A pH study is a test, which measures gastroesophageal reflux (GOR) over a 24-hour period. It helps us to establish whether your child’s symptoms are due to acid reflux. Gastroesophageal reflux is when the stomach contents are brought back up into the oesophagus (food pipe). It can occur for a number of reasons, including a weak valve (laxed gastroesophageal sphincter). Repeated reflux of stomach acid may cause your child’s oesophagus to become inflamed, which can be painful.
Why it is needed?
A pH study is needed to determine the severity of your child’s GOR. The test allows us to determine what the relationship is between your child’s particular symptoms or complaints and episodes of acid reflux. The test is performed to examine patients with heartburn, regurgitation, chest pain, cough, sore throat, voice hoarseness, and unexplained distressed episodes (in young children). This will help us to decide the appropriate treatment.
What happens before the test?
We will explain the test in more detail and at this point you’re welcome to ask any questions and discuss any concerns with the team.
Your child may need to stop some of their current medications that they are taking such as:
- Gaviscon and antacids should not be given the morning of the test
- Ranitidine and domperidone must be stopped 48 hours before the test.
- Proton pump inhibitors (omeprazole, lansoprazole, esomeprazole, pantoprazole) must be stopped 72 hours before the test.
What does the test involve?
A thin flexible tube containing the pH probe is inserted into the nose and down the back of the throat into the oesophagus. The tube will sit a few centimetres above the opening to the stomach so that the probe can measure the pH values, which are continually recorded for the next 24 hours by a monitor attached to the other end of the tube. The probe can be inserted while your child is awake in clinic or whilst having a general anaesthetic (GA) for an endoscopy.
How is the pH probe inserted?
If your child is awake, they can sit or be cuddled while the tube is being inserted. Your child may be uncomfortable for a short while. It may make your child sneeze, cough, retch and make their eyes water. A drink of small water sometimes makes it easier for the end of the tube to travel to the oesophagus.
Once the probe is in the desired position, the nurse will secure it to your child’s cheek, a chest x-ray will be taken to confirm that the probe is in the correct position. The probe may need to be repositioned by inserting or withdrawing the tube slightly. Your child will not be allowed to eat or drink until the position is confirmed.
Your child should not be in any discomfort whilst the probe is in place but may find that the tube tickles the throat a little.
What happens while the probe is recording?
You must return if the probe becomes displaced. The tube will be removed in outpatient the following day. Your child should eat and drink as usual. You will need to fill in an activity diary; this will be explained in detail.
Are there any risks?
Your child could have a nosebleed when the tube is inserted into the nostril. This tends to happen more with children who have a history of nosebleeds.
There is a risk of the tube being removed accidentally or being vomited out. If the tube has come out completely, the study will be aborted and the tube will be removed. However, if the tube is removed accidentally after more than 18 hours of study, the data can still be used for analysis.
There is a very small risk the tube could damage your child’s gut, but this is very unlikely as the tube is thin and flexible.
There is a small risk of aspiration (leaking) of stomach contents into the lungs during the insertion of the tube. We therefore ask that you do not give your child anything to eat or drink for a minimum of 2 hours prior to your appointment.
There is a small risk of the tube going into a lung instead of the oesophagus although this is unlikely. If this does occur it is unlikely to cause any harm as the position is confirmed on an X-ray.
What happens afterwards?
After the PH study, please restart all anti-reflux medication until the results are known.
Katie’s experience of having the pH study test
8-year-old Katie, shares her experience of having the pH study.
She hopes that her speaking about her experience will help to ease the anxiety from other children coming in to have this done.
Jamies experience of having the pH study test
15-year-old Jamie shares his experience of having the pH study.
He hopes that speaking about his experience will help to ease the anxiety from other children coming in to have this done.