Value of the 24 hour intraoesophageal pH monitoring in children.

Twenty four hour oesophageal intraluminal pH probe studies were performed in 114 children (range age: one month-12 years) referred for symptoms or signs compatible with gastroesophageal reflux. Forty five patients had reflux disease alone, 69 had evidence of oesophagitis which was assessed endoscopically and histologically. Recordings were also performed in 63 control patients. The occurrence of reflux was analysed for the total study period and particularly while awake, asleep, fasting, and during postcibal periods. Oesophageal acid exposure time and the number of reflux episodes lasting greater than five minutes during the total study period provided the best discrimination between patients and controls; however, 20% and 30% of all reflux patients had both normal (with 2 SD of control) acid exposure time and number of long lasting reflux episodes, respectively. Patients with oesophagitis had significantly more acid reflux than those with simple uncomplicated disease during postcibal, fasting, awake periods, but not during sleep; however, increasing severity of oesophagitis was not associated with increasing acid exposure. The ability of the intraluminal oesophageal pH test to discriminate patients with various degrees of reflux disease decreased if only postprandial pH variables were taken into account. We conclude that: (1) the 24 hour intraoesophageal pH monitoring may present false negative results that limit overall sensitivity of the test; (2) the presence of oesophagitis does not seem to be associated with increased oesophageal acid exposure during sleep; (3) limiting the pH recording to postprandial periods reduces the discriminatory power of the test.