Residual rectal fluid in normal, constipated and incontinent subjects

Abstract:

The retention of residual fluid (RF) in the rectum after defaecation was evaluated in 20 healthy subjects (mean age 35.7 years), 25 patients with chronic constipation (mean age 33.4 years) and 20 with faecal incontinence (mean age 31.2 years). The defaecation act was studied by faecoflowmetry. A one-litre water enema was administered, and faecoflowmetric studies were done while the subject was evacuating the enema. After evacuation a 28 French rectal tube was introduced to retrieve the RF for quantitative assessment. Six of the 20 healthy volunteers had a mean RF of 32.3 ml. All of the constipated patients had RF with a mean of 370.6 ml. Residual fluid was found in 2 of the 10 patients with partial incontinence (25 and 30 ml) and in none of the completely incontinent patients. The estimation of the RF after defaecation might be useful as an investigative tool in the diagnosis of defaecation disorders. The test is simple, non-invasisive and non-radiologic.