Interobserver variability in antroduodenal manometry.

Interobserver variability affects investigations involving assessment of complex visual data, such as histopathology, radiology and motility. This study assessed interobserver variation for interpretation of antroduodenal manometry (ADM), as this has not been previously investigated. Thirty-five ADM recordings from children aged 0.3-18 years were independently evaluated by five experienced paediatric gastroenterologists who were blinded to cases' clinical histories. Intra-class correlation (ICC) was analysed for detection and measurement of phase three of the migrating motor complex (MMC) and Cohen's kappa statistic was calculated between observer pairs for detection of specific motility features and final diagnosis. Observers were unanimous on the differentiation of normal and abnormal motility in 63% of cases. There was excellent interobserver agreement for the number of phase three of the MMC in fasting (ICC = 0.82, P < 0.0001) and for measurements of phase three of the MMC (ICC = 0.9999, P < 0.0001). Detection of other normal and abnormal motility patterns varied more. Objective findings such as the presence of phase three of the MMC correlated more closely than findings that involved the integration of several variables, such as final diagnosis. However, these data overall indicate that agreement between expert observers for the distinction of normal and abnormal antroduodenal motility compares favourably with other standard medical assessments.

Comparison of morning and evening administration of rabeprazole for gastro-oesophageal reflux and nocturnal gastric acid breakthrough in patients with reflux disease: a double-blind, cross-over study.

AIM: To assess the effect of timing of rebeprazole (RB) 20 mg/d administration on oesophageal acid exposure and nocturnal gastric acid breakthrough (NGAB) in patients with GERD. METHODS: 20 GERD patients received two 7-day treatments of RB in the morning (a.m.) or in the evening (p.m.) hours. The regimens were randomized in a double-blind fashion and separated by a 7-day washout period. The tablets were taken 30 min before standardized meals. A combined (oesophageal & gastric) 24-hour pH monitoring was performed before and on day 7 of each treatment. RESULTS: Total oesophageal acid exposure was normalized in 10/14 (71.4%) patients with RB p.m. and in 6/15 (42.8%) with RB a.m. RB p.m. significantly decreased the nocturnal supine oesophageal acid exposure vs. RB a.m., 0.2% vs. 3.4%. The mean NGAB duration was significantly shortened with RB a.m. and p.m. vs. the baseline recording, 4.1+/-1.8 and 3.4+/-1.5 hours vs. 7.8+/-1.7 hours. CONCLUSIONS: Rabeprazole significantly reduced the NGAB duration and significantly increased the mean nocturnal gastric pH; RB p.m. normalized more effectively the total oesophageal exposure than RB-a.m.; RB p.m. provided significantly better control of nocturnal supine gastro-oesophageal reflux than a.m. dosing. These data suggest that administration of a PPI before the evening meal maximizes acid control and would be the preferred dosing schedule in GERD patients, particularly those with nocturnal symptoms.

Effect of cisapride on nocturnal transient lower oesophageal sphincter relaxations and nocturnal gastro-oesophageal reflux in patients with oesophagitis: a double-blind, placebo-controlled study.

AIM: To investigate the effect of cisapride, a selective 5-hydroxytryptamine-4 receptor agonist, on the frequency of nocturnal transient lower oesophageal sphincter relaxations and oesophageal acid exposure in patients with gastro-oesophageal reflux disease. METHODS: In a double-blind, placebo-controlled study, 10 patients with gastro-oesophageal reflux disease (six male and four female; mean age, 54 +/- 10.4 years) were randomly assigned to 5-day treatments with cisapride, 10 mg q.d.s., or placebo, separated by a 2-day washout period before the treatment crossover. Sleep stages, lower oesophageal sphincter tone and oesophageal pH were monitored overnight at the end of each treatment regimen. Gastric emptying was assessed before treatment. RESULTS: Cisapride decreased the frequency of transient lower oesophageal sphincter relaxations during sleep (1.2 +/- 0.2/h vs. 2.7 +/- 0.5/h with placebo; P=0.004) and oesophageal acid exposure (17.2 +/- 9.9% with placebo vs. 7.2 +/- 4.2% with cisapride; P=0.4). Cisapride increased lower oesophageal sphincter tone from 12.7 +/- 2.8 mmHg with placebo to 16.9 +/- 3.9 mmHg (P=0.03), and decreased heartburn episodes and antacid consumption. All patients had normal gastric retention data over 4 h. CONCLUSIONS: In patients with gastro-oesophageal reflux disease, cisapride significantly decreased the frequency of transient lower oesophageal sphincter relaxations during sleep and increased lower oesophageal sphincter pressure without changing gastric emptying. We hypothesize, therefore, that 5-hydroxytryptamine-4 mechanisms are important in the control of transient lower oesophageal sphincter relaxations in humans.

Sustained esophageal contraction: a motor correlate of heartburn symptom.

Heartburn occurs in the presence as well as the absence of acid reflux. We searched for a motor correlate of heartburn. Twelve subjects with heartburn were studied with 24-h synchronized pressure, pH, and high-frequency intraluminal ultrasound (HFIUS) imaging of the esophagus. The HFIUS images were analyzed every 2 s for a period of 2 min before and 30 s after the onset of heartburn during 20 acid reflux-positive and 20 acid reflux-negative heartburn episodes. The esophageal muscle thickness was measured as a marker of contraction. Esophageal pressure and HFIUS images were recorded during the Bernstein test in 15 subjects. Sustained esophageal contractions (SECs) were identified during 13 of 20 heartburn episodes associated with acid reflux and 15 of 20 heartburn episodes without acid reflux. SECs were detected during 2 of 40 matched control periods only (P < 0.05). The duration of SECs was 44.9 +/- 26.9 s. The Bernstein test reproduced heartburn symptoms in 8 of 15 subjects. SECs were identified during 6 of 8 (75%) Bernstein-positive and in 1 of 7 (14.3%) Bernstein-negative tests (P = 0.04). We conclude that a SEC precedes both spontaneous and induced heartburn symptoms and may be the cause of heartburn sensation.

Relationship between esophageal muscle thickness and intraluminal pressure: an ultrasonographic study.

A number of studies show a close temporal relationship between the rate of change in muscle thickness as detected by high-frequency intraluminal ultrasonography (HFIUS) and intraluminal pressure measured by manometry. There is a marked variability in esophageal contraction amplitude from one swallow to another at a given level in the esophagus and along the length of the esophagus. Furthermore, peristaltic pressures are higher in the distal compared with the proximal esophagus. The goal of this study was to evaluate the relationship between the baseline and peak muscle thickness and the contraction amplitude during swallow-induced contractions along the length of the esophagus. Fifteen normal subjects were studied using simultaneous esophageal pressures and HFIUS or HFIUS alone. Recordings were made during baseline and standardized swallows in the lower esophageal sphincter (LES) and at 2, 4, 6, 8, and 10 cm above the LES. HFIUS images were digitized, and esophageal muscle thickness and peak contraction amplitudes were measured. In the resting state, muscle thickness is higher in the LES compared with the rest of the esophagus. Baseline muscle thickness is also significantly higher at 2 cm vs. 10 cm above the LES. In a given subject and among different subjects, there is a good relationship between peak muscle thickness and peak peristaltic pressures (r = 0.55) at all sites along the length of the esophagus. The positive correlation between pressure and muscle thickness implies that the mean circumferential wall stress is fairly uniform from one swallow to another, irrespective of the contraction amplitude.

The effect of mechanoreceptor stimulation of the laryngopharynx on the oesophago-gastric junction.

Stimulation of the pharynx by injection of minute amounts of water induces prolonged period of lower oesophageal sphincter (LOS) relaxation and augmentation of the crural diaphragm (CD) contraction. The purpose of this study was to determine the effects of stimulating mechano-receptors at the laryngopharynx on the LOS and CD by using an air pulse stimulation device. Air pulses were delivered via the internal channel of a flexible endoscope. Oesophageal, LOS, and CD pressures; CD electromyogram; and oesophageal pH 5 cm above the LOS were recorded in nine healthy subjects. Stimulation of the laryngopharynx induced LOS relaxation in the absence of swallow and oesophageal peristalsis. The stimulation of epiglottis and arytenoid produced higher incidence of LOS relaxation compared to the base of tongue. The magnitude of LOS relaxation differed significantly between the three anatomical sites, with greater relaxation occurring at the epiglottis and arytenoid compared with the base of the tongue. None of the LOS relaxations induced by laryngeal stimulation resulted in inhibition of the CD or gastroesophageal reflux. We conclude that stimulation of the laryngopharyngeal mechanoreceptors induces LOS but not CD relaxation. The LOS relaxation induced by laryngopharyngeal stimulation is not accompanied by acid reflux in fasting state.

Lower esophageal sphincter monitoring with sphinctometer: in vitro and in vivo studies.

The sphinctometer is a solid-state device system for prolonged ambulatory recordings of the lower esophageal sphincter (LES) pressure. The aims of this study were to determine 1) the pressure sensitivity and the latency of sphinctometer responses in vitro, 2) if the sphinctometer can record transient LES relaxations (TLESR) in vivo, and 3) if the currently accepted criteria for TLESR are applicable to sphinctometer recordings. Different segments of the sphinctometer were positioned in a chamber at known pressures to assess the sphinctometer readings as well as the latency of the response. Ten healthy subjects were investigated with the use of a solid-state transducer sphinctometer assembly and a pH probe for 4 h. The LES pressure was analyzed during baseline periods, swallow-induced LES relaxations (SILESR), and LES relaxations associated with acid reflux episodes (pH <4) (presumed TLESRs). Our results showed that sphinctometer readings were linearly related to the chamber pressure and the length of the segment exposed to the pressure; however, the latter was considerably underestimated. We also found that sphinctometer segments of equal length but at different levels showed different pressure readings, the mean response time of sphinctometer was 0.25 s, and sphinctometer output was susceptible to temperature changes of the environment. In humans, only 25 of 45 episodes (64%) and 17 of 22 episodes (77%) were detected by the sphinctometer as being SILESRs and TLESRs, respectively. The pattern of the LES pressure during acid reflux events resembled classical TLESR. We concluded that the sphinctometer is a useful device for determining qualitative changes in LES pressure. However, its major limitations are pressure underestimation, different sensitivity of various segments, pressure drifts, and underscoring of LES relaxations.

Sustained esophageal contraction: a marker of esophageal chest pain identified by intraluminal ultrasonography.

BACKGROUND & AIMS: Intraluminal pressure recording systems have not demonstrated predictable esophageal motor correlates of unexplained chest pain. This study used continuous high-frequency intraluminal ultrasonography to characterize esophageal contraction at the time of spontaneous and provoked chest pain. METHODS: Intraluminal pressure, pH, and ultrasound images of the esophagus were recorded for a maximum of 24 hours in 10 subjects with unexplained chest pain. Changes in esophageal muscle thickness were measured as a marker of muscle contraction. Ten additional subjects with suspected esophageal chest pain were studied after edrophonium chloride injection to provoke symptoms. Ten healthy subjects were studied as controls. RESULTS: Eighteen of 24 spontaneous chest pain episodes were preceded by a sustained esophageal contraction (SEC) detected on ultrasonography (mean duration, 68.0 seconds). This motor pattern was not accompanied by changes in intraluminal pressure. Four of 24 asymptomatic control periods were accompanied by SEC, although these contractions were of shorter mean duration (29.0 seconds; P < 0.001). SEC was observed in 5 subjects with a positive chest pain response to edrophonium and in none of the 5 subjects with a negative response. SEC was not detected in normal subjects. CONCLUSIONS: There is a strong temporal correlation between a previously unrecognized esophageal motor event, SEC, and both spontaneous and provoked esophageal chest pain.

Comparison of three urease tests for detection of Helicobacter pylori in gastric biopsy specimens.

OBJECTIVE: To propose two modified urease tests for the detection of Helicobacter pylori in gastric biopsy specimens. PATIENTS AND METHODS: The presence of H. pylori infection was determined in 237 patients undergoing upper gastrointestinal endoscopy. Three media were used for the urease tests: Christensen's 2% urea broth and two urea agar media, modified by increasing the concentration of urea (to 4% and 10%) and phenol red and omitting the nutrients. RESULTS: The modified tests had good sensitivity (> 78%), specificity (96%) and accuracy (> or = 86%) at 2 h using small amounts (15%) of biopsy homogenates. They were statistically more sensitive and accurate than Christensen's broth. CONCLUSION: Both the modified 4% and 10% urea agar tests are simple, sensitive and specific and can be performed with small amounts of sample.