Esophageal Function Tests | Description | Precautions | Side effects | Purpose | Risks
Definition
The esophagus is the muscular tube through which food passes on its way from the mouth to thestomach. The main function of the esophagus is to propel food into the stomach. In order to ensure material does not go the wrong way (reflux), sphincters at either end of the esophagus close when material is not passing through them in the correct direction. Esophageal function tests are used to determine if these processes are normal or abnormal.
Purpose
The esophagus has two sets of constricting muscles (or sphincters) at the top and bottom. Each of these muscular areas must contract in an exact sequence for swallowing to proceed normally. The upper esophageal sphincter normally stops the back-flow of stomach contents into the pharynx and larynx. The lower esophageal sphincter guards against stomach acid moving up into the esophagus. The lower sphincter should be tightly closed, except to allow food and fluids to enter the stomach.
The three major symptoms occurring with abnormal esophageal function are difficulty with swallowing (dysphagia ), heartburn, and chest pain. Doctors perform a variety of tests to evaluate these symptoms. Endoscopy, which is not a test of esophageal function, is often used to determine if the lining of the esophagus has any ulcers, tumors, or areas of narrowing (strictures). Many times, however, endoscopy only shows the doctor if there is an injury to the esophageal lining, and the procedure gives no information regarding the cause of the problem. Therefore, in addition to endoscopy, several studies are available that measure esophageal function. There are three basic types of tests used to assess esophageal function:
· Manometry is used to study the way the muscles of the esophagus contract, and is most useful for the investigation of difficulty with swallowing.
· Esophageal pH monitoring measures changes in esophageal acidity, and is valuable for evaluating patients with heartburn or gastroesophageal reflux disease (GERD).
· X-ray studies investigate dysphagias, either by using a fluoroscope to follow the progress of barium during the process of swallowing, or by using radioactive scanning techniques.
Precautions
Since sedatives may alter test values, they are not administered prior to esophageal functiontesting. Eating prior to the test will also alter the results. Pregnant patients undergoing x-ray exams should carefully review the risks and benefits of any proposed tests with their doctors. Additionally, patients with bowel obstruction should not participate in any test using barium. Also, esophagealfunction tests are contraindicated in those patients who are unable to cooperate with the test.
Description
Manometry
This study is designed to measure the pressure changes produced by contraction of the muscular portions of the esophagus. An abnormality in the function of any one of the segments of the esophagus can cause difficulty in swallowing (dysphagia). This exam is most useful in evaluating patients whose endoscopy yields normal results.
During manometry, the patient swallows a thin tube carrying a device that senses changes in pressures in the esophagus. Readings are taken at rest and during the process of swallowing. Medications are sometimes given during the study to aid in the diagnosis. The results are then transmitted to recording equipment. Manometry is most useful in identifying diseases that produce disturbances of motility or contractions of the esophagus. In 2001, a solution containing five drops of peppermint oil in 10 mL of water was found to improve the manometric features of diffuseesophageal spasm (DES). The peppermint oil solution eliminated simultaneous esophagealcontractions in all patients in the study.
ESOPHAGEAL PH MONITORING. This procedure measures the esophagus' exposure to acid reflux from the stomach. The test is ideal for evaluating recurring heartburn or gastroesophageal reflux disease (GERD). Excessive acid reflux may produce ulcers, or strictures resulting from healed ulcers, in addition to the symptom of heartburn.
Normally, acid refluxes into the esophagus in small amounts for short periods of time. The loweresophageal sphincter usually prevents excessive reflux (in patients without disease). Spontaneous contractions that increase esophageal emptying and production of saliva also act to prevent damage to the esophagus.
Researchers have shown that in the esophagus, the presence of acid is damaging only if it persists for prolonged periods. Therefore, esophageal pH monitoring has been designed to monitor the level of acidity over 24 hours, usually in the home. In this way, patients are able to maintain their daily routine, document their symptoms, and correlate symptoms with specific activities. During this period, a thin tube with a pH monitor remains in the esophagus to record changes. After the study, a computer is used to compare changes in acidity with symptoms reported by the patient.
Additional tests, the Bernstein test (also known as the acid perfusion test) and the acid clearing test, may be performed. In the Bernstein test, hydrochloric acid (HCl) is directed into the esophagus. If the patient experiences pain with the administration of the HCl, the test is positive for reflux esophagitis. If there is no discomfort, another cause must be found to explain the patient's symptoms. In the acid clearing test, HCl is also directed into the esophagus. However, in this test, the patient's ability to quickly swallow the HCl is examined. If the patient needs more than 10 swallows, it indicates the patient has problems with esophageal motility.
pH monitoring is usually performed before surgery to confirm the diagnosis and to judge the effects of drug therapy. In 2005, studies showed that integrated esophageal and gastric acidity provided better quantitative measures of GERD pathophysiology than conventional pH parameters. This finding has implications for the evaluation of therapeutic interventions.
X-RAY TESTS. X-ray tests fall into two categories: (1) those performed using barium and afluoroscope; and (2) those performed with radioactive materials. Studies performed with fluoroscopy are especially useful in identifying structural abnormalities of the esophagus. Oftentimes a sandwich or marshmallow coated with barium is used to identify the site of an obstruction. However, fluoroscopy can diagnose or provide important information about a number of disorders involvingesophageal function, including craniopharyngeal achalasia (a swallowing disorder of the throat), decreased or reverse peristalsis, and hiatal hernia.
During fluoroscopy, the radiologist can observe the passage of material through the esophagus in real time, and video recordings may also be made. This is particularly useful when the swallowing symptoms appear to occur mostly in the upper region of the esophagus. The most common cause of difficulty swallowing is a previous stroke, although other diseases of the neuromuscular system (like myasthenia gravis) can produce similar symptoms.
Scans using low-dose radioactive materials are useful because they may demonstrate that food passes more slowly than normal through the esophagus, and how slowly the bolus may be passing. These studies involve swallowing food coated with radioactive material, followed by a nuclear medicine scan. Scans are often used when other methods have failed to make a diagnosis, or if it is necessary to determine the degree of the abnormality.
Preparation
Patients should not eat or drink anything after midnight before the exam. Many medications affect the esophagus; doses may need to be adjusted or even discontinued prior to testing. Patients must inform their physician of any and all medications they take, including over-the-counter medications, and any known allergies.
Aftercare
For most of these studies, no special care is needed after the procedure. Patients can often engage in normal daily activities following almost all of these tests. One exception is that patients who undergo a x-ray exam with the use of barium may experience constipation. A cathartic may be given to those patients.
Complications
Exposure to x rays, especially in the first three months of a woman's pregnancy, can be extremely harmful to the fetus. Barium swallows may also cause impaction (hardening) of fecal matter. Additionally, although the tubes passed through the esophagus during some of the esophagealfunction tests are small, and most patients adjust to them quite well, some patients may gag and aspirate (breathe in) some gastric juices.
Results
Normal findings include:
· lower esophageal sphincter pressure ranging from 10-20 mm Hg
· normal peristaltic waves
· normal size, shape, position, patency and filling of the esophagus
· negative acid reflux
· acid clearing in less than 10 swallows
· negative Bernstein test
Manometry is used to diagnose abnormalities related to contraction or relaxation of the various muscular regions of the esophagus. These studies cannot distinguish whether injury to either the muscle or nerves of the esophagus is producing the abnormal results—only the final effect onesophageal muscle is identified. Results should be interpreted in light of the patient's entire medical history.
For example, there are many diseases that cause poor relaxation of the lower esophagealsphincter. When no cause is found, the condition is called achalasia. Achalasia is a frequent finding in individuals with Down's syndrome.
Abnormal results of pH tests can confirm symptoms of heartburn or indicate a cause of chest pain (or rarely, swallowing difficulties). Doctors may want to initiate or change medications based on these results, or even repeat the test using different doses of medication. As noted above, these studies are indicated before surgical treatment of GERD.
X-ray tests can serve to document an abnormality, and they are far from perfect. If they are negative, then other studies are often needed.
Health care team roles
The health care team may consist of the physician, the nurse, and others. A radiologist will be required if the procedure involves scans, x-rays, or nuclear medicine studies. Unlicensed assistive personnel (UAPs), such as GI assistants, GI technicians or medical technicians may have direct patient care responsibility. They are supervised by a registered nurse (RN). UAPs can assist the physician and RN during diagnostic and therapeutic procedures. The RN is responsible for the assessment of patient care needs and for determining the capability of assistive personnel to whom a task is delegated. An advanced practice nurse (APN) specializing in gastroenterology may perform a comprehensive history and physical assessment. Depending on the practice, the APN may also order and/or perform diagnostic studies. Otherwise, these tasks are performed by the physician.
Training
An APN is a nurse who has completed an advanced degree in nursing (master's or doctorate). An APN may be a nurse practitioner or a clinical nurse specialist. UAPs may receive on-the-job training in their duties.
Patient education
If barium is used in the testing, the patient should understand that all of the barium needs to be excreted. At first, the patient's stools will be white, but once the barium has been completely excreted, the stools will return to normal.
Advise the patient that a sore throat is common after tests requiring tube placement. Explain to the patient that sedatives are not given prior to testing involving tube placement, due to the interference with the test results and test administration.
KEY TERMS
Achalasia— Failure to relax. Often applied to sphincter muscles, the normal function of which is persistent contractions with periods of relaxation.
Bolus— "A lump." May describe a mass of food ready to be swallowed, or a preparation of medicine via the oral or intravenous (IV) route.
Cathartic— An active agent which produces bowel movements.
Craniopharyngeal achalasia— A a swallowing disorder of the throat.
Diffuse esophageal spasm (DES)— An uncommon condition that results in simultaneous contractions of the esophagus.
Esophagus— The muscular canal between the throat and the stomach.
Heartburn— Acid liquid raised from the stomach, causing a burning sensation in the esophagus.
Hiatal hernia— A condition in which part of the stomach pushes up through the same hole in the diaphragm that the esophagus passes through.
Peristalsis— The contraction of muscles which passes food from the mouth to the stomach and out the anus.
Resources
BOOKS
Castell, June A., and R. Matthew Gideon. "Esophageal Manometry." In The Esophagus, 3rd edition, edited by Donald O. Castell and Joel E. Richter. Philadelphia: Lippincott, 1999, pp. 101-117.
Pagana, Kathleen D., and Timothy J. Pagana. Diagnostic Testing and Nursing Implications, 5th ed. St. Louis, MO: Mosby, 1999, pp. 62-64 and 69-70.
Smout, Andre. Ambulatory Monitoring of Esophageal pH and Pressure." In The Esophagus, 3rd edition, edited by Donald O. Castell and Joel E. Richter. Philadelphia: Lippincott, 1999, pp. 119-133.
PERIODICALS
Gardner, J.D., Rodriguez-Stanley, S., Robinson, M. "Integrated acidity and the pathophysiology of gastroesophageal reflux disease." American Journal of Gastroenterology 96, no. 5 (May 2001): 1363-70.
Mujica, V.R., Mudipalli, R.S., Rao, S.S. "Pathophysiology of chest pain in patients with nutcracker esophagus." American Journal of Gastroenterology 96, no. 5 (May 2001): 1371-7.
Pimentel, M., Bonorris, G.G., Chow, E.J., Lin, H.C. "Peppermint oil improves the manometric findings in diffuse esophageal spasm." Journal of Clinical Gastroenterology 33, no. 1 (July 2001): 27-31. Online at: 〈http://www.jcge.com/article.asp?ISSN=0192-0790&VOL=33&ISS=1&PAGE=27〉.
Zarate, N., Mearin, F., Hidalgo, A., Malagelada, J.R. "Prospective evaluation of esophageal motor dysfunction in Down's syndrome." American Journal of Gastroenterology 96, no. 6 (June 2001): 1718-24.
ORGANIZATIONS
The American Society for Gastrointestinal Endoscopy (ASGE). Thirteen Elm Street, Manchester, MA 01944-1314. (978) 526-8330. 〈http://www.asge.org〉.
Illinois Nurses Association—Advanced Practices Registered Nurses (APRNs) statistics. 105 W. Adams Suite 2101. Chicago, IL 60603. 〈http://www.illinoisnurses.org/aprn.html〉.
The Society for Gastroenterology Nurses and Associates (SGNA). 401 North Michigan Avenue, Chicago, IL 60611-4267. (800) 245-7462. 〈http://www.sgna.org〉.
