Esophageal pH and Impedance monitoring

Reflux monitoring involves placing a thin catheter into the esophagus for 24 hours. Traditional pH monitoring records all acidic reflux events (pH below 4), which are responsible for mucosal damage and symptoms. 

Newer impedance monitoring detects non-acidic reflux events (pH above 4). Although non-acidic reflux does not directly damage the mucosa, it can irritate submucosal nerve endings and cause symptoms. If it reaches the lungs, it may trigger an inflammatory response. Impedance monitoring detects all types of esophageal content movement, including gas, and can help identify causes of atypical upper abdominal symptoms. 

Medications affecting stomach acidity significantly influence examination results. Discuss potential medication pauses with the physician who referred you to the examination. Diagnostic examination is typically done after a sufficient medication break: one week for commonly used proton pump inhibitors, two days for short-acting medications, and only on the day of the test for fast-acting antacids. 

To assess treatment response, impedance monitoring may be done without a medication break—continue taking your proton pump inhibitor as usual on the day of the test. 

A break may also be skipped if symptoms would become intolerable. A partial 1–2 day break usually prevents the test from being performed. pH monitoring without a sufficient medication break is done only in exceptional cases at the explicit request of the treating physician. 

Avoid alcohol for 1½ days before the test. Try to sleep well the night before. Fast for at least 5 hours before the examination to prevent stomach contents from affecting acidity or entering the airways during catheter placement. You may take necessary medications with a small amount of water. 

A specially trained nurse places the catheter; a physician is needed only in exceptional cases. The nurse records your personal information and reviews your preparation. You will also identify your three main symptoms for documentation. 

While seated, the nurse guides a flexible 2 mm diameter catheter into one nostril. No anesthetic or lubrication is used, as these would impair measurement accuracy. The nasal mucosa may become mildly irritated. 

When the catheter reaches the lower pharynx, you may gag. It is important not to panic and to follow the nurse’s instructions carefully. The catheter cannot be pushed directly into the esophagus—you must actively “swallow” it. Tilting your head downward helps guide the catheter into the esophagus. You will be asked to swallow small sips of water through a straw to open the esophageal passage. The catheter tip is advanced into the upper stomach to measure pH briefly. It is then pulled back into the esophagus. If the correct location is already known, the catheter can be placed directly. If a pressure profile test is performed, you may be asked to take a deep breath or swallow water. In pH mapping, the catheter is slowly withdrawn while monitoring pH readings. Once the correct position is reached, the catheter is secured with tape to the nose and cheek, and a safety loop is placed behind the ear. 

The device automatically records reflux events. You do not need to operate it actively. However, for analysis, you should use the device buttons to mark the start and end of meals, time spent lying down, and any symptoms. Ideally, each symptom should be recorded a few to several times. If a symptom is continuous, press the symptom button during the worst moments. If symptoms occur frequently, record only the most bothersome episodes. 

A traditional paper diary complements the device recordings. You should log meal times and the type of food or drink consumed. For symptoms, note the start and end times, and optionally provide a more detailed description. You may also include brief notes about events or sensations you believe are relevant to the study. 

During recording, you should live as normally as possible. Going to work is usually feasible (and beneficial), as the device is mostly a cosmetic inconvenience. A doctor may grant a sick day if you work in public-facing roles or if your job poses a risk of damaging the device. Even then, stay active at home rather than sedentary. Remote work may be a good option in some cases. The device does not prevent use of public transportation. 

You may engage in moderate physical activity, provided the device is not bumped. Do not get the device wet—showering or sauna use is not allowed. 

Reserve at least eight hours for nighttime rest. Even if you cannot sleep, you must lie down for this duration. During the day, avoid prolonged lying down; rest in a seated position instead. 

To ensure successful testing, maintain a normal, nutritious eating pattern—do not switch to liquid-only meals. Frequent snacking is not beneficial; eat a few main meals and skip snacks. You may drink coffee or tea with meals. Eating may cause the catheter to move slightly, which is harmless. 

Since the examination aims to detect acid reflux, avoid acidic foods and drinks. The nurse will provide detailed instructions when the device is installed, but you should especially avoid fruits, berries, and sour dairy products. Most drinks are acidic, so water is recommended. After meals, drink a glass of water to help remove any food particles stuck to the catheter. 

The 24-hour monitoring does not cause serious health risks. The catheter may irritate the nasal and throat mucosa and slightly hinder eating, but a Finnish study found that only one in four patients experienced a significant decline in quality of life during the test day. Sleep may be a concern, but humans are adaptable—only 10–15% of patients reported notable sleep disturbances. The 24-hour pH and impedance monitoring often provides crucial information for treatment planning, making the minor discomfort worthwhile. 

If the catheter catches on something (i.e. a door handle), it may tear off the tape and pull out of the esophagus. A strong gag reflex may bring the catheter tip into the mouth even if the tape remains intact. Do not attempt to reinsert the catheter yourself. The disposable catheter can be discarded in household waste. Store the recording device for example in a plastic bag and return it at the agreed time. The need for a repeat test will be assessed individually. 

A dangling catheter may attract small children or pets, so take appropriate precautions. 

After 24 hours, return to the installation site at the agreed time. Catheter removal is quick—the nurse removes the tape and gently pulls out the catheter. Before leaving, diary entries are reviewed, and you may clarify events from the examination day. 

The examination does not require follow-up or impose restrictions on normal life. 

The nurse transfers the recording to a computer and adds event markers. A report is sent to the physician, who reviews the data and provides an interpretation. The report is forwarded to the referring physician. 

The physician who referred you for the examination will inform you of the results and the next steps in your care. Contact your care unit if you do not have a scheduled appointment or call time.