Significance of esophageal manometry and long-term pH monitoring for the evaluation of gastroesophageal reflux in infancy and childhood

Why do the published data fail to clarify the relationship between gastroesophageal reflux and asthma?

The relationship between gastroesophageal reflux (GER) and asthma has troubled physicians for centuries and has been a source of debate among pulmonologists, allergists, and gastroenterologists for decades. Attempting to tie together the pieces of the puzzle, numerous investigators have struggled to show that in patients with asthma, GER symptoms occur too frequently, gastric acid dwells for too long in the esophageal lumen, and refluxed gastric acid injures the esophageal mucosa more than expected. Unfortunately, all of the work done by these fine investigators has failed to demonstrate a "cause and effect" relationship. Although they have succeeded in convincing us that GER occurs more frequently in asthmatics than in nonasthmatics, they still must continue until we all know how to predict which patients have gastroesophageal-induced or gastroesophageal-exacerbated asthma.

Gastroesophageal reflux and asthma

The medical literature has been deluged with articles on the relation between gastroesophageal reflux (GER) and asthma. In an effort to piece together the complex puzzle, investigators from all disciplines have gathered their patients with wheezing and heartburn and studied the epidemiology, the possible cause or effect mechanisms and the therapeutic response to GER treatment. Indeed, since humans first began to hunker down and work together to discuss interesting observations, the world has begun to breathe easier. Epidemiological evidence for a GER/asthma association suggests that about three-fourths of asthmatics, independent of the use of bronchodilators, have acid GER, increased frequency of reflux episodes, or heartburn; and 40% have reflux esophagitis. Physiological studies suggest that 2 separate mechanisms are involved in the GER/asthma relationship: (1) a vagally mediated pathway and (2) microaspiration. In any given patient, however, there is no acceptable diagnostic method available to confirm the presence or absence of GER-induced asthma. Clinical trials, using antireflux medical therapy and antireflux surgery have begun to provide some clues about GER-related pulmonary symptoms. The trials of medical therapy using acid suppressing drugs (e.g. histamine-2 receptor antagonists) have ranged from no benefit to modest improvement of only nocturnal asthma symptoms. Studies with proton-pump inhibitors are underway. In uncontrolled surgical studies, antireflux surgery has resulted in partial or complete remission of asthma symptoms in a large proportion of patients. Despite the uncontrolled nature of these studies, many patients have had dramatic subjective improvement in pulmonary symptoms. It appears for now that clinical trials are the only available means to assess whether medical or surgical treatment of GER in patients with both GER and asthma improves the symptoms of asthma and decreases the need for pulmonary medications. One conclusion is certain: We no longer can ignore the important co-existent nature of these 2 afflictions.

A dose-ranging study of ranitidine and its effect on intragastric and intra-oesophageal acidity in subjects with gastro-oesophageal reflux disease

METHODS

This randomized, double-blind, single-centre, crossover study was designed to assess the effects of three regimens of ranitidine (150 mg b.d., 300 mg b.d. and 300 mg q.d.s.) and placebo on intra-oesophageal and intragastric pH in subjects with gastro-oesophageal reflux disease (GERD). Twenty-six subjects were screened, and 9 were evaluable by the admission criteria. These 9 subjects received each of the regimens for 72 h, and a wash-out period of at least 48 h followed each dosing period. Standard meals and beverages were provided.

RESULTS

With increasing doses of ranitidine, 24-h intragastric mean H+ and integrated H+ fell, and the percentage of the time the pH was equal to or greater than 4 (% time pH > or = 4) rose: the minimum effective dose for these effects was ranitidine 300 mg daily. With increasing doses of ranitidine there was also a progressive decline in mean 24-h intra-oesophageal H+ and integrated H+, and increasing % time pH > or = 4. The minimal effective dose was 300 mg daily for intra-oesophageal mean H+ and integrated H+, and 600 mg for % time pH > or = 4. The minimal effective dose to decrease the number of reflex episodes was 1200 mg ranitidine. For the daytime upright position, a dose effect of increasing ranitidine was also seen, with minimal effective ranitidine doses of 300 mg for a decrease in mean H+, and 1200 mg for % time pH > or = 4.

CONCLUSION

If these higher doses of ranitidine are confirmed to be more effective than the standard 150 mg b.d. regimen for the treatment of patients with gastro-oesophageal reflux disease, then the mechanism of this action probably relates to the lower exposure of the oesophageal mucosa to acid.

Normal 24-hr ambulatory esophageal pH values. Influence of study center, pH electrode, age, and gender

Although the most sensitive and specific test for diagnosing gastroesophageal reflux disease, normal standards for prolonged esophageal pH monitoring are based on small sample sizes with questions raised about the effects of pH electrode, older age, gender, and methods of data analysis on pH variables. Recently three groups have established normal data bases using similar methodology. Multiple regression and nonparametric analyses showed that the values for the six traditional pH parameters were comparable across study centers. Therefore, the groups were combined for a total study population of 110 healthy subjects (47 men, 63 women, mean age 38 years with a range of 20-84 years). Further nonparametric analyses revealed the following: (1) type of pH electrode (antimony vs glass) is not significantly related to parameters of physiologic acid reflux; (2) age is not independently related to pH parameters; (3) men tend to have more physiologic reflux than women; and (4) older men tend to experience longer episodes of reflux than younger men and women. There was a significant effect of gender and a significant interaction between age and gender on the number of episodes greater than 5 min (P = 0.008). Nearly significant differences were found for percentage of total acid exposure time (P = 0.03), total reflux episodes (P = 0.02), and the longest reflux episode (P = 0.02). We believe these normal esophageal pH values can be used confidently as standards in any laboratory, and consideration should be given to developing separate standards for men and women.

Motor efficiency of the refluxing esophagus in basal conditions and after acid challenge

We have investigated manometrically and endoscopically 60 children with extended pH metering-documented gastroesophageal reflux (GER) and a control group of 14 children of comparable ages. In an attempt to simplify the evaluation of esophageal peristalsis, we measured the frequency of propulsive waves (in waves/hour) and their mean pressure (in mm Hg) in the body of the esophagus and multiplied both values to result in one single figure that reflected esophageal motor efficiency (EME) in some way. We performed the tests in basal conditions (EMEB) and after instillation of 5 mL of 0.1 N CIH into the esophageal lumen (EMECIH). In comparison with controls, refluxing children had a lower sphincter pressure (LESP) (14.9 +/- 8 v 11.8 +/- 6.9 mm Hg, P less than 0.05), an increased proportion of nonpropulsive waves (38.8 +/- 29.3% v 68 +/- 27%, P less than 0.001), and a significantly lower EMEB (896.6 +/- 777 v 375 +/- 306, P less than 0.001). These results suggest that both the sphincteric antireflux barrier and esophageal pump can be damaged in GER. There was a weak, but significant, correlation between EMEB and esophagitis grade (rs = -.25, P less than 0.05). Furthermore, esophageal motor response after CIH instillation may have some prognostic value because EMECIH was significantly higher in those of the 52 children followed-up for more than a year who responded to medical treatment (n = 16) than in those in whom medical treatment was a failure (n = 36) (981.2 +/- 617.4 v 460.5 +/- 452.3, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of gastroesophageal reflux following repair of esophageal atresia

Gastroesophageal reflux (GER) was looked for retro- and prospectively by various diagnostic methods in 67 patients, subdivided into three groups according to age at time of investigation. Pathological reflux was found in only one-quarter of the patients aged 16-23 years, but in three-quarters of both younger groups followed up for 1.5-14 years so far. Whereas pathological findings were most frequently disclosed by manometry in the older patients, radiological findings were most often decisive in younger patients. Following closure of recurrent tracheoesophageal fistulas and resection of anastomotic stenoses, eight patients developed reflux complications during the first months of life; these were so severe that antireflux plasty became unavoidable. Factors influencing the incidence of GER following esophageal repair were: the definition of GER based on the diagnostic method employed, the patient's age at the time of diagnosis, and anastomotic complications requiring a second operation. The essential time for treatment was the first year of life.