Can pH monitoring reliably detect gastro-oesophageal reflux in preterm infants?
- aDepartment of Paediatrics, Southern General Hospital, Glasgow, Scotland, UK, bRespiratory Unit, Royal Hospital for Sick Children, Glasgow
- Dr Cochran, Respiratory Unit, Royal Hospital for Sick Children, Yorkhill, Glasgow G3 8SJ, Scotland, UKbellcochran{at}supanet.com
- Accepted 25 April 2001
Gastro-oesophageal reflux (GOR) is the regurgitation of gastric contents into the oesophagus. It is alleged to be the cause of many clinical problems in premature infants, such as failure to thrive, apnoea, desaturation, bradycardia, and stridor.1 2
Twenty four hour oesophageal pH monitoring is currently regarded as the optimal method of diagnosing occult GOR in infants with respiratory events. European and North American working parties have produced guidelines for the methodology and interpretation of oesophageal pH studies in infants and children.3 4 However, pH monitoring in preterm infants has shortcomings, which makes the diagnosis of GOR in this group more difficult and its clinical significance more uncertain than in older children. This review seeks to highlight these shortcomings and to discuss the future of pH monitoring in preterm infants.
Normal values
The lack of published normal values for reflux variables in preterm infants makes interpretation of pH monitoring difficult. A reflux index (% of time pH < 4) of > 10% is widely accepted to be indicative of pathological GOR in infants, but this value is based on a study of term infants.5 There are only a few small studies involving preterm infants, with variable results6-10; they are summarised in table 1. Inconsistencies in feeding methods, ventilation, and positioning are reflected in the varying reflux indices.
- In this window
- In a new window
Summary of studies on normal values in preterm infants
Defining upper limits of normal is further hampered by the reporting of mean values for reflux indices rather than ranges.6 7 9 10 Vandenplas et al,5 who studied the largest series of mature infants, showed that the reflux index is not normally distributed in this population.5 Attempting to define the upper limit of normal in preterm infants using mean (SD) is unlikely to be meaningful for this reason. It may …
