24 Hour pH and impedance studies- what are they?

pH monitoring studies are performed via the insertion of a ‘flexible catheter’ into the stomach via the nose. This allows doctors to see if there is any reflux- movement of gas or liquids from the stomach up into the oesophagus (gullet).

While the tube is inserted, your child can walk about and do most regular daily activities, with the portable recorder attached.

This tube is approximately 2mm in diameter, and has an attached pH electrode to measure the pH (acidity level).

MII-pH monitoring (pH monitoring/impedance studies) is becoming the investigation of choice for diagnosing GOR in children due to its ability both in detecting all types of reflux episodes and evaluating the association of symptoms with reflux events irrespective of their chemistry.

Indication

The indications of MII-pH monitoring in children are to measure GOR and ascertain symptoms association, to quantify reflux in children not responding to therapy and in research.

Preparation

Your child should should ideally be fasted for 2–4 hours (depending on their age) before tube insertion to avoid inducing vomiting. Acid suppression therapy should be stopped before the procedure; histamine 2 (H2) blockade should be stopped 48 hours and proton pump inhibitors 7 days before the study. Prokinetics should be stopped 48 hours and antacids 6 hours before the study.

HOW LONG WILL THE PROCEDURE TAKE?

The study duration should be ideally for 24 hours but a minimum of 16 hours and should incorporate an overnight recording.

Please also see Reflux Studies.

Mutalib, M., Rawat, D., Lindley, K., Borrelli, O., Perring, S., Auth, M. and Thapar, N. (2017). BSPGHAN Motility Working Group position statement: paediatric multichannel intraluminal pH impedance monitoring—indications, methods and interpretation. Frontline Gastroenterology, 8(3), pp.156-162.