Relative contributions of “pressure pump” and “peristaltic pump” to gastric emptying

2000 ◽  
Vol 278 (4) ◽  
pp. G604-G616 ◽  
Author(s):  
K. Indireshkumar ◽  
James G. Brasseur ◽  
Henryk Faas ◽  
Geoffrey S. Hebbard ◽  
Patrik Kunz ◽  
...  
Keyword(s):  
High Pressure ◽  
Gastric Emptying ◽  
Muscle Tone ◽  
Contractile Activity ◽  
Average Rate ◽  
Gastric Volume ◽  
Peristaltic Pump ◽  
Pressure Pump ◽  
Significant Difference ◽  
Common Cavity

The relative contributions to gastric emptying from common cavity antroduodenal pressure difference (“pressure pump”) vs. propagating high-pressure waves in the distal antrum (“peristaltic pump”) were analyzed in humans by high-resolution manometry concurrently with time-resolved three-dimensional magnetic resonance imaging during intraduodenal nutrient infusion at 2 kcal/min. Gastric volume, space-time pressure, and contraction wave histories in the antropyloroduodenal region were measured in seven healthy subjects. The subjects fell into two distinct groups with an order of magnitude difference in levels of antral pressure activity. However, there was no significant difference in average rate of gastric emptying between the two groups. Antral pressure history was separated into “propagating high-pressure events” (HPE), “nonpropagating HPEs,” and “quiescent periods.” Quiescent periods dominated, and average pressure during quiescent periods remained unchanged with decreasing gastric volume, suggesting that common cavity pressure levels were maintained by increasing wall muscle tone with decreasing volume. When propagating HPEs moved to within 2–3 cm of the pylorus, pyloric resistance was found statistically to increase with decreasing distance between peristaltic waves and the pylorus. We conclude that transpyloric flow tends to be blocked when antral contraction waves are within a “zone of influence” proximal to the pylorus, suggesting physiological coordination between pyloric and antral contractile activity. We further conclude that gastric emptying of nutrient liquids is primarily through the “pressure pump” mechanism controlled by pyloric opening during periods of relative quiescence in antral contractile wave activity.

Relative contribution of “pressure pump” and “peristaltic pump” to gastric emptying

1998 ◽  
Vol 114 ◽  
pp. A770 ◽  
Author(s):  
K. Indireshkumar ◽  
H Faas ◽  
JG Brasseur ◽  
GS Hebbard ◽  
P Kunz ◽  
...  
Keyword(s):  
Gastric Emptying ◽  
Peristaltic Pump ◽  
Pressure Pump ◽  
Relative Contribution

Modulation of gastric motor activity by a centrally acting stimulus, circular vection, in humans

2001 ◽  
Vol 280 (5) ◽  
pp. G850-G857 ◽  
Author(s):  
Henryk Faas ◽  
Christine Feinle ◽  
Paul Enck ◽  
David Grundy ◽  
Peter Boesiger
Keyword(s):  
Gastric Emptying ◽  
Healthy Subjects ◽  
Time Course ◽  
Delayed Gastric Emptying ◽  
Contractile Activity ◽  
Subjective Symptom ◽  
Gastric Volume ◽  
Rapid Decrease ◽  
Resonance Imaging ◽  
Baseline Activity

The aims of this study were to investigate gastric motor correlates of vection, a centrally acting stimulus, and relate these responses to the induction of motion sickness symptoms. Antral contractile activity and gastric volume retained after a liquid nutrient meal (600 ml) were assessed by magnetic resonance imaging in healthy subjects during two different protocols. Vection was induced by an optokinetic drum, and subjects repeatedly rated the intensity of vection and nausea on 0–10 analog scales. Vection delayed gastric emptying {99% (89–102%) [median (interquartile ranges)] of volume retained at 28 min; control situation: 79% (69–81%), P < 0.05}. Antral contractile activity followed a distinct time course of rapid decrease [−64% (−72 to −59%) change from baseline activity] immediately after onset of drum rotation followed by gradual recovery upon withdrawal of the stimulus. No relationship was found between the severity of nausea and inhibition of gastric emptying or antral contractile activity. The inhibition of antral contractile activity appears to be a good measure of the peripheral response to vection but is probably independent of subjective symptom induction.

Three-dimensional imaging of the stomach: role of pylorus in the emptying of liquids

1987 ◽  
Vol 253 (1) ◽  
pp. G79-G85 ◽  
Author(s):  
D. Kumar ◽  
E. L. Ritman ◽  
J. R. Malagelada
Keyword(s):  
Gastric Emptying ◽  
Contractile Activity ◽  
Three Dimensional ◽  
Isotonic Saline ◽  
Casein Hydrolysate ◽  
Intestinal Perfusion ◽  
Proximal Jejunum ◽  
Constant Rate ◽  
Significant Difference ◽  
Anesthetized Dogs

Using the dynamic spatial reconstructor and manometry, we measured gastric emptying, pyloric size, and antral contractile activity in three anesthetized dogs in the prone position. Our objective is to evaluate the effect of intestinal perfusion of equicaloric, neutral, and isosmolar nutrients (Maltose 32.5 mg/ml, casein hydrolysate 32.5 mg/ml, and oleic acid 15.5 mg/ml) at a constant rate of 10 ml/min in the proximal jejunum on the dynamics of the antropyloric region. Isotonic saline perfusion was used as a control solution. Test meal in the stomach was 600 ml of isotonic Gastrograffin. Antral phasic pressure activity was recorded using an antroduodenal six-channel (ports 5 mm apart) perfused probe(2 mm OD). Gastric emptying in response to intestinal perfusion of fat was significantly slower (P less than 0.02) in comparison to other nutrients or isotonic saline. There was no significant difference in the maximum or minimum pyloric diameter in response to the four intestinal perfusates. However, the pylorus was closed for a significantly longer duration (P less than 0.05) during the perfusion of fat in the upper intestine. Antral contractions were related to pyloric opening in an “antral contraction followed by pyloric opening” sequence. This study suggests that the presence of fat in the upper intestine delays gastric emptying and that this effect is regulated in part by increased resistance to flow offered by the pylorus.

scholarly journals Gastric Sensory and Motor Functions and Energy Intake in Health and Obesity—Therapeutic Implications

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1158
Author(s):  
Lizeth Cifuentes ◽  
Michael Camilleri ◽  
Andres Acosta
Keyword(s):  
Energy Consumption ◽  
Gastric Emptying ◽  
Food Intake ◽  
Gastric Volume ◽  
Obesity Management ◽  
Bariatric Endoscopy ◽  
Motor Functions ◽  
Therapeutic Implications ◽  
Intestinal Functions

Sensory and motor functions of the stomach, including gastric emptying and accommodation, have significant effects on energy consumption and appetite. Obesity is characterized by energy imbalance; altered gastric functions, such as rapid gastric emptying and large fasting gastric volume in obesity, may result in increased food intake prior to reaching usual fullness and increased appetite. Thus, many different interventions for obesity, including different diets, anti-obesity medications, bariatric endoscopy, and surgery, alter gastric functions and gastrointestinal motility. In this review, we focus on the role of the gastric and intestinal functions in food intake, pathophysiology of obesity, and obesity management.

Demonstration of a piston type integrated high pressure pump-energy recovery device for reverse osmosis desalination system

Desalination ◽  
2021 ◽  
Vol 507 ◽  
pp. 115033
Author(s):  
Daiwang Song ◽  
Yin Zhang ◽  
Haitao Wang ◽  
Lidong Jiang ◽  
Chengpeng Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Reverse Osmosis ◽  
Energy Recovery ◽  
Pump Energy ◽  
High Pressure Pump ◽  
Pressure Pump ◽  
Reverse Osmosis Desalination

scholarly journals Study on the sealing defects impact on high pressure pump

2020 ◽  
Vol 997 ◽  
pp. 012005
Author(s):  
D P Bistriceanu ◽  
S G Pal ◽  
F C Ciornei ◽  
C Bujoreanu
Keyword(s):  
High Pressure ◽  
High Pressure Pump ◽  
Pressure Pump

Evaluating the Role of Anesthesia on Intraoperative Blood Loss and Visibility during Endoscopic Sinus Surgery: A Meta-analysis

2021 ◽  
pp. 194589242198915
Author(s):  
David C. Moffatt ◽  
Robert A. McQuitty ◽  
Alex E. Wright ◽  
Tawanda S. Kamucheka ◽  
Ali L. Haider ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Loss ◽  
Endoscopic Sinus Surgery ◽  
Average Rate ◽  
Meta Analysis ◽  
Sinus Surgery ◽  
Total Blood Loss ◽  
Total Blood ◽  
Intraoperative Bleeding ◽  
Significant Difference

Background Previous studies and meta analyses have led to incongruent and incomplete results respectively when total intravenous anesthesia (TIVA) and inhalational anesthesia (IA) are compared in endoscopic sinus surgeries in regards to intraoperative bleeding and visibility. Objective To perform a more comprehensive meta-analysis on randomized controlled trial (RCTs) comparing TIVA with IA in endoscopic sinus surgery to evaluate their effects on intraoperative bleeding and visibility. Methods A systematic review and meta-analysis of studies comparing TIVA and IA in endoscopic sinus surgery for chronic rhinosinusitis was completed in May 2020. Utilizing databases, articles were systematically screened for analysis and 19 studies met our inclusion criteria. The primary outcome included intraoperative visibility scores combining Boezaart, Wormald and Visual Analogue Scale (VAS). Secondary outcomes included rate of blood loss (mL/kg/min), estimated total blood loss (mL), Boezaart, Wormald scores, VAS, heart rate, and mean arterial pressure (MAP). Results 19 RCTs with 1,010 patients were analyzed. TIVA had a significantly lower intraoperative bleeding score indicating better endoscopic visibility (Boezaart, VAS, and Wormald) than IA (−0.514, p = 0.020). IA had a significantly higher average rate of blood loss than TIVA by 0.563 mL/kg/min (p = 0.016). Estimated total blood loss was significantly lower in TIVA than IA (−0.853 mL, p = 0.002). There were no significant differences between TIVA and IA in the mean heart rate (−0.225, p = 0.63) and MAP values (−0.126, p = 0.634). The subgroup analyses revealed no significant difference between TIVA and IA when remifentanil was not utilized and whenever desflurane was the IA agent. Conclusion TIVA seemed to have superior intraoperative visibility scores and blood loss during endoscopic sinus surgery when compared to IA. However, the results are not consistent when stratifying the results based on the use of remifentanil and different inhaled anesthetics. Therefore, the conclusion cannot be made that one approach is superior to the other.

Effect of insulin-induced hypoglycaemia on antral, pyloric and duodenal motility in fasting subjects

1991 ◽  
Vol 81 (2) ◽  
pp. 281-285 ◽  
Author(s):  
R. Fraser ◽  
J. Fuller ◽  
M. Horowitz ◽  
J. Dent
Keyword(s):  
Blood Glucose ◽  
Gastric Emptying ◽  
Phase I ◽  
Blood Glucose Concentration ◽  
Migrating Motor Complex ◽  
Control Group ◽  
Motor Complex ◽  
Significant Difference ◽  
Interdigestive Migrating Motor Complex ◽  
Pyloric Motility

1. Hyperglycaemia alters gastric motility and delays gastric emptying. By contrast, there is little information regarding the effect of sub-normal blood glucose concentrations on gastric and, in particular, pyloric motility, although limited data suggest that hypoglycaemia is associated with accelerated gastric emptying despite an apparently increased basal pyloric pressure. 2. To determine the effects of hypoglycaemia on pyloric motility, we compared the effects of an intravenous injection of insulin (0.15 units/kg) with those of a placebo injection of saline in eight healthy human volunteers during phase I of the interdigestive migrating motor complex. 3. All subjects developed profound hypoglycaemia (mean blood glucose concentration 1.6 mmol/l compared with 4.0 mmol/l in the control group). 4. There was no significant difference in the number of antral (9 versus 7, P = 0.34), pyloric (3 versus 0, P = 0.31) or duodenal (21 versus 13, P = 0.42) pressure waves or in the basal pyloric pressure (0.3 mmHg versus 0.1 mmHg, P = 0.37) in the 45 min after insulin injection (hypoglycaemia) when compared with the 45 min after saline injection (euglycaemia). In both the euglycaemic and hypoglycaemic studies there was a time-dependent increase in the numbers of antral and duodenal waves consistent with the expected changes in the interdigestive migrating motor complex. 5. These results indicate that insulin-induced hypoglycaemia has no significant effect on pyloric motility during phase I of the interdigestive migrating motor complex.

Effect of adrenalectomy on convulsions induced by high-pressure oxygen

1979 ◽  
Vol 57 (7) ◽  
pp. 688-694 ◽  
Author(s):  
A. K. Singh ◽  
E. W. Banister
Keyword(s):  
High Pressure ◽  
Acid Level ◽  
Amino Acid Level ◽  
Aminobutyric Acid ◽  
Pressure Oxygen ◽  
Significant Difference ◽  
High Pressure Oxygen ◽  
Brain Gaba ◽  
The Brain ◽  
Adrenalectomized Rats

Adrenalectomized rats exposed to high pressure oxygen (OHP) until convulsion convulse much later than sham-operated or normal rats. No significant changes in the concentration of noradrenaline (NA) and total catecholamines (TC) in the brain were noted in sham-operated or adrenalectomized rats resulting from sham or real surgery and no change occurred in these variables in normal sham-operated or adrenalectomized animals after OHP leading to convulsion. Brain adrenaline (A) concentration, however, decreased significantly in all three groups following OHP-induced convulsions. Activity of catecholamine O-methyltransferase (COMT) decreased significantly only in adrenalectomized rats. Brain γ-aminobutyric acid (GABA), glutamate, and other amino acid level remained unchanged after adrenalectomy whereas the concentration of ammonia decreased significantly when normal rats were adrenalectomized. After OHP-induced convulsions, the concentrations of brain GABA and glutamate decreased and ammonia and glutamine plus asparagine increased significantly in normal, sham-operated, and adrenalectomized rats. In the blood no significant difference was noted in the concentration of the catecholamines, ammonia, and amino acids either in normal or sham-operated rats. In adrenalectomized rats, the blood A and NA concentrations decreased significantly and tyrosine increased significantly. The concentration of NA, ammonia, and glutamine plus asparagine in rats from all three groups increased after OHP-induced convulsions, whereas the concentration of glutamate decreased significantly. Since the concentration of A increased significantly after convulsions in normal and sham-operated rats but did not change in adrenalectomized rats, it might be proposed that adrenalectomy protects against OHP-induced convulsions by reducing the circulating concentration of A and ammonia.However, these are not the only factors involved in the protection since the sham-operated rats also convulsed much later than normal rats but had similar ammonia and A concentrations to normal animals.

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