Examination of Visceral Perception and Gastric Tone by Gastric Stimulation Using Air Inflation during Endoscopy

Endoscopic pressure study integrated system for the diagnosis of achalasia

OBJECTIVES

The endoscopic pressure study integrated system (EPSIS) is a novel diagnostic tool used to evaluate lower esophageal sphincter (LES) function. EPSIS allows the measurement of intragastric pressure (IGP) during gastric insufflation through esophagogastroduodenoscopy (EGD) and records its pressure waveform. This study aimed to assess the usefulness and applicability of EPSIS as an adjunct diagnostic modality for achalasia.

METHODS

This case-control study was conducted using a database of patients who underwent EGD, barium swallow (BS), high-resolution manometry (HRM), and EPSIS between January 2022 and December 2022. The achalasia (experimental) group (n = 35) consisted of patients with a definitive diagnosis of achalasia. The control group (n = 34) consisted of patients with no abnormalities in EGD, BS, or HRM and no abnormal acid reflux confirmed with 24-h pH-impedance monitoring. EPSIS findings were compared between the two groups and characterized by the waveform pattern (uphill or flat), maximum IGP (IGP-Max), pressure difference, and the gradient of the waveform.

RESULTS

All patients in the achalasia group showed an uphill pattern, in contrast to 21 patients (61.8%) in the control group. IGP-Max demonstrated the best diagnostic accuracy for achalasia, with a cut-off value of 15.8 mmHg (100% sensitivity, 58.8% specificity, and area under the curve [AUC] 0.78). The pressure gradient also demonstrated good diagnostic accuracy, with a cut-off value of 0.40 mmHg/s (80% sensitivity, 61.8% specificity, and AUC 0.76).

CONCLUSION

This study demonstrated that EPSIS can be applied as a diagnostic modality in patients with achalasia.

Characterization of intragastric pressure waveform in endoscopic pressure study integrated system: Novel diagnostic device for gastroesophageal reflux disease

OBJECTIVES

Endoscopic pressure study integrated system (EPSIS) is a novel diagnostic tool for gastroesophageal reflux disease (GERD). EPSIS has been developed to evaluate lower esophageal sphincter function by monitoring the intragastric pressure (IGP) while insufflating the stomach during gastroscopy. Based on previous data, EPSIS could diagnose GERD with good accuracy by assessing IGP waveform pattern. This study aimed to further characterize the waveform to improve the diagnostic yield of EPSIS.

METHODS

We conducted a retrospective analysis of patients with typical GERD symptoms who underwent both EPSIS and 24-h impedance-pH monitoring (MII-pH) at a single tertiary referral center from October 2018 to May 2020. EPSIS was performed by using a through-the-scope catheter connected to the pressure measuring system (TR-W550, TR-TeH08, AP-C35; Keyence, Osaka, Japan) to monitor IGP. Abnormal acid reflux was defined as acid exposure time (AET) over 6.0%. Pressure waveform was characterized as follows: (i) Basal IGP, (ii) Maximum IGP, (iii) Pressure difference, (iv) Gradient of the waveform.

RESULTS

A total of 57 patients with GERD symptoms were analyzed. Twenty-one patients presented abnormal AET on MII-pH. Among EPSIS parameters, pressure difference during insufflation correlated with AET (ρ = -0.66, P < 0.01) and showed the best diagnostic accuracy for AET with the cutoff value of 4.7 mmHg (area under the curve [AUC], 0.87). The gradient of EPSIS waveform also revealed good diagnostic accuracy for abnormal AET with the cutoff value of 0.07 mmHg/s (AUC, 0.81).

CONCLUSIONS

Endoscopic pressure study integrated system waveform parameters, especially pressure difference, presented high diagnostic accuracy for the presence of abnormal acid reflux.

Measurement of intragastric pressure: an objective method to ascertain whether gastric wall extension is sufficient for assessment of the non-extension sign

Background and study aims  The optimal intragastric pressure (IP) for strong gastric wall extension is unclear. We aimed to develop an accurate method to measure IP using endoscopy and determine the pressure required for strong gastric wall extension. Methods  An in vitro experiment using an endoscope with a rubber attached at its tip was conducted. The process of inserting the pressure measurement probe into the forceps channel was skipped, and the tube of the pressure measurement device was directly connected to the forceps channel. In vivo, the pressure in 51 consecutive patients at the time of strong gastric wall extension was measured. Strong extension of the gastric wall was defined as when the folds in the greater curvature were flattened as a result of sufficient extension of the gastric wall by insufflated air during upper gastrointestinal endoscopy. The IP at that time was measured. Results  In vitr o , 20 mL of tap water was injected once into the forceps channel and then aspirated for 10 seconds. Pressure measurement after irrigation of the forceps channel as well as the measurement by inserting the probe procedure were accurately performed. In vivo, among the 51 included patients, the mean IP (range) was 14.7 mmHg (10-23). Strong extension of the gastric wall was obtained in 96.1 % of patients when the IP was 20 mmHg. Conclusions  We developed an accurate method to measure IP using upper gastrointestinal endoscopy. Strong extension of the gastric wall was obtained in almost all patients when the IP was 20 mmHg.

The effect of arabinoxylooligosaccharides on gastric sensory-motor function and nutrient tolerance in man

BACKGROUND

Intestinal microbiota regulates gastrointestinal sensory-motor function. Prebiotics such as arabinoxylan-oligosaccharide (AXOS) are non-digestible, fermentable food ingredients beneficially affecting intestinal microbiota, colon activity, and improving human health. We wanted to investigate whether acute AXOS or maltodextrin (placebo) administration may alter gastric sensitivity (GS), accommodation (GA), nutrient tolerance (NT) in man.

METHODS

Thirteen HV (6 M, 32.2 ± 1.8 years; BMI 22.3 ± 0.2) underwent two 48 h treatment periods with oral 4 × 9.4 g AXOS or 4 × 10 g maltodextrin (at least 1 week wash-out) for gastric barostat assessment of GS, gastric compliance (GC), GA to a liquid test meal, on day 1, and NT drink test, on day 2. Oro-cecal transit-time (OCTT), colonic fermentation (CF) were assessed simultaneously with (13) C-lactose ureide, H2 breath tests.

KEY RESULTS

Arabinoxylan-oligosaccharide significantly increased CF on day 1 and 2 (565 ± 272 vs 100 ± 24, 365 ± 66 vs 281 ± 25 H2 ppm/min, AXOS vs maltodextrin, both p < 0.05), not the OCTT. AXOS did not alter GC, sensitivity before and after the meal. Gastric accommodation was not significantly influenced by AXOS (volume increment: 171 ± 33 vs 130 ± 28 mL, AXOS vs maltodextrin, p = NS). On day 1, AXOS fermentation was associated with significantly higher postprandial bloating scores (960 ± 235 vs 396 ± 138 mm*min, AXOS vs maltodextrin, p < 0.05). On day 2, AXOS did not affect maximal NT (946 ± 102 vs 894 ± 97 mL, AXOS vs maltodextrin, p = NS), increased the bloating score (1236 ± 339 vs 675 ± 197 mm*min, AXOS vs maltodextrin, p < 0.05).

CONCLUSIONS & INFERENCES

Acute AXOS administration, associated with increased CF, does not affect GA, is not associated with increased meal-induced satiety or perception scores.

Intragastric pressure as a determinant of food intake

BACKGROUND

Different studies indicated a correlation between intragastric pressure (IGP) and satiation. Our aim was to investigate this correlation while artificially increasing the IGP.

METHODS

In 12 fasted healthy volunteers an infusion catheter and a manometry probe were positioned intragastrically. Intragastric pressure was increased using a custom-made belt before or progressively during intragastric nutrient infusion. Nutrient drink (1.5 kcal mL(-1)) was intragastrically infused at 60 mL min(-1) . The subjects scored satiation using a 6-point Likert scale until maximum, when the infusion ended and the belt was released. Results are presented as mean ± S.E.M. and compared using a paired t-test.

KEY RESULTS

When the belt was tightened before the nutrient infusion, fasting IGP was significantly increased (13.6 ± 1.3 vs 9.6 ± 0.9 mmHg; P < 0.05) but no differences in satiation could be observed. When progressively tightening the belt during nutrient infusion the IGP increased with 0.43 ± 0.04 mmHg per minute while in control experiments this was 0.28 ± 0.05 mmHg per minute (P < 0.01). During the latter experiment satiation linearly increased with 0.35 ± 0.03 and 0.29 ± 0.02 units per minute until maximal satiation (P < 0.01) while maximum volume consumed was 926 ± 66 and 1095 ± 82 mL when progressively increasing the IGP vs control respectively (P < 0.01).

CONCLUSIONS & INFERENCES

These findings indicate that IGP per se does not affect satiation but that a gradual IGP increase during food intake is associated with decreased food intake, indicating that gastric accommodation is an important determinant of food intake.

Response to air insufflation in patients with non-erosive gastro-oesophageal reflux disease (NERD)

This study compared changes in intragastric pressure (IGP) in response to a gastric distension stimulus caused by air insufflation in 25 patients with non-erosive gastro-oesophageal reflux disease (NERD) and 34 healthy volunteers (controls). In four NERD patients, IGP responses were also measured before and after oral treatment with 10 mg rabeprazole daily for 2 weeks. The rate of increase in IGP at the start of insufflation was significantly higher in NERD patients than in controls. The time to appearance of symptoms (i.e. time to threshold) was significantly shorter in NERD patients than in controls. Direct measurement of IGP showed that visceral hypersensitivity and impaired fundal relaxation are both characteristic of NERD. Administration of rabeprazole led to a marked prolonging of time to threshold, indicating that treatment could alleviate this hypersensitivity.

Intragastric pressure during food intake: a physiological and minimally invasive method to assess gastric accommodation

BACKGROUND

The stomach relaxes upon food intake and thereby provides a reservoir while keeping the intragastric pressure (IGP) low. We set out to determine whether we could use IGP as a measurement for stomach accommodation during food intake.

METHODS

In fasted healthy volunteers (n = 7-17) a manometer and an infusion catheter were positioned in the proximal stomach. After a stabilization period a nutrient drink was intragastrically infused at 15, 30 and 60 mL min(-1). To investigate the effect of impaired accommodation the effect of N(G)-monomethyl-L-arginine (L-NMMA) was examined. The volunteers scored satiation until maximum, when the experiment ended. The IGP was presented as a change from baseline (mean ± SEM) and compared with repeated measures anova.

KEY RESULTS

Independent on the ingestion speed, the IGP decreased initially and gradually increased thereafter. Volunteers scored maximal satiation after 699 ± 62, 809 ± 90 and 997 ± 120 mL nutrient drink infused (15, 30 and 60 mL min(-1) respectively; P < 0.01). Maximum IGP decrease was 3.4 ± 0.5 mmHg after 205 ± 28 mL, 5.1 ± 0.7 mmHg after 212 ± 46 mL, and 5.2 ± 0.7 mmHg after 296 ± 28 mL infused volume [15, 30 and 60 mL min(-1) respectively; not significant (ns)]. Post hoc analysis showed significant correlations between IGP and satiation score increase. During L-NMMA infusion IGP was significantly increased while subjects drank significantly less (816 ± 91 vs 1032 ± 71 mL; P < 0.005). Interestingly, the correlation between IGP increase and satiation score increase did not differ after L-NMMA treatment.

CONCLUSIONS & INFERENCES

The IGP during nutrient drink ingestion provides a minimally invasive alternative to the barostat for the assessment of gastric accommodation. These findings furthermore indicate that IGP is a major determinant of satiation.

Review article: the role of gastric motility in the control of food intake

BACKGROUND

From a classical point of view, gastric motility acts to clear the stomach between meals, whereas postprandial motility acts to provide a reservoir for food, mixing and grinding the food and to assure a controlled flow of food to the intestines.

AIM

To summarise findings that support the role of gastric motility as a central mediator of hunger, satiation and satiety.

METHODS

A literature review using the search terms 'satiety', 'satiation' and 'food intake' was combined with specific terms corresponding to the sequence of events during and after food intake.

RESULTS

During food intake, when gastric emptying of especially solids is limited, gastric distension and gastric accommodation play an important function in the regulation of satiation. After food intake, when the stomach gradually empties, the role of gastric distension in the determination of appetite decreases and the focus will shift to gastric emptying and intestinal exposure of the nutrients. Finally, we have discussed the role of the empty stomach and the migrating motor complex in the regulation of hunger signals.

CONCLUSIONS

Our findings indicate that gastric motility is a key mediator of hunger, satiation and satiety. More specifically, gastric accommodation and gastric emptying play important roles in the regulation of gastric (dis)tension and intestinal exposure of nutrients and hence control satiation and satiety. Correlations between gastric accommodation, gastric emptying and body weight indicate that gastric motility can also play a role in the long-term regulation of body weight.

Leaks and endoscopic assessment of break of integrity after NOTES gastrotomy: the LEAKING study, a prospective, randomized, controlled trial

BACKGROUND

Gastric leak testing after natural orifice transluminal endoscopic surgery (NOTES) gastrotomy closure may help reduce the risk of leaks after transgastric procedures.

OBJECTIVE

To develop a novel endoscopy-based system to determine the presence of a leak after NOTES gastrotomy and to compare this system prospectively with radiographic leak testing.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Academic Medical Center laboratory.

SUBJECTS

Fifty swine.

INTERVENTION

During the pretrial phase, an endoscopic system for the measurement of intragastric pressure was developed. In the trial phase, swine with a NOTES gastrotomy were randomized to endoscopic versus radiographic leak testing. If a leak was demonstrated, the gastrotomy was reclosed by using a second-generation prototype T-anchor system. The primary outcome was leak detection after gastrotomy closure. The secondary outcome variables included necropsy findings, peritoneal fluid analysis, histologic examination, and clinical outcome.

RESULTS

Fourteen swine were included in the pretrial phase and 36 in the randomized trial. Swine were survived for a mean of 9 days postoperatively. Endoscopic pressure monitoring demonstrated a reproducible change in intragastric pressure with insufflation; r = 0.735, P = .001 and r = 0.769, P < or = .000 for the total and maximum pressures, respectively. Post-peritoneoscopy, there was a detectable and significant decrease in the mean total and mean maximum pressures versus baseline (P = .006 and P = .009). There was no significant difference between the radiologic and endoscopic arms in leak detection rate (4/18 vs 3/18, respectively, P = .500). Clinical outcomes and mean weight gain were equivalent. There was 1 operative abdominal wall injury and no deaths.

LIMITATIONS

Animal study.

CONCLUSION

Endoscopic pressure monitoring was reproducible, demonstrated the presence of gastric leak, and was as reliable as contrast-based radiographic leak testing.