What is 24-Hour Oesophageal pH Monitoring?

Oesophageal pH monitoring consists of inserting a thin probe, with 1 or 2 incorporated pH sensors, through the nose until it reaches the stomach. This probe is connected to a portable device (a Holter monitor) for 24 hours, which continuously records the pH in the oesophagus.

A fasting period of at least 4-6 hours is required before the test. If you take medication to change the acidity of the gastric contents - such as omeprazole, lansoprazole, pantoprazole, rabeprazole or esomeprazole - you should stop taking it 7-10 days before the test. In the case of famotidine, only 3 days beforehand is required. If you suffer pain or discomfort during this period, you can take antacids up to 8 hours before the test. 

Patients have to follow a series of instructions on the day of the test:

• Noting meal times, postural changes and any symptoms they have over the 24 hours. Continuing with their normal pace of life both at home and at work. 
• Not taking antacids.
• Not taking a shower, in order to protect the device.
• If the probe comes out due to vomiting or discomfort, it should be carefully removed and wrapped in a handkerchief without touching anything; before returning the next day to the health centre with all the equipment. 
• Once the 24 hours have passed, the patient has to go to the health centre to have the probe removed, then the notes can be reviewed and any questions answered. After the test, activity and medication can be resumed.

The probe is very thin (about 2.1 mm) and flexible, so even though inserting the probe through the nose and throat may be uncomfortable, it should be tolerable. However, any discomfort can be minimised with a local anaesthetic gel. Nausea or coughing may also occur. 

As the test requires nasal intubation, minor trauma to the nose, pharynx, larynx or oesophagus with bleeding may occur. It rarely causes perforation, vocal cord injury or bronchial spasms. Such situations are exceptional.