Esophageal Manometry
The
esophagus is the tube that carries food and liquid from the throat to the
stomach. Although it seems like a simple organ, the esophagus is not a rigid
tube. The wall of the esophagus contains muscle that rhythmically contracts
whenever a person swallows. This contraction occurs as a sweeping wave
(peristalsis) carrying food down the esophagus. It literally strips the food or
liquid from the throat to the stomach.
Another important part of the esophagus is the lower valve muscle (lower
esophageal sphincter, or LES). This is a specialized muscle that remains closed
most of the time, only opening when swallowed food or liquid is moved down the
esophagus or when a person belches or vomits. This muscle protects the lower
esophagus from caustic stomach acid and bile. These substances, of course, cause
the discomfort of heartburn and in time can lead to damage and scarring in the
esophagus. At times, everyone has heartburn, especially after a large or fatty
meal.
Manometry is the recording of muscle pressures within an organ. So esophageal
manometry measures the pressure within the esophagus. It can evaluate the action
of the stripping muscle waves in the main portion of the esophagus as well as
the muscle valve at the end of it.
Equipment
The equipment for manometry consists of thin tubing with openings at various
locations. When this tube is positioned in the esophagus, these openings sense
the pressure in various parts of the esophagus. As the esophagus squeezes on the
tube, these pressures are transmitted to a computer analyzer that records the
pressures on moving graph paper. It is much like an electrocardiogram. The
physician can evaluate these wave patterns to determine if they are normal or
abnormal.
Reasons for the Exam
There are a number of symptoms that originate in the esophagus. These include
difficulty swallowing food or liquid, heartburn, and chest pain. Additionally,
an x-ray (barium swallow or upper GI series) or endoscopy may show abnormalities
that need studied further by manometry. The exam is often done before and after
medical or surgical treatment of the esophagus. Esophageal manometry is very
effective in evaluating the contraction function of the esophagus in many
situations.
Preparation
The preparation for esophageal manometry is very simple. The patient should take
no food or liquid for about eight hours before the exam. The physician will
usually (although not always) want to study the esophagus in its natural state.
In other words, there should not be any medicine in the body that can affect the
function of the esophagus. The physician informs the patient what medications
should and should not be taken.
The following drugs may affect the contractile pattern of the esophagus. They
usually need to be discontinued at least 48 hours beforehand. Check with your
physician about all your medications.
The Procedure
The procedure takes about one hour from start to finish. While seated in a chair
or lying on the side, thin soft tubing is gently passed through the nose, or
occasionally the mouth. Upon swallowing, the tip of the tube enters the
esophagus and the technician then quickly passes it down to the desired level.
There is usually some slight gagging at this point, but it is easily controlled
by following instructions. During the exam, the technician usually asks the
patient to swallow saliva (called a dry swallow) or water (called a wet
swallow). Pressure recordings are made and the tubing is withdrawn. Patients can
usually resume regular activity, eating, and medicines immediately after the
exam.
Results
To a layperson, the contractile pattern of the esophagus looks like a chaotic,
wiggling line. However, the tracing has very specific meanings depending on how
the esophagus contracts and exerts pressure through the tube into the manometry
machine.
A
normal pattern may be seen where the esophagus has regular, sweeping contraction
waves and excellent function of the valve at the end of the esophagus.
A common abnormal pattern results when the lower esophageal valve is weak and
does not close properly. This allows food and acid to reflux up into the food
pipe.
Another abnormal pattern occurs when the esophagus has lost its normal
sweeping waves. This condition is called dysmotility, and it means that there
are ineffective, weak, or disorganized contractions. This pattern is often seen
in older individuals.
Intense esophageal spasms may be found where severe pain originates in the
esophagus. This pattern shows very intense contractions throughout the esophagus
and may be accompanied by pain.
Finally, there is a condition called achalasia in which the lower valve is
very spastic and tight and the body of the esophagus has weak contractions.
So there are a variety of findings possible. The physician reviews these
findings with the patient and explains what they mean.
Benefits
The primary benefit of the exam is that the physician has clear documentation of
the muscle function of the esophagus. With this information, a specific
treatment program can be outlined or reassurance provided if the exam is normal.
Alternatives to Manometry
Nothing really takes the place of manometry. Other techniques that are used to
study the esophagus include: upper GI x-ray series using swallowed liquid
barium; fiberoptic or video endoscopy to visualize the inside lining of the
esophagus; and a 24-hour probe left in the end of the esophagus to measure
acidity as it refluxes from the stomach.
Side Effects and Complications
There are really no serious problems associated with manometry. Slight gagging
is normal during the exam, and a temporary sore throat may be present afterward.
Summary
Esophageal manometry is a very valuable method of recording and evaluating the
muscular function of the esophagus. The test is simple and quick to perform.
With this information, the physician can usually develop effective treatment for
most patients with esophageal muscle disorders.
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