About Your ZepHr® pH Monitoring System

This information will help your prepare for your ZepHr® pH Monitoring System test at Memorial Sloan Kettering (MSK).

About the ZepHr pH Monitoring System

The ZepHr pH monitoring system measures reflux. Reflux is when your stomach contents move out of your stomach and back up your esophagus (food pipe).

Your doctor may ask you to do this test if you:

  • Have acid reflux (heartburn)
  • Regurgitate food and liquids (burp foods and liquids into your mouth after eating or drinking)
  • Have reflux that isn’t helped by medications to prevent it
  • Are thinking about having surgery to stop your reflux

The ZepHr system has 2 parts:

  • A probe that’s placed through your nose and esophagus into your stomach
  • A recorder that you wear on your waist

The ZepHr system will stay in place for 24 hours. During this time, you will write down all of your food and activities in a diary. You will also use the recorder to keep track of your body position. You can go home and do most of your normal activities while the probe is in place.

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About Your ZepHr Probe Placement

There are 2 ways that a ZepHr probe can be placed. Your doctor will tell you which one you’re having.

  • ZepHr probe placement with esophageal manometry

    Some people may have the ZepHr probe placed with an esophageal manometry. An esophageal manometry is a test that measures the pressure in your esophagus. This will help your doctor decide exactly where to place the ZepHr probe. The test doesn’t hurt.

    If you’re having your ZepHr probe placed with esophageal manometry, you won’t receive anesthesia (medication to make you sleep) during your procedure. You can go home by yourself after your procedure.
  • ZepHr probe placement with upper endoscopy

    Some people may have the ZepHr probe placed with an upper endoscopy. During an upper endoscopy, your doctor will use an endoscope (thin, flexible tube with a video camera) to look at the inside of your esophagus, stomach, and the first part of your small intestine.

    If you’re having your ZepHr probe placed with an upper endoscopy, you will receive anesthesia during your procedure. You will need someone to take you home after your procedure.
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Before Your Procedure

Ask about your medications

Medication for acid reflux

If you take a proton-pump inhibitor (PPI) or H2 blocker to control acid reflux, stop taking it 7 days before your procedure or as directed by your doctor. Examples of these medications are listed below.

Common PPI medications Common H2 blocker medications
  • dexlansoprazole (Dexilant®)
  • esomeprazole (Nexium®)
  • lansoprazole (Prevacid®)
  • omeprazole (Prilosec®)
  • pantoprazole (Protonix®)
  • rabeprazole (Aciphex®)
  • cimetidine (Tagamet®)
  • famotidine (Pepcid®)
  • ranitidine (Zantac®)

Medication for diabetes

If you take insulin or another medication for diabetes, you may need to change the dose on the day of your procedure. This is because you can’t eat after midnight the night before your procedure.

Ask the doctor who prescribes your diabetes medication what you should do the day before and the morning of your procedure.

3 days before your procedure

Three to 5 days before your procedure, an endoscopy nurse will call you. The nurse will review the instructions in this guide with you and ask you about your medical history. They will also review your medications and tell you which ones to take on the morning of your procedure.

Use the space below to write down which medications to take the morning of your procedure.

write down your medications

The day before your procedure

Note the time of your procedure

A clerk from the Admitting Office will call you after 11:00 am the day before your procedure. They will tell you what time you should arrive at the hospital for your procedure. If you’re scheduled for your procedure on a Monday, you will be called on the Friday before. If you don’t receive a call by 5:00 pm, call 212-639-7882.

If you need to cancel your procedure for any reason, call the doctor who scheduled it for you.

The evening before your procedure

Instructions for eating and drinking before your surgery

12 ounces of water

  • Do not eat anything after midnight the night before your surgery.
  • Between midnight and up until 2 hours before your scheduled arrival time, you may drink a total of 12 ounces of water (see figure).
  • Starting 2 hours before your scheduled arrival time, do not eat or drink anything. This includes water. Do not put anything in your mouth.
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The Day of Your Procedure

Things to remember

  • Take only the medications your nurse told you to take the morning of your procedure. Take them with a few sips of water.
  • Don’t put on any lotion, cream, deodorant, makeup, powder, or perfume.
  • Don’t wear any metal objects. Remove all jewelry, including body piercings.
  • Leave all valuables, such as credit cards and jewelry, at home.
  • If you usually wear contact lenses, wear your glasses instead.

What to bring

  • A list of the medications you take at home.
  • Your rescue inhaler (such as albuterol for asthma), if you have one.
  • Only the money you may need for the day.
  • A case for your glasses.
  • Your Health Care Proxy form, if you have completed one.

Where to park


MSK’s parking garage is located on East 66th Street between York and First Avenues. If you have questions about prices, call 212-639-2338.

To reach the garage, turn onto East 66th Street from York Avenue. The garage is located about a quarter of a block in from York Avenue, on the right-hand (north) side of the street. There is a pedestrian tunnel that you can walk through that connects the garage to the hospital.

There are also other garages located on East 69th Street between First and Second Avenues, East 67th Street between York and First Avenues, and East 65th Street between First and Second Avenues.

Where to go

Your procedure will be done in the Endoscopy Suite at MSK’s main hospital. The building is located at 1275 York Avenue, between East 67th and East 68th Streets.

Once you’re in the building, take the M elevator to the 2nd floor. Enter through the glass doors and check in at the desk.

What to expect

Once you arrive at the hospital, you will be asked to state and spell your name and date of birth many times. This is for your safety. People with the same or similar names may be having procedures on the same day.

When it’s time to change for your procedure, you will get a hospital gown to wear.

After changing into a hospital gown, you will meet your nurse. They will check your heart rate, breathing, and blood pressure. If you’re going to receive anesthesia during your procedure, your nurse will also place an intravenous (IV) line into a vein, usually in your hand or arm. At first, you will get fluids through the IV, but it will be used later to give you the anesthesia.

You will also meet with your doctor before your procedure. Your doctor will explain the procedure to you and answer your questions. They will also ask you to sign a consent form if you haven’t already.

When it’s time for your procedure, you will be brought into the procedure room in your bed.

If you’re receiving anesthesia, a nurse will hook you up to equipment to monitor your heart rate, breathing, and blood pressure. You will also receive oxygen through a thin tube that rests below your nose. After the equipment and oxygen are in place, you will get anesthesia through your IV.

Next, you will have an esophageal manometry or upper endoscopy.

After the esophageal manometry or upper endoscopy, your doctor will insert the ZepHr probe through your nose and into your stomach. It will be taped to your nose to keep it in place and attached to the recorder by a wire.

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After Your Procedure

In the hospital

If you received anesthesia during your procedure, you will wake up in the Post Anesthesia Care Unit (PACU). Your nurse will continue to monitor your heart rate, breathing, and blood pressure. Once you’re fully awake, your nurse will remove your IV. If you have someone waiting with you, your nurse will explain your discharge instructions to both of you before you go home.

If you didn’t receive anesthesia during your procedure, you can go home right after your procedure.

At home

You shouldn’t have any pain after your procedure. You may still feel sleepy if you had anesthesia.

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While You Have the ZepHr pH Monitoring System

  • Don’t take a shower or bath. The recorder and probe can’t get wet.
  • Eat and drink the things you normally do.
    • Don’t chew gum or suck on throat lozenges or candy. These foods will affect the test results.
  • Continue your normal activities, including working and exercising. Try to do activities that will bring on your symptoms.
  • Sleep as flat as possible. It doesn’t matter if you sleep on your side or back.
  • Don’t take your acid reflux medications (PPI or H2 blockers) unless your doctor tells you to take them during the test.

Write down your foods and activities

You will get a diary on the day of your procedure. Be sure to write down the following:

  • All reflux symptoms you have, such as coughing, heartburn, and burping food into your mouth (regurgitation).
  • The medications you take and times you take them.
  • The things you eat and drink and the times you eat or drink.
  • The times you lie down to go to sleep and when you get out of bed.

It’s important to keep accurate records in this diary. This will help your doctor learn the most about your symptoms.

Use the ZepHr recorder

You will also have a ZepHr recorder. It will be attached to the ZepHr probe by a wire. It’s important to keep the recorder close to you at all times. You should wear it around your waist while you’re awake and put it under your pillow when you sleep.

Use the buttons to record your body position and symptoms.

  • Press the “up” button when you sit or stand up.
  • Press the “down” button when you lie down.
  • Press the “symptom” button when you have symptoms. Be sure to also write the symptoms in your diary.

Follow-up appointment

You will have an appointment with the doctor who performed your procedure 24 hours after your procedure. During this appointment, your nurse will remove the probe and the recorder.

Bring the diary with you and give it to your nurse.

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Call Your Doctor if You Have:

  • A temperature of 101° F (38.3° C) or higher
  • Severe or constant stomach pain, hardness, or bloating
  • Severe or constant pain in your chest
  • Difficulty swallowing
  • Nausea or vomiting (including stomach contents or blood)
  • Severe or constant bleeding from your nose
  • Any unexplained or unexpected problems
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