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Dynamic monitoring of small bowel contractile activity is a cornerstone in the modern diagnosis of pseudo-obstruction and other motility disorders. Continuous recording of intra-luminal pressures at several different locations in the small bowel gives a picture of the contractile activity of the gut over time. During fasting there are normally a recurring pattern of propagated activity complexes followed by periods of motor quiescence. Food intake changes the motility pattern into so called digestive motility, which comprises more uniform segmental and propagated contractions. Measurement of small bowel motor activity can also be done in order to investigate the effects of different drugs on gastrointestinal motility.
Different methods for manometry
Ambulatory 24-hour manometry from at least 3 measurement points covering a distance of 30 cm of the proximal small bowel is currently viewed as the best technique for diagnosing intestinal motor disorders. Stationary manometry is usually done in the recumbent position and this requires the patient to stay in the laboratory during the whole measurement period. The main advantage of the stationary technique is that it allows the use of a large number of measurement points. That advantage does not outweigh disadvantages like limited time for investigation and inability to study night-time motor activity.
Preparing the patient
All drugs that can interfere with motor activity must be stopped at least 48 hours prior to the investigation. Some opiates that have a slow degradation may have to be stopped 7 days prior to the investigation. The patient should stay fasting for at least 8 hours before intubation.
Intubation and placement of the manometry catheter
Intubation techniques may vary from one type of catheter to another. Catheters for stationary manometry usually have room for a guide wire whereas catheters with electronic pressure transducers for ambulatory manometry are equipped with an inflatable balloon at the tip of the catheter. Intubation is done via the nose, the pahrynx and the oesophagus to the stomach. After passage of the catheter tip through the pylorus the balloon can be inflated in order to utilise peristalsis for the placement of the catheter for ambulatory manometry. Fluoroscopy is used for checking the location of the catheter. At least one measurement point should be in the jejunum below the ligament of Treitz.
Protocol for ambulatory manometry
The patient is allowed 3 meals during the 24-hour measurement period. The first meal is taken in the laboratory and consists of a standardized test meal. After having had the first meal the patient is allowed to return home. An evening meal, also with a defined composition and energy content, is taken at home. The manometry recording continues during the night. The patient returns to the laboratory after breakfast. On some occasions a drug (octreotide) is given 2 hours after intake of breakfast. The location of the catheter is checked fluoroscopically before termination of the investigation at 24 hours.
Protocol for stationary manometry
The stationary study is done with the patient in a recumbent position at the laboratory. When 2 activity complexes have been registered or when 6 hours of fasting activity have been recorded the patient is given a standardized test meal. The recording continues for another 2 hours after intake of food. Before termination of the investigation the location of the catheter is checked using fluoroscopy.
Analysis of the manometry recording
Measurement data are transferred to a PC for subsequent display and analysis. The analysis is mainly visual for determining the presence or absence of normal and abnormal contractile activity. Examples of normal and abnormal motility patterns can be studied in the section *Motility patterns.
Sponsored by Socialstyrelsen (The National Board of Health and Welfare) and Karolinska Institutet. Copyright © 1997-2003 Greger Lindberg, MD.
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