Bravo® (wireless pH monitoring)

Wireless pH monitoring (also known as Bravo®) is a test that measures the amount of acid that travels from the stomach into the food pipe or oesophagus. It is used to determine if someone has a disease called Gastroesophageal Reflux Disease. A small capsule which measures acid is placed at the bottom of the oesophagus/food pipe. It attaches by suctioning on to the side of the oesophagus. It is placed during a routine gastroscopy, normally performed under sedation. The data is sent via radio waves to a small, box-like receiver, which is carried on a belt or strap. 

You wear the device for 4 days (96 hours). During this time, you must keep the box close to you (within 1 meter). You will tell us when you get symptoms, when you eat and drink and when you lie down flat. This is done my pressing buttons on the box and writing in a paper diary. The clinician will teach you how to use this when you come in for the test.   

The capsule contains nickel, if you are allergic to nickel please contact us prior to the procedure. Contact details can be found at the bottom of this page.

Wireless pH monitoring allows us to investigate whether there is too much acid in the oesophagus. We also determine if certain symptoms you experience are being caused by acid entering the oesophagus. Common symptoms you may have include:  

• Heartburn 
• Acid regurgitation (acid coming up)
• Chest pain

The acid in the oesophagus can also be measured by a test called impedance-pH monitoring. This lasts for 24 hours and involves a tube being placed through the nose into the stomach. Your doctor may have referred you for wireless pH monitoring instead of the 24-hour wired test because: 

• You did not tolerate the 24-hour wired test.
• A longer recording period is needed to assess your symptoms.

This is a test which allows the doctor to look directly at the upper part of your digestive system (oesophagus, stomach and first part of the small intestine). The test is sometimes called an endoscopy or an OGD (oesophago-gastro-duodenoscopy). A thin, flexible tube which works like a camera is passed through your mouth and into your stomach, as shown in the picture.

To reduce the discomfort of the pressure of the scope on the back of the throat and stomach, the procedure is normally performed under sedation. The endoscopist will administer the sedation via a small needle in the back of your hand and it should take a few minutes to work. You will feel sleepy, but you will not be unconscious and may be aware of what is going on around you. You will also be given oxygen during the procedure.  

There are a few important points to note:   

• Please ensure there is someone to take you home after the procedure and to stay with you overnight.  
• For the gastroscopy and Bravo® procedure, you need to stop specific medication (please see section 'How should I prepare for wireless pH monitoring' below for further details).

The procedure starts with a gastroscopy to examine the oesophagus and stomach. If the endoscopist doing the procedure sees something that means the capsule is no longer appropriate, they may stop after the gastroscopy. If they do, they will explain why after you have recovered from the sedation. An example would be because they saw severe inflammation.

The capsule is passed through your mouth using a very thin, flexible tube and put in the correct position. The capsule then suctions onto the wall of the oesophagus, it also has a pin to help hold it in place. The procedure is normally painless.

The Bravo capsule usually stays in place for several days. There is a risk of the capsule dropping early (around 10% for each day). If the capsule drops early, we may need to repeat the test depending on the data that was captured.

The capsule drops off as part of the body’s normal healing process. This means there is no way for us to predict when the capsule drops. Once the capsule drops off, it passes through the stomach, small and large bowel and is passed with your stools without you being aware. You do not need to worry about finding the capsule after it passes through.

If you have one of the following conditions, please contact us as this could affect the capsule passing through the bowel and we may need to do some extra tests before you have the capsule:

• Inflammatory Bowel Disease: Crohn’s or Colitis
• History of surgery to the small or large bowel (surgery to the stomach, gall bladder or appendix is okay)
• Have been told you have narrowing in you small or large intestine.

Please do not eat for six hours and do not drink for four hours before the procedure. You may have sips of water up to two hours before the procedure.   

If you are taking any blood thinning medications such as warfarin, clopidogrel, rivaroxaban or apixaban please inform us as you will need to be given specific instructions on what to do regarding these medicines. If you need advice on stopping your blood thinning medications, please contact Endoscopy Recovery on 020 3447 3218.   

We usually ask patients to stop taking warfarin for five days before the procedure. If you have had a heart valve replacement, you must not stop your warfarin, but you must let us know as you will need to be given specific instructions on how to come off it whilst you replace it with another blood thinner a few days in advance. If you are taking clopidogrel (Plavix®) this should be stopped seven days before your procedure. If you have a coronary stent or are unsure whether you can stop this, you must let us know. You will be able to restart the medication 4 days after the Bravo capsule is placed.  

If you are diabetic and on insulin, it is important that you continue taking your insulin, but you should reduce your doses on the night before and on the day of the test. If you take diabetic tablets, please do not take them on the day of the test until after the procedure has been done.

You will need to stop any medications which your doctor has prescribed for your stomach or oesophagus and stay off these medications until the study has finished.

Please stop taking the following medications at least one week before your test:   

• Omeprazole (Losec®)
• Lansoprazole (Zoton®)
• Pantoprazole (Protium®)
• Esomeprazole (Nexium®)
• Rabeprazole (Pariet®)

Please stop taking the following medications at least four days before your test:   

• Ranitidine (Zantac®)
• Cimetidine (Tagamet®)
• Famotidine (Pepcid®)
• Nizatadine

Please stop taking the following medications at least two days before your test:   

• Cisapride (Prepulsid®)
• Metaclopramide (Maxalon®)
• Domperidone (Motilium®)
• Ondanstetron (Zofran®)
• Buscopan®
• all other anti-sickness drugs

You must stop all other antacids and indigestion medicines such as Gaviscon®, sucralfate and Rennie’s® at least 24 hours before the test.

If you are on any opiated (morphine, codeine, tramadol), please consider stopping them if you are able to. We can still proceed with the test if you cannot stop them.

You should remain off the medication for the duration of the study (4 days) after which you can resume whatever medicines you were taking. Medications not mentioned in this section or the previous sections above (How is the capsule placed in the oesophagus? and How long will the capsule stay in place?) can be continued as normal.

As the capsule is placed during a gastroscopy procedure, the risks are mainly related to the gastroscopy. For most people a gastroscopy is a simple and safe procedure. Uncommon complications do sometimes arise and include chest infections, damage or perforation (a hole) in the oesophagus, stomach or intestine wall, allergy to sedative medication, bleeding or damage to teeth.  

With regard to capsule insertion, there is a theoretical risk of a tear in the wall of the oesophagus from the capsule itself, but to the best of our knowledge this has not been reported in the UK. There is also a very small risk of feeling a lump in the bottom of the oesophagus due to the presence of the capsule, but this should pass when the capsule drops off.   

There is a small risk of chest pain severe enough to warrant repeat endoscopy to remove the capsule, although in reality the need to remove the capsule is very rare. Also, there is a very small risk that if there is a blockage or narrowing in the small or large bowel, the capsule could get stuck (see How long will the capsule stay in place?). There is a theoretical risk that while lying flat during endoscopy, if the capsule comes up the oesophagus rather than down, it might be inhaled, however, this has never actually been reported as having happened.   

The capsule is an electronic device and electronic devices can fail. This happens very rarely but if it does, we need to repeat the test. We will not know if the device has failed until we review the data.  

To minimise this risk, we do not use anaesthetic throat spray during the procedure. This means that your natural cough reflux should prevent this from happening.   

It is important that you do not have an MRI for 30 days following insertion of the capsule or unless you have seen the capsule drop out into the toilet.   

Please contact Endoscopy Recovery if you have a pacemaker in place or if you are known to have problems with bleeding (e.g., low platelets). Please also inform us if you have a nickel allergy as you would not be suitable for the Bravo procedure.

You are free to choose not to have the procedure. In this circumstance, the information we have available will be used to make a decision on your diagnosis and treatment options.

We will involve you in all decisions about your care and treatment. At consent any questions that have not yet been answered can be addressed and any concerns you have can be explored. Once we are absolutely sure that you fully understand all the benefits and risks, that all your questions have been answered and that you wish to proceed with wireless pH monitoring, we will ask you to sign the consent form. If there are any concerns or questions that arise afterwards, we will be more than happy to discuss these, and the procedure can be reconsidered at any time.

Normally you should feel no different than how you usually do. You will be asked to continue with your normal daily activities so that reflux that usually occurs can be recorded. You will also be asked to fill in a food and sleep diary and to press buttons on the recorder whenever symptoms take place so that we can associate your reflux events with your symptoms.   

After four days, you will be asked to return the recorder and your diary to the GI Physiology Unit (the address is at the end of this leaflet and on your diary). Please be sure to return the recorder to the GI physiology unit in the Elizabeth Garrison Anderson Wing. Please DO NOT return is elsewhere and please do not hand it to security.  

A report will be prepared and sent to your referring clinician so that the results can be explained to you on follow-up in clinic. 

Important points to remember 

• Do stop medications as instructed on this page. 
• Do fast for six hours prior to the procedure.
• Do ensure someone accompanies you home after the procedure.
• Do not drive for 24 hours. Please have someone to take you home in a car, taxi or public transport.
• Do not drink alcohol for 24 hours after sedation is given.
• Do not drive a car or operate heavy machinery for 24 hours after sedation is given.
• Do not have an MRI for 30 days following the Bravo® procedure.

Endoscopy   

Endoscopy Booking Team (Monday to Friday 09:00-17:00)   
Direct line: 020 3456 7022
Switchboard: 08451 555 000 / 020 3456 7890 ext. 67022
E-mail: uclh.endoscopy@nhs.net

Endoscopy Recovery (Monday to Friday 09:00-17:00)
Direct line: 020 3447 3282
Switchboard: 08451 555 000 / 020 3456 7890 ext. 73282

On-call Gastroenterology Registrar (out of hours emergencies only)   
Switchboard: 08451 555 000 / 020 3456 7890  
Address: Endoscopy Unit, University College Hospital, 2nd Floor Podium, 235 Euston Road, London, NW1 2BU   

GI Physiology   

GI Clinical Scientists/Physiologists (Monday to Friday 09:00-17:00)   
Direct line: 020 3447 9130
Switchboard: 08451 555 000 / 020 3456 7890 ext. 79130   
E-mail: uclh.giphysiology@nhs.net    
Address: GI Physiology Unit, Lower Ground Floor, EGA Wing, Grafton Way, London, WC1E 6DB