Mean Reflux Index Research Articles

Gastric Emptying Time, Esophageal pH-Impedance Parameters, Quality of Life, and Gastrointestinal Comorbidity in Obese Children and Adolescents

To provide further evidence regarding the relationship between obesity and gastroesophageal reflux disease (GERD) in children, through the use of 13C-octanoic acid breath test for gastric emptying time (GET) assessment and esophageal multichannel intraluminal impedance pH-testing (MII-pH). Obese children aged 4-17 years completed a questionnaire investigating reflux symptoms, the presence of functional gastrointestinal disorders, and quality of life. A subgroup of obese patients with and without GERD symptoms were asked to undergo 13C-octanoic acid breath test. Symptomatic patients were also required to undergo MII-pH. Age- and sex- matched asymptomatic nonobese children were enrolled as a comparison group. Of 113 enrolled patients, 44 (38.9%) reported reflux symptoms; 22 of the 44 underwent MII-pH. Their mean reflux index was 14.6%, and their mean number of daily reflux episodes was 51.8. The mean T½ GET of symptomatic was 107.6 minutes vs 116.5 minutes in asymptomatic obese children. Healthy nonobese children had a mean T½ GET of 100.1 minutes. The mean GET of symptomatic obese patients having >70 daily reflux events was 121.8 vs 87.6 minutes of patients with <70 daily reflux events (P <.05). Both symptomatic and asymptomatic obese patients had a worse quality of life than nonobese (P = 0.003 and P = 0.0002, respectively); a narrow waist circumference was directly related to GET (P = 0.01). A high percentage of obese children and adolescents experience GERD symptoms. GET was directly related to the narrow waist circumference of obese children with GERD and was significantly delayed in obese children with increased reflux events. Both symptomatic and asymptomatic obese patients had a worse quality of life compared with nonobese healthy patients.

Comparison of the efficiencies of esophageal manometry, vector volume analysis and esophagus pH monitoring in the diagnosis of gastroesophageal reflux.

In this study, we aimed to compare the superiorities of esophageal manometry, vector volume analysis and 24-hour pH meter studies in showing gastroesophageal reflux disease. The files of the patients who presented to pediatric surgery and pediatric gastroenterology outpatient clinics of our hospital with suspicious gastroesophageal reflux disease between 2011 and 2012 and who were investigated were examined and 21 patients whose investigations had been completed were included in the study. The patients were evaluated by treatment method and were divided into three groups as Group 1 who were followed up with medical treatment, Group 2 in whom surgical intervention was performed and Group 3 who were not treated. Chi-square test was used in evaluation of the categorical variables, Kruskal Wallis test was used in comparison of the mean values between the groups and Dunn test was used in subgroup analyses when Kruskal Wallis test was found to be significant. A p value of <0.05 was considered statistically significant. Thirteen of 21 patients included in the study were female and eight were male. The mean age of the patients was 5.71 years (one-16 years). In the 24-hour pH monitoring study, the mean reflux index was found to be 48.7% in Group 1, 42.4% in Group 2 and 28.3% in Group 3. In esophageal manometry studies, the pressure difference at lower esophageal sphincter (LES) was found to be 13,4 cm H2O in Group 1, 31.8 cm H2O in Group 2 and 4.3 cmH2O in Group 3. In vector volume analyses, the mean vector volume was calculated to be 96.01 cm(3) in Group 1, 2 398.9 cm(3) in Group 2 and 196.3 cm(3) in Group 3. In the 24-hour pH monitoring study, a statistically significant difference (p<0.05) was found in terms of showing reflux, whereas statistical significance could not be shown in terms of need for surgical treatment or need for medical treatment in any other method (p>0.05). Twenty-four-hour pH monitoring was found to be efficient in making a diagnosis of gastroesophageal reflux disease, whereas esophageal manometry and vector volume analyses were not found to be efficient.

Eosinophilic esophagitis: Is it also a surgical disease?

BackgroundEosinophilic esophagitis (EoE) is a chronic immune/antigen-mediated disease with esophageal dysfunction and eosinophil-predominant inflammation. An association between EoE and gastro-esophageal reflux disease (GERD) has not been well established. AimsThe aim was to evaluate patients with EoE who underwent pH-Multichannel Intraluminal Impedance (pH-MII), investigating proton-pump-inhibitors (PPI) therapy/anti-reflux surgery requirement. MethodsTwenty-five patients [mean age 7.6 (range 1–17years)] with EoE underwent pH-MII. The children were then divided into Group 1 (pathological pH-MII) and Group 2 (normal pH-MII). PPI was administered for two months in Group 1 and in those children in Group 2 unresponsive to standard EoE therapy (diet and corticosteroids). All patients underwent endoscopy and clinical follow-up. Data are described as mean (range). ResultsGroup 1 (n=16, M:F=14:2) had mean reflux index (RI) 13.9% (0.8%–53.4%) with a mean number of total reflux episodes (RE) of 65.8 (14–341). Group 2 (n=9, M:F=6:3) had a mean RI 1.2% (0.2%–2.7%) with a mean number of total RE of 27.4 (14–39). There was a histological response to repeated cycles of PPI in 11/16 (69%) children in Group 1 and 4/9 (44%) children in Group 2. Fundoplication, because of dependence on PPI, was required in 4/11 PPI-responders in Group 1, allowing discontinuation without relapse of EoE. ConclusionsThe use of PPI is suggested in EoE at time of diagnosis in addition to standard treatment and may even have benefit in children who do not appear to have significant GERD but are unresponsive to standard therapy.

Intrathoracic airway obstruction and gastroesophageal reflux: A canine model

Gastroesophageal reflux (GER) is common in children with airway disorders. Previous studies have shown an association between upper airway obstruction and GER in experimental animal models. However, the cause and effect relationship between intrathoracic airway obstruction (IAO) and GER is obscure. The goal of this study is to investigate the association between IAO and GER using the canine model. In sedated dogs, a telemetric implant was placed subcutaneously (with one pressure sensor tip each in intrapleural space and abdomen) to monitor intrapleural pressure (IPP) and intrabdominal pressure (IAP). The IPP and the IAP were monitored intraoperatively and in conscious dogs on the 7th to 10th postoperative days. GER was assessed by determining the reflux index (RI), based on the intraesophageal pH recording performed continuously for a 24 hr period using a pH probe. After 2-3 weeks following placement of the telemetric implant, IAO was surgically created in the dog. After maintaining IAO for 2 weeks, the IPP, IAP, and pH measurements were monitored again following the same protocol as before IAO. After the creation of IAO, there was no significant change observed in the mean RI either in the distal (P = 0.716) or proximal (P = 0.962) esophageal lumens. The IPP became significantly more negative (P = 0.006) and the IAP turned significantly negative (P < 0.001) from being positive compared to the respective values before IAO. However, transdiaphragmatic pressure (Pdi) did not change significantly (P = 0.08). We conclude that moderate IAO does not cause GER in our animal model. It can be explained by the absence of significant change in Pdi after creation of IAO.

Pharmacodynamics and Safety of Pantoprazole in Neonates, Preterm Infants, and Infants Aged 1 Through 11 Months with a Clinical Diagnosis of Gastroesophageal Reflux Disease

Limited data on proton pump inhibitors in infants led regulatory agencies to request sponsors to conduct pediatric studies. To determine the pharmacodynamic response to pantoprazole in infants with GERD to aid the dose selection for an efficacy study. In two open-label studies, neonates and preterm infants (study 1, ~1.2 mg/kg [high dose]) and infants 1 through 11 months (study 2, ~0.6 [low dose] or ~1.2 mg/kg [high dose]) received once-daily pantoprazole. Twenty-four-hour dual-electrode pH-metry parameters were compared between predose and steady state (≥5 days) (two-sided paired t test). Treatment was administered for ≤6 weeks. In studies 1 and 2, 21 and 24 patients, respectively, were enrolled for pharmacodynamic evaluation. The high dose provided similar responses in the two studies and improved these parameters significantly: mean gastric pH and percent time gastric pH > 4 increased (p < 0.05 both studies), normalized area under the curve (AUC) of gastric H(+) activity decreased (p < 0.05 study 2), and normalized AUC of esophageal H(+) activity decreased (p < 0.05 both studies). The AUC of esophageal pH < 4 decreased. Normalized AUC of esophageal H(+) activity decreased (p < 0.05 both studies), indicating refluxate pH increased, although this was not reflected in any change in mean esophageal pH or reflux index. The normalized AUC of esophageal H(+) activity was a more sensitive measure of changes in esophageal pH. In neonates, preterm infants, and infants aged 1 through 11 months, pantoprazole (high dose) improved pH-metry parameters after ≥5 consecutive daily doses, and was generally well tolerated for ≤6 weeks.

The Use of pH Monitoring and Esophageal Manometry in the Evaluation of Results of Surgical Therapy for Gastroesophageal Reflux Disease

Surgery is indicated for the treatment of gastroesophageal reflux disease (GERD) when medical treatment fails or complications are encountered in children. However, it has not been fully established how the results after surgery can be evaluated. A prospective study was performed to evaluate the results of surgical therapy for GERD by pH monitoring (PM) and esophageal manometry (EM) in children. Patients who were candidates for anti-reflux surgery between 2003 and 2004 were evaluated for symptoms, growth and results of PM and EM both in the pre- and postoperative periods. Thirteen patients were included (mean age = 6.65 +/- 3.28 years, male/female ratio = 10/3). Most frequently occurring symptoms were recurrent respiratory infections (RRI) (n = 11) and vomiting (n = 8). Nissen fundoplication was performed because of unresponsiveness to treatment (n = 10), RRI (n = 9), failure to thrive (n = 7) and esophagitis (n = 2) after medical treatment (2 - 36 months). Symptoms were resolved in 83.9 % of patients and were not changed in 16.1 % following surgery. Weight percentiles had significantly improved (pre: 12.38, post: 25.4, p < 0.05) during a short follow-up period (1 - 4 months). Mean reflux index (pre: 24.73 +/- 21.07 %, post: 0.93 %, min: 0 - max: 3.6, p < 0.05), reflux time (pre: 368 +/- 313 min, post: 17.1 +/- 15.9 min, p < 0.05), number of episodes (pre: 344.7 +/- 343.6, post: 19.53 +/- 11.13, p < 0.05) and number of reflux episodes longer than 5 minutes (pre: 4.3, min: 0 - max: 58, post: 0.61, min: 0 - max: 3, p < 0.05) were found to be reduced after surgery by PM. Lower esophageal sphincter pressure (pre: 55 +/- 27 cmH (2)O, post: 64.46 +/- 30.85 cmH (2)O), contraction amplitude (pre: 141.92 +/- 69.11 cmH (2)O, post: 130.69 +/- 45 cmH (2)O) and contraction velocity (pre: 1.94 cm/s, min: 0.1 - max: 7.5, post: 4.29 cm/s, min: 0.2 - max: 10) did not differ postoperatively (p > 0.05). However, contraction times were decreased postoperatively (pre: 73.6 +/- 52.9 s, post: 27.67 +/- 20.1 s, p < 0.05) and were found to be correlated with reflux time and the number of reflux episodes longer than 5 minutes. Nissen fundoplication is effective for the treatment of GERD. It supports the anti-reflux mechanism without affecting esophageal motility except for contraction times. The decrease in contraction time after surgery can be explained by the decreases in reflux time and in the number of reflux episodes longer than 5 minutes. PM and EM confirmed the clinical improvement and can be used for the evaluation of results of NF.

Pulmonary Aspiration Shown by Scintigraphy in Gastroesophageal Reflux-Related Respiratory Disease

Gastroesophageal reflux (GER) may underlie respiratory manifestations via vagally mediated airway hyperresponsiveness or microaspiration, and intraesophageal pH monitoring is generally used to identify GER in patients with such manifestations. We aimed to establish the frequency of retrograde pulmonary aspiration in patients with unexplained respiratory manifestations. Fifty-one patients with refractory respiratory symptoms (cough, n = 18; pneumonia, n = 14; apnea, n = 8; asthma, n = 7; and laryngitis, n = 4) were prospectively evaluated. They underwent 24-h intraesophageal pH monitoring and gastroesophageal 99Tc scintigraphy with lung scan 18 to 20 h after the test meal. Thirteen of 51 patients (25.5%) had abnormal intraesophageal pH study results (mean reflux index, 11.3%; range, 6.5 to 50%); and in 25 of 51 patients (49%), overnight scintigraphy showed pulmonary aspiration. Nineteen of these 25 patients had entirely normal pH study results, whereas 6 of 13 patients with abnormal pH study results had aspiration. Pulmonary aspiration was demonstrated in all patients with apnea and 61.5% of patients with recurrent pneumonia. Nine of 25 patients (36%) with aspiration had histologic evidence of esophagitis, whereas histologic esophagitis was present in 5 of 13 patients (38.4%) with pathologic GER as shown by intraesophageal pH monitoring. Pulmonary aspiration as demonstrated by overnight scintigraphy is common in children with unexplained and refractory respiratory manifestations, suggesting that GER could be the underlying cause of these manifestations. Since only a few children with chronic or recurrent respiratory symptoms have a pathologic gastroesophageal acid reflux, a normal intraesophageal pH study result does not rule out GER in these children.

Acid suppression does not change respiratory symptoms in children with asthma and gastro-oesophageal reflux disease

Background: Epidemiological studies have shown an association between gastro-oesophageal reflux disease (GORD) and asthma, and oesophageal acid perfusion may cause bronchial constriction. However, no causative relation has been proven. Aim:...

OMEPRAZOLE AND ASTHMA OUTCOME IN CHILDREN WITH ASTHMA AND GASTROESOPHAGEAL REFLUX DISEASE: A RANDOMISED CONTROL TRIAL

Aim: Gastroesophageal reflux disease (GERD) is prevalent in asthma patients, and esophageal acid perfusion may cause bronchial constriction and asthma symptoms under experimental conditions. To assess whether acid reflux may induce asthma symptoms in a clinical setting, we performed a randomised control trial with omeprazole in children with concomitant asthma and GERD. Methods: Children between 7 and 16 years old with asthma and symptoms suggestive of GERD were offered an esophageal pH-monitoring, and those with pathological reflux (reflux index >5.0) were randomized to 12 weeks of treatment with omeprazole 20 mg daily or placebo. Primary outcome measures were asthma symptoms (daytime wheeze, symptoms at night, in the morning and during exercise) and the Pediatric Asthma Quality of Life Questionnaire (PAQLQ). Changes in lung function from baseline (FEV1% and FEF25-75) and the use of short-acting bronchodilator were secondary endpoints. pH-monitoring was repeated at the end of the study to confirm the efficacy of acid suppression with omeprazole. Results: 38 children (mean age 10.8 years; 7.2-16.8, 29 males) were allocated to omeprazole or placebo treatment, 19 in each group. The groups were similar in age and gender distribution, and mean reflux index was 8.8 (O) vs 9.7 (P). Two patients withdrew because of suspected side effects, one in each group. The improvement in total symptom score were identical in the two groups (−1.38), and no significant differences were found for the subscores. The total PAQLQ score improved by 0.62 (O) and 0.50 (P), p = 0.51. The FEV1% decreased by 1.4 (O) and 2.0 (P), p = 0.76, whereas FEF25-75 changed by -0.07(O) vs 0.04 l/sec (P), p = 0.12. The changes in need for short-acting bronchodilators were similar (−1.9 doses/2 weeks). Adequate acid suppression was achieved in the omeprazole group (mean RI 3.2). Conclusion: Omeprazole did not change asthma symptoms and lung function in children with asthma as compared to placebo.

Glass and antimony electrodes for oesophageal pH monitoring in distressed infants

Although antimony electrodes are by far the most popular for performing oesophageal pH monitoring, there are few data comparing the accuracy of glass and antimony electrodes. Therefore, we tested the accuracy of both electrodes in the prediction of oesophagitis. pH monitoring using a glass electrode and an antimony electrode was performed in 60 distressed infants, aged between 1 and 6 months. An upper endoscopy with oesophageal biopsies was also performed in all infants. A reflux index (percentage of the total time with pH < 4.0) greater than 5% was considered to be abnormal and was found in 40/60 patients. Histological oesophagitis was present in 26/60 infants. The reflux index was > 5% with the glass electrode in 18/26 children with histological oesophagitis and with the antimony electrode in 10/26 children with histological oesophagitis. Histology of the oesophagus was normal in 22/40 children with abnormal pH monitoring. With the glass electrode, the mean reflux index in the group with oesophagitis was significantly higher than in the group with normal histology, although there was an important overlap. With the antimony electrode, the mean reflux indices in the groups with and without oesophagitis were not different. Regarding normal/abnormal, there was discordance in 35% of the pH studies. No reflux index could be related to a clinically useful sensitivity and specificity to predict oesophagitis. The reflux index does not accurately predict oesophagitis. Oesophageal pH monitoring and endoscopy provide complementary information.

P1040 GASTROESOPHAGEAL REFLUX (GER) AND APPARENT LIFE THREATENING EVENT (ALTE); IS THERE A RELATIONSHIP?

Introduction: Previous studies have shown a variable incidence of GER among infants with ALTE. The goals of this study were to characterize the incidence of pathologic GER in our patient population with ALTE and to define an association between GER and ALTE. Methods: We conducted a retrospective chart review of infants who underwent pH probe as part of ALTE workup at New York Presbyterian-Weill Cornell Medical Center over the past 5 years. Patients with complex medical problems and inpatients were excluded. We analyzed data including date of birth, age at the time of ALTE, previous symptoms of GER, and description of feeds. pH probes were conducted using single or double channels for a minimum of 20 hours, with 2 acid provocations. Number of reflux episodes, time of longest episode, and reflux index (RI) were recorded. If reflux occurred following provocation, 30 minutes were subtracted from the total time. Pathologic reflux was defined as a RI of >12%. Delayed esophageal clearance was defined as a reflux episode longer than 20 minutes. Results: Twenty-six infants, 15 males and 11 females, ages 1 day to 8 months were included. Forty-six percent(12) were preterm infants (median gestational age 34 weeks). The mean age at the time of ALTE event was 47.6 days in premature infants and 44.9 days in full-term infants. There were 11 dual and 15 single-channel probes. Presentations of ALTE included cyanosis or color change in 57%(16) patients and apnea/gasping and/or floppiness in 38%(10). No patient had an ALTE episode during the pH probe. Six infants had previous GER symptoms. The mean RI in the lower probe was 2.6% in preterms and 3.4% in full-terms, thus no infant had pathologic GER. The mean number of reflux episodes was similar in preterms (49.9) compared to full-terms (58.6). The mean longest episode in preterms was 72.5 minutes compared with 44.3 for full-terms. Eighty-one percent(13/16) of patients with cyanosis had delayed esophageal clearance(mean time 70 minutes). Conclusion: It is remarkable that based on current pH probe guidelines, no patient had pathologic GER in this seemingly high-risk group. We cannot comment on the association between ALTE and GER as there were no recorded ALTE symptoms during the pH. In our study, patients with cyanosis were more likely to have delayed esophageal clearance. We may hypothesize that episodes of acid reflux associated with prolonged esophageal exposure may be responsible for a cyanotic event,perhaps from aspiration or neuropathic mechanism. Further studies investigating the relationship of acid reflux and ALTE using concomitant pH probe and polysomnography are warranted.

Oesophageal pH monitoring and reflux oesophagitis in irritable infants

Acid reflux and/or oesophagitis may be responsible for inconsolable crying in infants. We evaluated prospectively the presence of acid reflux disease, oesophagitis and the accuracy of pH monitoring in the prediction of oesophagitis in a population of irritable infants. A 24-h oesophageal pH monitoring with a glass electrode and an upper gastro-intestinal tract endoscopy with grasp biopsies were performed in 60 irritable infants, aged 1 to 6 months, not responding to cow's milk elimination. The 24-h oesophageal pH monitoring was considered abnormal in 40/60 (66%) babies and histological oesophagitis was present in 26/60 (43%). In the infants with histological oesophagitis, the reflux index (% of the investigation time with a pH < 4.0) was > 5% in 18/26 (69%). Histology of the oesophagus was normal in 22 of the 40 (55%) infants with an abnormal pH monitoring. The mean reflux index in the group with oesophagitis (12.20%) was significantly higher than in the group with normal histology (8.74) (P = 0.036), although there was an important overlap. The sensitivity and specificity to predict oesophagitis with a reflux index of 5.0% or more was 69.2 and 35.3, respectively. There was not a reflux index which could be related to a clinically useful sensitivity and specificity to predict oesophagitis. Acid gastro-oesophageal reflux disease and/or histological oesophagitis were diagnosed in 66% and 43% of irritable infants, respectively. There was no relation between symptoms and abnormal pH metry or oesophagitis; however, the reflux index does not accurately predict oesophagitis and normal histology does not accurately exclude acid gastro-oesophageal reflux disease. Oesophageal pH monitoring and endoscopy provide additional information.

Meta-analysis of randomized controlled trials on the benefits and risks of using cisapride for the treatment of gastroesophageal reflux in children.

Gastroesophageal reflux is a common problem in infancy. Cisapride is a commonly used therapy for gastroesophageal reflux in children. In view of recent concern regarding adverse effects this study aims to evaluate the benefits and risks of cisapride for the treatment of gastroesophageal reflux in children. A meta-analysis of randomized controlled trials of cisapride using a random-effects model. Ten trials involving 415 children were identified. There was no evidence of a significant reduction in vomiting severity with cisapride as measured by a clinical score (five trials, standardized weighted mean difference -0.18; 95% confidence interval (CI) -0.51 to 0.15). Twenty-four-hour esophageal pH monitoring data showed the mean reflux index was significantly lower in the children treated with cisapride compared with controls (five trials, weighted mean difference -6.24; 95% CI -8.81 to -3.67). With cisapride treatment, there was no reduction in the mean number of reflux episodes lasting greater than 5 min (three trials, weighted mean difference -0.72; 95% CI -1.92 to 0.47) or in the number of children with esophagitis at final follow up compared with baseline (two trials, relative risk 0.80; 95% CI 0.40 to 1.61). There was no significant difference in reported side-effects or adverse events (six trials, relative risk 1.16; 95% CI 0.95 to 1.41). No clinically important benefits of cisapride in children with gastroesophageal reflux have been demonstrated. Nor was there any evidence of adverse or harmful events.

Normal Ranges of 24‐Hour pH‐metry Established in Corrected Esophageal Atresia

ABSTRACTBackground:This study was undertaken to determine baseline values of 24‐hour pH‐metry in children who had undergone correction for esophageal atresia.Methods:A 24‐hour pH‐metry without medication was conducted in 13 patients with an uncomplicated postoperative course after correction of esophageal atresia. The pH‐metry was performed in the hospital with a flexible glass electrode.Results:The mean reflux index was 4.08%, the mean total number of reflux periods with a pH less than 4 was 21, and the mean number of periods of pH less than 4 lasting longer than 5 minutes was 2.5.Conclusions:Twenty‐four‐hour pH‐metry values in asymptomatic esophageal atresia patients are the same as in children from the same age group with normal anatomy.

Normal ranges of 24-hour pH-metry established in corrected esophageal atresia.

This study was undertaken to determine baseline values of 24-hour pH-metry in children who had undergone correction for esophageal atresia. A 24-hour pH-metry without medication was conducted in 13 patients with an uncomplicated postoperative course after correction of esophageal atresia. The pH-metry was performed in the hospital with a flexible glass electrode. The mean reflux index was 4.08%, the mean total number of reflux periods with a pH less than 4 was 21, and the mean number of periods of pH less than 4 lasting longer than 5 minutes was 2.5. Twenty-four-hour pH-metry values in asymptomatic esophageal atresia patients are the same as in children from the same age group with normal anatomy.

Gastroesophageal reflux in preterm infants: norms for extended distal esophageal pH monitoring.

Preterm infants are predisposed to gastroesophageal reflux, which may manifest itself in many ways ranging from failure to thrive to vomiting. Extended distal esophageal pH monitoring is the gold standard for diagnosing reflux in the preterm infants and it is our objective to establish extended distal esophageal pH norms (reference values) for well, asymptomatic preterm infants and to compare with norms already established for term infants, children, adolescents, and adults. Twenty-one well, asymptomatic preterm infants consuming at least 70% of required maintenance oral feedings were recruited. The mean +/- standard deviation birth weight was 1549 +/- 439 g (range, 670-2470 g); the mean postconceptional age was 30.7 +/- 2.6 weeks (range, 25-35 weeks) and the mean postnatal age was 14 +/- 9 days (range, 2-40 days). Extended distal esophageal pH monitoring was performed on each of the infants, and the following parameters were calculated: reflux index, number of reflux episodes per day, number of reflux episodes lasting more than 5 minutes per day, and the longest recorded reflux episode. The mean reflux index was 0.7 +/- 1.1%, the mean number of reflux episodes per day was 7.6 +/- 11.2, the mean number of reflux episodes lasting more than 5 minutes per day was 0.5 +/- 1.1 and the mean longest recorded reflux episode was 4.2 +/- 6.1 minutes. These results were comparable to those seen in term infants, children, adolescents, and adults. The trends for pH norms according to postconceptional age and postnatal age seemed to suggest that lower esophageal sphincter maturation might be related to postconceptional age, but the differences observed were not statistically significant (p > 0.05). The norms (reference values) for well, asymptomatic preterm infants were comparable to those seen in term infants, children, adolescents, and adults. With the establishment of these norms, the search for a causal link between many of the respiratory problems encountered in prematurity and gastroesophageal reflux may be aided and the complications associated with gastroesophageal reflux may consequently be reduced.

Gastric emptying and gastro-oesophageal reflux in preterm infants.

Gastro-oesophageal reflux is common in preterm infants, but the role of gastric emptying as a causal factor has not been studied before. Gastric emptying was therefore measured in 19 healthy preterm infants (median gestational age 32 weeks) while concurrently measuring 24 hour lower oesophageal pH, using an antimony pH electrode, positioned manometrically. Real time ultrasonic images of the gastric antrum were obtained, and measurements of antral cross-sectional area (ACSA) were made immediately before a nasogastric feed and then during subsequent gastric emptying until ACSA returned to its pre-feed value. Half emptying time (50% delta ACSA) was calculated as the time taken for the ACSA to fall to half the maximal postprandial increment. Mean (SEM) reflux index for the group was 11.9 (2.0)%; number of reflux episodes per 24 hours: 15.4 (1.7); and number of reflux episodes longer than five minutes 5.5 (0.8). Average half emptying times for an individual infant were: median (range) 46 (18-105) minutes. There was no association between gastric emptying rates and any of the indices of gastro-oesophageal reflux, either during the entire 24 hour period for which the lower oesophageal pH was recorded, or in the postprandial periods after the feeds which were studied ultrasonically. Gastro-oesophageal reflux was also unrelated to feed volume and feed type. Asymptomatic gastro-oesophageal reflux is common in preterm infants, but gastric emptying time is not a determinant of it. Inappropriate relaxation of the lower oesophageal sphincter or abnormal oesophageal motility offer more plausible explanations.

Percutaneous Endoscopic Gastrostomy in Children: Influence on Gastroesophageal Reflux

Few data exist in the literature about the relationship between percutaneous endoscopic gastrostomy (PEG) and gastroesophageal reflux (GER) in children, and the data that do exist are contradictory. The aim of the present study was to evaluate the effect of PEG on GER. Twenty children underwent PEG for enteral nutrition. They were 55 +/- 55 months old and weighed 13 +/- 10 kg. A pH study was performed before and after PEG without treatment when GER status was unknown (n = 10) or under treatment (n = 10) if previous GER was demonstrated. In these cases, the pH study was performed under the same treatment before and after PEG. Six pH studies had abnormal results before PEG. After PEG, the GER of these 6 children significantly improved after the treatment was intensified (n = 50 or spontaneously normalized (n = 1). Results of 13 pH studies that were previously normal remained normal. Only one child with a normal reflux index before PEG had GER after it. For the 20 children, the mean reflux index did not change significantly after PEG (5.5% vs 5.6%). Contrary to surgical gastrostomy, PEG does not worsen GER. Therefore, GER is not a contraindication to PEG.

Does mechanical ventilation precipitate gastro-oesophageal reflux during enteral feeding?

The influence of intermittent positive pressure ventilation on gastro-oesophageal reflux in preterm infants is not known. In many neonatal units, however, concern that ventilation may increase gastro-oesophageal reflux (and therefore aspiration) leads to avoidance of enteral feeding during ventilation. We have therefore performed a crossover study of gastrooesophageal reflux by monitoring lower oesophageal pH in a group of nine enterally fed, very low birthweight infants both during assisted ventilation and normal breathing. All infants had less reflux during intermittent positive pressure ventilation (mean (SEM) reflux index 2.3 (0.6%)) than during normal breathing (mean (SEM) reflux index 6.1 (1.1%)). Assisted ventilation was associated with a significant reduction in the gastro-oesophageal pressure gradient, an effect which may be related to the use of positive and end expiratory pressure during ventilation. These data show that fear of gastro-oesophageal reflux should not preclude the use of enteral feeding in preterm infants receiving ventilation.

Gastro-oesophageal reflux in preterm infants.

Gastro-oesophageal reflux in very low birthweight infants was studied using a new 1 mm monocrystalline antimony oesophageal pH electrode. Gastro-oesophageal reflux was detected in 30 (85%) subjects. The mean (SEM) number of episodes of reflux in 24 hours was 12.1 (2.1), and 3.2 (0.6) lasted over five minutes. The mean reflux index was 4.5 (1.0)%, and the longest episode 17.1 (4.6) 17.1. Reflux was unrelated to postconceptional age or to resting lower oesophageal sphincter pressure. The mean reflux index was low at rest before feeds, being 1.8 (0.6)%, and increased slightly after feeds (3.8 (1.0)%), but was significantly increased after nursing care to 16.4 (3.0)%, and while xanthines were being given (5.9 (1.6)%. A subgroup of seven infants with xanthine resistant apnoea had severe gastro-oesophageal reflux that was not clinically apparent (reflux index 27.4 (3.6)%). Successful treatment of the reflux (reflux index: 3.6 (1.2)%) was associated with cessation of the apnoea. We conclude that gastro-oesophageal reflux is common, and is usually not clinically apparent, even when severe. It is important to consider gastro-oesophageal reflux in the differential diagnosis of xanthine resistant apnoea in preterm infants.