Presentation Authors: Habiba Yasmin*, Bogdan Toia, Richard Axell, Megan Duffy, Mahreen Pakzad, Rizwan Hamid, Jeremy Ockrim, Tamsin Greenwell, London, United Kingdom
Introduction: The thinnest transurethral catheter compliant with international guidelines for good urodynamic practices is the 6F dual lumen. No consensus exists in the published literature regarding its impact on urinary flow parameters. Multiple parameters including underlying pathology, voided volumes, position of void and patient inhibition may also affect flow rate. We have assessed the effect on flow rate of a 6Ch urodynamic catheter.
Methods: A prospectively collected database of video-urodynamic (VUDS) tests performed with a 6Ch dual lumen urethral catheter in a tertiary centre between 2016-2018 was screened for adult patients who voided a minimum of 150ml on free flow immediately before VUDS. Participants were categorised according to their VUDS results into 4 groups: 1) normal pressure, normal flow void2) detrusor underactivity3) bladder outlet obstruction4) impaired detrusor contraction with associated obstructionPatients who voided off detrusor overactivity, had non-diagnostic VUDS or incomplete data were excluded. Paired samples t test and One-way ANOVA were used and statistical significance was determined as p < 0.05.
Results: 413 patients met the inclusion criteria. 39 (9.4%) were excluded as they did not have a representative void during their VUDS due to inhibition (36) or catheter related pain (3). A further 19 (4.6%) were excluded, as they were unable to void with the catheter in situ. _x000D_
The remaining 355 patients (221 women and 134 men, mean age 52Â± 15y) had a significantly higher mean maximum flow rate (Qmax) on their free flow Qmax= 21.7Â±10.9 ml/s compared to a Qmax= 14.9Â±8.3 ml/s with the catheter in situ (p < 0.001). The mean voided volume on free flow was 298Â±137 ml, less than the mean volume of 405Â±161 ml voided during VUDS (p < 0.001). 65 (18.3%) voided sitting during their VUDS, with a significantly reduced Qmax of 17.4Â±9ml/s compared to 22.4Â±9ml/s on the free flow. Minor differences were noted in the residual volumes at the beginning and end of VUDS, mean 90 and 86 ml respectively (p=0.57). _x000D_
Significant differences were also noted in Qmax before and after catheterisation in 3 of the 4 patient groups in both women and men as detailed in Table 1.
Conclusions: The 6F catheter significantly influences urinary flow and might lead to inability to void in 5%. Free flow remains an essential component of urodynamic investigations.