Symptom Association Probability Index Research Articles

Correlation between cardiorespiratory events and gastro-esophageal reflux in preterm and term infants: Analysis of predisposing factors

BackgroundThe association between cardiorespiratory events (CRE) and gastro-esophageal reflux (GER) among neonates is still controversial. AimsTo test such an association in preterm and term infants. Study designProspective observational study. SubjectsForty-seven infants with suspected GER and recurrent CRE admitted at a neonatal intensive care unit, who underwent simultaneous and synchronized 24-hour recording of heart rate (HR), peripheral oxygen saturation (SpO2) and pH-impedance monitoring (MII-pH). HR/SpO2 data were filtered to avoid artefactual episodes of hypoxia and hypoperfusion. Outcome measuresThe main outcome measure was the symptom association probability (SAP), with a 2-minute time window. Infants with positive (>95%) and negative (≤95%) SAP index tests were compared by univariate and multivariate statistics. ResultsMedian gestational age at birth was 294/7 weeks, median age at study 36 days. We recorded 3341 GER events and 4936 CRE (4710 desaturations, 226 bradycardias); 609/4936 (12%) CRE were temporally associated with GER episodes: 338 preceded and 271 followed GER events. The SAP index was significant in 5/47 (11%) patients. The SAP index including only CRE following GER events was significant in 3/47 (6%). There was no significant difference in the number of acid, weakly acid, non-acid, pH-only events preceding or following CRE between infants with SAP-positive and SAP-negative tests. Infants with positive SAP-index tests compared to those with SAP-negative tests had lower weight gain in the three days preceding the test and tended to have lower birth weight. ConclusionsGER and CRE were associated in <11% of patients. The evaluation of ponderal growth might be helpful in predicting such an association.

Cardiorespiratory events in infants with gastroesophageal reflux symptoms: Is there any association?

Cardiorespiratory (CR) events (apnea, bradycardia, oxygen desaturation) and gastroesophageal reflux (GER) symptoms often coexist in infants admitted to Neonatal Intensive Care Unit, leading to over-prescription of drugs and delayed discharge. We aimed to evaluate the relationships between CR and GER events. The temporal associations between CR and GER events were analyzed in symptomatic infants who underwent synchronized CR and pH-impedance monitoring. The symptom association probability (SAP) index was used to identify infants with a significant number of temporal associations. Gastroesophageal reflux characteristics and the chronological sequence of CR and GER events occurring within 30seconds of each other were evaluated according to SAP index. Of the 66 infants enrolled, aged 29 (18-45) days, 58 had CR events during monitoring. From these 58 patients, a total of 1331 CR events and 5239 GER (24% acidic) were detected. The SAP index was positive in seven (12%) infants. These infants had greater GER frequency, duration, and proximal extent (P<.05). The number of temporal associations was 10 times greater in the positive SAP group. Gastroesophageal reflux events preceded CR events in 83% of these associations. These GER events had a higher proximal extent (P=.004), but showed no differences in pH values. The simultaneous evaluation of CR and GER events could be useful to identify infants with severe GER and significant temporal associations between these events. Treatment of GER could be indicated in these infants, but as the GER events involved are mainly non-acidic, empirical treatment with antacids is, often, inappropriate.

Categorization of Patients With Reflux Symptoms Referred for pH and Impedance Testing While Off Therapy

Patients with suspected gastroesophageal reflux disease (GERD) often are treated empirically with proton pump inhibitors (PPIs). Patients whose symptoms are not reduced during the PPI trial are referred for further tests. We investigated whether patients referred for the evaluation of reflux symptoms had GERD. We also aimed to categorize patients with a poor response to PPIs into groups with hypersensitive esophagus or functional heartburn. We performed a retrospective study, searching a clinical database of patients referred for GERD testing from 2006 through 2011. We collected data on all patients who underwent upper endoscopy, esophageal manometry, and 24-hour pH-impedance monitoring, and were off PPIs for at least 1 week. Evidence of GERD was determined by an abnormal upper endoscopy or 24-hour pH-impedance monitoring. Further categorization was determined by impedance results and the symptom association probability index. We identified 221 patients (mean age, 47.6 ± 13.3 y; 56% male; 61% Caucasians); 97% previously had been prescribed PPIs, before they were tested. The patients had erosive esophagitis (n = 21; 10%), nonerosive reflux disease with increased pH (n = 61; 27%), nonerosive reflux disease with abnormal impedance (n = 18; 8%), hypersensitive esophagus (n = 30; 14%), functional heartburn (n = 18; 8%), functional disorders other than heartburn (n = 30; 14%), and undetermined disorders (n = 43; 19%). In a retrospective analysis of 221 patients, roughly half of the patients referred for testing did not have evidence of GERD. Further categorization of patients can help guide diagnosis and management.

Signal detection theory approach to gastroesophageal reflux disease: a new method for symptom analysis of impedance-pH data

An accurate reflux-symptom relationship analysis method is an unmet need in gastroesophageal reflux disease (GERD) diagnosis. The aim of this study was to adapt signal detection theory (SDT) approach to reflux-symptom relationship analysis to develop a new diagnosis method. Patients with predominant symptoms of heartburn and regurgitation were enrolled. Proton pump inhibitor (PPI)-responsive and PPI-unresponsive groups were created via interview and PPI trial. Patients then underwent stationary esophageal manometry and 24-hour multichannel intraluminal impedance-pH monitoring. SDT measurement parameters (discriminability: d' and criterion: c) were calculated using empirically selected time windows (0.5, 1, 2, 3, 4 and 5 minutes). The time window that provided the highest d' value was selected as the optimal time window. A cut-off d' value that optimally separates two groups was found using receiver operating characteristics analysis. Sixty-three patients completed the study (45 PPI responsive). Optimal time window and cut-off d' value were found as 1 and 0.767 minute, respectively. Symptom association probability (SAP) index values showed good correlation (rS = 0.7182, P < 0.0001) with d' values. SDT approach to reflux-symptom relationship analysis showed sensitivity (89% vs. 78%) and negative predictive values (75% vs. 60%) favorable over SAP index analysis. SDT approach using 1-minute time window and 0.767 cut-off d' value provides us a new and more accurate measure of reflux-symptom relationship than SAP index analysis.

658 Surgical and Medical Treatment of GERD Lead to a Comparable Increase in Baseline Impedance Levels

BACKGROUND: Presence of pepsin in bronchoalveolar lavage fluid, laryngeal biopsy and sputum may be a consequence of gastroesophageal reflux disease (GERD). A novel noninvasive test to detect it in saliva/sputum (PEP-Test) has been proposed to diagnose GERD. A correlation between PEP-Test and multichannel impedance pH monitoring (MII-pH) has never been performed. AIM: The aim was to evaluate the PEP-Test accuracy for the diagnosis of GERD in patients with reflux symptoms by means of MII-pH. PATIENTS ANDMETHODS: 35 patients with GER symptoms were studied. All patients with negative endoscopy underwent pathophysiological examinations, after wash-out from proton pump inhibitors. Samples of saliva/sputum were obtained by requesting the patient to cough up and spit into a tube containing 0.01 M citric acid within 15 minutes from experiencing reflux symptoms. Patients were grouped on the basis of MII-pH results as follows: True-NERD (increased acid exposure time, AET/reflux number); Hypersensitive Esophagus, HE (normal AET/reflux number, positive symptom association probability index, SAP); no-GERD patients (normal AET/reflux number, negative SAP). Roc curve was performed to obtain diagnostic accuracy of test. RESULTS: Male/Female was 18/17, mean age was 49.8 yrs, mean BMI was 24.9. The mean BMI was similar in three sub-groups. Nine patients were abitudinary smokers and five had a regular alimentary alcohol use. Eleven out of thirty-five patients presented hiatal hernia. No patients showed abnormal esophageal motility. MII-pH results showed: 16 True-NERD patients (median AET 9.5); 12 HE (median AET 3); 7 no-GERD (median AET 1.1). PEPTest was positive in 93.7% of True-NERD, in 58.3% of HE, and negative in 100% of noGERD patients. Accuracy of PEP-Test is reported in Table 1. CONCLUSIONS: PEP-Test is a simple, economic, reproducible, highly specific test to detect the presence of GERD. Accuracy PEP-Test

657 Use of a Non-Invasive Pepsin Diagnostic Test to Detect GERD: Correlation With MII-pH Evaluation in a Series of Suspected NERD Patients. A Pilot Study

BACKGROUND: Presence of pepsin in bronchoalveolar lavage fluid, laryngeal biopsy and sputum may be a consequence of gastroesophageal reflux disease (GERD). A novel noninvasive test to detect it in saliva/sputum (PEP-Test) has been proposed to diagnose GERD. A correlation between PEP-Test and multichannel impedance pH monitoring (MII-pH) has never been performed. AIM: The aim was to evaluate the PEP-Test accuracy for the diagnosis of GERD in patients with reflux symptoms by means of MII-pH. PATIENTS ANDMETHODS: 35 patients with GER symptoms were studied. All patients with negative endoscopy underwent pathophysiological examinations, after wash-out from proton pump inhibitors. Samples of saliva/sputum were obtained by requesting the patient to cough up and spit into a tube containing 0.01 M citric acid within 15 minutes from experiencing reflux symptoms. Patients were grouped on the basis of MII-pH results as follows: True-NERD (increased acid exposure time, AET/reflux number); Hypersensitive Esophagus, HE (normal AET/reflux number, positive symptom association probability index, SAP); no-GERD patients (normal AET/reflux number, negative SAP). Roc curve was performed to obtain diagnostic accuracy of test. RESULTS: Male/Female was 18/17, mean age was 49.8 yrs, mean BMI was 24.9. The mean BMI was similar in three sub-groups. Nine patients were abitudinary smokers and five had a regular alimentary alcohol use. Eleven out of thirty-five patients presented hiatal hernia. No patients showed abnormal esophageal motility. MII-pH results showed: 16 True-NERD patients (median AET 9.5); 12 HE (median AET 3); 7 no-GERD (median AET 1.1). PEPTest was positive in 93.7% of True-NERD, in 58.3% of HE, and negative in 100% of noGERD patients. Accuracy of PEP-Test is reported in Table 1. CONCLUSIONS: PEP-Test is a simple, economic, reproducible, highly specific test to detect the presence of GERD. Accuracy PEP-Test

Long-term Therapeutic Outcome of Patients Undergoing Ambulatory pH Monitoring for Chronic Unexplained Cough

Ambulatory pH monitoring is frequently performed to determine temporal associations between reflux events and chronic unexplained cough. We further explored the clinical value of ambulatory pH monitoring in predicting long-term symptomatic outcome of therapy in chronic cough. Symptom scores and reflux indicators from ambulatory pH study [acid exposure time, symptom association probability (SAP), and symptom index] were extracted from records of subjects undergoing esophageal evaluation for chronic cough. Intensity of antireflux therapy administered and symptomatic outcome were determined by telephone interview. Univariate and logistic regression analysis were performed to identify predictors of a high degree response (HDR), defined as sustained, durable symptom improvement lasting >3 months. Fifty-three subjects (mean age 63+/-2 y, 42 females) fulfilled the inclusion criteria. Reflux parameters were abnormal on ambulatory pH monitoring in 54.7%. After a mean interval of 3+/-0.3 years, cough intensity improved significantly, 19 subjects (35.8%) achieving HDR. Only female sex and positive SAP predicted HDR on univariate analysis; SAP and intensity of antireflux therapy were retained as independent predictors (P<or=0.03) on logistic regression analysis. Sequential use of acid exposure time, SAP, and symptom index had the best value, with the highest likelihood of HDR when all three were positive (85.7%, P<0.01). Reflux disease is a frequent cause of chronic unexplained cough and aggressive antireflux therapy forms a vital component of management. Positive SAP is an independent predictor of outcome, but hierarchical or sequential use of abnormal gastroesophageal reflux disease parameters on ambulatory pH testing has value in predicting long-term symptomatic response.