What is the best method for calculating the optimal position of an esophageal pH probe in children?

In assessment of distal esophageal pH, the sensor of the probe should be placed above the upper border of the lower esophageal sphincter. There are several methods to estimate the distance from the nose where the probe should be fixed according to the patient's height. We studied the accuracy of these methods. Data of patients who underwent esophageal monitoring were collected prospectively. The esophageal pH electrode was set with the aid of fluoroscopy in all cases, considering the location recommended by the current guideline. Esophageal probe position and anthropometric data of each patient were recorded. We compared the actual esophageal pH electrode distance from the nose with that estimated by Nowak's, Strobel's, Staiano-Clouse's, and Moreau's formulae and the Great Ormond Street Hospital (GOSH) table. A total of 98 patients were included, with ages ranging from 2 months to 19 years old. The highest success rate (67%) for all age groups was achieved by Nowak's formula (3.2 + 0.2 × height in cm). Considering only children under 3 years old, the GOSH table reached the highest-yet probably overestimated-fraction of adequate predictions. A corrected Staiano and Clouse's formula (4.28 + 0.191 × height in cm) had a slightly lower success rate than Nowak's due to a poorer performance in younger children. In conclusion, Nowak's formula is the most accurate regardless of age. It can help reduce radiation due to systematic fluoroscopy, as well as the subsequent manipulation of the esophageal probe. However, it still leads to pH sensor misplacements in more than one-third of children. In consequence, a confirmatory X-ray is advisable even after using the formula.

Retrieval of a Esophageal pH Monitoring Probe Dislodged Into the Laryngopharynx: A Case Report.

Esophageal pH monitoring via wireless probes is used to evaluate chest pain and atypical symptoms and diagnose gastroesophageal reflux. These probes are commonly placed during esophagogastroduodenoscopy performed by gastroenterologists in an ambulatory anesthesia setting. Dislodgment and aspiration of these probes can cause morbidity, require surgical removal, and involve the anesthesia provider in prolonged emergency care. We present a case of a probe dislodgment where aspiration was avoided and describe how retrieval of this device is different from typical hypopharyngeal foreign body removal.

Dual pH Probes Without Proximal Esophageal and Pharyngeal Impedance May Be Deficient in Diagnosing LPR.

BACKGROUND: Laryngopharyngeal reflux (LPR) is commonly treated with empiric acid suppression. More evidence points to pepsin in the pathophysiology of LPR. Previous studies have evaluated esophageal impedance in patients who had previously failed high dose proton pump inhibitor (PPI) using older catheters without proximal esophageal (just under the upper esophageal sphincter) and pharyngeal impedance sensors. The aim of this study was to compare what traditional diagnostic tools, used for esophageal reflux, would detect and diagnose compared with what a combined hypopharyngeal-esophageal MII catheter with dual pH (HEMII-pH) can detect in the esophagus and pharynx in patients with suspected LPR. METHODS: Forty-two subjects with presumed LPR were referred for HEMII-pH testing. The number of distal and proximal esophageal impedance events, number of pharyngeal impedance events, symptom correlation, and event acidity were recorded. Previous normative values (>1 pharyngeal impedance events every 24 hours) were used to designate what was pathological LPR on HEMII-pH. RESULTS: Forty-two total subjects had pharyngeal impedance sensor data recorded. Twelve (28.6%) of the subjects were tested while taking high-dose PPI therapy. The mean number of proximal esophageal events was 23.3. The mean number of pharyngeal impedance events was 10. Thirty-four subjects (81%) tested positive for pharyngeal reflux. All patients who tested positive using traditional proximal impedance criteria also tested positive using pharyngeal criteria. Of patients who tested negative using traditional criteria, 72% were positive based on pharyngeal criteria. CONCLUSIONS: HEMII-pH catheters should be considered in patients with LPR symptoms. Traditional criteria used for diagnosing esophageal reflux may not translate into LPR.

Correlation of sleep-disordered breathing and laryngopharyngeal reflux: a two-channel triple-sensor pHmetry catheter study.

PURPOSE: To investigate the relationship between sleep-disordered breathing with gastroesophageal reflux (GER) and laryngopharyngeal reflux (LPR) using a two-channel triple-sensor pHmetry catheter. METHODS: The study was carried out on a total of 34 people with complaints of snoring, witnessed apnea and daytime sleepiness. 24-h pH monitoring with a two-channel, triple-sensor antimony pH catheter was applied to individuals simultaneously with polysomnography (PSG) on the day they would sleep in the sleep laboratory. Obstructive sleep apnea syndrome (OSAS) severity and reflux grade were compared with each other. Data obtained from PSG and pHmetry results were numerically compared with each other. The relationship between apnea, hypopnea, and arousal periods and reflux episodes was then examined by overlaying pHmetry graphics for each patient. RESULTS: A total of 34 individuals (18 males-52.9% and 16 females-47.1%), age ranging from 27 to 71 years (mean 50.5 ± 11.0) participated in the study. GER was detected in 52.9% and LPR in 85.3% of the patients. In 35.3% of cases, pathologic GER was not observed despite LPR detection. No statistically significant relationship was found between the numerical values of apnea-hypopnea index (AHI) and arousal numbers and reflux parameters of individuals and between OSAS severity and LPR and GER (p > 0.05). There was no statistically significant correlation between respiratory events and reflux episodes with regard to timing (p > 0.05). CONCLUSION: The prevalence of GER and LPR is found to be high in patients with sleep-disordered breathing. There is no significant relationship between OSAS severity and GER and LPR grade or respiratory events and reflux episodes with regard to timing.

Analyses of the relationship between a 'number of reflux episodes' exceeding 70 and the pH index in neurologically impaired children by evaluating esophageal combined pH-multichannel intraluminal impedance measurements.

BACKGROUND: The present study aimed to evaluate the characteristics associated with a number of reflux episodes (NoRE) of 70 by comparing the clinical and multichannel intraluminal impedance pH measurements (pH/MII) and pH index (pHI) in neurologically impaired (NI) children. PATIENTS AND METHODS: NI children (1-16 years of age) in whom pH/MII had been measured for GERD study were enrolled in this study. All children were divided into NoRE >70 or ≤70 and pHI >4.0 or ≤4.0, >5.0 or ≤5.0 or >7.0 or ≤7.0. In addition, the NI children with pHI >4.0, >5.0 and >7.0 were subdivided into NoRE >70 and ≤70 groups. The clinical and pH/MII measurements were compared between each of the two groups. The cutoff values of pHI and baseline impedance (BI) (Z6) were calculated to discriminate NoRE >70 and ≤70. RESULTS: A total of 61 NI children were enrolled in this study. There was a significant difference in the acid-related parameters, the NoRE (nonacid) and BI between NoRE >70 and ≤70, acid-related parameters and BI between pHI >4.0 and ≤4.0, >5.0 and ≤5.0 and >7.0 and ≤7.0 groups. Furthermore, a significant difference was still observed in the BI between NoRE >70 and ≤70 groups among patients with pHI >4.0, >5.0 or >7.0. The cutoff values of pHI and BI (Z6) for discriminating NoRE >70 and ≤70 were 9.2 and 1049Ω, respectively. CONCLUSION: The present study indicates that NoRE 70 corresponds to GERD in which patients suffer severe acid exposure with pH of around 9% and esophageal mucosal damage with low BI value in NI children.

Long-term wireless pH monitoring of the distal esophagus: prolonging the test beyond 48 hours is unnecessary and may be misleading.

Wireless pH monitoring of the esophagus has been widely used to detect GERD for more than a decade. It is generally well tolerated and accepted by patients, but it is still unclear whether prolonging a recording beyond the usual 48 hours can improve the test's diagnostic value. The aim of this study is to examine the diagnostic yield of 96-hour pH monitoring vis-à-vis 24- and 48-hour tests, and to ascertain whether any gain in diagnostic terms was of genuine clinical utility. Patients with suspected GERD underwent 4-day PPI-off wireless pH monitoring of the distal esophagus. The capsule was inserted under endoscopic control, 6 cm above the squamocolumnar junction. Average acid exposure time was calculated after 24, 48, and 96 hours of recording. Ninety-nine patients completed the 96 hour test, and formed the study sample. The wireless test method was used in 42 patients (42.4%) unable to tolerate the traditional pH-monitoring catheter, and in 57 (57.6%) with a previous negative pH study despite symptoms suggestive of GERD. On complete analysis, 47 patients (47.5%) had a pathological test result: 19 patients within the first 24 hours (19.2%, 24 hour group); another 16 after 48 hours (+16.2%, 48 hour group), and a further 12 (+12.1%, 96 hour group) only after 96 hours of monitoring. All 47 patients with an abnormal acid exposure were offered and accepted surgery (10 patients) or medical therapy (37 patients). Clinical follow-up was obtained in all patients with a positive Bravo test result after a median 67 months (IQR: 38-98) using a validated symptom questionnaire. A good outcome after fundoplication or medical therapy was achieved in 73.7% of patients in the 24 hour group, in 62.5% of those in the 48 hour group, and in only 25% of those in the 96 hour group, P = 0.02. Long-term wireless pH monitoring enables an increase in the diagnostic yield over traditional 24- and 48-hour pH studies, but prolonging the test may constitute an unwanted bias and prompt the recruitment of more complex patients, in whom the outcome of surgical or medical therapy may prove less than satisfactory. These findings should be taken into account when establishing the guidelines for assessing GERD with such long-term pH monitoring methods.

Safety and Efficacy of Wireless pH Monitoring in Patients Suspected of Gastroesophageal Reflux Disease: A Systematic Review.

INTRODUCTION: The primary aim of this systematic review was to determine the safety, technical efficacy, and effectiveness of 48-hour wireless pH monitoring (WM) for gastroesophageal reflux disease (GERD), compared with no pH monitoring in patients who failed to tolerate a catheter. In the absence of eligible studies, the secondary aim was to determine these performance characteristics for WM relative to catheter-based pH monitoring (CBM) in patients suspected of GERD, who are able to tolerate a catheter. METHODS: A protocol was registered on the PROSPERO database (CRD42013005852) before conducting the systematic review, which included the study selection criteria, and critical appraisal methods. Several key databases were searched to identify eligible comparative studies. RESULTS: Chest pain occurred more often with WM compared with CBM; however, other adverse events were reported less frequently with WM. Technical failures, mostly due to attachment failures and early capsule detachments, were 3 times higher with WM, compared with CBM, [pooled relative risk (from meta-analysis)=3.3; 95% confidence interval, 1.63-6.81; I=0%; P=0.012; k=8). The sensitivity and specificity of WM varied widely, depending on type of analysis, monitoring time, capsule placement, reference standard, and diagnostic threshold. DISCUSSION: WM is usually better tolerated than CBM but has more technical problems. Test accuracy was highly variable between studies; therefore, conclusions could not be drawn regarding the performance of the 2 tests. To make meaningful comparisons between WM and CBM a consensus is needed on the diagnostic threshold for GERD, monitoring time, appropriate capsule positioning, and the reference standard.

Interference with daily activities and major adverse events during esophageal pH monitoring with bravo wireless capsule versus conventional intranasal catheter: a systematic review of randomized controlled trials.

For three decades, ambulatory 24-hour intranasal pH monitoring has been the established gold standard for detecting acid reflux in patients with refractory gastroesophageal reflux disease. However, device-associated adverse events and unpleasant experiences, reported by patients during pH monitoring have led to the invention of more convenient pH monitors such as Bravo wireless capsule. To compare the interference with daily activities and major adverse events during pH monitoring with Bravo wireless capsule (Bravo) versus conventional intranasal catheter (catheter), PubMed, Cochrane Library, Clinical Trials.gov, and Google Scholar were searched up to March 20, 2015. Only randomized controlled trials in adult patients that compared the interference with routine daily activities and adverse events between Bravo and catheter pH monitors were included. After screening 574 articles, three unique studies with 167 patients met our inclusion criteria. The average age of patients enrolled in these studies was 51 years. Interference with normal daily activities was more in the catheter than Bravo group: 75 ± 5 versus 92 ± 2, P < 0.001 (Andrews et al, findings were reported as100 mm, mean visual analogue scale (VAS) ± standard error of the mean, 100 = completely normal); Wong et al. (mean ± standard error of the mean): 1.3 ± 0.2 versus 0.32 ± 0.1, P = 0.001 and Wenner et al. using 10 cm median VAS (Interquartile range),10 been the worst is 5.7 (2.3-8.0) compared to 0.7 (0.2-3.4), P < 0.0001, respectively. Overall adverse events were more in the catheter group than Bravo (39 ± 4 vs. 26 ± 4, P = 0.012 for Andrews et al. (100 been the worst) and 5.1 (2.0-6.6) vs. 2.1 (0.5-4.6), P < 0.001 for Wenner et al.). No overall adverse events recorded for Wong et al. Most patients in catheter group complained of nasal and throat symptoms. Significantly, runny nose in 24 out of 25 patients (96%) catheter versus 13 out of 25 (52%) Bravo, P = 0.001 and nose pain 15 out 25 (60%) versus 8 out of 25 patients (32%), P = 0.047, respectively for Wong et al. Andrews and Wenner et al also showed profound nasal discomforts in catheter group compared to Bravo (39 ± 3 vs. 10 ± 3, P < 0.001 and 6.5 (1.5-8.0) versus 0.2 (0.0-1.9), P < 0.0001, respectively. Throat symptoms reported in Wong et al. were mainly throat discomfort in catheter group 23 out of 25 patients (92%) versus Bravo 12 out of 25 (48%), P = 0.001 and throat pain catheter (12 out of 25 patients (48%) vs. Bravo 4 out of 25 (16%)), P = 0.032. This trend was also observed in Andrews et al. with profound throat discomfort in the catheter group 43 ± 4 compared to Bravo 19 ± 4, P < 0.001. Majority of the patients randomized to Bravo group reportedly perceived chest pain higher than those in catheter group; 9 out of 25 patients (36%) versus 2 out of 25 (8%), P = 0.037 in Wong et al. 29 ± 4 versus 14 ± 3, P = 0.001 for Andrews et al., 2.4 (0.3-5.9) versus 1.1 (0.3-2.9), P = 0.084 in Wenner et al. respectively (though not statistically significant). Bravo wireless capsule pH monitor interfered less with daily activities and adverse events were minimal compared to conventional intranasal catheter.

Sedation and Afternoon Placement of the 48-Hour Wireless Ambulatory pH Capsule Results in More Reflux on the First Day.

BACKGROUND: A 48-hour wireless capsule results often vary from the first to second day. Previous investigations comparing discrepant acid reflux readings have yielded variable results. In this study we investigated differences in data obtained on day 1 versus day 2, and the effect of time of capsule placement on discrepancies. METHODS: We performed a retrospective cohort study. Patients undergoing a 48-hour wireless capsule study between January 2012 through November 2013 were eligible for inclusion. We collected reflux data for each patient and calculated the proportion of patients in four groups based on abnormal DeMeester score groups (+/+, -/+, +/-, -/-). We placed patients into morning placement or afternoon placement categories and calculated the proportions of patients with various DeMeester score discrepancies. KEY RESULTS: This study evaluated 229 patients. The mean day 1 DeMeester score was 28.38 and the mean day 2 DeMeester score was 23.24 (P<0.0001). The mean day 1 DeMeester score in the morning group was 24.9 and 31.7 in the afternoon group (P<0.05). The mean total DeMeester score in the morning placement group was 23.1 and 30.6 in the afternoon group (P<0.05). Twenty-five percent of afternoon patients had a +day 1/-day 2 DeMeester discordance, whereas only 12% of morning placement patients had this discordance (P=0.26). CONCLUSIONS: Afternoon capsule placement is associated with a significantly increased amount of acid reflux on day 1. Approximately 10% of 48-hour esophageal wireless monitoring studies may falsely overestimate reflux when the capsule is placed in the afternoon. Capsule placement should ideally be performed in the morning.

Two years' experience of using the Bravo wireless oesophageal pH monitoring system at a single UK tertiary centre.

AIM: The Bravo wireless pH monitoring system enables oesophageal pH to be monitored in children intolerant to nasal catheters and records measurements over 48 hours. This study aimed to document the minimum child weight that enabled successful capsule placement and any associated complications. We also compared the diagnostic sensitivity of 48 hours versus 24 hours. METHODS: We included 203 consecutive patients (122 male children) with clinically documented or suspected reflux symptoms. The age range was two years to 19 years, and the minimum weight was 9.29 kg. The pH capsule was deployed endoscopically under general anaesthetic. Recordings taken over 24 and 48 hours were compared to determine the frequency of differences and correlations in the reflux index and DeMeester scores. RESULTS: Testing using the detached probe was successful in 190 children (93.6%) with weight as low as 9.29 kg, with no side effects, with failed deployment being the most frequent problem. Clinically different results in the reflux index were found in 16% of the children's day 1 or day 2 readings (p < 0.0001), suggesting the benefit of 48-hour measurements. CONCLUSION: Measuring oesophageal pH with the Bravo wireless pH monitoring system was successful in 93.6% of cases. A 48-hour test improved the detection rate of gastro-oesophageal reflux disease by 16%.

Accuracy of the Air Flow Sphincter Locator system in identifying the lower esophageal sphincter for placement of pH catheters.

The Air Flow Sphincter Locator (AFSL) is marketed as an alternative method to manometry for localizing the lower esophageal sphincter (LES) for pH probe placement. Such a system is desirable due to the additional time, cost, and discomfort associated with dual nasal intubation, but its accuracy has never been assessed. To assess the accuracy of the AFSL in localizing the LES. Fifty consecutive outpatients presenting for pH and manometry studies were included. The upper border of the LES was determined using HRM and the AFSL by two technicians independently. LES locations measured by technicians using AFSL versus manometry, as well as the manometrically determined LES locations by technicians versus MDs were compared. Differences in LES locations determined by HRM as read by MDs versus technicians were small; none were >3 cm, and 92% were within 2 cm. Comparison between LES locations determined by technicians using HRM versus the AFSL revealed that 52% had a difference of 2-3cm and 32% had a difference of >3 cm. Hiatal hernia was associated with a difference in LES location of >3 cm. Excluding patients with hiatal hernia, nonetheless, still produced a >3 cm difference in 24% of studies. Prior reports have suggested that a difference greater than +/-3 cm in pH probe placement is considered unacceptable for clinical studies. Based on our study, the AFSL placed the LES outside of this range in 32% of patients, and may be particularly inaccurate in the setting of a hiatal hernia. This suggests that the device may not be an acceptable alternative to manometry in determining LES location for pH probe placement.

Sensibilidad y especificidad del Cuestionario Gastrointestinal Corto en el diagnóstico de la enfermedad por reflujo gastroesofágico / Sensitivity and specificity of the Gastrointestinal Short Form Questionnaire in diagnosis of gastroesophageal reflux disease

Introducción: el Cuestionario Gastrointestinal Corto (GSFQ) es un cuestionario diseñado para el diagnóstico de enfermedad por reflujo gastroesofágico (ERGE), con versión en español. No ha sido comparado con una prueba diagnóstica objetiva. Objetivos: determinar el poder diagnóstico del GSFQ usando como referencia la pH-metría de 24 horas en dos hospitales de tercer nivel. Métodos: pacientes adultos consecutivos con síntomas típicos de ERGE (pirosis, regurgitación), a los que se solicita pH-metría, rellenaron el GSFQ (rango puntuación 0-30, proporcional a probabilidad de ERGE). Se estableció el diagnóstico de ERGE cuando la exposición ácida del esófago distal fue superior a 4,5% o cuando la probabilidad de asociación sintomática fue superior al 95%. Se calcularon curvas ROC (receiver operator characteristic) y se determinó el mejor punto de corte, con sus correspondientes sensibilidad, especificidad y ratios de probabilidad (LR) (intervalo de confianza del 95% para cada determinación). Resultados: se incluyeron 152 pacientes (59,9% mujeres; edad 47,9 ± 13,9; 97,4% pirosis; 71,3% regurgitación). La pH-metría fue patológica en el 65,8%. La puntuación media del GSFQ fue 11,2 ± 6. El área bajo la curva ROC fue 56,5% (47- 65,9%). El punto de corte óptimo fue 13 o mayor: sensibilidad 40% (30,3-50,3%), especificidad 71,2% (56,9-82,9%), LR positiva 1,39 (0,85-2,26) y LR negativa 0,84 (0,67-1,07). Excluir las preguntas 1 y 3 del GSFQ, referidas a síntomas parecidos a los de la dispepsia, mejoró sólo marginalmente el poder diagnóstico (AUROC 59,1%). Conclusión: el GSFQ no predice los resultados de la pH-metría en pacientes con síntomas típicos de ERGE en un entorno de hospital terciario (AU)

Introduction: Gastrointestinal Short Form Questionnaire (GSFQ) is a questionnaire for gastroesophageal reflux disease (GERD) diagnosis, with a version in Spanish language, not yet compared to an objective test. Aims: To establish GSFQ diagnostic performance against 24-hour pH monitoring carried out in two tertiary care hospitals. Methods: Consecutive adult patients with typical GERD symptoms (heartburn, regurgitation) referred for pH monitoring fulfilled the GSFQ (score range 0-30, proportional to probability of GERD). Diagnosis of GERD was established when acid exposure time in distal esophagus was superior to 4.5% or symptom association probability was greater than 95%. Receiver-operator characteristic (ROC) curves were calculated and best cut-off score determined, with corresponding sensitivity, specificity and likelihood ratios (LR) (95% confidence interval for each). Results: One hundred and fifty-two patients were included (59.9% women, age 47.9 ± 13.9; 97.4% heartburn; 71.3% regurgitation). pH monitoring was abnormal in 65.8%. Mean GSFQ score was 11.2 ± 6. Area under ROC was 56.5% (47.0-65.9%). Optimal cut-off score was 13 or greater: sensitivity 40% (30.3-50.3%), specificity 71.2% (56.9-82.9%), positive LR 1.39 (0.85-2.26) and negative LR 0.84 (0.67-1.07). Exclusion of questions 1 and 3 of the original GSFQ, easily interpreted as referred to dyspepsia and not GERD, improved only marginally the diagnostic performance: AUROC 59.1%. Conclusion: The GSFQ does not predict results of pH monitoring in patients with typical symptoms in a tertiary care setting (AU)

Added Value of pH Multichannel Intraluminal Impedance in Adults Operated for Esophageal Atresia.

BACKGROUND: Gastroesophageal reflux (GER) and dysphagia are common following repaired esophageal atresia (EA). The risk of esophagitis and Barrett esophagus is increased compared with the general population. As yet, the causes are not fully explained. PURPOSE: The aim of this study was to investigate how GER, measured by pH multichannel intraluminal impedance (pH-MII), is correlated to the esophageal symptoms and histological findings. METHODS: Twenty-nine adult subjects operated for EA in Gothenburg from 1968 to 1983 were evaluated with pH-MII, manometry, and gastroscopy. RESULTS: pH-MII was performed in 15, manometry in 19, and gastroscopy in 24 subjects. Eleven subjects displayed pathological reflux parameters of any kind, mainly nonacid reflux (10/15). Dysphagia correlated to the number of weakly acidic reflux episodes. Lower esophageal sphincter (LES) incompetence, which correlated to a pathological number of acid reflux episodes (p = 0.012), was noted in 21/24 subjects, but the majority had a normal resting pressure. Esophagitis was present in 14/24, two of whom had Barrett esophagus. Histological changes correlated to the reflux index and the number of weakly acidic reflux episodes (p = 0.028 and 0.040) and tended to correlate to dysphagia (p = 0.052). CONCLUSION: pH-MII adds further information when it comes to explaining what causes symptoms and esophageal histological changes in adults operated for EA.

Continuous 48-Hour Wireless Esophageal pH Monitoring in Children: Comparison Between Days 1 and 2.

AIM: Comparison of days 1 and 2 to each other and to the total recording of 48 hours in continuous 48-hour wireless esophageal pH monitoring in children. METHODS: A retrospective study of 105 patients who underwent 48-hour pH monitoring (Bravo) studies between January 1992 and June 2010 was performed. Reflux variables were compared between days 1 and 2. RESULTS: A total of 58 (55.2%) patients were men. The number of reflux episodes, number of long reflux >5 minutes, duration of the longest reflux (minutes), time pH <4 (minutes), fraction time pH <4 supine (%), fraction time pH <4 upright (%), reflux index, and DeMeester score did not differ between days 1 and 2. CONCLUSIONS: No effect of anesthesia was observed on the gastroesophageal reflux parameters on children.

Implementation of objective activity monitoring to supplement the interpretation of ambulatory esophageal PH investigations.

Conventional catheter-based systems used for ambulatory esophageal pH monitoring have been reported to affect patient behavior. As physical activity has been associated with gastroesophageal reflux disease (GERD), there is a risk that abnormal behavior will degrade the value of this diagnostic investigation and consequent management strategies. The aim of this study was to quantify the effect of conventional pH monitoring on behavior and to investigate the temporal association between activity and reflux. A total of 20 patients listed for 24 hours pH monitoring underwent activity monitoring using a lightweight ear-worn accelerometer (e-AR sensor, Imperial College London) 2 days prior to, and during their investigation. PH was measured and recorded using a conventional nasogastric catheter and waist-worn receiver. Daily activity levels, including subject-specific activity intensity quartiles, were calculated and compared. Physical activity was added to the standard pH output to supplement interpretation. Average patient activity levels decreased by 26.5% during pH monitoring (range -4.5 to 51.0%, P = 0.036). High-intensity activity decreased by 24.4% (range -4.0 to 75.6%, P = 0.036), and restful activity increased on average by 34% although this failed to reach statistical significance (-24.0 to 289.2%, P = 0.161). Some patients exhibited consistent associations between bouts of activity and acidic episodes. The results of this study support the previously reported reduction in activity during ambulatory esophageal pH monitoring, with the added reliability of objective data. In the absence of more pervasive pH monitoring systems (e.g. wireless), quantifying activity changes in the setting of activity-induced reflux might guide the physicians' interpretation of patient DeMeester scores resulting in more appropriate management of GERD.

Catheter-based acoustic interrogation device for real-time monitoring of the dynamics of the lower esophageal sphincter: in vitro and pilot canine studies.

This paper presents a novel minimally-invasive catheter-based acoustic interrogation device for real-time monitoring the dynamics of the lower esophageal sphincter (LES). Dysfunction of the LES could result gastrointestinal (GI) diseases, such as gastroesophageal reflux disease (GERD). A micro-oscillator actively emitting sound wave at 16 kHz is located at one side of the LES, and a miniature microphone is located at the other side of the LES to capture the sound generated from the oscillator. Thus, the dynamics of the opening and closing of the LES can be monitored. The device was tested in vitro by utilizing a custom-designed LES simulator, as well as in vivo in a pilot canine model. In the in vitro test, the sound was captured by the microphone and its strength was correlated with the level of LES opening and closing which was controlled by the simulator. The measurements showed statistically significant (p < 0.05) Pearson correlation coefficients (0.905 on the average in quiet environment and 0.736 on the average in noisy environment, DOF = 9). In the in vivo test, the LES was forced open and closed by a transoral endoscope, which was monitored in real-time by a transpyloric endoscope inserted from the duodenum and positioned into the distal stomach. Frame-by-frame video analysis validated the interrelation between the sound strength and the LES opening and closing. The LES dynamics monitored by the proposed device has the potential to become a valuable minimally-invasive technique for understanding LES dysfunction.

Esophageal pH Monitoring in Children: A Simple Mathematical Formula for pH Probe Positioning.

Correct pH probe placement is vital for the precision of esophageal pH monitoring. This study aimed at finding the optimal formula for placement of pH probe in the locus proposed by the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition European Pediatric Impedance Working Group, that is, 2 vertebrae above the diaphragm. An analysis of data regarding 353 children ages 0-18 years in whom the position of the pH sensor was determined radiographically revealed that a mathematical formula (3.2 + 0.2 × body length or height, centimeter) could guide the probe to within 1/12 of thoracic spine length of the desired location in 71.7% of all of the patients.

A new method to estimate catheter length for esophageal multichannel intraluminal impedance monitoring in children.

BACKGROUND: Multichannel intraluminal impedance combined with pH (MII-pH) is the gold standard test for diagnosing gastro-esophageal reflux disease (GERD). It provides an opportunity to study acid and non-acid GOR and temporal association between symptoms and reflux. Accurate catheter placement is essential to prevent erroneous recording of reflux events. The aims of our study were to assess the accuracy of our devised method in predicting the catheter length for MII-pH in children (Great Ormond Street Hospital (GOSH) Table) and to compare the results with Strobel and Monreau methods. METHODS: Retrospective review of all records of infants and children who underwent MII-pH studies between January to October 2014. Desired catheter position was calculated using Strobel, Monreau and GOSH formulas and compared to X ray position. KEY RESULTS: One hundred and forty-four children were included; mean age was 5.1 (±4.5) years, 73 males and 71 females. In the whole group, the correlation between desired catheter position and GOSH Table was 0.95, for Strobel was 0.84, and Monreau was 0.85. In the first group (age <3 years), the correlation was: GOSH Table 0.91, Strobel 0.56, and Monreau 0.6; in the second group (3-10 years): GOSH Table 0.78, Strobel 0.82, and Monreau 0.82; the third group (>10 years): GOSH 0.81, Strobel 0.43, and Monreau 0.43. CONCLUSIONS & INFERENCES: GOSH Table is an accurate method to estimate the insertion length of MII-pH catheters from nares to a point of approximately two vertebral bodies above the diaphragm in children. Although radiography is required to confirm final catheter position, using GOSH Table will reduce the need for repeated catheter manipulation after initial insertion and will reduce the use of a mathematically complicated formulae.

Proton pump inhibitor-responsive esophageal eosinophilia: a historical perspective on a novel and evolving entity / Esofagitis eosinofílica respondedora a los inhibidores de la bomba de protones: perspectiva histórica sobre una entidad nueva y en desarrollo

Eosinophilic esophagitis (EoE) is an emerging chronic esophageal disease, first described in 1993, with a steadily increasing incidence and prevalence in western countries. Over the 80´s and early 90´s, dense esophageal eosinophilia was mostly associated gastroesophageal reflux disease (GERD). For the next 15 years, EoE and GERD were rigidly considered separate entities: Esophageal eosinophilia with pathological acid exposure on pH monitoring or response to proton pump inhibitor (PPI) therapy was GERD, whereas normal pH monitoring or absence of response to PPIs was EoE. Updated guidelines in 2011 described a novel phenotype, proton pump inhibitor-responsive esophageal eosinophilia (PPI-REE), referring to patients who appear to have EoE clinically, but who achieve complete remission after PPI therapy. Currently, PPI-REE must be formally excluded before diagnosing EoE, since 30-40 % of patients with suspected EoE are eventually diagnosed with PPI-REE. Interestingly, PPI-REE and EoE remain undistinguishable based on clinical, endoscopic, and histological findings, pH monitoring, and measurement of tissue markers and cytokines related to eosinophilic inflammation. This review article aims to revisit the relatively novel concept of PPI-REE from a historical perspective, given the strong belief that only GERD, as an acid peptic disorder, could respond to the acid suppressing ability of PPI therapy, is becoming outdated. Evolving evidence suggests that PPI-REE is genetically and phenotypically undistinguishable from EoE and PPI therapy alone can almost completely reverse allergic inflammation. As such, PPI-REE might constitute a subphenotype of EoE and PPI therapy may be the first therapeutic step and diet/ steroids may represent step up therapy. Possibly, the term PPI-REE will be soon replaced by PPIresponsive EoE. The mechanism as to why some patients respond to PPI therapy (PPI-REE) while others do not (EoE), remains to be elucidated