg, and 9 (90%) of 10 measured had pH < or = 2.5. In the breast-fed group the residual gastric volume was 0.71 +/- 1.1 mL/kg (P = not significant [NS]) and the pH was 2.6 +/- 1 (P = NS). All eight (33%) breast-fed infants had gastric volumes > or = 0.4 mL/kg (P = NS), seven (29%) had gastric volumes > or = 1 mL/kg (P = 0.03), and four (50%) of eight measured had pH < or = 2.5 (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗

PubMed1993

Regulation of gastroduodenal bicarbonate secretion by capsaicin-sensitive sensory neurons in rats.

We investigated the role of capsaicin-sensitive sensory neurons in regulation of gastroduodenal HCO3- secretion in anesthetized rats. The stomach (under acid inhibition by omeprazole 60 mg/kg i.p.) or the duodenum was perfused with saline (pH 4.5) and HCO3- output was determined by pH change in the perfusate. Both the duodenum and stomach responded to prostaglandin E2 (PGE2; 300 micrograms/kg i.v.) or luminal acid by a significant increase in pH and HCO3- output. These tissues also responded to luminal application of capsaicin (0.3-6 mg/ml for 30 min), resulting in a significant increase of pH and HCO3- output in a concentration-related manner. The HCO3- stimulatory action of capsaicin was markedly attenuated by functional ablation of capsaicin-sensitive sensory neurons, significantly mitigated by indomethacin, and exhibited tachyphylaxis after repeated application at a high concentration. The acid-induced pH and HCO3- responses were also significantly mitigated by sensory deafferentation and by indomethacin, whereas those induced by PGE2 remained unaffected. In addition, defunctionalization of these sensory nerves resulted in macroscopically visible damage in the duodenum when acid secretion was concomitantly stimulated by histamine. We conclude that capsaicin-sensitive sensory neurons may be involved in the regulatory mechanism of gastroduodenal HCO3- secretion and contribute to protection of the mucosa against acid. Endogenous PGs may be involved in the HCO3- stimulatory action mediated by capsaicin-sensitive sensory neurons.

Afferent Pathways↗

PubMed1994

Gastric tonometry in multiple trauma patients.

Splanchnic ischemia, leading to intestinal mucosal damage, is thought to be common in patients after severe trauma. The adequacy of mucosal oxygenation can indirectly be determined by gastric intramucosal pH (pHi) measurement. We prospectively examined the posttraumatic gastric pHi values in 15 multiple trauma patients. In all patients gastric pHi was measured using a tonometer via the nasogastric route. A pHi value < or = 7.32 was used to differentiate between normal and low gastric pHi. Six hours after the injury four patients showed abnormally low pHi levels. Four other patients with normal initial pHi values exhibited low pHi values during one or more of the next measuring periods. Three of these eight patients developed major complications (two, ARDS) and two of them subsequently died. The seven remaining patients never had abnormal pHi levels and all patients had an uncomplicated recovery. Although intestinal ischemia was expected to be a common condition in multiple trauma patients, no consistent pattern of abnormal pHi measurements in the direct posttraumatic course could be discovered. No correlation was found between initial pHi values (at 6 hours) and ISS, shock, and lactic acidosis or APACHE II scores on admission. It is concluded that monitoring gastric pHi is useful in severely injured patients admitted to the ICU.

Adolescent↗

PubMed1975

Effect of rising intragastric pH induced by several antacids on serum gastrin concentrations in duodenal ulcer patients and in a control group.

The interrelationship of the effects of antacids and of rising intragastric pH on serum gastrin levels was examined by comparing the effect of three antacids (Mg(OH)2Al(OH)3, and CaCO3), and their nonbuffering chloride compounds (MgCl2, AlCl3, and CaCl2), on serum gastrin and intragastric pH in duodenal ulcer patients. In the case of calcium, the effect of CaCl2 with a pH of 10, and in another group, CaCl2 with a pH of 2, was studied. In the case of magnesium, a control group was also investigated. In another group, the effect of a nonionized suspension (BaSO4) was studied in order to assess the contribution of intragastric volume. Serum gastrin was determined radioimmunologically, and pH measurements were performed in vitro using a glass electrode. Serum gastrin concentrations rose significantly whenever intragastric pH was raised. Serum gastrin also rose after MgCl2, AlCl3, and CaCl2 with a pH of 2, when intragastric pH was not significantly altered. This rise, however, was significantly smaller than after administration of the antacids, except in the MgCl2-Mg(OH)2 and in the CaCl2 pH 10-CaCO3 groups. No significant rise of serum gastrin levels was observed after BaSO4. In nonulcer subjects, gastrin response was smaller than in the duodenal ulcer patients. The results suggest that administration of nonbuffering Mg-, Al-, and Ca-chlorides leads to elevated serum gastrin levels in duodenal ulcer patients; rising intragastric pH, however, exerts an additional serum gastrin response.

Adult↗