Validation of electrode placement in neonatal electrogastrography

Tachygastria in Preterm Infants: A Longitudinal Cohort Study

OBJECTIVES

Tachygastria is a gastric dysrhythmia (>4 to ≤9 cycles per minute, cpm) associated with gastric hypomotility and gastrointestinal disorders. Healthy preterm infants spend more time in tachygastria than adults; however, normative values are not defined. We sought to determine the percent of time preterm infants spend in tachygastria.

METHODS

We conducted a longitudinal, prospective cohort study with weekly electrogastrography (EGG) recordings in 51 preterm <34 weeks' gestation and 5 term (reference) infants. We calculated percentage recording time in tachygastria (% tachygastria) and determined the mean ± standard deviation (SD) across EGG sessions. Mixed effects model was performed to test weekly variance in % tachygastria and gestational age effect. Successive pre- and post-prandial measurements were obtained to assess reproducibility of % tachygastria. We compared time to achieve full feeds between subjects with % tachygastria within 1 SD from the mean versus % tachygastria >1 SD from mean.

RESULTS

Three hundred seventy-six EGG sessions were completed (N = 56). Mean % tachygastria was 40% with SD ±5%. We demonstrated no change in % tachygastria across 9 postnatal weeks (P = 0.70) and no gestational age effect. No difference was demonstrated between successive pre- (P = 0.91) and post-prandial (P = 0.96) % tachygastria. Infants with 35%-45% tachygastria (within 1 SD from mean) had higher gestational age and less time to achieve full feeds than infants with <35% or >45% tachygastria.

CONCLUSIONS

EGG is a reproducible tool to assess % tachygastria in preterm infants. Clinical significance of increased or decreased % tachygastria needs further investigation to validate if 35%-45% tachygastria is safe for feeding.

TRANSCUTANEOUS MULTICHANNEL ELECTROGASTROGRAPHY: NORMAL PARAMETERS IN A BRAZILIAN POPULATION

BACKGROUND

Electrogastrography (EGG) is a noninvasive technique for the assessment of gastric myoelectrical activity using electrodes placed on the abdominal surface. Changes in gastric myoelectrical activity may be associated with diseases such as gastroparesis, functional dyspepsia, nausea, and recurrent vomiting. In Brazil, no studies to date have assessed gastric myoelectrical activity using multichannel EGG in healthy individuals.

OBJECTIVE

To establish normal values of transcutaneous multichannel EGG in healthy Brazilian individuals.

METHODS

This was a prospective study including 20 healthy individuals who underwent EGG. Recording was performed during two periods: a preprandial recording was performed for 30 minutes, and a postprandial recording was performed for 30 minutes after a soft-solid meal of 400 kcal (20 grams of proteins, 60 grams of carbohydrates, and 9 grams of fat).

RESULTS

We assessed dominant frequency (DF) parameters, %DF distribution, the instability coefficient, and the power ratio (PR). A total of 20 individuals (11 women and 9 men) with a mean age of 39.5±7.4 years were included. Mean DF (95%CI) ranged from 2.4 to 3.1 cpm in the resting phase and 2.6 to 3.2 cpm in the postprandial period. The %DF in normogastria range was >70% in all healthy individuals. We identified that only one individual did not present a positive response to the test meal, and the other 19 individuals showed a PR greater than 1. The instability coefficient did not change significantly with meal intake.

CONCLUSION

Multichannel EGG may be applied in future studies to evaluate gastric motility disorders in the Brazilian population.

Simple gastric motility assessment method with a single-channel electrogastrogram

Surface electrogastrography (EGG) is a non-invasive technique that is used to record myoelectrical activity of the stomach using cutaneous electrodes placed on the abdomen. Gastric motility assessment by EGG is a candidate for standard clinical procedure based on the quantification of parameters characteristic of gastric motility disorders. Despite its noticeable benefits, EGG is not widely implemented in clinical practice. The main reasons are: (1) lack of standardization of electrode placement, (2) time-consuming diagnostic procedures and (3) a complex multi-channel recording setup. We proposed a methodology in which an easy-to-use single-channel EGG, with a less time-consuming protocol (<1 h), would provide sufficient information for gastric motility assessment. Recordings from the three anatomical landmarks in 20 healthy young subjects were compared under two conditions, fasting and postprandial by evaluating the dominant frequency (DF). Our results showed that there is a statistically significant increase of DF after meal ingestion (p<0.05) in each of the three channels. However, when the study group was divided into two subgroups based on body mass index (BMI), the most appropriate recording location was above the body of the stomach (according to statistical significance p=7.82×10-6). We showed that a less time-consuming recording session with light meal intake could be used for the assessment of gastric myoelectrical activity (GMA).

Electrogastrography in adults and children: the strength, pitfalls, and clinical significance of the cutaneous recording of the gastric electrical activity

Cutaneous electrogastrography (EGG) is a non-invasive technique to record gastric myoelectrical activity from the abdominal surface. Although the recent rapid increase in the development of electrocardiography, EGG still suffers from several limitations. Currently, computer analysis of EGG provides few reliable parameters, such as frequency and the percentage of normal and altered slow wave activity (bradygastria and tachygastria). New EGG hardware and software, along with an appropriate arrangement of abdominal electrodes, could detect the coupling of the gastric slow wave from the EGG. At present, EGG does not diagnose a specific disease, but it puts in evidence stomach motor dysfunctions in different pathological conditions as gastroparesis and functional dyspepsia. Despite the current pitfalls of EGG, a multitasking diagnostic protocol could involve the EGG and the (13)C-breath testing for the evaluation of the gastric emptying time-along with validated gastrointestinal questionnaires and biochemical evaluations of the main gastrointestinal peptides-to identify dyspeptic subgroups. The present review tries to report the state of the art about the pathophysiological background of the gastric electrical activity, the recording and processing methodology of the EGG with particular attention to multichannel recording, and the possible clinical application of the EGG in adult and children.

Electrogastrography: methodology, validation and applications

Electrogastrography (EGG) is a non-invasive method for the measurement of gastric myoelectrical activity. It was first discovered in 1921 and popularized in 1990s. EGG is attractive because it is non-invasive. However, due to its non-invasive nature, there have also been controversies regarding validity and applications of EGG. The aim of this review is to discuss the methodologies, validation and applications of EGG. Pros and cons of EGG will also be discussed in detail. First, the gastric slow wave and its correlation with gastric motility are presented. The association between gastric dysrhythmia and impaired gastric motility is reviewed. Secondly the method for recording the electrogastrogram is presented in detail and pitfalls in the recording and analysis of EGG are discussed. Thirdly, findings reported in the literature demonstrating the accuracy of EGG in recording gastric slow waves and gastric dysrhythmia are reviewed and discussed. The correlation of the electrogastrogram with gastric contraction is carefully discussed. Finally, applications of EGG in a few major areas are reviewed.

Electrogastrography: methodology, validation and applications

Electrogastrography (EGG) is a non-invasive method for the measurement of gastric myoelectrical activity. It was first discovered in 1921 and popularized in 1990s. EGG is attractive because it is non-invasive. However, due to its non-invasive nature, there have also been controversies regarding validity and applications of EGG. The aim of this review is to discuss the methodologies, validation and applications of EGG. Pros and cons of EGG will also be discussed in detail. First, the gastric slow wave and its correlation with gastric motility are presented. The association between gastric dysrhythmia and impaired gastric motility is reviewed. Secondly the method for recording the electrogastrogram is presented in detail and pitfalls in the recording and analysis of EGG are discussed. Thirdly, findings reported in the literature demonstrating the accuracy of EGG in recording gastric slow waves and gastric dysrhythmia are reviewed and discussed. The correlation of the electrogastrogram with gastric contraction is carefully discussed. Finally, applications of EGG in a few major areas are reviewed.

[Electrogastrography in the elderly and effect of hot stupes on the solar plexus]

OBJECTIVES

Constipation affects as many as 26% of elderly men and 34% of elderly women and is a problem that has been related to a diminished quality of life. The aim of this study was to investigate the influence of aging on electrogastrograms (EGGs). On the basis of the EGGs of elderly individuals, the effect of hot stupe application on the epigastrium was also evaluated.

METHODS

The first group included 14 healthy, young participants (age, 20-25 years) and the second group comprised 14 healthy, elderly participants (age, 65-76 years). EGGs were obtained for the first 30 min in a sitting position and for the next period (> 150 min) in a supine position. A hot stupe was placed on the epigastrium of each elderly patient 90 min after the postural change. We evaluated EGGs by spectral analysis and nonlinear analysis.

RESULTS

On comparing the gastrointestinal electrical activity of the elderly group with that of the young group, the activity in the former revealed an overall decrease. With hot stupe application, translation error in the elderly individuals was significantly larger than that without hot stupe application (p < 0.01). We also observed a gender-specific characteristic, wherein the gastrointestinal motility of the young women was likely only influenced by postural change. Moreover, the translation error in the EGGs of the elderly individuals increased during hot stupe heating.

CONCLUSIONS

This increase in the translation error suggests that the electrical synergy between the stomach and intestine could be enhanced by the application of a hot stupe. Our findings also indicated that hot stupe application on the epigastrium was effective for improving gastrointestinal motility in elderly individuals.

Evaluation of residual stomach motility after proximal gastrectomy for gastric cancer by electrogastrography

The relationship between the motility and the size of the residual stomach after proximal gastrectomy was evaluated using electrogastrography (EGG). Based on fast Fourier transformation, recorded slow waves could be analyzed to obtain the following parameters: dominant frequency (DF), percentage normal frequency (% 3 cycles per minute [cpm]), and power ratio (PR). EGG parameters, the length of the greater curvature of the residual stomach (LGC), were recorded in 18 gastrectomized patients. Compared to 12 healthy controls, the gastrectomized patients had abdominal EGG parameters including lower %3cpm (43 +/- 21% vs 83 +/- 7%; P < 0.05), DF (2.2 +/- 0.4 vs 3.0 +/- 0.2 cpm; P < 0.05), and PR (1.5 +/- 0.8 vs 2.5+/- 0.8; P < 0.05). In relation to LGC and parameters, there was no difference between the patients whose LGC was > 20 cm and controls in PR (2.3+/- 0.9 vs 2.5+/- 0.8; n.s.). In conclusion, the motility of the residual stomach would be equal to that of the nonresected stomach as if the volume of the residual stomach was more than half.

Multiscale modelling of human gastric electric activity: can the electrogastrogram detect functional electrical uncoupling?

During recent years there has been a growing interest in the assessment of gastric electrical health through cutaneous abdominal recordings. The analysis of such recordings is largely limited to an inspection of frequency dynamics, and this has raised doubts as to whether functional gastric electrical uncoupling can be detected using this technique. We describe here a computational approach to the problem in which the equations governing the underlying physics of the problem have been solved over an anatomically detailed human torso geometry. Cellular electrical activity was embedded within a stomach tissue model, and this was coupled to the torso using an equivalent current source approach. Simulations were performed in which normal and functionally uncoupled (through the introduction of an ectopic antral pacemaker) gastric slow wave activity was present, and corresponding cutaneous electrogastrograms were produced. These were subsequently analysed using the currently recommended techniques, and it was found that the functionally uncoupled situation was indistinguishable from normal slow wave activity using this approach.

Use of electrogastrography in children

Electrogastrography (EGG), the measurement of gastric pacemeaker activity by means of surface electrodes, provides a noninvasive technique to detect and quantify the characteristics of the gastric slow wave. With a predominant frequency of three cycles per minute, the activity of the specialized cells responsible for this pacing, the interstitial cells of Cajal, is crucial in providing the underlying electrophysiologic changes that enable coordinated smooth muscle contraction and synchronized peristalsis. Advances in electronics and software to define frequency distribution, stability of the signal, postprandial changes, and other parameters have contributed to more widespread interest in EGG and its application to the investigation of functional gastrointestinal disturbances. Definition of pediatric norms and postnatal changes in the EGG of premature infants has provided the foundation for further studies investigating correlative changes with such important functions as gastric emptying and motility. The EGG remains a promising diagnostic tool. Future studies will help define its usefulness in identifying abnormal functions of the interstitial cells of Cajal.