Abbreviated oesophageal pH monitoring in infants

[Esophageal pH monitoring study of eight hours in pediatric patients with suspected gastroesophageal reflux]

PURPOSE

To study the pH monitoring over eight hours, analyzing variables such symptomatology and esophagogastroduodenoscopy, as well as the following pH monitoring parameters: number of reflux episodes, number of episodes longer than five minutes, length of reflux time during the eight hours, and the episode of longest duration, for the diagnosis of gastroesophageal reflux.

METHODS

A prospective study. Continuous measurement of esophageal pH was performed over eight hours on 35 patients whose ages ranged from four months to 11 years. The DPS-100 Diagnosis pH meter System was utilized, programmed in accordance with the methodology suggested by Vandenplas. The pH monitoring results were divided into positive and negative and compared with all the variables and parameters of the examination.

RESULTS

We obtained statistically significant differences in all the pH monitoring parameters analyzed, with the reflux index being the most effective for identifying the pathological reflux, independent of age. None of the qualitative variables of age, symptomatology and esophagogastroduodenoscopy showed statistically significant differences when compared to the pH monitoring results.

CONCLUSION

The esophageal pH monitoring of eight hours has its pH monitoring parameters validated for the diagnosis of gastroesophageal reflux.

Reflux in children

Gastro-oesophageal reflux (GOR) is an extremely common paediatric problem that often runs a harmless and self-limited course. Physiological GOR however can lead to marked parental anxiety, many unnecessary investigations and often unwarranted and potentially harmful therapeutic interventions. Our ability to better define GOR and gastro-oesophageal reflux disease (GORD) has improved in the past 15 years with a better understanding of the pathophysiology in infants and children due to the development and wider use of flexible endoscopy, 24-hour oesophageal pH monitoring and, more recently, the use of micromanometric methods for studying oesophageal motility. This will be further enhanced in the future with the development of non-invasive breath testing to study gastrointestinal motility and the use of electrical impedance to study fluid movement. Our therapeutic interventions have also improved particularly in the areas of acid suppression, improved surgical techniques and most recently laparoscopic fundoplication. This chapter reviews these advances in the paediatric area especially with regard to pathophysiology, diagnostic testing and therapeutic intervention.

The role of gastro-oesophageal reflux in the aetiology of SIDS

Gastro-oesophageal reflux (GOR) has been identified as a possible cause of SIDS. Several features of GOR unique to infants presenting with apparent life-threatening events (ALTEs) have led to its 'pathogenic' definition. One is that the life-threatening apnoea itself is initiated by GOR, another is that the ALTE relates to prolonged reflux during sleep, in a vulnerable sleep-state, and finally that the ALTE relates to excessive quantities of GOR. The presumption of GOR 'pathology' as a cause of SIDS however, is questionable in these susceptible infants for three reasons: firstly, GOR is physiological and occurs in most infants; secondly, there is no general consensus on what constitutes normal physiological reflux, and thirdly, variation in the recording technique and methods of data analysis and interpretation may account for the differences between study groups. It seems likely therefore if GOR is implicated in SIDS, additional factors are involved. Under certain circumstances, physiological GOR may trigger life-threatening apnoea in apparently healthy infants, that leads to SIDS. One mechanism that could explain such a death is reflex apnoea by stimulation of laryngeal chemoreceptors (LCR) during sleep. The conditions under which this could be fatal are the occurrence of gastric contents refluxed to the level of the pharynx during sleep, in the young infant who has depressed swallowing and arousal. That is, the occurrence of GOR to the level of the pharynx during sleep, an infrequent event that is usually innocuous, could be converted to a fatal event if swallowing is impaired and arousal depressed, by a variety of mediating factors such as prone sleeping, prematurity, sedatives, seizures or upper respiratory tract infections. The identification of LCR responses, particularly in prone sleeping and premature infants provide further evidence that this mechanism may be implicated in the aetiology of SIDS in apparently healthy infants.

Gastro-oesophageal reflux in infancy

Gastro-oesophageal reflux (GOR) is a common phenomenon in infants, which may occur with or without accompanying symptoms. Although most infants presenting with regurgitation have a normal physical examination, it is now recognized that infants may also present with a wide variety of symptoms. Oesophagitis is associated with increased oesophageal acid exposure. The determination of cause and effect is difficult, as there are many aspects of reflux disease where cause and effect relationships are cyclic. Reflux disease is present when there is an imbalance between a number of factors that can contribute to a decrease, as well as an increase, of GOR. Oesophageal pH monitoring with a semi-disposable monocrysant antimony pH catheter with three sensors is very good at documenting oesophageal acidification and gastric buffering and, therefore, quantifies acid reflux frequency and duration. However, the interpretation of the data is complex as they are influenced by numerous factors, such as position, activity (sleep, crying), feeding (frequency and composition) or medication. The duration of buffering of gastric acidity during pH monitoring might, in the future, appear to be a relevant factor in the interpretation of oesophageal pH data.