Oesophageal pH monitoring is a test that measures the amount of acid in your oesophagus (gullet).
Acid is produced by the stomach and helps digest food. Normally, acid remains in the stomach, but sometimes acid may wash up (reflux) from the stomach into the oesophagus. Your doctor may suspect reflux if you have heartburn, or other chest or abdominal discomfort, if you suffer from a cough, frequent sore throats or chest complaints. Measuring oesophageal pH or acid over 24 hours is an accurate way to diagnose reflux. It provides important information about how much acid rises into the oesophagus and when this occurs during the day. It can then be decided whether reflux is responsible for your symptoms and what treatment is required.
The amount of acid in the oesophagus is measured by a sensitive probe called a pH electrode on the end of a plastic tube about 2mm wide. At the beginning of the test, the throat and one side of the nose are made numb with local anaesthetic spray and jelly. The exact distance of the lower end of the oesophagus from the nose is then worked out by passing a soft tube through the nose and measuring the movements of the oesophagus. This part of the test is called oesophageal manometry. A separate brochure is available to describe this in more detail. This tube is then taken out and the pH probe is passed down through the nose into the lower end of the oesophagus. You will be given water to drink through a straw to help these tubes pass down without difficulty. Positioning this equipment should take 20-30 minutes. The pH probe remains in position for the duration of the test, approximately 24 hours.
During the test, information from the pH probe is recorded by a small box that you will carry around with you on a strap worn over the shoulder. To ensure a good quality recording, the equipment must not be wet or bumped.
Following insertion of the tube, you should not have anything hot to eat or drink for one hour, until the local anaesthetic has worn off.
You do not receive general sedation for this test and so you can usually drive and carry out other normal activities as usual. The tube may be a little uncomfortable at first and it is best to arrange transport home from the test.
During the test, you will be able to perform most activities and eat and drink normally.
However, there are some dietary restrictions that will be fully explained before the test. These include avoiding acid-containing foods such as tomatoes, and oranges as well as fizzy soft drinks.
At the end of the recording period, you can return to the hospital where the pH probe will be removed. This involves little discomfort and does not require any local anaesthetic or other preparation. The results are analysed by computer and are examined by the specialist. Your doctor will receive a report within a few days.
Reminder: please do not wet the recorder.
During the recording period, you will be asked to make a note of when your symptoms occur, when you eat your meals and when you are lying down. This information is recorded by pressing buttons on the recorder and also by writing it down in a diary. How to do this will be explained further just before the test begins. You will be given a sheet of paper to take home with you with instructions and space to use as your diary. Again, if you have any questions or problems during the day, please contact the hospital at the numbers given below. vomiting or sneezing is rare. The nose may be wiped gently if required during the test without disturbing the tube.
The test is tolerated well by most people. There may be difficulty passing the tubes if you have had previous surgery or injuries to the nose. If you have had nose problems, please inform the doctor before the test. The local anaesthetic can cause temporary irritation of the nose and of the eyes. After the pH probe is inserted at the beginning of the test, you should not have anything hot to eat or drink for one hour to allow the local anaesthetic to wear o. Some people notice discomfort in the throat during the test. This is usually mild and can be improved by lying down or taking sips of water. If discomfort remains unpleasant, feel free to contact the hospital to discuss the situation. Vomiting due to irritation of the throat is uncommon. Dislodgment of the tube due to vomiting or sneezing is rare. The nose may be wiped gently if required during the test without disturbing the tube.