Inter- and intraobserver agreement for gastroesophageal reflux detection in infants using multiple intraluminal impedance.

The multiple intraluminal impedance (MII) technique is a new method that allows pH-independent gastroesophageal reflux detection via changes in impedance caused by a liquid bolus inside the esophagus. We wanted to know whether this technique yields objective and reproducible results. Twenty 3- to 6-hour recordings of MII from 19 preterm infants (median gestational age at birth 30 weeks, range 24-34 weeks; age at study 26 days, range 13-93 days) were divided into 23-second segments and analyzed for reflux episodes by three investigators; one investigator analyzed the data set twice.