How to measure gastroesophageal reflux disease (GERD) in the esophagus?

From the Guidelines

Wireless pH monitoring is the preferred method for measuring gastric reflux in the esophagus, as it allows for up to 96 hours of monitoring and assesses the relationship between patient-reported symptoms and acid reflux episodes. This method uses a pH capsule introduced via a trans-oral catheter during sedated esophagogastroduodenoscopy, which adheres to the distal esophagus and measures acid exposure 1. The advantages of wireless pH monitoring include its ability to assess acid exposure over a prolonged period, ease of placement during sedated upper endoscopy, and patient tolerance.

Some key points to consider when using wireless pH monitoring include:

• It measures acid exposure in the distal esophagus for up to 96 hours, allowing for a more comprehensive assessment of gastric reflux 1
• It assesses the relationship between patient-reported symptoms and acid reflux episodes, providing valuable insights into the patient's condition 1
• Normal acid exposure time (<4.0%) on all 4 days of a 96-hour wireless study has been shown to predict successful PPI withdrawal, while abnormal acid exposure time on ≥2 days predicts the need for continuing PPI treatment 1

In cases where wireless pH monitoring is not available, 24-hour impedance-pH monitoring off PPI therapy can be utilized as an alternative, particularly in the evaluation of extra-esophageal symptoms 1. However, expertise in frame-by-frame interpretation is required for this method. Ultimately, the choice of diagnostic test depends on specific diagnostic needs, available resources, and clinical presentation.

From the Research

Measuring Gastric Reflux in the Esophagus

To measure gastric reflux in the esophagus, several methods can be employed, including:

• 24-hour pH monitoring with multichannel intraluminal impedance, which is considered the gold standard in diagnosing gastroesophageal reflux disease (GERD) 2
• Ambulatory 24-hour esophageal pH monitoring, which measures increased esophageal exposure to gastric juice by detecting the concentration of hydrogen ions (pH <4) in the distal esophagus 3
• Combined multichannel intraluminal impedance and pH monitoring, which can evaluate both bolus transport and all types of reflux (acid, weakly acidic and weakly alkaline) without radiation hazards 4

Diagnostic Techniques

The following diagnostic techniques can be used to measure gastric reflux in the esophagus:

• Gastroscopy, which can diagnose gastroesophageal reflux disease by detecting macroscopic lesions, such as erosions, in the esophagus above the cardia of the stomach 2
• Impedance-pH monitoring, which can establish a diagnosis of GERD, qualify patients for anti-reflux surgery, and find the cause of inefficient reflux disease treatment or extra-esophageal symptoms of reflux disease 2
• 24-hour impedance monitoring, which can detect reflux of a liquid and/or gas bolus into the esophagus, as well as its distribution, composition, and clearing 5

Advantages and Limitations

The advantages and limitations of these diagnostic techniques include:

• 24-hour pH metry alone is inferior to additional impedance monitoring in the diagnosis of GERD, particularly in the presence of reduced gastric acid secretion 6
• Impedance monitoring can detect non-acidic reflux, which may not be detected by 24-hour pH metry alone 6
• Combined multichannel intraluminal impedance and pH monitoring can provide higher rates of sensitivity and specificity than standard techniques in the diagnosis of pathological gastroesophageal reflux 4