Ultrasonography for the positioning of esophageal multichannel intraluminal impedance/pH-metry catheter in newborns

Objectives: To assess the use of ultrasound (US) to visualize and determine the correct position of a multichannel intraluminal impedance-pH probe (MII-pH). Methods: This is a monocenter study recruiting newborns who underwent MII-pH for suspicious of gastroesopahegal reflux (GER). Catheter position was based on US and was confirmed by X-ray. Moreover, the depth of the probe was compared with those calculated with several mathematical formula used for pH impedance. The US was performed using (US) system Alpinion-eCube-i7® in B-mode with linear and convex probe. US was used to evaluate the correct positioning of the MII-pH catheter before the beginning and during the MII-pH execution to evaluate any changes of the position. The results were also compared with retrospective cases collected in our center in previous years. Results: Thirty-six newborns were included. US allowed to visualize the esophageal probe in all the newborn tested. US-based positioning was correct in 100% of patients considering an error acceptance of 1 cm, and 66.7% with an error acceptance of 0.5 cm, compared to X-ray. The median duration of the US was 3.2 min (range 2.5–5.78 min), with prolonged time in crying babies. Previous cohort consisted of 35 newborns who underwent MII-pH: one patient had the probe in the respiratory tract and six patients needed new positioning of the MII-pH probe and second X-ray control because of bad positioning or accidental removal of the probe. Conclusions: US seems to be a valid alternative for the assessment of the MII-pH probe position and the identification of the pH sensor and the lower esophageal sphincter in real time. However, US expertise is needed to provide accurate results.