Preparing for and having treatment

HALO radiofrequency ablation (RFA)

Preparing for your HALO treatment

As soon as you receive the date of your procedure:

  • make a note of the date of your appointment. 
  • arrange for an adult to take you home after your appointment, and stay overnight if you plan or have been advised to have sedation

If you do not organise a suitable escort or have not arranged for someone to collect you, we will not be able to give you sedation and your procedure might be cancelled.

Stopping eating and drinking

To make sure the endoscopist has a clear view, your stomach must be completely empty. 

Do not eat anything for 6 hours before your appointment, or drink anything for 4 hours before. You may have small sips of water for up to 2 hours before.

Medicine instructions

You may need special instructions if any of these applies to you. Tell the nursing staff as soon as you receive your appointment date, if you:

  • take medicines to thin your blood or to prevent blood from clotting (anticoagulants or antiplatelets, such as warfarin, rivaroxaban, dabigatran or clopidogrel). You do not need to call if you only take aspirin
  • take sedatives or chronic pain medication
  • have diabetes and are on insulin
  • have any allergies to any medicines
  • are allergic to latex.
  • take any regular medicines including ones you buy from a shop or pharmacy (and any herbal or homeopathic medicines)

If these instructions are not followed, your procedure will be cancelled and rebooked for another day.

On the day of your procedure

Wear loose-fitting clothes on the day of the test. 

Remember, do not eat anything for 6 hours before your appointment, or drink anything for 4 hours before. You may have small sips of water for up to 2 hours before.

Regular medicines can be taken in the morning with a sip of water. You can take all of your other medicines as normal, unless you have been told otherwise by the doctor or endoscopist. This includes proton pump inhibitors (such as omeprazole) which need to be taken up to and including the day of the procedure.

When you arrive

When you arrive a nurse will ask you about your medical history. Please tell them if you have had any reactions or allergies to other examinations in the past.

We ask you to complete a health questionnaire which helps to speed up your admission or pre-assessment. This can be filled in on the day of your admission in reception.

Once you are ready you will be taken to a waiting area.

You might be asked to remove your shoes, loosen any tight clothing and remove any false teeth or glasses. You can change into a gown is you wish. You might want to bring your dressing gown and slippers with you (we do supply non slip socks).  

You will need to take off all your jewellery, so it’s best if you leave any valuables at home as we cannot be responsible for any valuables in the unit. You will need to keep your belongings with you at all times.

All metal needs to be removed as we use an instrument that uses an electrical current to stop any bleeding. 

Please be prepared to be with us for the whole morning or afternoon (depending on your appointment time).

Our endoscopists are usually running up to 5 procedure rooms at the same time, so sometimes another patient who arrived after you may be called in before you are. This does not mean you have been forgotten, but that the other person is on a different list to you. We do everything we can to avoid keeping you waiting and will keep you updated, but because every procedure takes a different time to complete, it’s hard to give exact timings.

We also deal with emergencies in the department. This means we might have to ask you to wait. We are sorry if this happens, but please be patient and check at the reception desk if you are concerned.

Having sedation

If you have sedation, we insert a small needle into your arm or hand and give an injection through this in the procedure room. You can also have an injection of painkillers.

Sedation is medicine that makes you feel relaxed and sleepy but does not put you to sleep. You will be able to respond to the doctor or nurse. 

During the procedure

The procedure is carried out by an endoscopist who will pass a long, thin tube, called a gastroscope, through your mouth and into your food pipe. 

You will be placed on your left side on a trolley. To keep your mouth slightly open, we place a mouthpiece between your teeth. We gently insert the gastroscope into your mouth through the mouthpiece and pass it down into your stomach. If you have a lot of saliva in your mouth, the nurse will clear this using a sucker (like at the dentist).

The endoscopist might put some air down the gastroscope to get a clearer view. This might make you feel slightly bloated but will not be painful. 

The endoscopist finds the area that needs treatment and then passes a catheter (thin tube) that has a special balloon at the end of it, down the gastroscope. We give HALO radiofrequency ablation using different catheter sizes, depending on the size of area that needs treating. Often there is some discomfort during the procedure and your doctor will give painkillers during and afterwards if this is the case.

The balloon gets inflated against the wall of your food pipe in the area we need to treat. The catheter is connected to the HALO machine that uses radio waves to produce an electrical current to heat up and remove the targeted mucosa (this is called ablation). 

Sedation and painkillers are given through a vein (intravenously) so that you feel the minimum of discomfort during the procedure. It takes about 20 minutes to have the procedure.

A nurse will stay with you throughout the procedure.

After the procedure

We take you to the recovery area. If you have had sedation, you will need to rest quietly until your observations (heart rate, blood pressure, pulse) are stable, which is usually about an hour.

When you are stable we take you to the discharge waiting area where you will be offered a hot drink and biscuits.

We will discuss your procedure, outcome and next steps with you before your discharge and give you a copy of your report.  

You might need more than one RFA treatment to get rid of the abnormal cells. We will tell you after your procedure or at your follow-up appointment if this will be needed.

You will be able to leave hospital after you are stable (at least 1 to 2 hours after your procedure). A doctor will check you to make sure you are fit to leave.

If you had sedation, you must have someone to escort you home and stay with you overnight. They should come with you for the appointment or be contactable by phone when you are ready to leave.

If you cannot arrange for someone to collect you and stay with you overnight, please contact us to discuss alternative arrangements.

Resource number: 5147/VER2
Last reviewed: March 2023
Next review: March 2026

Contact us

If you need to change or cancel your appointment, call 020 7188 8887

For medical advice, contact the endoscopy unit Monday to Friday, 9am to 5pm.

Nurse in charge: 020 7188 7188 ext 54059

St Thomas' reception desk: 020 7188 7188 ext: 54046

In an emergency, out of hours (6pm until 8am the next day and on Saturday or Sunday) phone 020 7188 7188 and ask to be put through to the on-call gastroenterology registrar.

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

Is this health information page useful?