Intragastric pH

The clinical value of the pH-metry of the upper digestive tract consists in the best diagnosis of functional disorders in acid-dependent gastrointestinal diseases, which allows in all cases, especially with combined pathologies, to develop an adequate treatment tactic and monitor the course of treatment. pH-metry is especially important in cases where standard treatment regimens for gastroenterological, as well as potentially related cardiac, bronchopulmonary, lorfaringeal, dental and other pathologies do not give a positive result.

The following main types of intragastric pH-metry are distinguished:

• daily pH meter of the esophagus (within 24 hours or more);
• daily pH-metric of the stomach (within 24 hours or more);
• short-term intragastric pH-metry (within 2-3 hours);
• express pH-metry (within 15-20 minutes);
• endoscopic pH meter(during gastroscopy ).

Short-term intragastric pH measurement

Short-term intragastric pH-metry is used to study the acid-forming and acid-neutralizing functions of the stomach under basal conditions and after stimulation (with histamine or pentagastrin ). The average pH levels in different parts of the stomach are measured, and a conclusion is drawn from them. Assessment of the neutralizing function of the antrum is carried out according to the difference between the minimum pH in the stomach and the maximum in the antrum.

The main functional test for short-term intragastric pH metering is the Noller alkaline test. It consists in the fact that 0.5 g of sodium bicarbonate ( baking soda ) dissolved in 30 ml of water is injected into the stomach through the mouth by a patient, and the pH dynamics in the stomach body are recorded using an intragastric pH meter. As a result of the introduction of alkali , a neutralization reaction of hydrochloric acid HCl + NaHCO ₃ = NaCl + CO ₂ + H ₂ O takes place, the pH level rises, and after the so-called alkaline time it returns to its original level due to the release of hydrochloric acid in the stomach .

With express pH measurement , only the basal level of acidity is determined, i.e. the question of the presence or absence of hydrochloric acid is solved and the pH level in the body of the stomach is determined.

For short-term and rapid pH-metering, you can use a multi-channel device, which allows you to examine several patients simultaneously.

Endoscopic pH measurement

Endoscopic pH metering is performed using a special endoscopic pH probe inserted through the instrument channel of the endoscope . The study is performed during gastroscopy , extending the usual procedure by about 5 minutes. During this time, acidity is measured at 9 standard points of the stomach and duodenum under visual control.

When interpreting the results, it is necessary to take into account that endoscopic examination itself is a factor stimulating acid formation.

Indications for pH measurement are:

• gastroesophageal reflux disease (GERD);
• peptic ulcer of the stomach and duodenum;
• various forms of chronic gastritis , duodenitis , dyspepsia ;
• Zollinger-Ellison Syndrome ;
• Barrett's esophagus ;
• assessment of the action of drugs that reduce secretion , their individual selection for the patient;
• conditions after resection of the stomach .

Contraindications

Contraindications to the study consist of contraindications to the introduction of a gastric tube and contraindications to the use of certain stimulants or inhibitors of gastric secretion.

Contraindications to the introduction of a pH probe

• gastric bleeding (during bleeding and within 10 days after its completion);
• aortic aneurysm ;
• burns, diverticulums, strictures of the esophagus;
• severe forms of hypertension and coronary insufficiency;
• nasopharyngeal obstruction;
• severe maxillofacial injuries;
• severe forms of coagulopathy.

Relative contraindications to the introduction of a pH probe

• recent surgery in the upper gastrointestinal tract ;
• tumors and ulcers of the esophagus;
• the presence of varicose veins of the esophagus ;
• bleeding from the upper gastrointestinal tract (after stopping bleeding, it is possible to conduct a long pH-metry to monitor the effectiveness of antisecretory drugs that prevent the development of repeated bleeding).

• Gastric Sounding

• Rapoport S.I., Lakshin A.A., Rakitin B.V., Trifonov M.M. pH-metry of the esophagus and stomach in diseases of the upper digestive tract / Ed. Academician RAMS F.I. Komarova. - M.: ID MEDPRAKTIKA-M, 2005, 208 p. ISBN 5-98803-014-9 .