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Esophageal Manometry & 24-hour pH Study


THE SUCCESSFUL TREATMENT OF ESOPHAGEAL DISORDERS is dependent upon the skills of dedicated clinicians. These clinicians, in turn, must be well-versed in the most precise and reliable diagnostic methods and tools. Esophageal manometries and 24-hour pH studies can provide a wealth of knowledge about esophageal function and the ways in which that function can break down.

“ESOPHAGEAL MANOMETRY is a test that provides information regarding the muscle function of the upper and lower esophageal sphincters as well as peristalsis, or movement of food bolus,” says Satish SC Rao, MD, PhD, FRCP (Lon), professor of medicine and director, nNeurogastroenterology and GI motility at the University of Iowa. “It provides information on the resting tone of the sphincters, how they relax, whether or not they relax appropriately and also about the peristaltic activity of the body.”

Esophageal manometry can be a helpful diagnostic tool in several different circumstances. For example, certain types of dysphagia are common indications for the procedure. “Typically a dysphagia which is otherwise unexplained or a non-obstructive dysphagia,” says Rao. “If someone comes in with difficulty swallowing, we expect them to have a narrowing or a stricture, or a cancer, and you want to exclude that. Once you’ve done that, if the dysphagia is still present, manometry is the way to go.” Rao also points out that patients with significant acid reflux disease are prime candidates for manometries in order to document how weak muscle function is at the lower esophageal sphincter.

“The other thing they do an esophageal manometry for is for patients with esophageal spasms, referred to as non-specific chest pain,” says Jean Bondi, RN, CGN, BSN, staff nurse at the Cincinnati VA Medical Center. Bondi notes that a cardiac work-up would be the first step in exploring nonspecific chest pain, but that an esophageal manometry may be ordered if the cardiac tests come back negative.

Manometries may also be helpful in confirming a diagnosis before administering surgery such as fundoplication. “We would do this a lot for pre-surgery where the doctor thinks they’re going to do some type of a wrap to tighten up the esophageal sphincter, but obviously before he does that he wants to make sure that is indeed the problem,” Bondi explains.

Rao emphasizes that assumptions can be very dangerous in this regard. “There’s a condition called achalasia where there is muscle and nerve dysfunction of the esophagus and may also cause difficulty swallowing, and if you assume they have reflux disease and you wrap their muscle up, then you’re really going to create a major problem,” he says.

In order to measure and record esophageal function during an esophageal manometry, several pieces of equipment are required, including a probe that can be kept in close proxim-for this so they can swallow when we ask them to swallow. So this is where patients have a hard time with it,” she says. “Many people don’t like having tubes in their nose — it’s just not very comfortable. That’s where you have to be careful about explaining everything you’re doing to the patient. I think it’s really important that you develop a bond or a trust with them, so it’s nice to talk to them. I always tell the patient, ‘I’ll do my best, with this procedure and you do your best and between the two of us we’ll get it done.’ Also, sometimes it can be difficult to pass it through the nose just because they’ve had a broken nose or they’ve got nasal polyps or something like that.”

24-hour pH Study

As the name implies, 24-hour pH studies measure acid exposure in the esophagus over a 24-hour period. This test can accurately measure whether or not gastroesophageal reflux disease (GERD) is present. “Regarding the pH study, it identifies patients who have significant acid reflux; it helps to correlate the symptoms with acid reflux as well as the occurrence of chest pain and if the pain is related to reflux or not,” says Rao. “For example, there are patients who reflux bile without acid, and in these folks, treatment with an acid blocker is unlikely to relieve their pain.”

An important interrelationship exists between the two tests in that esophageal manometries can be extremely helpful in determining the correct placement for the probe that measures esophageal pH. “When you need to do a 24-hour pH study, you need to know exactly where to put the probe inside the esophagus,” Rao says. “Normal data for pH is very precise at a level 5 cm above the lower esophageal sphincter. If you place the probe 3 cm, 2 cm or 6 cm, the normal values vary. Because the normative data was obtained at a location of 5 cm, we have to place the probe exactly at that level, otherwise our data is all messed up.”

“You can do a pH study very much like a manometry, but because the pH changes are recorded over a prolonged period of time, 24 to 48 hours, today we use ambulatory miniaturized data recorders,” Rao explains. “In the old days, we kept patients in the lab, like we do with manometry, tied down to a tube for three or four hours and gave them a meal and studied how much acid was refluxing up into the esophagus.

However, with the advent of an ambulatory recorder, we place a 2 mm thin probe through the nose into the esophagus, which is then hooked up to a portable device (the size of a Walkman tape player). The subjects go home with this device and wear it continuously for 24 hours. The pH signals are continuously recorded by the box. The next day, we download the data onto a computer and analyze it. We can correlate the symptoms and assess how much acid has refluxed over the 24-hour period.”

Probe placement for both studies is relatively simple. “We just pass it through the nose, so it’s a relatively simple procedure,” Rao continues. “We usually numb the nose with a local anesthetic both for the pH and the manometry study. The pH probe is much thinner — only 2 mm. The manometry probe is typically 4 mm to 5 mm in diameter; both are less than a pencil thickness. The manometry takes between 20 and 30 minutes, and the pH study takes 24 hours.”

Choosing the right equipment is also important in successfully performing the pH study. “Things you’re going to want to look for there are ease of use, how well does it work as far as set-up, is it a universal type of unit, is it flexible, and how many channels of pH can it record or gather,” explains Sawyer. “Also, how easy it is to intubate patients and send them home, and when they come back, to download the data, review the analysis and print a report that the doctor can look at and use to diagnose the patient.”

Recently, technological advances have provided a new system for performing the 24-hour pH study called the Bravo pH technique. “Here, we can clip a capsule (pH sensor) to the esophageal lining using a clip-fixing device that is passed through the mouth,” says Rao. “The capsule detects pH changes and sends radio frequency signals to a small data recorder that can be worn around the waist. With this you can record for one or two days. This is a recent advance and is often described as a tubeless pH recording technique.”

Generally speaking, both procedures are safe and free of potential adverse reactions. “If a patient can’t tolerate the tube or can’t keep it down, that would be the main one,” says Bondi. “It’s a nurse-driven procedure because there are so few complications.”

“There really aren’t any major complications,” Rao says. “Some patients report nasal irritation or minor bleeding, throat discomfort, hoarseness of voice, dry cough and difficulty with swallowing. These are often transient and resolve within one to two days. Occasionally, if the probe goes down the windpipe, then you may induce some choking and coughing. This is very rare. Rarely there are reports of esophageal perforation, but I’ve never seen that in my lab and we do about 700 of these per year. I’ve directed this lab for 12 years and we’ve never had any such complications.”

Both tests can prove indispensable in exploring possible disorders of the esophagus. “The tests can give us very useful information regarding esophageal function,” Rao says. He explains that esophageal manometry is the best way to diagnose achalasia, ineffective peristalsis or dysmotility, weak lower or upper esophageal sphincters, and poor motility. Additionally, it helps to define location for placement of the pH probe.

In most cases, repeat manometries and 24-hour pH studies are not necessary. There are a couple rare situations in which another test may be called for, however. “For example, if someone has a 24-hour pH study and we found they had abnormal acid reflux, then we put them on treatment. If they don’t respond to treatment or if there is only partial response, or if this person is not compliant, then you can repeat the study on treatment to see what happens,” says Rao. “If on treatment you find that they’re still having acid reflux, that tells you that the treatment is not efficacious.”


24-Hour Esophageal Manometry is mainly used to see if intermittent symptoms, such as chest pain, dysphagia and heartburn, are related to problems with contraction of the food pipe. Sometimes the food pipe can causing pain. Because this spasm may occur intermittently, this test allows a longer period of time to look at food pipe pressure. The most common conditions studied are:

  • Diffused esophageal spasms (DES), which create problems with swallowing
  • Nutcracker esophagus, which is high-pressure movement of the food pipe
  • Nonspecific esophageal motility disorders and symptoms, such as non-cardiac chest pain and intermittent trouble swallowing

Source: Cedars-Sinai

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