Evaluating ambulatory urodynamics: a prospective study in asymptomatic women

To identify abnormal detrusor contractions in asymptomatic women undergoing ambulatory urodynamics, to standardise the investigation technique for women with urinary symptoms for clinical practice.

Prospective observational study.

Two tertiary referral urogynaecology units: one in London, UK and one in Varese, Italy.

Women without urinary symptoms were recruited into the study. Ambulatory urodynamics was performed according to the King's College Hospital protocol. All the traces were analysed in four different ways: 1. without the second bladder transducer measurements displayed on the screen and without the diary; 2. as in 1. but with the diary; 3. with the second bladder sensor displayed on the screen but without the diary; 4. as in 3. but with the diary. The diary was always interpreted at the end of the test with the woman present. For each method we reported the total number of detrusor contractions and whether the woman would have been diagnosed as having abnormal detrusor contraction. Cochran's Q test was used for statistical analysis.

Twenty-six women (mean age 31.7 years) were recruited. Ambulatory urodynamic testing lasted an average of 3.57 hour. The diagnosis of abnormal detrusor contraction varied by 65.4% depending on the method of analysis used. The diary and the women's symptoms during the test were the most discriminating factors. A significant difference between the diagnoses was obtained when comparing the four different ways of analysis. According to our protocol only three women (11.5%) had abnormal detrusor contractions.

Using our protocol almost 90% of asymptomatic women have a stable bladder on ambulatory urodynamics. This is similar to the results of labouratory urodynamic testing of asymptomatic women but is in contrast to previous reports of ambulatory urodynamics of asymptomatic women. The technique used during ambulatory urodynamics determines the tests ability to detect detrusor instability with an accurate symptom diary being the most important.