REDUCING ARTIFACTS IN AMBULATORY URODYNAMICS

Objective To compare the diagnoses derived from a retrospective analys is of 50 ambulatory urodynamic recordings, unaware of the final diagno sis, and to evaluate the importance of the symptom diary and the prese nce of two transducers in the bladder rather than one. Patients and me thods Fifty women underwent ambulatory urodynamics (duration 4 h) afte r video cystourethrography. A single solid-state microtip pressure cat heter was inserted with both transducers inside the bladder, and anoth er was inserted in the rectum. The women were asked to complete a symp tom diary and the results were analysed with the active participation of the patient. Detrusor 'instability' was diagnosed on ambulatory uro dynamics if there was a simultaneous increase in detrusor pressure and in the 'urethral' line in the presence of symptoms (urgency or leakag e). All 50 recordings were analysed retrospectively in four combinatio ns, i.e. with and without the additional 'urethral' line displayed on the screen and with and without the diary information, The total numbe r of detrusor contractions was then calculated for each reading and 'a bnormal detrusor activity' diagnosed when a contraction occurred with or without symptoms as recorded in the diary. The final diagnosis for each reading was then compared with that made at the time of the test with the patient present. Results Using the information from the diary reduced the number of pressure rises classified as 'abnormal detrusor activity' by 58%; using a second bladder pressure transducer further reduced the number of pressure rises classified as 'abnormal' by 19%. Overall, using both techniques together reduced the number of spurious pressure rises misclassified as 'abnormal detrusor activity' by 64%. Conclusions Both the symptom diary and the placement of two transducer s in the bladder can decrease, by almost two-thirds, the diagnosis of pathological detrusor activity on ambulatory urodynamics.