Gastric Manometry Research Articles

Monitoring respiratory mechanics during assisted ventilation.

Accurate monitoring of the mechanical properties of the respiratory system is crucial to understand the pathophysiological mechanisms of respiratory failure in mechanically ventilated patients, to optimize mechanical ventilation settings and to reduce ventilator-induced lung injury. However, although the assessment of respiratory mechanics is simple in patients undergoing fully controlled ventilation, it becomes quite challenging in the presence of spontaneous breathing activity. Aim of the present review is to describe how the different components of respiratory mechanics [resistance, static compliance, and intrinsic positive end-expiratory pressure (PEEP)] can be measured at the bedside during assisted modes of ventilation. Available techniques for bedside measurement of resistance during assisted ventilation are complex and not commonly implemented. On the contrary, an increasing number of reports indicate that measurement of static compliance and intrinsic PEEP can be easily obtained, both with advanced monitoring systems (esophageal and gastric manometry, diaphragm electromyography, electrical impedance tomography) and, with some limitations, with simple airways occlusion maneuvers. Assessment of respiratory mechanics in spontaneously breathing patients, with some limitations, is feasible and should be included in everyday clinical practice; however, more data are needed to understand the clinical relevance of the measures obtained during assisted ventilation.

Passive Wireless Pressure Sensing for Gastric Manometry.

We describe a wireless microsystem for gastrointestinal manometry that couples a microfabricated capacitive transducer to a dual-axis inductor, forming a resonant inductor-capacitor (LC) sensor within an ingestible 3D printed biocompatible capsule measuring ø 12 mm × 24 mm. An inductively coupled external telemetry unit wirelessly monitors the pressure dependent resonant frequency of the LC sensor, eliminating the need for integrated power sources within the ingested capsule. In vitro tests in saline show pressure response of −0.6 kHz/mmHg, interrogation distance up to 6 cm, and resolution up to 0.8 mmHg. In vivo functionality is validated with gastrointestinal pressure monitoring in a canine beagle over a 26-hour period.

Artifact Rejection Methodology Enables Continuous, Noninvasive Measurement of Gastric Myoelectric Activity in Ambulatory Subjects

The increasing prevalence of functional and motility gastrointestinal (GI) disorders is at odds with bottlenecks in their diagnosis, treatment, and follow-up. Lack of noninvasive approaches means that only specialized centers can perform objective assessment procedures. Abnormal GI muscular activity, which is coordinated by electrical slow-waves, may play a key role in symptoms. As such, the electrogastrogram (EGG), a noninvasive means to continuously monitor gastric electrical activity, can be used to inform diagnoses over broader populations. However, it is seldom used due to technical issues: inconsistent results from single-channel measurements and signal artifacts that make interpretation difficult and limit prolonged monitoring. Here, we overcome these limitations with a wearable multi-channel system and artifact removal signal processing methods. Our approach yields an increase of 0.56 in the mean correlation coefficient between EGG and the clinical “gold standard”, gastric manometry, across 11 subjects (p < 0.001). We also demonstrate this system’s usage for ambulatory monitoring, which reveals myoelectric dynamics in response to meals akin to gastric emptying patterns and circadian-related oscillations. Our approach is noninvasive, easy to administer, and has promise to widen the scope of populations with GI disorders for which clinicians can screen patients, diagnose disorders, and refine treatments objectively.

Gastric Function in Children with Oesophageal Atresia and Tracheoesophageal Fistula.

Oesophageal atresia and tracheoesophageal fistula (OA–TOF) are a multifaceted condition which affects patients throughout their lives. Even though it is one of the most common gastrointestinal malformations, most of the current studies focus on gastro-oesophageal reflux disease, anastomotic strictures, and feeding difficulties. However, there is increasing evidence that a proportion of patients with OA–TOF also have abnormal gastric function. This review aims to provide a comprehensive understanding of studies of gastric function in patients with OA–TOF. The etiology of this abnormality has been hypothesized to be congenital and/or acquired. Several modalities are currently available for the investigation of gastric function, each of them trying to answer specific clinical questions. This review summarizes the studies that have looked at gastric function in the OA–TOF cohort with gastric emptying studies (gastric emptying scintigraphy and 13C octanoic breath test), gastric manometry, electrogastrography, and oral glucose tolerance test. However, these modalities are limited due to poor age-specific normative values and heterogeneous methodologies used. The evaluation of symptoms in this cohort is crucial, modalities for abnormal gastric function are also described. With appropriate investigations and symptoms questionnaires, treatment strategies can be implemented to correct abnormal gastric function and thereby improve the outcomes and quality of life of patients with OA–TOF. This review highlights the need for large international multicentre collaborative studies and high-quality prospective randomized controlled trials to improve our understanding of gastric function in this cohort.

High-resolution manometry for the evaluation of gastric motility.

This review focus on the utility of HRM for the evaluation of gastric motility. The evaluation of gastric motility has clinical implications for the study of a myriad of diseases. Disordered motility represents a spectrum of dysfunction ranging from delayed gastric emptying to abnormally rapid gastric transit. Gastric motility may be measured by a variety of methods with different efficacy and different variables that may be obtained. High-resolution manometry was created and added to the diagnostic armamentarium. The methods and outcomes for the study of proximal motility that may be useful to assess the thoracoabdominal pressure gradient, gastric filling and accommodation are described. Also, studies on antroduodenal manometry are reviewed. High-resolution manometry allows gastric manometry without technical limitations found on conventional manometry; however, studies are still on the phase of understanding the normal findings.

Respiratory Muscle Pressure Development during Breath Holding in Apnea Divers

We sought to characterize the patterns of active pressure development of the inspiratory and expiratory rib cage muscles (P(rcm,i) and P(rcm,e)), the diaphragm (P(di,i)), and the expiratory abdominal muscles (P(abm,e)) during maximal "dry" breath holding in trained apnea divers (n = 8). Respiratory contractions were assessed via esophageal and gastric manometry. It was expected that inspiratory/expiratory pressures would progressively increase in both magnitude and frequency during the struggle phase, and that inspiratory rib cage muscle pressures would rise at a rate exceeding that of the diaphragm by the break point. P(rcm,i), P(di,i), P(rcm,e), and P(abm,e) significantly increased from the beginning until the end of the struggle phase (P < 0.05). Moreover, P(di,i)/P(rcm,i) and P(abm,e)/P(rcm,e) ratios had declined by the break point (P < 0.05), indicating that rib cage muscles increased their contribution to net inspiratory/expiratory pressure development by the end of the breath hold, relative to that contributed by the diaphragm and abdominal muscles. The pressure-time indices of the diaphragm and inspiratory rib cage muscles continuously increased over the struggle phase (P < 0.05). The "extradiaphragmatic" shift in inspiratory muscle recruitment, commensurate with increasing P(rcm,e) and P(abm,e), may reflect an extreme loading response to breathing against a heavy elastance (i.e., closed glottis). In addition, the relative intensity of diaphragmatic and inspiratory rib cage muscle contractions approaches potentially "fatiguing" levels by the break point of maximal breath holding.

Use of gastric balloon manometry for estimation of intra‐abdominal pressure in horses

Standing laparoscopic procedures, facilitated by abdominal insufflation with carbon dioxide, are being employed to an increasingly greater extent in horses. However, a sustained increase in abdominal pressure may be life-threatening. A practical method for intra-abdominal pressure (IAP) assessment is imperative. Although indirect methods for estimating IAP have been extensively studied in man, little work has been performed in veterinary medicine. To investigate the utility of gastric manometry for purposes of evaluating IAP in horses. Gastric pressure (P(ga) ) was estimated by balloon manometry in 8 healthy, mature horses, before and during a 30 min passive pneumoperitoneum induced by right paralumbar puncture. The balloon manometer was positioned within the gastric lumen and inflated using 2 separate volumes of air: 10 and 50 ml. P(ga) Gastric pressure was determined at baseline (0) and 5, 15 and 30 min after induction of passive pneumoperitoneum. Intra-abdominal pressure was measured directly by right paralumbar puncture using an 8 gauge needle at baseline and immediately following establishment of passive pneumoperitoneum. Baseline IAP values were negative and increased (P≤0.05) during development of passive pneumoperitoneum. However, recorded P(ga) measurements for both inflation volumes were positive before (baseline) and during the course of the passive pneumoperitoneum. Measured P(ga) values did not correlate with IAP at any time. Our results suggest that the indirect method used in human patients for estimating IAP by P(ga) is not applicable for horses.

Gastric motility following oesophagectomy.

The motility of the vagally denervated transposed stomach after oesophagectomy was examined by ambulatory gastric manometry and videofluoroscopy. Two groups of subjects were studied. Group 1 comprised ten patients who had undergone oesophagectomy 6-12 months previously and group 2 consisted of six normal control subjects. Studies were performed on fasting and fed subjects, and following injection of erythromycin 8 mg/kg. No distinguishable manometric wave activity was seen in either group while fasting. Feeding generated a measurable wave pattern in the patient group only. A significant increase in the mean (s.e.m.) distal wave amplitude was identified after infusion of erythromycin in both patients (34.0(15.1) versus 12.2(3.1) mmHg, P < 0.05) and controls (15.1(3.4) versus 5.0(0.0) mmHg, P = 0.05). The response to erythromycin was more rapid in patients than in controls (mean(s.e.m.) 113(16) versus 377(133) s, P < 0.05) and the effect persisted for longer (more than 1 h) in those who had undergone oesophagectomy. Videofluoroscopy confirmed purposeful motility in both the normal and vagally denervated stomach. It is concluded that the transposed stomach is a dynamic conduit. Enhancement of motility was greatest in the denervated stomach, indicative of denervation supersensitivity.

354 Surface Electrogastrography in Growing Preterm Neonates

Background: The ability to provide enteral nutrition to preterm infants is limited by immaturity of GI motor function. Manometry and electrogastrography(EGG) have been used to study gastric dysrhythmias and GI motor disorders in adults. EGG has been shown to be a reliable non-invasive alternative technique to gastric manometry in preterm infants. The information on pattern and maturation of EGG is limited in preterm infants. Objective: To investigate the effect of gestational and postnatal age on the pattern of gastric myoelectrical activity in preterm infants without feeding intolerance and those with gastroesophageal reflux(GER). Methods: EGG signals were recorded at 10Hz and bandpass filtered between 1.2 and 18 cycles/min(cpm), 30 minutes before and 2 hours after feeds. Signals were analyzed by FFT spectral analysis. The percentage of regular 2–4 cpm normal slow wave activity (NSW) and tachygastria(4–10cpm)was determined from a running power spectrum analysis generated at 10 minute intervals. Results: 70 EGGs were obtained in 31 infants; BW 1550±758SD g, range 618 to 3494, GA 30.7±4.5 SD wks, range 25 to 40, study age 38±24SD days, range 2–112. Preterm infants at term PCA had lower pre feeds NSW than those born at term(30.1±5.9% vs 41.7±14.8%). After feeds NSW increased in both groups ( 37.9±3.8% vs 52.1±10.8%). GER babies had 35% lower NSW than controls before feeds. NSW increased 53% after feeds in GER babies vs 13% in controls. tachygastria activity was 1.4 vs 7.8% (p=0.03) pre feeds, and 6.1 vs 6.8% post feeds in GER group as compared to controls. Conclusions: Preterm infants have less normal slow wave activity as compared to term infants which persisted up to term PCA. The response to feeds was less but similar to babies born at term. Maturation of Gastric myoelectrical activity of preterm infants with GER appears to lag behind that of infants without feeding intolerance.

Synchronous electrogastrographic and manometric study of the stomach as an esophageal substitute

To investigate the electric and contractile mechanisms involved in the deranged function of the transposed stomach in relation to the course of the symptoms and the changes in contractile and electrical parameters over time. Twenty-one patients after subtotal esophagectomy and 18 healthy volunteers were studied. Complaints were compiled by using a questionnaire, and a symptom score was formed. Synchronous electrogastrography and gastric manometry were performed in the fasting state and postprandially. Eight of the operated patients were symptom-free and 13 had symptoms. The durations of the postoperative periods for the symptomatic (9.1+/-6.5 mo) and the asymptomatic (28.3+/-8.8 mo) patients were significantly different. The symptom score correlated negatively with the time that had elapsed since the operation. The percentages of the dominant frequency in the normogastric, bradygastric and tachygastric ranges differed significantly between the controls and the patients. A significant difference was detected between the power ratio of the controls and that of the patients. The occurrence of tachygastria in the symptomatic and the symptom-free patients correlated negatively both with the time that had elapsed and with the symptom score. There was a significant increase in motility index after feeding in the controls, but not in the patients. The contractile activity of the stomach increased both in the controls and in the symptom-free patients. In contrast, in the group of symptomatic patients, the contractile activity decreased postprandially as compared with the fasting state. The patients' post-operative complaints and symptoms change during the post-operative period and correlate with the parameters of the myoelectric and contractile activities of the stomach. Tachygastria seems to be the major pathogenetic factor involved in the contractile dysfunction.

Forward of reverse gastric pacing do not affect gastric emptying of liquid meal in dogs

the changes in gastric motility, using electrugastrogram (EGG) and miniature pressure sensor placed in the antrum, and autonomic nerve functions after administration of CRH. [Subjects and Methods] 7 healthy volunteers participated in this study (6 male and 1 female, 18-22'].o.). EGG electrodes were attached on the bilateral mid-cravicular line of the hypochondrium and reference electrode was placed on 2cm above of the umbilicus. Dominant frequency of the EGG was calculated by FFT method. EGG frequency data were expressed as % of each range of the waves (Brady 1.6-2.4cpm, Normal 2.4-3.6cpm, Tachy >3.6). Antral manometry catheter was inserted into the gastric antrum and recorded in the data logger. Motility index (M.I.) was calculated by gastrointestinal motility software produced by White chapel Society. Heart rate variability were computed by holter ECG using FFT method and calculated LF/HF. EGG, gastric manometry and heart rate variability were recorded for 2 hr in the fasting period and 2 hr after administration of CRH (lOO/~g, bolus injection). Data, 20 minutes each, were calculated before and after CRH injection. Statistical evaluation was performed using Wilcoxon's signed-rank test. All the data were expressed as mean -+SD. [Conclusion] Peripheral injection of CRH has no influence on EGG, astral motility and sympathetic discharge in normal controls.

Effects of octreotide and erythromycin on gastric myoelectrical and motor activities in patients with gastroparesis.

Simultaneous recordings of gastric manometry and myoelectrical activity were made in 10 patients with gastroparesis. Intravenous erythromycin (100 mg) was administered in the fasting state for a period of 30 min. Subcutaneous injection of octreotide (100 microg) was administered before one of the four identical test meals. It was found that octreotide significantly decreased the antral motility index (30-min fasting: 4.51+/-1.04 vs 1.75+/-0.97, P < 0.02; 60-min fed: 5.16+/-1.44 vs 3.4+/-1.41, P < 0.05) and the dominant power of the EGG (fasting power: 35.19+/-1.54 vs 30.84+/-1.57 dB, P < 0.004; postprandial power increase: 5.52+/-1.06 vs -0.27+/-0.87, P < 0.001). Erythromycin significantly increased the antral motility index (3.16+/-0.96 vs 9.5+/-0.61, P < 0.001) and the dominant power of the EGG (28.86+/-1.57 dB vs 33.55+/-1.59 dB, P < 0.005) in the fasting state. An improvement in the regularity of the gastric slow wave was also noted with erythromycin. It was concluded that: (1) the inhibitory effect of octreotide on postprandial gastric motility and myoelectrical activity suggests that caution should be exercised when octreotide is used in patients with gastroparesis; and (2) the stimulatory effect of erythromycin on gastric myoelectrical activity may enhance gastric motility and gastric emptying in patients with gastroparesis.

Gastric Manometry in Hypertrophic Pyloric Stenosis

Gastric Manometry in Hypertrophic Pyloric Stenosis

Stasis Syndromes Following Gastric Surgery

We retrospectively reviewed the records of 60 patients who had been referred for gastrointestinal manometry because of stasis after gastric surgery. Nausea, vomiting, bloating, abdominal pain, and weight loss were the most common symptoms. Two thirds of these patients had a well-documented history of peptic ulcer before their initial operations; in others, surgery was performed for other reasons, such as obesity (5%) or reflux esophagitis (8%). Twelve patients had undergone truncal vagotomy and a "drainage operation" and 48 had received a partial gastrectomy with a gastroenterostomy: Billroth I (n = 8), Billroth II (n = 11), Roux-en-Y (n = 29). All patients had recordings of gastrointestinal manometry; 16 also had a scintigraphic measurement of gastric emptying. Measurements were compared with data from healthy controls. Gastric manometry, which could be assessed only in the group with an intact antrum, was characterized by antral hypomotility (p less than 0.05). Gastric emptying studies showed rapid early emptying of liquids and delayed emptying of solids (both p less than 0.05). In the whole group, fasting jejunal motility was characterized by absence of phase II in 13, presence of bursts of phasic activity in 18, and abnormal propagation of phase III in 8. A significantly increased frequency of phase III of MMC was noted in the patients after Billroth II and Roux-en-Y operations. Postprandially, 19 patients failed to develop a "fed pattern."(ABSTRACT TRUNCATED AT 250 WORDS)

Postprandial disruption of migrating myoelectric complex in dogs. Hormonal versus extrinsic nervous factors.

Our aim was to determine the mechanism whereby the jejunoileum regulates postprandial gastroduodenal motility. Five dogs were prepared with a proximal jejunal infusion catheter and with gastric manometry catheters and serosal intestinal electrodes for recording gastric and intestinal motility. After two weeks, fasted dogs were studied during jejunal infusion of either isosmolar NaCl (154 mM) or isosmolar mixed nutrient solution (50% Meritene) on four separate days each. After completion of these baseline studies, the dogs underwent a model of autotransplantation of the entire jejunoileum (extrinsic denervation, disruption of intrinsic neural continuity with proximal duodenum). Two weeks later, identical studies as before were repeated with the now "autotransplanted" jejunoileum. Before transplantation, infusion of NaCl did not interrupt the characteristic interdigestive migrating motor complex either in the gastroduodenum or in the jejunoileum. However, infusion of nutrients interrupted the migrating motor complex both in the gastroduodenum and jejunoileum for the duration of the infusion (5 hr). After autotransplantation of the jejunoileum, the migrating motor complex continued to occur in the gastroduodenum and in the jejunoileum during infusion of NaCl, but the migrating motor complex cycled independently in each region without any temporal coordination. Jejunal infusion of nutrients interrupted the MMC in both regions for the duration of infusion (5 hr). Because inhibition of the gastroduodenal and jejunoileal migrating motor complex continued to occur during infusion of nutrients into the transplanted jejunum, we concluded that jejunoileal regulation of postprandial inhibition of interdigestive motility in the stomach and duodenum is mediated by hormonal factors and does not require intrinsic neural continuity.