Reproducibility of gastroesophageal reflux scintigraphy and the standard acid reflux test

Patterns of food and acid reflux in patients with low-grade oesophagitis--the role of an anti-reflux agent

BACKGROUND

Food and acid have been shown to be refluxed independently of each other in healthy volunteers, and anti-reflux agents decrease the reflux of both parameters. Until now this phenomenon had not been studied in patients with low-grade oesophagitis, who are the group most likely to use anti-reflux medication.

AIM

To assess patterns of gastro-oesophageal reflux of acid and food in 12 ambulant patients with endoscopically proven oesophagitis of between grades I and II, but who were otherwise healthy. Also to assess the effectiveness of a single dose of an alginate-containing anti-reflux agent in controlling food and acid reflux in this patient group.

METHODS

Oesophageal pH monitoring and external ambulatory gamma detection were used to study food and acid reflux. A pH electrode was positioned 5 cm above the cardia and the gamma detector was positioned externally over the pH electrode. The patients then received a technetium-99m labelled meal designed to provoke reflux. Thirty minutes later the patients were given a 20 ml dose of alginate (Liquid Gaviscon), or 20 ml of tap water. Incidence of reflux was monitored for approximately 4 h from the end of the meal. Allocation to treatment group was randomized, with patients receiving the alternative treatment on the second study day after approximately a 7-day washout period.

RESULTS

The mean percentage time oesophageal pH remained below 4 was 16.3 min for the control group and 5.4 min for the treatment group (P = 0.03). Food reflux was detected 23.7% of the time in the control group compared to 12% of the time in the treatment group (P = 0.02). The anti-reflux agent was also successful in decreasing the number of events, but the duration of the reflux events was not significantly different.

CONCLUSIONS

Patients with grades I and II oesophagitis reflux food and acid independently, and are predominantly either food refluxers or acid refluxers, but not both. Liquid alginate decreases the number of both food and acid reflux events, but does not change their duration.

Long-term manometry of tubular esophagus in progressive systemic sclerosis

Long-term manometry of the tubular esophagus was performed in 20 consecutive patients (18 females, 2 males; median age 56.5 years) with progressive systemic sclerosis (PSS) and a control group of 20 healthy subjects (18 females, 2 males; median age 56.5 years). The measurements were performed via a data logger of 1 MByte memory capacity with the help of two pressure sensors placed 8 and 18 cm above the lower esophageal sphincter. Esophageal contractions were analyzed with respect to pressure amplitudes in the esophagus distal and proximal, quotient of pressure amplitudes distal/proximal, number of contraction waves in a 24-h period, and kind of spreading (propulsive, simultaneous). In the PSS group there was a significant decrease in pressure amplitudes in the distal sensor (median 31.5 versus 39.5 mbar in controls, P < 0.02), in the quotient of pressure amplitudes distal/proximal (median 0.885 versus 1.25 in controls, P < 0.001), in the number of waves in 24 h (median 939.5 versus 1656 in controls, P < 0.01), and in the occurrence of propulsive waves (median 34% versus 57% in controls, P < 0.01). Fifteen patients (75%) had hypomotility disorders as compared to the control group, in which the lower limit of normal values was defined by the 5th percentile of descriptive analysis. These first data of long-term manometry in patients with PSS indicate that long-term manometry may be an effective method for identifying esophageal involvement in PSS.

Non-invasive detection of gastro-oesophageal reflux using an ambulatory system

The aim of this study was the separate measurement of reflux of food and acid into the oesophagus in 37 healthy, ambulant subjects. This was performed by radiolabelling the food and monitoring its reflux with a small directional gamma detector, which was placed externally over the oesophagus, and connected to an ambulatory data recorder. The pH was measured with a conventional oesophageal pH electrode. This method permitted the separate characterisation of acid and neutral (food) components of gastro-oesophageal reflux. The gastric emptying characteristics of the test meal were also monitored by gamma scintigraphy in a separate experiment. The oesophageal pH fell below 4 for 3.2 + 8.6/-2.3% (mean (SD)) of the recording time. Food reflux alone occurred for 17.8 + 53.2/-13.8% of the recording time. Simultaneous food and acid reflux occurred for only 0.95 + 5.2/-1.2% of the time. Not every reflux event detected by a fall in pH was seen as an increase in counts as a result of reflux of food, and vice versa. This poor correlation of food and acid reflux implies incomplete mixing of food and acid in the stomach, and further shows the inadequacy of reflux diagnosis methods that depend on pH detection alone.