Intermittent catheterization is the gold standard method for bladder management in individuals with urinary retention and/or incontinence. It is therefore important to understand the performance of urinary catheters, especially on parameters associated to risks of developing urinary tract infections, and that may impact the quality of life for urinary catheter users. Examples of such parameters include, urine flowrate, occurrence of flow-stops, and residual urine left in the bladder after flow-stop. Reliable in-vitro and/or ex-vivo laboratory models represent a strong asset to assess the performance of urinary catheters, preceding and guiding in-vivo animal studies and/or human clinical studies. Existing laboratory models are generally simplified, covering only portions of the catheterization process, or poorly reflect clinical procedures. In this work, we developed an ex-vivo porcine lower urinary tract model that better reflects the catheterization procedure in humans and allows to investigate the performance of standard of care catheters. The performance of three standard of care catheters was investigated in the developed model showing significant differences in terms of flowrate. No differences were detected in terms of residual volume in the bladder at first flow-stop also when tuning the abdominal pressure to mimic a sitting down and standing up position. A newly discovered phenomenon named hammering was detected and measured. Lastly, mucosal suction was observed and measured in all standard of care catheters, raising the concern for microtrauma during catheterization and a need for new and improved urinary catheter designs. Results obtained with the ex-vivo model were compared to in-vivo studies, highlighting similar concerns.

Urinary tract infections (UTIs) are common and troublesome complications of clean intermittent catheterisation (CIC) in individuals suffering from incomplete bladder emptying, which may exacerbate the underlying disease and lead to hospitalisation. Aside from the design of the intermittent catheter and its handling, a recent review highlighted residual urine as one of several UTI risk factors. A new urinary intermittent catheter with multiple micro-holes has been developed for improved bladder emptying. In a controlled crossover study, adult male CIC users were randomised for a health care professional-led catheterisation with the new micro-hole zone catheter (MHZC) and a conventional eyelet catheter (CEC) in two individual test visits to compare the number of flow-stops and the residual urine at the first flow-stop as co-primary endpoints. In 42 male CIC users, the MHZC resulted in significantly fewer flow-stop episodes compared to the CEC (mean 0.17, 95% CI [0.06, 0.45] vs. mean 1.09, 95% CI [0.75, 1.6], respectively; p < 0.001) and significantly less residual urine at the first flow-stop (mean 5.10 mL, SE [1.14] vs. mean 39.40 mL, SE [9.65], respectively; p < 0.001). No adverse events were observed in this study. The results confirm the enhanced performance of the MHZC compared to a CEC, ensuring an uninterrupted free urine flow with no need to reposition the catheter until the bladder is thoroughly empty.

PURPOSE: To assess the performance of a new urinary intermittent catheter (IC) prototype designed with a micro-hole drainage zone compared to a conventional eyelet catheter (CEC) in terms of flow-stop, bladder emptying, and hematuria. DESIGN: Randomized controlled crossover studies. SUBJECT AND SETTING: The sample comprised 15 male healthy volunteers (HV) and 15 IC users, along with 15 female HV and 15 IC users. The age range was lower for HV participants than for IC users (range: 20-57 years for HV vs 21-82 years for IC users). The study setting was the Department of Urology, located in Rigshospitalet, Copenhagen. METHODS: Number of flow-stop incidents, residual urine volume at first flow-stop (RV1), and dipstick hematuria were measured during and after catheterization by a health care professional (HCP) and by IC-users. Results from the 3 studies were combined for HV and IC users on RV1 and number of flow-stop incidents but separated on sex. For incidents of hematuria, an effect of underlying condition was assumed, and a combined analysis on sex was performed, separating HV and IC users. RESULTS: When compared to the micro-hole drainage zone design, catheterizations with CEC resulted in a significantly higher mean RV1 (mean difference: 49 mL in males and 32 mL in females, both P < .001) and average number of flow-stop incidents (8 and 21 times more frequent for males and females, respectively, both P < .001). The likelihood for hematuria was 5.84 higher with CEC than with micro-hole drainage hole design, P = .053, during normal micturition in HV postcatheterization. No serious adverse events were reported. CONCLUSION: The micro-hole drainage zone catheter provides IC users fewer premature flow-stops. This design feature reduces modifiable urinary tract infection risk factors, such as residual urine and micro-trauma; additional research is needed to determine its effects on bladder health.

The original version of this Article contained a repeated error, where the pressure unit was incorrectly given as 'mbar' instead of 'mmHg'. In the Results and discussion section, under the subheading 'Intra-catheter pressure' , "The average pressure variation for Brand A was-364 ± 42 mbar,-248 ± 81 mbar for Brand B and-272 ± 59 mbar for Brand C at 20 cmH 2 O. When the abdominal pressure was adjusted to 50 cmH 2 O, the average pressure for Brand A was-383 ± 50 mbar,-323 ± 47 mbar for Brand B and-330 ± 93 mbar for Brand C. " now reads: "The average pressure variation for Brand A was-364 ± 42 mmHg,-248 ± 81 mmHg for Brand B and-272 ± 59 mmHg for Brand C at 20 cmH 2 O. When the abdominal pressure was adjusted to 50 cmH 2 O, the average pressure for Brand A was-383 ± 50 mmHg,-323 ± 47 mmHg for Brand B and-330 ± 93 mmHg for Brand C. " Additionally, "The measured intra-catheter pressure variation for Brand B at 20 cmH 2 O was equal to-296 ± 56 mbar (N = 9, SD) for the tests where mucosal suction was perceived by the operator. Conversely, the intra-catheter pressure variation that could be measured at the first flow-stop for Brand B at 20 cmH 2 O when mucosal suction was not detected by the operator was equal to-180 ± 64 mbar (N = 6, SD). A similar scenario was seen for Brand C at 50 cmH 2 O, where the measured intra-catheter pressure variation was equal to-373 ± 62 mbar (N = 11, SD) when mucosal suction was perceived by the operator, and to-212 ± 45 mbar (N = 4, SD) when mucosal suction was not perceived by the operator. " now reads: "The measured intra-catheter pressure variation for Brand B at 20 cmH 2 O was equal to-296 ± 56 mmHg (N = 9, SD) for the tests where mucosal suction was perceived by the operator. Conversely, the intra-catheter pressure variation that could be measured at the first flow-stop for Brand B at 20 cmH 2 O when mucosal suction was not detected by the operator was equal to-180 ± 64 mmHg (N = 6, SD). A similar scenario was seen for Brand C at 50 cmH 2 O, where the measured intra-catheter pressure variation was equal to-373 ± 62 mmHg (N = 11, SD) when mucosal suction was perceived by the operator, and to-212 ± 45 mmHg (N = 4, SD) when mucosal suction was not perceived by the operator.