Multichannel Intraluminal impedance-pH Studies Research Articles

Prevalence of gastroesophageal reflux disease in children with extraesophageal manifestations using combined-video, multichannel intraluminal impedance-pH study

Gastroesophageal reflux disease (GERD) might be either a cause or comorbidity in children with extraesophageal problems especially as refractory respiratory symptoms, without any best methods or criterion for diagnosing it in children.To evaluate the prevalence of extraesophageal GERD using conventional and combined-video, multichannel intraluminal impedance-pH (MII-pH), and to propose novel diagnostic parameters.The study was conducted among children suspected of extraesophageal GERD at King Chulalongkorn Memorial Hospital between 2019 and 2022. The children underwent conventional and/or combined-video MII-pH. The potential parameters were assessed and receiver operating characteristic was used for the significant parameters.Of 51 patients (52.9% males), aged 2.24 years were recruited. The common problems were cough, recurrent pneumonia, and hypersecretion. Using MII-pH, 35.3% of the children were diagnosed with GERD by reflux index (31.4%), total reflux events (3.9%), and symptom indices (9.8%) with higher symptom recorded in the GERD group (94 vs 171, P = 0.033). In the video monitoring group (n = 17), there were more symptoms recorded (120 vs 220, P = 0.062) and more GERD (11.8% vs 29.4%, P = 0.398) by symptom indices. Longest reflux time and mean nocturnal baseline impedance were significant parameters for diagnosis with receiver operating characteristic areas of 0.907 (P = 0.001) and 0.726 (P = 0.014).The prevalence of extraesophageal GERD in children was not high as expected. The diagnostic yield of symptom indices increased using video monitoring. Long reflux time and mean nocturnal baseline impedance are novel parameters that should be integrated into the GERD diagnostic criteria in children.

Correlation of Esophageal Mean Nocturnal Baseline Impedance With Markers of Laryngopharyngeal Reflux.

Mean nocturnal baseline impedance (MNBI) is a measure of the esophageal epithelial barrier function calculated via high-resolution impedance manometry and can be used as a diagnostic tool and treatment response predictor for gastroesophageal reflux disease (GERD). However, its utility for laryngopharyngeal reflux (LPR) has been minimally studied. We aimed to investigate the relationship of MNBI between patients with suspected LPR, healthy controls, and their 24-h multichannel intraluminal impedance-pH (MII-pH) study results. Retrospective patient series analysis was performed of patients with suspected LPR and healthy controls who underwent 24-h MII-pH monitoring. MNBI values were calculated from impedance channels at the level of the hypopharynx, proximal esophagus, and distal esophagus. We compared these MNBI values between the subject groups with secondary analysis on MII-pH results, reflux symptom index, reflux findings score, DeMeester score, and salivary pepsin levels. Twenty-three patients with suspected LPR and 14 healthy controls were enrolled. Decreased distal esophageal MNBI was found to be significantly decreased in patients with suspected LPR compared with healthy controls (p< 0.01) and in subjects with positive MII-pH studies compared to negative MII-pH studies (p< 0.01). There were no significant correlations of MNBI at the hypopharynx or proximal esophagus. Distal esophageal MNBI has significant correlations with many phenotypic and biological markers of LPR. These findings indicate that MNBI has the potential to be applied to LPR, similar to its emerging use as a diagnostic tool and treatment response predictor for GERD. 3 Laryngoscope, 133:1927-1932, 2023.

346. CUTOFF VALUE OF THORACOABDOMINAL PRESSURE GRADIENT FOR GASTROESOPHAGEAL REFLUX DISEASE ON STARLET HIGH-RESOLUTION MANOMETRY

Abstract Derangement of thoracoabdominal pressure gradient (TAPG) associates with gastroesophageal reflux disease (GERD). High-resolution esophageal manometry (HRM) is the gold standard to assess pathophysiology of GERD. Starlet HRM is widely used in Japan; however, TAPG values on Starlet HRM system have been unstudied. The aim of this study is to propose the cutoff value of TAPG to discriminate GERD on Starlet HRM system. We included patients who underwent both Starlet HRM and 24-hour multichannel intraluminal impedance pH study (MII-pH) at our hospital between July 2018 and February 2022. Patients were divided into 3 groups; control group (both HRM and MII-pH were within normal limits), GERD group (acid exposure time [AET] ≥4.0% and/or DeMeester score ≥ 14.72), and non-pathological reflux group. Normal MII-pH values were defined according to our previous study using healthy Japanese volunteers (Yano, et al. Esophagus, 2017); AET &amp;lt;2.5%, DeMeester score &amp;lt; 11, and liquid reflux episodes &amp;lt;80.0. TAPG and adjusted TAPG were analyzed (shown in Figure). Total 102 patients met the study criteria (mean age 53.0 ± 16.0 years, 32 females). Thirty-four patients were categorized into the control group, 31 patients were into the GERD group, and 37 patients were into the non-pathological reflux group. In the control group, 5th and 95th percentiles of TAPG were − 3.4 and 24.3 mmHg, and those of adjusted TAPG were − 50.7 and 1.6 mmHg. TAPG poorly correlated with acid exposure time (AET) (rs = 0.287, p = 0.003); however, adjusted TAPG well-correlated with AET (rs = 0.505, p &amp;lt; 0.001). ROC analysis showed that the estimated cutoff of adjusted TAPG was −11.1 mmHg (sensitivity 71.0%, specificity 71.8%, AUC 0.742, p &amp;lt; 0.001). Adjusted TAPG is associated with antireflux competency across the esophagogastric junction. Estimated cutoff value of adjusted TAPG was −11.1 mmHg in the study cohort. Further study is warrantied.

High-resolution Manometry Determinants of Refractoriness of Reflux Symptoms to Proton Pump Inhibitor Therapy.

Background/AimsImpaired esophageal motility and disrupted esophagogastric junction (EGJ) on high-resolution manometry (HRM) have been associated with increased reflux severity in gastroesophageal reflux disease (GERD) patients. However, there are limited data evaluating HRM parameters in proton pump inhibitors (PPI) non-responders.MethodsClinical and endoscopic data, HRM and multichannel intraluminal impedance-pH studies performed of PPI therapy in patients with typical GERD symptoms were reviewed from 3 international centers. Frequency of GERD symptoms was assessed on and off PPI therapy in both non-responders (< 50% symptom improvement on PPI therapy) and responders. Rome IV definitions identified non-erosive reflux disease, reflux hypersensitivity, and functional heartburn. Univariate and multivariate analyses were performed to determine predictors of non-response.ResultsOf 204 patients, 105 were PPI non-responders and 99 were responders. Non-responders showed higher EGJ contractile integral values, and a lower frequency of type II and III EGJ morphology (P ≤ 0.03 for each comparison). Esophageal body diagnoses on HRM (fragmented peristalsis, ineffective esophageal motility, or absent peristalsis) did not predict non-response. On multivariate analysis, non-pathological acid exposure time (OR, 2.5; 95% CI, 1.2-5.0; P < 0.001), normal mean nocturnal baseline impedance values (OR, 2.7-2.4; 95% CI, 1.0-6.1; P < 0.05), normal EGJ contractile integral values (OR, 3; 95% CI, 1.3-7.4; P = 0.012), and presence of type I EGJ morphology (OR, 1.9; 95% CI, 1.0-3.4; P = 0.044) were associated with an unfavorable response to PPIs.ConclusionsIntact EGJ metrics on HRM complement normal reflux burden in predicting non-response to PPI therapy. HRM has value in the evaluation of PPI non-responders.

Failed Swallows on High-Resolution Manometry Independently Correlates With Severity of LPR Symptoms

Abnormal esophageal motility is prevalent in gastroesophageal reflux disease patients; however, its relationship with laryngopharyngeal reflux (LPR) symptom severity remains unclear. Altered esophageal transit may contribute to LPR symptoms. We aimed to examine the relationship between reflux symptom index (RSI), a validated questionnaire for LPR symptoms, and abnormal esophageal motility on high-resolution manometry (HRM). A total of 133 consecutive patients (55.9 ± 14.6 years, 69.9% female) with suspected LPR referred for HRM and multichannel intraluminal impedance-pH study (MII-pH) at a tertiary center from March 2015 to October 2017 were included. RSI questionnaire was prospectively collected prior to motility testing. Authors analyzing HRM and MII-pH were blinded to RSI findings. Statistical analyses were performed using Student's t test or Pearson's correlation (univariate) and general linear regression (multivariable). Mean RSI was higher among patients with ineffective esophageal motility than those with normal motility (23.7 vs 18.6, P=0.01). Significant positive correlation was found between RSI and percent failed swallows (R2=0.21, P=0.03), but not percent weak swallows. On multivariable analysis, percent ineffective (failed or weak) swallows was significantly associated with RSI (β-coefficient: 0.072, P=0.05) after controlling for age, gender, BMI, smoking, prior PPI use, and reflux on MII-pH. When analyzed separately, percent failed swallows (β-coefficient: 0.095, P= 0.02), but not percent weak swallows, independently predicted higher RSI. Ineffective swallows, particularly failed swallows, are independently associated with higher RSI in patients with suspected LPR, even after controlling for reflux on MII-pH. Esophageal dysmotility may play a role in suspected LPR symptoms independent of reflux. HRM should be routinely considered in evaluating these patients.

Efficacy of Vonoprazan, a Novel Potassium-Competitive Acid Blocker, in Patients with Proton Pump Inhibitor-Refractory Acid Reflux

Background/Aim: We evaluated the efficacy of vonoprazan (VPZ), a novel potassium-competitive acid blocker, in patients with proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD), exhibiting continued pathological esophageal acid exposure (EAE). Methods: Despite ≥8 weeks of appropriate PPI therapy, patients with ­persistent reflux symptoms and pathological EAE times (EAETs ≥4%) were invited to switch to VPZ treatment. After an 8-week-course of once-daily VPZ (20 mg), multichannel intraluminal impedance-pH (MII-pH) monitoring was repeated to compare gastric acid exposure times (GAETs), EAETs, and other reflux parameters relative to the baseline values. Before each MII-pH study, reflux symptom severities were scored using the Gastrointestinal Symptom Rating Scale; erosive esophagitis and fasting plasma gastrin levels were also assessed. Results: From among the 124 patients undergoing MII-pH monitoring, 13 patients (median age, 69 years; females, 64%) were monitored at baseline (while on PPI therapy) and after VPZ therapy. The median GAET associated with VPZ treatment (23.8%) was less than that for PPI treatment (41.1%; p = 0.01), including both daytime and nighttime measurements. VPZ therapy resulted in better median EAET values (4.5%) than did PPI therapy (10.6%) during the 24-h monitoring period (p = 0.055). EAE normalization was achieved in 46% of VPZ-treated patients and was associated with complete gastric acid suppression (p = 0.005). After switching to VPZ, reflux symptoms (p < 0.01) and erosive esophagitis (p = 0.01) improved. Conclusion: In patients with PPI-refractory GERD, VPZ provides more potent gastric acid suppression, more effective EAE control, enhanced symptom improvement, and better esophagitis healing than PPIs.

Wireless 24, 48, and 96Hour or Impedance or Oropharyngeal Prolonged pH Monitoring: Which Test, When, and Why for GERD?

pH monitoring technologies are routinely utilized in practice to further evaluate symptoms of gastro-esophageal reflux disease and laryngopharyngeal reflux (LPR). This is a review of the recent literature of the available pH monitoring technology and creates an algorithm in the diagnostic work up of a patient with GERD or LPR. The catheter-free wireless pH monitor traditionally collects data for 48h. Recent studies have found that extending to 96h can be helpful in patients with conflicting results on the first 2days of the study. In addition, 96h can allow for testing both on and off of PPI therapy. The oropharyngeal monitoring device is a newer technology that is designed to aid in the diagnoses of LPR. There are limitations with this technology as there is no universal abnormal cutoff and some studies have suggested a poor correlation between multichannel intraluminal impedance-pH (MII-pH) and the oropharyngeal monitoring device. MII-pH has recently developed two additional parameters, the measurement of three 10-min nighttime periods and the post-reflux swallow-induced peristaltic wave (PSPW) index, both of which may increase accuracy of testing. Each of these technologies can provide unique data regarding acid reflux exposure in the esophagus and oropharynx. The wireless pH monitor performed off of PPI therapy can help to establish or exclude the diagnosis of GERD. For those patients with refractory symptoms on PPI, MII-pH study can be performed while on therapy and provides data regarding the response to treatment. Oropharyngeal pH monitoring is being utilized in some practices to aid in diagnosis of LPR, but the scientific validity is controversial.

Correlation of Gastroesophageal reflux disease Assessment Symptom Questionnaire to impedance-pH measurements in children.

Background:Esophageal multichannel intraluminal impedance-pH monitoring has become one of the preferred tests to correlate observed reflux-like behaviors with esophageal reflux events. The Gastroesophageal reflux disease Assessment Symptom Questionnaire is a validated tool used to distinguish infants with gastroesophageal reflux disease from healthy children. The aim of this study was to determine whether the Gastroesophageal reflux disease Assessment Symptom Questionnaire composite symptom scores and individual symptom scores correlate with outcomes in esophageal multichannel intraluminal impedance-pH monitoring.Methods:A total of 26 patients with gastroesophageal reflux disease–associated symptoms, aged 0–2 years, for whom both esophageal multichannel intraluminal impedance-pH monitoring and Gastroesophageal reflux disease Assessment Symptom Questionnaire survey results were available were included in the study. Gastroesophageal reflux disease Assessment Symptom Questionnaire score data were collected from a 7-day recall of parent’s responses about the frequency and severity of gastroesophageal reflux disease symptoms, which determined the individual symptom scores. The composite symptom scores is the sum of all individual symptom scores. Multichannel intraluminal impedance-pH study results were compared to Gastroesophageal reflux disease Assessment Symptom Questionnaire data using Pearson correlation.Results:Among 26 patients, a total number of 2817 (1700 acid and 1117 non-acid) reflux episodes and 845 clinical reflux behaviors were recorded. There were significant correlations between the reflux index and the individual symptom scores for coughing/gagging/choking (r2 = 0.2842, p = 0.005), the impedance score and individual symptom scores for coughing/gagging/choking (r2 = 0.2482, p = 0.009), the reflux symptom index for acid reflux-related coughing/gagging/choking and the individual symptom scores for coughing/gagging/choking (r2 = 0.1900, p = 0.026), the impedance score and individual symptom scores for vomiting (r2 = 0.1569, p = 0.045), and the impedance score and the composite symptom scores (r2 = 0.2916, p = 0.004). However, there were no significant correlations between fussiness, irritability, or abdominal pain–related multichannel intraluminal impedance-pH results and the individual symptom scores for abdominal pain.Conclusion:The impedance scores from multichannel intraluminal impedance-pH studies correlate with coughing/gagging/choking and vomiting in infants with gastroesophageal reflux disease. There are no significant correlations among the reflux index and impedance score versus the Gastroesophageal reflux disease Assessment Symptom Questionnaire scores for abdominal pain. We conclude that in infants with gastroesophageal reflux disease, multichannel intraluminal impedance-pH studies are more likely to demonstrate an association between gastroesophageal reflux disease and symptoms of coughing, gagging, or choking compared to an association between gastroesophageal reflux disease and pain in infants.

Combined Multichannel Intraluminal Impedance and pH Measurement in Detecting Gastroesophageal Reflux Disease in Children.

The aim of the study was to evaluate and compare multichannel intraluminal impedance-pH (MII-pH) monitoring with standard investigations including pH testing for detecting gastroesophageal reflux disease (GERD) in children. A retrospective review of all MII-pH studies performed between July 2007 and March 2013 at Sydney Children's Hospital. Results from MII-pH testing, esophagogastroduodenoscopy (EGD), barium meal and pepsin assay, symptoms, underlying comorbidities, age, and medication usage were evaluated. An additional 47.18% of children had GERD detected by MII-pH testing, which would have been missed by pH testing alone. Based on symptomatology, 50.49% of children with respiratory symptoms as a result of GERD and 47.54% of those with gastrointestinal symptoms would have been missed by pH testing alone. GERD was detected in an additional 39.47% of children with neurological impairment, 44.44% for those with cystic fibrosis, and 52.17% for those with esophageal atresia-tracheoesophageal fistula by MII-pH. In patients with persistent symptoms on anti-reflux medication, GERD would have been missed by pH testing alone in 50.40%. GERD was detected in an additional 62.79% of infants and 42.76% of older children by MII-pH compared with pH testing alone. With reference to MII-pH, the sensitivity of other standard investigations, pH testing (32.35%), barium meal (25.00%), EGD (45.26%), and pepsin assay (48.89%) was significantly lower in the detection of GERD in children. Of all abnormal MII-pH results, 51.1% were abnormal because of symptom association alone. Combined MII-pH testing is superior to standard investigations such as 24-hour pH testing, barium meal, EGD, and pepsin assay in detecting GERD in children, particular because of its ability to associate symptoms with acid and non-acid reflux events.

Impedance pH Confirms the Relationship Between GERD and BMI

During the last 20 years the prevalence of both gastroesophageal reflux disease (GERD) and obesity has been increasing in the United States. The pathophysiology of GERD is multifactorial and its relationship with obesity is still not well understood. To evaluate the association between BMI and GERD as detected by multichannel intraluminal impedance-pH (MII-pH) monitoring. Retrospective review of 122 consecutive MII-pH studies of adult patients while on PPI therapy. Patients were divided into normal (BMI < 25), overweight (BMI ≥ 25 and <30) and obese (BMI ≥ 30). Reflux episodes were classified as acid reflux (AR), nonacid reflux (NAR), and total number of reflux episodes, as detected by MII-pH. We evaluated the symptoms associated with reflux by using the symptom index (SI). We also assessed the number of reflux episodes during recumbency and compared them in the different BMI groups. The total number of reflux episodes and NAR episodes increased significantly as BMI increased. There was no significant difference between groups in AR. Similarly, during recumbency, total number of reflux episodes increased significantly when BMI increased. For symptoms associated with reflux, SI was more likely to be positive in the obese group. This study shows a clear association between increased reflux as detected by MII-pH and higher BMI. Obesity not only increases the likelihood of reflux events, as shown in previous studies, but also makes it more likely that symptoms reported during MII-pH studies are actually due to MII detected reflux.

Elderly Patients with Gastroesophageal Reflux Disease: Does It Matter If They Are Obese?

Purpose: Gastroesophageal reflux disease (GERD) and its complications are common in older patients. Aim: To evaluate effect of obesity in elderly and younger patients on GERD using Multichannel intraluminal impedance-pH (MII-pH) while on proton pump inhibitor (PPI) therapy. Methods: Retrospective review of 154 consecutive MII-pH studies of adult patients (99 females, mean age = 48 years); 49 elderly patient (age>60) and 105 younger patients age (18-60) as a control group. Mean age of elderly patients was 67 years. We evaluated the total number of reflux episodes for elderly patients older than 60 years of age using MII-pH and compared it to control group age < 60 and ≥ 18. Both age groups were further divided into 2 subgroups according to their BMI: normal ≤ 30 and obese ≥ 30. All MII-pH studies were done while patients were on daily proton pump inhibitor (PPI) therapy. Also, comparison of both BMI groups was done regardless of age difference. Symptom Index (SI) was calculated for each patient and considered positive when ≥ 50% and was compared in all different groups. Results: Regardless of age groups, obese patients had a statistically significant increase in MII-pH detected total number of reflux episodes (p = 0.02; unpaired t test). Among the obese groups elderly obese in comparison to elderly with normal BMI had a statistically significant higher total number of MII-pH detected reflux episodes (p = 0.03; unpaired t test). Most of those MII-pH detected refluxes were non-acid or weakly acid reflux episodes. There were no statistically significant differences in total number of MII-pH detected reflux episodes in: 1) young obese in comparison to young with normal BMI or 2) elderly and younger age regardless of BMI status. Positivity of SI was not significantly higher in any of the groups. Conclusion: Age alone does not change the risk of GERD as evidenced by number of MII-pH detected reflux episodes, but obesity does, particularly in elderly patients. SI does not seem to be affected by age or increase in BMI.Figure

The effects of a weakly acidic meal on gastric buffering and postprandial gastro-oesophageal reflux

Exclusion of the meal during ambulatory pH monitoring presumes that a meal completely buffers gastric acid and reflux of acidic food content cannot be distinguished from gastric acid. However, the ability of a meal to completely buffer gastric acid remains unclear. To determine the effect of a weakly acid meal on gastric buffering and oesophageal acid exposure. Patients undergoing multichannel intraluminal impedance pH studies were given a standard weakly acidic meal (pH = 5.9). Gastric and oesophageal pH was measured during the meal and in 15 min intervals for 2 h postprandially. The study included 30 patients, with pathological acid reflux detected in 18 patients. Complete gastric buffering occurred in seven patients (23%) and was lost in all patients within 75 min of the meal. Oesophageal acid was detected in 33% of patients within 30 min of the meal and 81% of patients during the 2 h postprandial period. Postprandial oesophageal acid exposure was greater in patients with pathological acid reflux (9 ± 2.7% vs. 1.7 ± 0.8% P = 0.05) with a trend towards more incomplete gastric acid buffering and significant differences when measuring weak acid reflux (pH 4-5). Acid reflux rarely occurred in the absence of gastric acid, with gastric acid present in 74 of 79 (94%) fifteen minute postprandial intervals with acid reflux. The ability of a meal to buffer gastric acid is poor. Early postprandial oesophageal acid reflux occurs in a substantial proportion of patients. Addition of a weakly acidic or pH neutral meal to ambulatory pH monitoring may unmask early postprandial acid reflux and provide data on gastric acid buffering.

Detection of Gastroesophageal Reflux in Children Using Combined Multichannel Intraluminal Impedance and pH Measurement: Data from the German Pediatric Impedance Group

To validate the use of combined multichannel intraluminal impedance (MII)-pH (MII-pH) monitoring for detecting gastroesophageal reflux (GER) in children in daily clinical practice. The patients were divided into 3 symptom groups based on the main indication for the procedure. MII-pH monitoring was performed in 700 children presenting with symptoms suggestive of GER, including 329 children with pulmonary symptoms, 325 with gastrointestinal symptoms, and 46 with neurologic symptoms. The MII-pH results were compared with pH monitoring alone, and retrograde bolus movements, symptom index, and symptom association probability were compared. Overall, 270 measurements were abnormal: 101 (37%) showed abnormal MII-pH study, 49 (18%) showed only pathological pH measurements and 120 measurements (45%) had an abnormal MII recording only. Extraintestinal symptoms of GER were seen more often in younger children and were more often related to a normal pH study but an abnormal MII study. Infants had a significantly higher number of retrograde bolus movements than older children. Symptom index and symptom association probability showed moderate agreement (Cohen kappa, 0.54). From this large systematically standardized data collection of MII-pH measurements in children, we conclude that 45% of the patients with abnormal GER would not have been recognized by 24-hour pH measurement alone. Our findings confirm that MII-pH is superior to pH monitoring alone in detecting GER.

T1121 Impedance-pH Characteristics of 47 Pre-Lung Transplantation Patients

AIM: There is a recognized relationship between acid reflux and allograft dysfunction in the lung transplant population. The occurrence and effect of reflux is not known in the pretransplant population, although it has been speculated to occur more frequently and even play a role in progression of end-stage lung disease. With the development of ImpedancepH testing to identify both acid and non-acid reflux (NAR), we aimed to characterize reflux disease in the end-stage lung disease, pre-transplant population. METHODS: We performed a retrospective analysis of the multichannel intraluminal impedance-pH studies of 47 VA patients undergoing pre-lung transplant reflux evaluation. RESULTS: There was no significant difference in the acid exposure data between established normals and the pre-lung transplant patients who were either on or off acid suppression therapy; the average percent time of acid reflux for all patients on and off acid suppression was 1.27%, (normal BID PPI < 1.3%; p = 0.54). The combined average number of acid reflux events for those on and off acid suppressive medication was 15.6, which was no different from that expected on maximal PPI (normal BID PPI < 12 events; p =0.09). Impedance data demonstrated the mean percent of all reflux events reaching the proximal esophagus was increased in the study population (44% in study vs. 34% in normal; p = 0.00003). The mean bolus transit times (BTT) in both groups on and off of acid suppression were prolonged at 12.6 seconds in comparison with the normal median (median normal = 7.9 seconds; p < 0.00001). However, this was not statistically different from the upper limit of normal (95th percentile). Symptoms of laryngo-pharyngeal reflux (LPR) were more prevalent than classic GERD symptoms. The most common symptoms were cough (28%), belch (16%), and heartburn (14%); reflux episodes were predominantly silent and correlated (positive symptoms index) with belch only but not cough or heartburn. CONCLUSIONS: Despite normal reflux patterns in the distal esophagus, patients with end-stage lung disease have an increased frequency of NAR reaching the proximal esophagus and increased bolus contact time. This suggests that proximal reflux frequency is increased in the lung transplantation population despite normal distal reflux patterns and functions as a risk for lung damage by increasing the frequency of aspiration events.

T1122 The National Survey of Prevalence of Gastroesophageal Reflux Disease in Russia

AIM: There is a recognized relationship between acid reflux and allograft dysfunction in the lung transplant population. The occurrence and effect of reflux is not known in the pretransplant population, although it has been speculated to occur more frequently and even play a role in progression of end-stage lung disease. With the development of ImpedancepH testing to identify both acid and non-acid reflux (NAR), we aimed to characterize reflux disease in the end-stage lung disease, pre-transplant population. METHODS: We performed a retrospective analysis of the multichannel intraluminal impedance-pH studies of 47 VA patients undergoing pre-lung transplant reflux evaluation. RESULTS: There was no significant difference in the acid exposure data between established normals and the pre-lung transplant patients who were either on or off acid suppression therapy; the average percent time of acid reflux for all patients on and off acid suppression was 1.27%, (normal BID PPI < 1.3%; p = 0.54). The combined average number of acid reflux events for those on and off acid suppressive medication was 15.6, which was no different from that expected on maximal PPI (normal BID PPI < 12 events; p =0.09). Impedance data demonstrated the mean percent of all reflux events reaching the proximal esophagus was increased in the study population (44% in study vs. 34% in normal; p = 0.00003). The mean bolus transit times (BTT) in both groups on and off of acid suppression were prolonged at 12.6 seconds in comparison with the normal median (median normal = 7.9 seconds; p < 0.00001). However, this was not statistically different from the upper limit of normal (95th percentile). Symptoms of laryngo-pharyngeal reflux (LPR) were more prevalent than classic GERD symptoms. The most common symptoms were cough (28%), belch (16%), and heartburn (14%); reflux episodes were predominantly silent and correlated (positive symptoms index) with belch only but not cough or heartburn. CONCLUSIONS: Despite normal reflux patterns in the distal esophagus, patients with end-stage lung disease have an increased frequency of NAR reaching the proximal esophagus and increased bolus contact time. This suggests that proximal reflux frequency is increased in the lung transplantation population despite normal distal reflux patterns and functions as a risk for lung damage by increasing the frequency of aspiration events.

Multichannel intraluminal impedance to detect relationship between gastroesophageal reflux and apnoea of prematurity

Background The association between gastroesophageal reflux and apnoea of prematurity is still controversial. Available data are biased by the heterogeneity of the infants enrolled as regard to some confounding factors and by the use of the traditional pH monitoring that is unable to detect non acid reflux events which might be prevalent in infants receiving frequent milk feeding. Multichannel intraluminal impedance has been recently introduced as a pH-independent method to investigate the bolus transport in hollow organs. Objective To assess if combined multichannel intraluminal impedance-pH study could be useful to detect an association between gastroesophageal reflux and apnoea of prematurity. Methods We prospectively evaluated a group of premature infants with apnoea of prematurity in absence of any confounding factors (ventilatory support, treatment with caffeine, permanent nasogastric tube, post-natal age older than 30 days) by simultaneous recording of 24-h multichannel intraluminal impedance-pH and cardiorespiratory monitoring. A temporal relationship between an apnoea and a reflux event was considered if both commenced within 20 s of each other. Results Six premature infants [three male; median gestational age 31 weeks (range 27–36); birth weight 1335 g (range 1200–2350); age at study 17 days (range 7–28)] were studied. A total of 405 reflux events [306 (76%) weakly acid and 99 acid reflux] and 142 apnoeas were detected. The frequency of apnoeas occurring during the reflux events period was significantly greater than the one calculated for reflux-free period [0.42/min (0.00–1.28) versus 0.016/min (0.003–0.028); p < 0.05]. The sub-analysis based on chemical composition and duration of refluxate showed that the frequency of apnoeas associated with weakly acid reflux events was significantly greater than the one calculated for reflux-free period [0.416/min (0.00–1.30) versus 0.016/min (0.003–0.028), respectively; p < 0.05] and that the frequency of apnoeas occurring during reflux events longer than 30 s was significantly higher than those occurring during shorter reflux events (22% versus 11%; p < 0.004). Conclusion Our data show that weakly acidic reflux events are more prevalent than acid reflux events in premature infants, confirming the need for the use of multichannel intraluminal impedance-pH monitoring for diagnosis of gastroesophageal reflux in those patients. Gastroesophageal reflux and apnoea of prematurity are both common occurrences and, in our experience, may be temporally related especially as regard to weakly acid refluxate and reflux events longer than 30 s.