Tachygastria in Preterm Infants: A Longitudinal Cohort Study

Abstract

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 aren’t 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 % 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 1SD from the mean vs. % tachygastria >1SD from mean.

Results:

376 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.

Introduction

Gastric motility can be assessed non-invasively using cutaneous electrogastrography (EGG). EGG measures gastric myoelectrical activity driven by the interstitial cells of Cajal, the pacemaker cells of the stomach (1). These cells generate the normal gastric rhythm (normal slow waves) with electrical frequencies between 2–4 cycles per minute (cpm) (2, 3). Normal healthy adults spend 70% or more of the time in normal gastric rhythm (>2 to ≤4 cpm) or normogastria (4). For the remaining 30% of the time, gastric rhythm intermittently shifts to dysrhythmias of low and high frequencies called bradygastria (>0 to ≤2 cpm) and tachygastria (>4 to ≤9 cpm) respectively. In adults and older children, increased percent time spent in tachygastria is associated with gastric hypomotility and functional gastrointestinal (GI) disorders (5). The percent time preterm infants spend in tachygastria is unknown, but values appear higher than older children and adults (6, 7), suggesting GI immaturity.

Gastrointestinal immaturity predisposes toward development of feeding intolerance and pathologic conditions in preterm infants, including sepsis, spontaneous bowel perforation, and necrotizing enterocolitis (NEC) (8). Identification of evolving GI pathology in preterm infants remains difficult due to dependence on non-specific clinical signs and symptoms. Currently, no method exists to predict development of GI pathology in preterm infants. EGG is a non-invasive, objective method for monitoring the GI system at the bedside that could be developed for more effective and early detection of impending GI pathology in preterm infants. EGG, consisting of electrodes placed on the abdominal skin, (9, 10) is validated (9–19) to measure gastric myoelectrical activity. However, normative values in preterm infants have not been defined because of small sample sizes (11, 20) and different methodologies across studies (21). We utilized EGG in a large longitudinal prospective cohort of preterm infants of different gestational ages (GA) to define the % recording time preterm infants spend in tachygastria (% tachygastria) and to determine reproducibility of successive pre- and post-prandial measurements.

Methods

Study Design

In a longitudinal, prospective cohort study, participants underwent weekly EGG monitoring from the first week of enrollment (first 14 postnatal days) until 40 weeks postmenstrual age (PMA), discharge, or death, whichever came first.

Participants

Fifty-six infants (51 preterm and 5 term) from the neonatal intensive care unit (NICU) at Parkland Health and Hospital System and Children’s Health in Dallas, Texas were included in the study after parental consent from 2017–2019. The Institutional Review Board at UT Southwestern Medical Center approved this study. Inclusion and Exclusion Criteria: Subjects were preterm infants <34 weeks’ gestation and term infants ≥37 weeks of gestation. We enrolled term infants as reference to ensure EGG results were consistent with published literature. Babies were excluded for any known congenital or chromosomal disorders, significant clinical instability, or major skin abnormalities that preclude placement of skin electrodes. EGG sessions from infants nil per os (NPO) or on continuous feeds were excluded because these lack pre- and post-prandial periods. EGG sessions from infants on high frequency ventilation (jet or oscillator) were excluded because of significant motion artifacts.

Apparatus

Electrogastrography (EGG):

Neonatal electrocardiogram electrodes were applied to the abdominal skin as described and validated in previous studies (9, 10, 22). Briefly, Nuprep® (Weaver and Company, Aurora, CO) skin prep gel was used gently to clean the skin and lower the impedance. Next, conductive paste Ten20® (Weaver and Company, Aurora, CO) was applied between skin and electrodes to allow transmittance of gastric electrical signals. See Supplemental Digital Content 1, showing EGG setup. Electrodes were connected to BIOPAC® MP36R System data acquisition unit (BIOPAC® Systems, Inc., Goleta, CA). Timing of EGG recording coincided with feeding and availability of study personnel. EGG session recording time was 6 hours to ensure inclusion of a 30-minute pre-prandial period and the entire post-prandial period that followed the feeding (See Figure 1, showing the timeline of EGG recording). Feeding management was at the discretion of clinicians (blinded to EGG results). To test reproducibility of results, two pre- and two post-prandial EGG measurements for each subject were obtained during each 6-hour session.

Figure 1.

Timeline of Electrogastrography Recording.

EGG analysis

Raw EGG data were pre-filtered using a 2^nd order Butterworth high-pass filter at 0.016 Hz (1 cpm) to help eliminate motion artifacts as described previously (10). Welch’s Power Spectral Density Analysis based on Fast Fourier Transformation was performed using Matlab® (MathWorks, Inc., Natick, MA) to calculate % tachygastria (>4 to ≤9 cpm) for pre- and post-prandial periods of every EGG session in each subject. Gastric dysrhythmia is the % recording time that the gastric rhythm is outside the normal >2 to ≤4 cpm range. The gastric dysrhythmia of interest was tachygastria (>4 to ≤9 cpm). Because measurements >9 cpm can be due to motion artifacts and intestinal myoelectrical activity (not gastric), measurements >9 cpm were excluded. Other EGG measures of % bradygastria (>0 to ≤2 cpm), % normogastria (>2 to ≤4 cpm), dominant frequency, dominant power, power ratio, and instability coefficient were also calculated for completion (23, 24). Running spectral analysis heat maps were generated using Matlab® (MathWorks, Inc., Natick, MA) for visual comparisons between EGG sessions. A blinded biomedical engineer verified the analysis.

Statistical Analyses:

Descriptive statistics were used to summarize participant demographic and clinical characteristics. The distribution of % tachygastria for each EGG session at every postnatal week was arranged and graphically displayed into 4 groups (23–25, 26–28, 29–33, and ≥37 weeks’ gestation) to account for possible developmental maturation effects.

Repeated measures analysis:

Linear mixed effects model with random subject effect was utilized to assess for weekly changes in % tachygastria across all subjects. This model was performed with an unstructured covariance matrix and maximum likelihood estimation method. Gestational age, birthweight, and continuous positive airway pressure (CPAP) during the first week were included as covariates. Because post-prandial recording periods have variable duration and may be dependent on type and volume of feed, the first pre-prandial measurement of the EGG session was used in the analysis above; however, if missing, the second pre-prandial period of the same EGG session replaced the first (replacement method). To determine reproducibility of EGG measurements in individual subjects, a linear mixed effects model with random subject effect was also utilized for comparisons between first and second pre-prandial measurements, first and second post-prandial measurements, and between first pre- and post-prandial measurements from the same EGG session. For this last comparison, if the first pre- or post- prandial measurement was missing, the second pre- or post-prandial measurement of the same EGG session replaced the first (replacement method).

Stratification of subjects into medium, low, and high % tachygastria groups:

Descriptive statistics, such as mean, median and range across all EGG sessions, were calculated to define the cohort’s % tachygastria. Subjects were stratified into 3 groups: medium, low, and high % tachygastria. Subjects in the medium group had % tachygastria values within 1SD from the mean in all EGG sessions (no outliers). Because this is an exploratory study, subjects were classified in the low and high groups if they had any values >1SD below or above the mean, respectively (outliers). If any subject had an equal number of outliers >1SD below and above the mean, they were classified in the high % tachygastria group. Thus, classification was weighed more towards the high % tachygastria group because of potential for gastric hypomotility and functional GI disorders in these subjects (seen in older children and adults). Independent samples Kruskal-Wallis, Chi-square, or Fisher exact tests were utilized for comparisons between the groups when appropriate. Comparisons included demographics, feeding type, age of first feed, length of hospitalization, parenteral nutrition, central line and NPO days, days to achieve full feeds, presence of patent ductus arteriosus (PDA), development of NEC, death, exposure to antibiotics, acid-suppressive medications and prokinetic agents. Analyses above were conducted using SPSS, version 28. P-values <0.05 were considered statistically significant.

Results

Study Cohort:

Fifty-nine patients consented to participate during the enrollment period between 2017–2019 (See Figure, Supplemental Digital Content 2, showing subject enrollment flowchart). Three subjects were excluded (1 unstable for recording, 1 with poor skin integrity prior to electrode placement, and 1 had surgical necrotizing enterocolitis before any EGG measurements). Five subjects withdrew prior to protocol completion because of personal reasons, unrelated to the study. However, for all 5, parental permission was obtained to analyze and include data acquired prior withdrawal. Thus, 56 subjects were included (51 preterm and 5 term). 376 EGG sessions were completed (2256 hours of EGG recordings). There were no skin complications related to this study. Median GA of the cohort was 28 weeks, median birth weight was 1.22 kilograms, with equal number of males and females. See Table, Supplemental Digital Content 3, showing baseline subject characteristics.

Percent recording time in tachygastria (% tachygastria) was 35–45% in this cohort:

Mean % tachygastria for all EGG sessions was 40% (actual 39.6%) with SD of 5%. The % tachygastria for preterm and term infants was similar, demonstrating no developmental maturation effect. Figure 2a shows % tachygastria for the first ten pre-prandial EGG sessions for each subject (n=56). In this cohort, % tachygastria within 1 SD from the mean was 35–45% for all 17 postnatal weeks (Figure 2b).

Figure 2. Percent Recording Time in Tachygastria.

a) Percent recording time in tachygastria was 35–45% (1SD from the mean). The first 10 weekly pre-prandial EGG sessions are shown for each subject. Data were arranged and displayed by gestational age groups. b) Boxplot showing distribution of % tachygastria for all EGG sessions of the cohort.

c) Repeated measures analysis (linear mixed effects model with random subject effect) for preterm infants (n=51) demonstrated consistency of the pre-prandial % tachygastria measure between weeks 1–9 (p=0.70) with a decrease in week 10 (p=0.009) and 13 (p=0.015). SD = standard deviation, cpm = cycles per minute.

Repeated measures analysis results:

Linear mixed effects model with random subject effect demonstrated no change in pre-prandial % tachygastria from postnatal weeks 1–9 (p=0.70). However, a decrease was noted in % tachygastria across all 17 postnatal weeks (p=0.01) with weeks 10 (p=0.009) and 13 (p=0.015) driving the significance (Figure 2c). Similar results were demonstrated across all 17 weeks when including GA, birthweight, and CPAP during the first week as covariates (decrease in % tachygastria (p=0.02) with weeks 10 (p=0.009) and 13 (p=0.02) driving the significance). These covariates were not statistically significant, which indicates they can be removed from the model. After week 9, most subjects (>52%) had missing data because of study completion at 40 weeks’ PMA, withdrawal, death, or discharge.

Successive pre- and post-prandial EGG measurements of % tachygastria were consistent, reproducible, and not influenced by feeding:

Linear mixed effects model with random subject effect demonstrated no difference between successive pre-prandial (p=0.91), post-prandial (p=0.96), and between pre-prandial and post-prandial measurements from the same EGG session (p=0.09). Of all EGG measures, only instability coefficient between pre- and post-prandial periods was different (p=0.01). See Table 1, showing results of additional EGG measures.

Table 1. Electrogastrography Measures.

Pre- and post-prandial results for all electrogastrography measures demonstrate that % tachygastria is reproducible in successive pre- and post-prandial periods and is not affected by feeding. Median (Range) is presented for continuous variables.

EGG Parameters		Feed 1	Feed 2	p-valuea
% Bradygastria, <2 cpm	Pre-prandial	24 (5–46)	24 (6–42)	0.45
	Post-prandial	23 (8–42)	23 (12–39)	0.84
	p-value a			0.06
% Normogastria, 2–4 cpm	Pre-prandial	23 (9–30)	22 (9–31)	0.37
	Post-prandial	22 (11–30)	22 (13–30)	0.75
	p-value			0.07
% Tachygastria, 4–9 cpm	Pre-prandial	40 (20–65)	40 (20–62)	0.91
	Post-prandial	40 (26–61)	40 (28–53)	0.96
	p-value			0.09
Dominant Frequency, cpm	Pre-prandial	0.6 (0.6–10.2)	0.6 (0.6–9)	0.55
	Post-prandial	0.6 (0.6–8.4)	0.6 (0.6–7.8)	0.40
	p-value			0.30
Dominant Power, mV2/Hz	Pre-prandial	0.03 (0–29.9)	0.04 (0–10.4)	0.83
	Post-prandial	0.05 (0–13.6)	0.06 (0–11.4)	0.90
	p-value			0.86
Power Ratio		1.35 (0.3–456)	1.3 (0.03–3978)	0.35
Instability coefficient	Pre-prandial	0.67 (0.14–1.3)	0.67 (0.21–1.2)	0.21
	Post-prandial	0.66 (0.16–1.2)	0.65 (0.3–1.2)	0.99
	p-value			0.01*

^aMixed effects model with random subject effect. Dominant frequency is the frequency at which the power in the power spectrum has a peak value. Dominant power is the power in the power spectrum at the dominant frequency. Power ratio is the ratio of the post-prandial and pre-prandial dominant powers. Instability coefficient specifies the stability of the dominant frequency and power of the EGG. cpm = cycles per minute, mV = millivolts, Hz = Hertz.

Characteristics of infants with medium (35–45%), low (<35%) and high (>45%) % tachygastria:

Of 376 EGG sessions, 279 had % tachygastria values 35–45% (1SD from the mean), 63 <35% (>1SD below the mean), and 34 >45% (>1SD above the mean). Subjects were stratified into 3 groups: medium (N=14), low (N=22), and high (N=20) % tachygastria as described in the methods section. We compared demographic and clinical characteristics between 3 groups (Table 2). Subjects in the medium (35–45%) group (compared to low and high groups) had higher median GA at birth and birthweight, lower hospital, parenteral nutrition, central line and NPO days, lower days to achieve full feeds (≥120 mL/kg/day), and lower antibiotic exposure >48 hours. The median age for starting feeds was higher for the high (>45%) group, compared to the medium (35–45%) and low (<45%) groups. No subject was exposed to acid-suppressive medications. The number of times NPO, age of first stool, number of early onset (≤72 hours) or late onset (>72 hours) culture positive septicemia/bacteremia were not different between the 3 groups (data not shown).

Table 2. Tachygastria Groups.

Demographic and clinical characteristics between 3 groups of infants who spent <35%, 35–45%, and >45% time in tachygastria. Median (Range) is presented for continuous variables and n (%) for categorical variables.

	Low <35% (N=22)	Medium 35–45% (N=14)	High >45% (N=20)	p-valuea
Gestational Age, weeks	28 (23–33)	33 (25–39)	28 (24–33)	0.002*
Birthweight, kg	1.13 (0.64–2.18)	1.89 (1.01–4.25)	1.08 (0.71–2.52)	0.001*
Sex				0.784
Female	11 (50)	6 (43)	11 (55)
Male	11 (50)	8 (57)	9 (45)
Race/Ethnicity				0.612
Black Non-Hispanic/Latino	5 (23)	5 (36)	5 (25)
White Non-Hispanic/Latino	0 (0)	0 (0)	1 (5)
Hispanic	17 (77)	9 (64)	13 (65)
Asian	0 (0)	0 (0)	1 (5)
Type of Feed				0.037*
All Breast Milk	5 (23)	4 (29)	2 (10)
All Formula	2 (9)	6 (43)	3 (15)
Combination	15 (68)	4 (29)	15 (75)
Age of First Feed, days	2 (1–4)	2 (1–3)	3 (1–4)	0.024*
Days of Hospitalization	66 (15–145)	25 (3–143)	71 (26–272)	0.015*
Days on Parenteral Nutrition	11 (0–125)	0 (0–33)	14 (0–71)	0.009*
Central Line Days	12 (0–124)	0 (0–38)	9 (0–27)	0.031*
Days to Full Feedsb	9 (5–25)	7 (2–17)	8 (5–34)	0.043*
Number of Days NPO	2 (0–18)	1 (0–7)	2 (0–29)	0.018*
Patent Ductus Arteriosus	8 (36)	2 (14)	3 (15)	0.172
Necrotizing Enterocolitis				1.00
Medical	0 (0)	0 (0)	0 (0)
Surgical or Death	0 (0)	0 (0)	2 (10)
Antibiotic Exposure >48 hrs	12 (55)	3 (21)	15 (75)	0.009*
Prokinetic medicationsc	1 (5)	0 (0)	0 (0)	0.455
Died	1 (5)	0 (0)	2 (10)	0.434

^aKruskal-Wallis test for continuous variables and either Chi-square or Fisher Exact test for categorical variables when appropriate.

^bFull feeds defined as 120 mL/kg/day.

^cAt discharge

Seven of 34 EGG sessions with >45% tachygastria belonged to 2 babies (1 who later developed surgical NEC and another who died from NEC). NEC developed 23–49 days after the first EGG session with >45% tachygastria. The baby who developed surgical NEC had 46.7% tachygastria on day 11 and developed NEC on day 60 (65.2% tachygastria on day of diagnosis). The baby who died from NEC had 54.9% tachygastria on day 16 and developed NEC and died on day 39 prior to surgery. One subject in the medium group (35–45%) had “suspected medical NEC,” which did not meet definition of definite NEC (modified Bell Stage ≥2 with definite pneumatosis or portal venous air). See Figure, Supplemental Digital Content 4, showing the pre-prandial running spectral analysis heat map of a subject with 35–45% tachygastria and a subject with >45% tachygastria who developed surgical NEC.

Discussion

The objective was to determine % tachygastria in preterm infants and if EGG was a reproducible tool to assess % tachygastria. To date, this is the largest longitudinal, prospective study to assess % tachygastria in preterm infants, with 56 infants (51 preterm, 5 term) and over 2200 hours of EGG recordings. Although multicenter studies must be conducted to establish normative values, we defined % tachygastria as 35–45% in our cohort (1SD from the mean). We demonstrated that the preterm infant stomach spends a large % of time in tachygastria and we confirmed this is more common in neonates than older children and adults (25–27), suggestive of GI immaturity (6, 7). We also confirmed that preterm infants had similar % tachygastria when compared to term infants. However, comparisons between preterm and term infants were outside the scope (preterm infants) and the number of term infants was too small for comparison (N=5). Thus, term infants were utilized as reference rather than a control group.

Results from linear mixed effects model with random subject effects showed no significant change in repeated weekly measures during the first 9 postnatal weeks. Significant decrease in % tachygastria was noted at weeks 10 and 13; however, this may be secondary to >52% decrease in sample size after week 9 because of study completion at 40 weeks’ PMA, withdrawal, death, or discharge. This is unlikely to be a result of maturation. Gestational age, birthweight, and CPAP during the first week did not influence results when included as covariates. Smaller studies have inconsistently reported changes in gastric rhythm after 4–6 months of age (20, 28). However, our cohort was less than 4 months old; therefore, progressive maturational changes are not expected in this cohort.

We demonstrated reproducibility of EGG in successive pre- and post-prandial measurements of % tachygastria from the same day in individual subjects. In contrast, EGG instability coefficient decreased slightly after feeding, suggesting a decrease in stability of the EGG dominant frequency and power after feeding. However, the clinical significance of a slight decrease in instability coefficient needs further investigation. Similar to previous studies (28–30), we demonstrated no difference between pre- and post-prandial % tachygastria. This suggests that feeding may not alter gastric rhythm. Instead of 6-hour EGG recording sessions, a 30-minute pre-prandial EGG session may be provide sufficient information about gastric dysrhythmias in preterm infants. Shorter recording times will speed up research that may lead to timely interventions to prevent GI pathology. Further, measuring % tachygastria with EGG could serve as a method to predict GI pathology if future studies show that low or high % tachygastria are associated with conditions like NEC or sepsis.

We demonstrated that infants with 35–45% tachygastria (1SD from the mean) in every EGG session are more mature (higher GA and birthweight) with less exposure to antibiotics. Additionally, this group demonstrated less feeding intolerance (i.e. less days to full feeds, fewer days NPO, lower parenteral nutrition, central line and NPO days) than their counterparts with <35% or >45% tachygastria (>1SD from the mean). Although low % tachygastria is associated with normal, mature motility in older children and adults (5, 31, 32), our cohort with low and high % tachygastria had lower median GA and more signs suggestive of feeding intolerance. The association of low and high % tachygastria with feeding intolerance needs to be explored further.

It is reasonable to select outliers for further scrutiny to ensure their presence is not because of random chance. Twenty percent of recording sessions >45% tachygastria (>1SD from the mean) belonged to the only 2 babies in our cohort who developed surgical NEC or death from NEC. A high % tachygastria has been associated with gastric hypomotility and functional GI disorders in older populations (5). However, this study is too small to draw any conclusions or associations with NEC.

Gastric rhythm is an upper GI tract measurement; therefore, its relationship to lower GI pathology warrants further investigation. A link between the stomach and lower GI tract may be partially explained by the gastrocolic reflex, the physiologic reflex that controls motility of the lower GI tract following a meal (33). Perhaps tachygastria-associated gastric hypomotility (5) can decrease motility of the lower GI tract through inhibition of this reflex. Altered intestinal motility can alter colonization of the intestine (34, 35). Further evidence exists that absence of lower GI tract motility in infants with Hirschsprung disease is associated with abundance of Proteobacteria and decreased Firmicutes that can lead to Hirschsprung-associated enterocolitis (36, 37). This finding is consistent with studies showing an association between NEC with abundance of Proteobacteria and decreased Firmicutes (38, 39).

We demonstrated that infants with 35–45% tachygastria in every EGG session had less extended antibiotic exposure >48 hours. Prolonged antibiotic exposure can alter the intestinal microbiome, which may instead affect gastric motility. Bacterial metabolites in the colon such as short-chain fatty acids can modify upper GI motility via peptide-YY hormone, inducing relaxation of the proximal stomach and lower esophageal sphincter, reducing gastric emptying (40). Additionally, colonic distension can inhibit gastric adaptive relaxation via the cologastric reflex (41). We speculate that the microbiome may alter colonic motility which induces tachygastria via the cologastric reflex. Future studies are needed to investigate if a relationship between tachygastria and altered microbiome exists.

Evaluation of GI motility in preterm infants is limited. In this study, we demonstrated that EGG is a reproducible tool to measure % tachygastria in preterm infants. Further, we showed that 30-minute pre-prandial EGG recordings are sufficient to measure % tachygastria because values do not change with feeding and are consistent during the first 9 postnatal weeks and across GA. We demonstrated that infants with 35%−45% tachygastria are more mature with less signs and symptoms of feeding intolerance. This provides the framework for further studies that utilize EGG in preterm infants to define normative values for % tachygastria and to determine clinical significance of low (<35%) and high (>45%) tachygastria.

Supplementary Material

Supplemental Digital Content 1

Figure, Supplemental Digital Content 1. Electrogastrography (EGG) Setup. Single-channel EGG consists of 3 electrodes: The positive electrode was placed midway between the umbilicus and xiphoid process, the negative electrode on the left upper quadrant of the abdomen at the level of the midclavicular line, and the ground electrode below the left costal margin at the mid-axillary line, horizontal to the positive electrode, forming an equidistant triangle with the positive and negative electrodes.

Supplemental Digital Content 2

Figure, Supplemental Digital Content 2. Subject Enrollment Flowchart.

Supplemental Digital Content 3

Table, Supplemental Digital Content 3. Demographics of the Longitudinal Cohort.

Supplemental Digital Content 4

Figure, Supplemental Digital Content 4. Running Spectral Analysis Heat Map. a) An EGG session of a subject with 35–45% tachygastria has warm colors predominant at >2 to ≤4 cycles per minute (cpm). b) An EGG session of a different subject who developed surgical necrotizing enterocolitis with >45% tachygastria has warm colors predominant at >4 to ≤9 cpm. The 30-minute pre-prandial period is shown with “0” being the feeding time). cpm = cycles per minute.

What is Known/What is New.

What is Known:

• Electrogastrography (EGG) measures gastric myoelectrical activity.

• Healthy adults spend <30% of recording time in tachygastria, a gastric dysrhythmia (>4 to ≤9 cycles per minute).

• Increased % tachygastria is associated with gastric hypomotility and functional gastrointestinal disorders.

What is New:

• Preterm and term infants spend 35–45% of recording time in tachygastria.

• Successive pre- and post-prandial EGG measurements are reproducible.

• A short 30-minute pre-prandial EGG session can provide useful information about gastric dysrhythmias in preterm infants.

• Infants with 35–45% tachygastria have higher gestational ages and achieve full feeds faster than infants with <35% or >45% tachygastria.