Esophageal Impedance


Esophageal Impedance

What is an esophageal impedance study?

An impedance study is a test to find out if contents from the stomach are coming up into the esophagus.  The test lasts 18-24 hours.

Why is it necessary?

The test is done to help determine if the cause of your child’s symptoms (e.g. pain with eating, cough, etc.) is due to gastroesophageal reflux.

How should I prepare my child?

  • Your child must have an empty stomach for an impedance study.
    • If your child is younger than six months, he/she must have NOTHING to eat or drink for 2 hours before the scheduled procedure time.
    • If your child is older than six months, he/she must have NOTHING to eat or drink for 4 hours before the scheduled procedure time.
  • If your child takes any medication that reduces the amount of acid in the stomach (such as ranitidine (Zantac®), omeprazole (Prilosec®), Prevacid®, Pepcid®, Protonix®, Nexium® as well as Maalox®, Tums®, or Gelusil®), please follow the instruction checked below:
    • Continue those medications as usual.
    • Give the last dose of those medications 5 days before the test.
  • We encourage being open and honest about the procedure. Explain in simple terms why it is needed, and allow your child to bring a favorite toy, blanket, or other object that will stay with him/her during the test.
  • A child life specialist may be available to help during the procedure. 

Where is the procedure done?

  • This tube is often placed in the GI procedure suite. If your child is already in the hospital, the test will be done in your child’s hospital room.

What happens before the test?

  • If your child is going home during the test, go directly to the GI procedure suite on the second floor of the Abercrombie building by taking the orange elevators. You may valet park your car in front of the West Tower and your ticket will be validated. When you arrive in the GI procedure suite, a nurse will greet you and your child, explain the test, and answer your questions.
  • If your child is going to stay overnight, please plan on registering in Admitting (3rd Floor Clinical Care Center) at least 2 hours before the scheduled time of the test.   It is important that you are on time. If you are late, the study may be canceled.
  • If your child is already admitted in the hospital, you do not need to re-register.

What happens during the test?

  • The nurse will check your child's height to help determine the length of the tube needed. 
  • Your child will receive numbing medicine for the nose.  General sedation medication may also be given.
  • The nurse will pass a tube through your child's nose into the stomach. You may stay with your child while the tube is passed.
  • Infants and young children may be snuggled in a blanket to help them to feel secure and stay still while the tube is being passed.
  • Older children, who are more likely to cooperate, may prefer to sit in a chair while the nurse passes the tube.
  • Passing the tube may cause your child to cough, sneeze, or gag. This feeling will pass after the tube is taped in place. Once in place, the tube should not bother your child.
  • Once the tube is taped in place, your child will have an x-ray to check the exact position of the tube.  Depending on the x-ray results, the tube may have to be repositioned and retaped.
  • Special sleeves may be put on infants and small children to prevent them from bending their elbows and pulling out the tube.
  • Your child will wear a device that is attached to the tube and will record the data.  This device will be placed in a pouch and worn either on the belt or attached to a strap over the shoulder.  For infants, the device will need to be carried along with the child.
  • A member of the GI team will remove the tube the next day. Removing the tube takes less than a minute and does not hurt. Some children cough or sneeze.

What do I need to do during the test?

  • You will be asked to write down what your child is doing while the tube is in place, such as eating, sleeping and coughing.  You will also be asked to press buttons on the recording device.  Your child's nurse will explain exactly what needs to be written down and what buttons to push to help with the study.

How will we be informed of the results?

  • When the tube is removed, a GI doctor will interpret the information recorded.  Please allow up to 2 weeks for results to be provided.

When should I call my child's doctor or nurse?

  • If your child is sick 24 to 48 hours before the test or if you have any further questions about the test, please contact your Texas Children’s Hospital gastroenterology provider on weekdays between 8 a.m. and 5 p.m.

    After hours, call the hospital page operator at (832) 824-2099, and ask for the GI fellow on call.