Rise In Intragastric Pressure Research Articles

The gastro-sphincteric pressure gradient: A new parameter to diagnose a rumination episode.

Rumination is defined as the repetitive, effortless regurgitation of recently ingested food into the mouth. These episodes are preceded by a rise in intragastric pressure (IGP) and mainly occur postprandially. IGP peaks >30mmHg have been proposed as a cutoff to differentiate rumination from reflux events. In clinical practice, we observed that this cutoff, which does not consider esophagogastric junction (EGJ) resistance, is not always reached. We studied 27 patients with rumination syndrome [age: 43.6, 59% female] and 28 gastro-esophageal reflux disease patients [age: 45.9, 54% female]. For each rumination episode, reflux event, transient lower esophageal sphincter relaxation (TLESR), or straining without regurgitation, the following parameters were registered: maximal IGP, IGP, and EGJ pressure preceding the respective episodes. We also quantified the gastro-sphincteric pressure gradient (GSPG) prior to the respective episodes. Five reflux episodes were characterized by a maximal IGP >30mmHg. In 28% of the rumination episodes, the IGP peak did not exceed 30mmHg. Median GSPG was positive for rumination episodes and significantly higher compared with TLESRs, reflux episodes, and straining without regurgitation (7 [3-13] vs. 0 [-1-0] vs. 0 [-1-0] vs. -9 [-13--2]; p<0.0001). Applying the proposed cutoff of 30mmHg, 28% of the rumination episodes were missed. We found that the GSPG differentiates between rumination (positive GSPG), TLESRs and reflux events (GSPG around 0), and straining without regurgitation (negative GSPG). We propose a GSPG value ≥2mmHg to distinguish rumination from reflux episodes, TLESRs, and straining without regurgitation.

Rumination syndrome: When the lower oesophageal sphincter rises

Background Rumination syndrome is an uncommon condition characterised by the self-induced regurgitation from the stomach to the mouth of recently ingested meal that is chewed and reswallowed. Rumination is caused by a voluntary rise in intra-abdominal and intra-gastric pressure leading to the reflux of the gastric content into the oesophagus. However, the precise mechanisms preventing reflux at the gastro-oesophageal junction during the rise in intra-gastric pressure remains unknown. Methods In 5 patients, rumination episodes were monitored using combined multiple intra-luminal impedance monitoring, high resolution manometry, and video-fluoroscopic recording. Results We showed that the gastro-oesophageal junction moved from the abdominal cavity into the thorax creating a “pseudo-hernia”. This occurred at a range of 1.4 ± 0.3 s before the rise in intra-oesophageal pressure and the gastro-oesophageal reflux. Conclusion This displacement of the gastro-oesophageal junction into thorax, rather than a lower oesophageal sphincter opening, explains the mechanism of voluntary regurgitations occurring during rumination syndrome.

Review article: the pathophysiology, differential diagnosis and management of rumination syndrome

Rumination syndrome, characterised by the effortless, often repetitive, regurgitation of recently ingested food into the mouth, was originally described in children and in the developmentally disabled. It is now well-recognised that rumination syndrome occurs in patients of all ages and cognitive abilities. To review a scholarly review on our current understanding of the rumination syndrome. The review was conducted on the basis of a medline search to identify relevant publications pertaining to the pathophysiology, clinical diagnosis and management of rumination syndrome. The Rome III consensus established diagnostic criteria for rumination syndrome in adults, children and infants. A typical history can be highly suggestive but oesophageal (high resolution) manometry/impedance with ingestion of a meal may help to distinguish rumination syndrome from other belching/regurgitation disorders. The pathophysiology is incompletely understood, but involves a rise in intra-gastric pressure, generated by a voluntary, but often unintentional, contraction of the abdominal wall musculature, at a time of low pressure in the lower oesophageal sphincter, causing retrograde movement of gastric contents into the oesophagus. To date, controlled trials in the treatment rumination syndrome are lacking. The mainstay of treatment for rumination syndrome is explanation and behavioural treatment which consists of habit reversal techniques that compete with the urge to regurgitate. Chewing gum, prokinetics, baclofen and even antireflux surgery have been proposed as adjunctive therapies, but high quality studies are generally lacking. Rumination is an under-recognised condition with incompletely understood pathophysiology. Behavioural therapy seems effective, but controlled treatment trials are lacking.

PTH-040 The effect of salivary nitrite on gastric emptying

Introduction Human saliva has a high nitrite concentration from the entero-salivary recirculation of dietary nitrate. Swallowed nitrite reacts with acidic gastric juice forming nitric oxide (NO). Increasing NO bioactivity, by inhibiting phosphodiesterase, enhances gastric accommodation and delays gastric emptying. Aims To determine (1) whether nitrite in saliva affects gastric emptying and (2) whether nitrite in saliva alters postprandial intragastric pressure (IGP). Methods 20 healthy subjects (11 males) were studied. On four separate days high-resolution manometry was performed during 15 min fasting and for 90 min following a standardised meal. Post-prandially, solutions of 0, 0.286, 2 and 14 mmol/l potassium nitrite were infused into the oral cavity. Solutions were randomised and double-blinded. Saliva was collected at baseline, 30, 60 and 90 min after the meal. Salivary nitrite concentrations were quantified by Griess reaction. Gastric emptying was assessed by means of a specially designed breath test. 14C labelled sodium acetate was incorporated, during baking, into a rolled oats flapjack which constituted part of our standardised meal. Following consumption of the flapjack, breath samples were taken at regular intervals. The quantity of 14C appearing in breath per unit time (μmol/minute) was calculated. A generalised linear regression method was used to estimate gastric half-emptying times (T½). Mean IGP was defined relative to atmospheric pressure as the lowest mean pressure recorded in the six most distal manometry sensors. Results are medians and ranges. Results Salivary nitrite concentrations at 60 min were 24.35 μmol/l (3.86–65.46), 80.42 μmol/l (20.88–158.79), 358.4 μmol/l (118.2–726.6) and 2694 μmol/l (600–8087) for the solutions containing 0, 0.286, 2 and 14 mmol/l nitrite, respectively. There was no significant difference in the rate of gastric emptying (T½) between the control solution (103.5 min, 56.2–239.1) and those containing 0.286 mmol/l (113.4 mins, 68.7–254.8, p=0.56), 2 mmol/l (121.7 min, 39.8–270.0, p=0.93) and 14 mmol/l (114.4 mins, 79.1–390.1, p=0.75). There was no difference in the increase in IGP recorded between the control solution (4.06 mm Hg, −2.64–7.31) and those containing 0.286 mmol/l (4.42 mm Hg, −4.55–8.45, p=0.61), 2 mmol/l (4.66 mm Hg, −0.94-9.16, p=0.27) and 14 mmol/l (4.24 mm Hg, −2.12–8.17, p=0.81) potassium nitrite. Conclusion Despite an excellent range of salivary nitrite concentrations, extending over and beyond the normal physiological range, no difference in the rate of gastric emptying or postprandial rise in IGP was seen. This suggests salivary nitrite does not affect gastric emptying.

From biological gastroenterology to fundamental neurosciences: How studies in gastric emptying have led to the discovery of a new mechanism of neuronal functioning

Gastric emptying undergoes complex regulation by the nervous system, which organizes in particular the inhibition of duodenum motility after a rise in intra-gastric pressure: the gastro-duodenal inhibitory reflex. It was first shown in mammals that this reflex could be organized by a sympathetic ganglion, the coeliac plexus. The excitation of gastric mechanosensitive fibres leads in this ganglion to the release of a neurotransmitter, which in turn activates ganglionic neurones leading to inhibition of the duodenum contractions. It rapidly became apparent that this reflex presented striking properties since it was organized in the absence of action potentials along the nerve fibres. Then it was shown that the neurotransmitter released in the coeliac plexus was gaseous: nitric oxide (NO). The nature of the mechanism conducting, without action potentials, the excitation along the nerve fibres was recently determined. This mechanism necessitates the integrity of particular areas of the neuronal membrane (the lipid rafts) and the activation in cascade of the following second messenger sequence: ceramide, calcium, NO and guanosine cyclic monophosphate (c-GMP). These results show how studies in biological gastroenterology have led to the rethinking of one of the central dogmas in neuroscience according to which excitation is only conducted along the nerves by the action potential.

Rumination or belching-regurgitation? Differential diagnosis using oesophageal impedance-manometry

Rumination is an eating disorder clinically suspected in the presence of chronic regurgitation of recently ingested food with subsequent re-mastication and swallowing. Oesophageal manometry is currently used to confirm the diagnosis, however, it is difficult to distinguish rumination from postprandial belching-regurgitation, being the manometric pattern identical in both situations. Oesophageal impedance allows recognition between liquid and gas gastro-oesophageal reflux. Our aims were (i) to improve diagnosis of rumination using combined impedance-manometry (ii) to assess the gastro-oesophageal pressure-flow pattern in rumination events. Sixteen patients with clinically suspected rumination underwent impedance-manometry monitoring for 1 h after a solid liquid meal. Manometry was first analysed blindly to the impedance pattern. All events marked by the patients and straining episodes were identified. After the manometric analysis, impedance tracings were unblinded and each straining episode was analysed for presence of liquid and/or gas oesophageal retrograde flow. Only rumination events were included for additional evaluation. Postprandial manometry showed a pattern compatible with rumination in 12/16 patients. In total, impedance-manometry confirmed the clinical diagnosis of rumination in eight of the 16 patients with clinical suspicion of rumination. In 102 clearly identified rumination events, the onset of gastric strain (manometry) occurred before the onset of oesophageal liquid retroflow (impedance) in 58% of cases or simultaneously in 37% of cases. In most cases (86%), oesophageal retrograde flow started after an initial increase in abdominal pressure but before the peak gastric strain pressure. Postprandial impedance-manometry monitoring improves diagnosis of rumination because it allows distinction between rumination and postprandial belching and regurgitation. During rumination, oesophageal liquid retrograde flow is first driven by an early small rise in intragastric pressure preceding the peak pressure observed during straining.

Esophageal replacement in the neonatal period in infants with esophageal atresia and tracheoesophageal fistula

Aim The aim of the study was to assess the outcome after esophageal replacement using gastric pull-up performed in critically ill neonates with esophageal atresia (EA) and tracheoesophageal fistula. Methods During 1998 to 2005, gastric transposition was performed in 27 neonates (mean birth weight, 2.32 kg [1.86-3.0 kg]; mean age, 6.08 days) for post–EA and tracheoesophageal fistula leaks in 17, long gap in 6, and pure EA in 4, using transhiatal route in all. Pyloromyotomy as the drainage procedure was added for all 27 neonates. Patients were followed up at 3, 6, and 12 months for clinical evaluation, gastric clearance, duodenogastric reflux, and gastric pressure profile. Results Six neonates had ongoing serious chest infection, 3 had lung collapse, and 2 had associated congenital heart disease. Postoperative elective ventilation was provided to all neonates for 2 to 40 days (mean, 10.6 days). Nine neonates developed postoperative leaks in the neck; all healed spontaneously before discharge. Mean hospital stay was 32.6 days (range, 9-87 days). Four newborns died on postoperative days 9, 13, 15, and 29 because of existing severe sepsis in 3 and major congenital heart disease in 1. Functional evaluations were done at 3, 6, and 12 months postoperatively. Values at 6 months revealed normal gastric emptying in 16 of 23, presence of duodenal gastric reflux in 11 of 23, and mass contractions with significant rise in intragastric pressure after bolus feeds in 16 of 23 cases. Values at 12months revealed normal gastric emptying in 14 of 20, presence of duodenal gastric reflux in 8 of 20, and mass contractions with significant rise in intragastric pressure after bolus feeds in 13 (65%) of 20cases. Conclusion Gastric transposition could be a lifesaving alternative to diversion, even in the critically ill newborns after major leaks. However, it requires technical surgical expertise and an effective pain relief and neonatal intensive care.

Oesophageal cancer is an uncommon cause of death in patients with Barrett's oesophagus

Rumination syndrome is an uncommon condition characterised by the self-induced regurgitation from the stomach to the mouth of recently ingested meal that is chewed and reswallowed. Rumination is caused by a voluntary rise in intra-abdominal and intra-gastric pressure leading to the reflux of the gastric content into the oesophagus. However, the precise mechanisms preventing reflux at the gastro-oesophageal junction during the rise in intra-gastric pressure remains unknown.In 5 patients, rumination episodes were monitored using combined multiple intra-luminal impedance monitoring, high resolution manometry, and video-fluoroscopic recording.We showed that the gastro-oesophageal junction moved from the abdominal cavity into the thorax creating a “pseudo-hernia”. This occurred at a range of 1.4 ± 0.3 s before the rise in intra-oesophageal pressure and the gastro-oesophageal reflux.This displacement of the gastro-oesophageal junction into thorax, rather than a lower oesophageal sphincter opening, explains the mechanism of voluntary regurgitations occurring during rumination syndrome.

Mechanisms contributing to gastric motility changes induced by PAF-acether and endotoxin in rats.

Platelet-activating factor (PAF) may be involved in the pathophysiology of gastrointestinal damage and motility changes. The effects of PAF in inducing gastric contractions in vivo have now been determined in pentobarbital sodium-anesthetized rats. Local intra-arterial infusion of PAF (5-50 ng.kg-1.min-1 for 10 min) induced a maintained rise in intragastric pressure followed by a further postinfusion increase. Inhibitors of eicosanoid biosynthesis had no effect on these gastric motility changes. However, pretreatment with cimetidine or methysergide decreased by 50% the initial increase in intragastric pressure, whereas mepyramine, adrenergic alpha- and beta-receptor blockade, atropine, hexamethonium, or vagotomy had no effect. During the local infusion of tetrodotoxin, the initial increase in intragastric pressure was not maintained, and the postinfusion increase was abolished. With these inhibitors and antagonists, there was no consistent correlation between the extent of PAF-induced mucosal damage and increase in intragastric pressure. Tetrodotoxin had no effect on the changes in intragastric pressure induced by the thromboxane mimetic U-46619. Administration of Escherichia coli and Salmonella typhosa endotoxin (50 mg/kg iv) also increased intragastric pressure, which peaked after 10 min and slowly declined thereafter. These effects were inhibited by the specific PAF-receptor antagonist L652,731, suggesting that the endogenous release of PAF may contribute to the endotoxin-induced increases in gastric motility. The present study suggests that PAF initially acts directly on smooth muscle and through histamine and serotonin release with a secondary motility response due to activation of nonadrenergic noncholinergic, neuronal activity.

Pressure activity patterns in the canine proximal stomach: response to distension.

The stomach accommodates to distension with a minimal rise in intragastric pressure, but the effects of gastric accommodation on overall gut motor activity are unknown. In four conscious fasted dogs, constant gastric distension (0, 10, 20, 40, 80, 160, 320, and 640 ml) was produced by an air-filled intragastric bag; intrabag and gastrointestinal pressure activities (fundus, antrum, and proximal intestine) were recorded for 4 h. With the bag empty (or without bag), the proximal stomach exhibited a fasting cyclic motor pattern synchronized with that in the antrum and upper intestine. During periods of activity the fundus generated powerful phasic pressure waves. Increasing intrabag volumes up to 80 ml gradually lengthened phase II of the intestinal interdigestive motor cycle. At 160 ml or more, gut cyclic motor activity disappeared and was replaced by continuous irregular activity, although the intrabag pressure increased to less than 7 mmHg. We concluded that gastric distension markedly alters gut motor activity even though gastric accommodation prevents a major increase in intragastric pressure.

"Precurarization" using d-Tubocurarine , Gallamine and Pancuronium: A Comparative Study

The depolarizing neuromuscular blocking agent succinylcholine, which was synthesized by Hunt and Taveau in 1906, is still regarded as the drug of choice when speed of onset and good intubating conditions matter most. This agent has several disadvantages, some of which may be unpredictable, serious and immediate, for example, muscle pain, bradycardia, rise in intragastric pressure, increase in intraocular pressure and elevation of serum potassium. These disadvantages may be regarded as the side effects of depolarization and indicate a need for a nondepolarizing neuromuscular blocking agent with rapid onset and good muscle relaxation. Simpson et al. described the neuromuscular blocking properties of the nondepolarizing .neuromuscular blocking agent, Fazadinium (AH 8165) in 1972. This initial work indicated a more rapid onset of action than occurs with succinyleholine and without muscle fasciculation or concomitant rise in plasma potassium concentration. However, Coleman et al., Young, t al., Hartley and Fidler, and Metha et al., concluded that using succinylcholine, a ignificantly greater number of patients had excellent intubating conditions at predetermined times after administration than when using Fazadinium. Several reports have indicated that administration of a small dose of nondepolarizing neuromuscular blocking agents would markedly diminish the fasciculation and muscle pains which so frequently occur, when succinylcholine is given. Many other reports have indicated that administration of a small dose of nondepolarizing neuromuscular blocking agents could attenuate or eliminate the adverse effects of succinylcholine such as increased intra-gastric pressure and intraocular pressure, bradycardia, arrhythmia and hyperkalemia. Several investigators have recommended that when small doses of nondepolarizing neuromuscular blocking aKent are given before succinylcholine administration, larger doses of succinylcholine should be given to achieve satisfactory relaxation. A comparative study using d-tubocurarine, gallamine and pancuronium for precurarization indicates that any of them successfully attenuates fasciculation. They have a little antagonizing effect of vocal cord relaxation after succinylcholine administration, but there was no difficulty during endotracheal intubation.

Effect of Changes in the Intragastric Milieu on Competence of the Gastro-Oesophageal Region

Acid-reflux studies were carried out in 10 healthy subjects in the basal state, during continuous infusion of pentagastrin (0.015 mug/kg body-weight) after bolus injection of insulin (0.2 IU/kg bodyweight), and after intragastric instillation of 200 ml hydrochloric acid. Basal gastro-oesophageal sphincter pressure and rise in intragastric pressure on leg raising were measured by means of perfused catheters. The increase of intragastric acidity during infusion of pentagastrin and during insulin-induced hypoglycaemia was not accompanied by changes in the competence of the gastro-oesophageal region. Instillation of hydrochloric acid was followed by a significant enhancement of the reflux tendency. Changes in intragastric pressure-rise were not demonstrated in any of the series of investigation. Gastric acid secretion and its significance at the evaluation of the results of reflux studies by means of pH-measuring equipment has not been clarified in patients. It can therefore reasonably be demanded of future acid reflux studies that details have to be stated with regard to acid secretion, and that these should be taken into account at the assessment of the results of the study.

EFFICACY OF CRICOID PRESSURE IN PREVENTING ASPIRATION OF GASTRIC CONTENTS IN PAEDIATRIC PATIENTS

SUMMARY The efficacy of cricoid pressure (Sellick’s manoeuvre) was evaluated for use in paediatric anaesthesia. From studies on eight infant cadavers, cricoid pressure was found to be effective in occluding the oesophagus in the presence or absence of a nasogastric tube despite an intra-oesophageal pressure of 100 cm H,O. In anaesthetized paediatric patients, cricoid pressure did not directly occlude any of the oesophageal tubes previously filled with contrast material. A nasogastric tube need not be withdrawn before induction of anaesthesia. It can act as a “blow-off” valve if a rise in intragastric pressure occurs while cricoid pressure will prevent regurgitation of gastric contents into the pharynx.

THE EFFECT OF SUXAMETHONIUM ON THE INTRAGASTRIC PRESSURE IN INFANTS AND CHILDREN

SUMMARY The effect of intravenous administration of suxamethonium on the intragastric pressure was investigated in thirty paediatric patients after induction of anaesthesia. In most patients there was a fall, while in five older children slight rise occurred, the maximum was 4 cm H2O. This seems to be related to the absence of strong muscle fasciculations, especially in infants and young children. Because of the lack of rise in intragastric pressure, and because of the antagonistic actions of the depolarizing and antidepolarizing types of block, prior administration of tubocurarine is not necessary in paediatric patients with a full stomach.

Physiological Effects of Exsufflation with Negative Pressure (E.W.N.P.)

The effects of Exsufflation With Negative Pressure (E.W.N.P.), a mechanical method of eliminating retained secretions, were studied in respect to cardiovascular function, diaphragmatic motion, and intragastric pressure. The physiological effects of E.W.N.P. were studied in 17 patients with bronchopulmonary disease with special reference to changes induced on the circulation. Although inspiratory pressures of 40 mm. Hg. were employed to inflate the lungs, the use of a negative lung deflating pressure of 40 mm. Hg. during the expiratory cycle resulted in comparatively low mean ventilatory pressures and, consequently, only slight rises in peripheral venous pressure, i.e., 5.8 cm. H2O. In contrast, a much higher venous pressure rise took place during the patients' natural vigorous cough, i.e., 16.1 cm. H2O. Small changes in arterial blood pressure also occurred during E.W.N.P., viz., an average increase of 8 mm. Hg. in systolic and 4 mm. Hg. in diastolic pressure in 22 subjects. Changes in the electrical axis of the heart due to nearly maximal lung inflation and deflation were similar to those induced by the deepest possible voluntary inspiration and expiration. Elimination of mucopurulent secretions by E.W.N.P. postoperatively seemed a somewhat safer procedure than the use of the patients' natural cough since intra-abdominal pressure was lower with this procedure: with E.W.N.P., the rise in intragastric pressure averaged 26 mm. Hg. in comparison to a rise of 85 mm. Hg. during the patient's cough. The reduction in pain at the wound site during the use of E.W.N.P. as compared to voluntary cough further suggested its value as a safety factor in respect to healing of abdominal wounds in the postoperative state. An average rise of 8 mm. Hg. systolic and 4 mm. Hg. diastolic in arterial blood pressure took place in 22 subjects. The change in electrical axis of the heart during the positive and negative pressure cycles were similar to those induced by the deepest possible voluntary inspiration and expiration. In 17 patients with bronchopulmonary disease and poliomyelitis an average venous pressure rise of 58 mm. H2O over the control level occurred during E.W.N.P. as compared to that of 161 mm. H2O in 12 of these subjects during their own natural cough. The relatively slight rise in blood pressure and venous pressure during E.W.N.P. was related to the low mean mask pressure found in this type of pressure breathing. Higher rises occurred in subjects who resisted inspiratory inflation by the apparatus. In conscious patients, cooperation with the technique of E.W.N.P. is an essential factor in the effective use of this apparatus.