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Biomedical subjects

C Heinrich

Publications and source records attributed to C Heinrich.

31 records · Page 2Linked to original sources
PubMed1989

Relation between fasting antroduodenal motility and transpyloric fluid movements.

The effect of fasting antroduodenal motility on duodenogastric fluid movements was studied in 12 healthy volunteers. Antroduodenal motility was recorded using a multilumen manometry tube. Gastric emptying and secretion and the duodenogastric reflux of bile acids and marker were measured simultaneously by means of a marker dilution technique. Gastric emptying and acid secretion were higher in phase II than in phase I of the fasting motor activity cycle [median (range) 1.74 (1.2-4.2) ml/min vs. 0.90 (0.0-2.4) ml/min and 63.5 (6.4-115.0) vs. 37.9 (5.8-86.4) mumol/min, P less than 0.01]. The duodenogastric reflux rates of bile acids and marker were similar in all phases and showed large intra- and interindividual variations. There was no correlation between antroduodenal coordination during phase II motility and gastric emptying and duodenogastric reflux. It is concluded that the interdigestive motility pattern has moderate effects on fasting emptying of liquid gastric contents and on gastric secretion but no effects on duodenogastric reflux.

Adult↗
PubMed1989

Intragastric bile acid concentrations in critically ill, artificially ventilated patients.

Bile acids have experimentally been found to damage the gastric mucosa and, thus, may be involved in stress lesion pathogenesis. We therefore measured intragastric bile acid concentrations in 26 critically ill, artificially ventilated patients. The control group consisted of eight healthy volunteers, whose treatment was similar to that of the patients with respect to bed rest, enteral feeding, and administration of H2-blockers. Gastric contents were aspirated via a gastric tube every hour for 24 h. Patients had higher intragastric bile acid concentrations than healthy controls, whether fasting [median 1.3 mmol/L (range 0.7-2.5) versus 0.3 (0.2-0.5) (p less than 0.05)] or fed via a gastric tube [1.3 (0.4-4.0) versus 0.4 (0.2-0.7) (p less than 0.05)]. Physiotherapy, nursing, and drugs (opiates, benzodiazepines, dopamine, pirenzepine, and metoclopramide) had no detectable influence on intragastric bile acid concentrations and pH in patients. We conclude that patients at risk to develop stress lesions have largely increased gastric bile acid concentrations that probably are due to increased duodenogastric reflux. This might be relevant for stress lesion pathogenesis.

Adult↗
PubMed1989

Is long-term esophageal pH monitoring of clinical value?

Two hundred eighty-nine patients with various chest symptoms were studied by interview for the presence and type of symptoms, and by long-term esophageal pH monitoring for acid reflux. One hundred eighty of the patients also had upper gastrointestinal endoscopy. There was significant correlation between the results of all three methods. pH monitoring was more sensitive (92.9% vs. 81.0%) and specific (41.3% vs. 23.9%), and classified more patients correctly (55.6% vs. 37.2%), than an interview by an experienced gastroenterologist when esophageal erosions were regarded as "gold standard" for pathologic reflux. Of all patients, 31.5% had unclear symptoms and therefore could not be diagnosed by interview alone. Forty nine percent of these had pathologic reflux on pH monitoring. Among the patients, 72.3% who had symptoms typical of reflux disease also had a pathologic result at pH monitoring. It is concluded that most patients with unambiguous symptoms of esophageal reflux can correctly be diagnosed by interview, but that esophageal pH monitoring has a role in the management of patients with less characteristic chest symptoms.

Adult↗
PubMed1988

Effects of albuterol (salbutamol) on esophageal motility and gastroesophageal reflux in healthy volunteers.

Orally or intravenously administered beta 2-adrenergic drugs have been found to inhibit esophageal motor function. Since inhalation of these drugs results in less systemic side effects, the present double-blind study was designed to investigate the influence of inhalation of the beta 2-adrenergic agonist albuterol (salbutamol) on esophageal motor function and gastroesophageal reflux in ten healthy volunteers. Esophageal motor function was recorded using a pneumohydraulically perfused multilumen manometry tube. Twenty-four-hour pH profiles were measured while the volunteers were ambulatory using a combined glass electrode connected to a portable recorder. Inhalation decreased neither lower esophageal sphincter pressure nor esophageal peristaltic amplitudes. Gastroesophageal reflux was similar on both occasions during inhalation of albuterol (3.1% [range, 1.0% to 25.5%] median upright time, with esophageal pH less than 4; and 0.1% [range, 0.0% to 10.7%] supine time) and during placebo treatment (3.6% [range, 1.6% to 19.8%] upright and 0.0% [range, 0.0% to 2.5%] supine time). Our data support the study of inhalation of beta 2-adrenergic drugs in asthmatic patients with accompanying gastroesophageal reflux.

Administration, Inhalation↗
PubMed1988

Balanced anesthesia and patient-controlled postoperative analgesia with fentanyl: minimum effective concentrations, accumulation and acute tolerance.

Minimum effective fentanyl concentrations (MEC) were determined in 230 ASA I-III patients undergoing a variety of elective surgical procedures under balanced anesthesia, and in 40 patients recovering from comparable operations and anesthesia during postoperative intravenous self-administration of fentanyl (demand dose 34.5 micrograms) by means of the On-Demand Analgesia Computer. Following induction of anesthesia with fentanyl 4 micrograms/kg, repetitive fentanyl reinjections (0.1-0.2 mg) were given intraoperatively whenever systolic blood pressure or pulse rate increased to more than 20% of preinduction values, resulting in an intraoperative fentanyl consumption of 4.2 +/- 1.2 micrograms/kg/h. Duration of postoperative patient-controlled analgesia (PCA) was 20.2 +/- 4.3 h during which time 15.5 +/- 12.9 demands per patient were registered, resulting in a postoperative fentanyl consumption of 0.46 +/- 0.35 micrograms/kg/h. MECs appeared to be log-normally distributed (intra-operative median 2.6 ng/ml, range 0.2-36.6; postoperative median 1.2 ng/ml, range 0.2-8.0). Mean intra- and interindividual variability in MEC was 37% intraoperatively or 27% postoperatively, and 68% or 63%, respectively. There was no obvious correlation between postoperative fentanyl consumption or individual mean MEC and analgesic efficacy, which was generally described as superior to conventional pain treatment. Individual MECs increased gradually during anesthesia (mean slope 0.0191 ng/ml/min) but decreased under PCA conditions (-0.0008 ng/ml/min); difference not significant. While the postoperative decrease could be explained by diminishing pain intensity during the observation period, the slight intraoperative increase is discussed as acute tolerance rather than as accumulation. It is concluded that repetitive fentanyl injections as indicated by clinical needs will not lead to relevant accumulation in serum, and that analgesic therapy should be individualized both intra- and postoperatively.

Adult↗
PubMed1987

Optimal thresholds, sensitivity, and specificity of long-term pH-metry for the detection of gastroesophageal reflux disease.

Long-term esophageal pH-metry has become the preferred test to quantify acid gastroesophageal reflux, but its accuracy in separating physiologic from pathological reflux is not well defined. To establish optimal thresholds of 24-h pH-metry, we studied 45 patients with clinically proven gastroesophageal reflux disease and 42 healthy volunteers. Twenty-four-hour esophageal pH was measured while the subject was ambulatory, using a combined glass electrode connected to a portable recorder. Percentage of time with esophageal pH less than 4, the number and mean duration of reflux episodes, the number of episodes lasting longer than 5 min, and the duration of the longest episode were calculated for periods of upright and supine body position, respectively. Discriminant analysis and receiver-operating-characteristic analysis were used to define optimal thresholds. A maximum of sensitivity (93.3%) and specificity (92.9%) was obtained using receiver-operating-characteristic analysis with the following criteria. Only percentage of time with esophageal pH less than 4 is considered. A subject is classified as "normal" if both values for the upright and supine body position are below the thresholds, otherwise the subject is classified as "pathological." The thresholds are 10.5% of time with esophageal pH less than 4 for the upright position and 6.0% for the supine position. Within the limits of this retrospective study, it is concluded that rather simple criteria yield a high diagnostic accuracy in the evaluation of long-term esophageal pH-metry. Nevertheless, a prospective and independent confirmation of these criteria is needed.

Adolescent↗
PubMed1987

Influence of smoking and esophageal intubation on esophageal pH-metry.

The effect of cigarette smoking on gastroesophageal reflux and the effect of the pH electrode on salivary secretion and swallowing frequency were studied in 30 healthy volunteers (15 habitual smokers, 15 non-smokers) and in 10 smoking patients with proven gastroesophageal reflux disease. Twenty-four-hour pH profiles were measured while the subjects were ambulatory using a combined glass electrode connected to a portable recorder. In 8 of the smoking volunteers, swallowing frequency and salivary secretion were measured, both when smoking and when not. Smokers had more reflux episodes than nonsmokers [median per hour 2.8 (range 0.4-7.1) for the upright body position and 0.5 (range 0.0-1.7) for the supine body position vs. 1.4 (range 0.0-2.1) upright and 0.0 (range 0.0-0.7) supine, p less than 0.01], but the total time of exposure of the esophageal mucosa to acid was affected neither by the status of being a smoker nor by actual smoking. Nasopharyngeal intubation with the pH electrode did not affect the swallowing frequency, but it increased salivary secretion two-to threefold for a period of 4 h. Six hours after introduction of the pH electrode and later, salivary flow was similar to baseline. It is concluded that smoking and nasopharyngeal intubation does not adversely affect the results of 24-h pH-metry.

Adult↗
PubMed1987

Healthy controls have as much bile reflux as gastric ulcer patients.

Data on duodenogastric reflux of bile in gastric ulcer are conflicting. We therefore measured intragastric bile acid concentration and its composition from individual bile acids, duodenogastric bile acid reflux rate, gastric emptying rate, and secretion rates of volume and acid in 30 patients with gastric ulcer and in 66 healthy controls, both in the fasting state and after feeding a liquid meal. Patients had higher gastric bile acid concentrations (p less than 0.05) than controls in the fasting state, but the overlap between the groups was considerable. In fasting patients with corpus ulcer, gastric secretion rates were significantly decreased when compared with controls. There was no difference between patients and controls with respect to gastric emptying rate, bile acid reflux rate, intragastric amount of bile acids, and bile acid composition in the fasting state. Postprandially, all parameters tested were similar in patients and controls. Controls showed high reflux rates with similar frequency as did ulcer patients. We conclude that increased gastric bile acid concentrations in the fasting stomach of patients with gastric ulcer are the result of gastric hyposecretion and not of increased reflux. They probably are pathogenetically irrelevant.

Adult↗
PubMed1987

Bile salt reflux after cholecystectomy.

Gastric bile salt concentrations, the rates of bile salt reflux, gastric emptying, and gastric volume secretion were measured in 9 women with previous cholecystectomy and 13 unoperated female controls. The subjects were studied using a marker technique with gastric intubation both fasting and after gastric instillation of a mixed liquid meal. Cholecystectomy was without effect on gastric emptying and gastric volume secretion. Cholecystectomized patients had increased bile salt reflux rates (1.4 +/- 0.4 versus 0.6 +/- 0.2 mumol/min) and gastric bile concentrations (1753 +/- 266) versus 441 +/- 114 mumol/l) in the fasting state, but lower rates (0.3 +/- 0.3 versus 3.4 +/- 0.9 mumol/min) and concentrations (131 +/- 46 versus 496 +/- 123 mumol/l) after feeding. These findings can be explained by the changes of bile flow into the duodenum induced by cholecystectomy.

Adult↗
PubMed1982

[Biotransformation of fentanyl. II. Acute drug interactions in rats and men (author's transl)].

Rat tissue homogenates were used to study fentanyl biotransformation. The liver was shown to be the most important metabolizing organ, whereas extrahepatic metabolism occurred only to a minor degree in the kidneys. The products of oxidative desalkylation, phenylacetic acid and norfentanyl, could be identified as well as small amounts of p-hydroxy-(phenethyl)fentanyl, which is pharmacologically still active. Major sex differences were observed, male rats showing nearly twice as much activity as female animals. Several anaesthetic agents, often used in combination with fentanyl, were tested with respect to their influence on fentanyl metabolism. Most of them caused an inhibition of biotransformation and/or variations in product distribution, when they were added to in-vitro incubations or given to the animals prior to enzyme preparation. This experimental design proved to be useful as a screening method to predict metabolic drug interactions. Halothane and enflurane, which are strong inhibitors in rats, were demonstrated to delay fentanyl metabolism in man, too. Fentanyl plasma levels under halothane anaesthesia were found to be more than twice as high as during neuroleptanaesthesia. The importance of other agents, e.g. ketamine, promethazine or local anaesthetics, remains to be examined. Variations of biotransformation reactions among patients as well as the reported drug interactions might explain some differences in fentanyl blood concentrations reported in the past, but must also be taken into account when intensity and duration of effects or side-effects are discussed.

Adult↗