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G I Physiology Department:


What is G I Physiology
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Gastrointestinal physiology is a branch of human physiology addressing the physical function of the gastrointestinal (GI) system. The major processes occurring in the GI system are that of motility, secretion, regulation, digestion and circulation. The function and coordination of each of these actions is vital in maintaining GI health, and thus the digestion of nutrients for the entire body.

What is an esophageal pH test?

An esophageal pH test measures and records the pH in your esophagus to determine if you have gastroesophageal reflux disease (GERD). The test can also be done to determine the effectiveness of medications or surgical treatment for GERD.

What is esophageal reflux?
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Esophageal reflux is a condition in which stomach acid refluxes or moves back into the esophagus (the "food pipe" leading from the mouth to the stomach).

What happens during esophageal reflux?

A specialized muscle, called the lower esophageal sphincter, is located where the esophagus meets the stomach (see figure). This sphincter opens to allow food and liquid to pass into the stomach, then closes. When the sphincter does not close tightly, food particles, stomach acid and other digestive juices can splash back up into the esophagus. When this happens, the condition is called gastroesophageal reflux. When reflux occurs on a regular basis, it can cause permanent damage to the esophagus. The esophageal pH test measures how often stomach contents reflux into the lower esophagus and how much acid the reflux contains.

How does the esophageal pH test work?

A thin, small tube with an acid sensing device on the tip is gently passed through your nose, down the esophagus ("food tube"), and positioned about 2 inches above the lower esophageal sphincter. The tube is secured to the side of your face with clear tape. The end of the tube exiting from your nose is attached to a portable recorder that is worn on your belt or over your shoulder. The recorder has several buttons on it that you will press to mark certain events. A nurse will review the monitoring instructions with you.

How do I prepare for the 24-hour esophageal pH test?
  • Seven days before the monitoring period, do not take proton pump inhibitors: Prilosec (omeprazole), Prevacid (lansoprazole), Aciphex (rabeprazole), Protonix (pantoprazole), Nexium (esomeprazole), Dexilant (dexlansoprazole).
  • Two days (48 hours) before the monitoring period, do not take the H2 blockers: Zantac (ranitidine), Tagamet (cimetidine), Pepcid (famotidine), Axid (nizatidine); or the promotility drug, Reglan (metoclopramide).
  • Six hours before the monitoring period, do not take antacids (such as Alka-Seltzer, Gaviscon, Maalox, Milk of Magnesia, Mylanta, Phillips, Riopan, Tums or any other brands)
  • Four to 6 hours before your appointment do not eat or drink

Please note: Occasionally, your doctor may want you to continue taking a certain medication during the monitoring period to determine if it is effective.

Once the test has begun, what do I need to know and do?
  • Activity: Follow your usual daily routine. Do not reduce or change your activities during the monitoring period. Doing so can make the monitoring results less useful.
  • Note: do not take a tub bath or shower; the equipment can get wet.
  • Eating: Eat your regular meals at the usual times. If you do not eat during the monitoring period, your stomach will not produce acid as usual, and the test results will not be accurate. Eat at least 2 meals a day. Eat foods that tend to increase your symptoms (without making yourself miserable). Avoid snacking. Do not suck on hard candy or lozenges and do not chew gum during the monitoring period.
  • Lying down: Remain upright throughout the day. Do not lie down until you go to bed (unless napping or lying down during the day is part of your daily routine).
  • Medications: Continue to follow your doctor’s advice regarding medications to avoid during the monitoring period.
  • Recording symptoms: Press the appropriate button on your recorder when symptoms occur (as discussed with the nurse).
  • Recording events: Record the time you start and stop eating and drinking (anything other than plain water). Record the time you lie down (even if just resting) and when you get back up. The nurse will explain this.
  • Unusual symptoms or side effects. If you think you may be experiencing any unusual symptoms or side effects, call your doctor.
    You will return the next day to have the tube removed. The information on the recorder will be downloaded to a computer and the results will be analyzed.
After completion of the study

Resume your normal diet and medications. Lozenges or hard candy may help ease any sore throat caused by the tube. Your doctor will discuss the results of your test with you during your next scheduled appointment.

What is esophageal manometry?

Esophageal manometry is a test used to measure the function of the lower esophageal sphincter (the valve that prevents reflux of gastric acid into the esophagus) and the muscles of the esophagus (see diagram). This test will tell your doctor if your esophagus is able to move food to your stomach normally. To know why you might be experiencing a problem with your digestive system, it helps to understand the swallowing and digestive processes.

The manometry test is commonly given to people who have:

  • Difficulty swallowing
  • Pain when swallowing
  • Heartburn
  • Chest pain
The swallowing and digestive processes

When you swallow, food moves down your esophagus and into your stomach with the assistance of a wave-like motion called peristalsis. Disruptions in this wave-like motion may cause chest pain or problems with swallowing.

In addition, the muscular valve connecting the esophagus with the stomach, called the esophageal sphincter, prevents food and acid from backing up out of the stomach into the esophagus. If this valve does not work properly, food and stomach acids can enter the esophagus and cause a condition called gastroesophageal reflux disease (GERD).

Manometry will indicate not only how well the esophagus is able to move food down the esophagus but also how well the esophageal sphincter is working to prevent reflux.

Before the test

Special conditions

Tell the physician if you have a lung or heart condition, have any other diseases, or have allergies to any medications

Medications

Please follow the instructions below (unless told otherwise by your doctor):

  • One day (24 hours) before the test, stop taking calcium channel blockers such as Calan®, Isoptin® (verapamil); Adalat®, Pro-cardia® (nifedipine); and Cardizem®(diltiazem). Also stop taking nitrate and nitroglycerin products such as Isordil® (isosorbide); Nitrobid®, Nitrodisc®, Nitrodur®, Nitrogard®, Transderm-Nitro®, and Tridil®
  • Twelve hours before the test, do not take sedatives such as Valium® (diazepam) or Xanax® (alprazolam)
  • Do not stop taking any other medication without first talking with your doctor.
Day of test

Eating and drinking

Do not eat or drink anything 4 to 6 hours before the test.

During the test

  • You are not sedated. However, a topical anesthetic (pain-relieving medication) will be applied to your nose to make the passage of the tube more comfortable.
  • A small, flexible tube is passed through your nose, down your esophagus and into your stomach. This tube is a high-resolution manometry catheter that is about 4 mm in diameter. The tube does not interfere with your breathing. You will be seated while the tube is inserted.
  • You may feel some discomfort as the tube is being placed, but it takes only about a minute to place the tube. Most patients quickly adjust to the tube’s presence. Vomiting and coughing are possible when the tube is being placed, but are rare.
  • After the tube is inserted, you will be asked to lie on your left side. The end of the tube exiting your nose is connected to a machine that records the pressure exerted on the tube. Sensors at various locations on the tubing sense the strength of the lower esophageal sphincter and muscles of the esophagus. During the test, you will be asked to swallow a small amount of water to evaluate how well the sphincter and muscles are working. The sensors also measure the strength and coordination of the contractions in the esophagus as you swallow.
  • The test lasts 10 to 15 minutes. When the test is over, the tube is removed. The gastroenterologist will interpret the recordings that were made during the test.
After the test
  • Your physician will notify you when the test results are available or will discuss the results with you at your next scheduled appointment.
  • You may resume your normal diet and activities and any medications that were withheld for this test.
  • You may feel a temporary soreness in your throat. Lozenges or gargling with salt water may help.c
  • If you think you may be experiencing any unusual symptoms or side effects, call your doctor.