Esophageal pH monitoring

Esophageal pH monitoring is the “gold-standard” procedure for the diagnosis of gastroesophageal reflux disease (GERD).

Given the fact that it allows us to identify a potential direct link between symptoms and reflux episodes, it is mainly indicated in cases of:

1. Symptoms that persist despite medical treatment,
2. Chronic cough, when all other causes have been excluded (in such cases, weakly acid reflux could be the cause of chronic cough) or
3. Other less common symptoms that could be a result of GERD.

In recent years, pH monitoring has been combined with “impedance monitoring”, which allows the detection of all reflux episodes, regardless of their composition (liquid, air, mixed) and degree of acidity.

Preparation:

The patient is instructed not to eat or drink for 4-6 hours prior to the test. In addition, any medical treatment that may affect the result should be discontinued (unless the referring physician wishes the study to be carried out under treatment to evaluate its efficacy), therefore:

1. Proton pump inhibitors (pantoprazole, esomeprazole, omeprazole, lansoprasole, rampeprazole) are discontinued for up to 10 days before the test.
2. H₂-histamine antagonists (ranitidine, cimetidine, famotidine) and other antacids are discontinued 48 hours before the test.

How does the pH-monitoring take place?

After local anesthesia, a thin, flexible catheter is passed through the nose and its tip reaches a few centimeters above the esophagogastric junction; it is then stabilized to the nose with adhesive tape.

The catheter is attached to a recording device; the latter has buttons that the patient presses when he or she takes meals, when lying down or when symptoms occur. In addition, the patient notes down in a journal the time of beginning and end of meals, their bedtime, as well as the nature of the symptoms that he or she may experience during recording and the time they occur.

The recording lasts 24 hours with the patient taking his daily meals and usual medication (except for the drugs listed above). The patient can also follow their usual daily routine, except for taking a shower or bath, because the equipment should not get wet.

The presence of the catheter can cause discomfort in the nasopharynx, resulting in rare cases in the interruption of the test. Apart from that, some patients feel quite uneasy carrying the catheter throughout their day at work and as a consequence, they modify their daily routine and the result of the test does not correspond to “real-life conditions”.

For these cases, there is the option of wireless pH monitoring through a Bravo® capsule, that is placed a few centimeters above the esophagogastric junction, during an upper endoscopy.

The capsule sends the pH fluctuations of the lower esophagus to a recording device via telemetry. The preparation for the test is the same as that mentioned above for the conventional technique.

The presence of the capsule may  in rare cases cause mild chest pain, dysphagia and a sensation of the presence of a foreign body. In general, it is very well tolerated and allows the patient to maintain his or her usual daily routine, to receive their usual meals and enjoy a good night’s rest.

However, the wireless pH monitoring is contraindicated in the following cases:

1. Patients with known diathesis for bleeding,
2. Patients carrying a pacemaker or defibrillator,
3. Esophageal stenosis or obstruction,
4. Esophageal varices and
5. Severe esophagitis

During wireless pH monitoring through a Bravo® capsule, the patient can also take his usual medication (unless the referring physician has instructed otherwise).

The capsule is detached by itself and eliminated from the digestive tube within 7-10 days. No MRI should be performed for 30 days after the placement of the capsule.