Catheter-associated bladder mucosal trauma during intermittent voiding: An experimental study in pigs

Abstract

Objective: The objective of this study is to characterize bladder mucosal trauma associated with intermittent catheterization with conventional eyelet catheters (CECs) and to assess if a microhole zone catheter (MHZC) design concept reduces this adverse effect.

Materials and methods: A porcine model was developed to reflect human catheterization and bladder drainage. Nine pigs were randomized for catheterization with CEC (n = 6) or MHZC (n = 3). The bladder was drained repeatedly 20 times through the catheter. Cystoscopy was performed before and after the procedure, and bladders were analysed by histopathology. Two additional pigs were used for cystoscopy visualization of suction events in vivo. Cystoscopy, gross pathology, histopathological score, leucocyte infiltration, and intracatheter pressure at flow stops during voiding were compared for each group.

Results: A significant higher pressure gradient was measured inside the CECs compared with MHZCs during flow stop. Consequently, CECs resulted in suction events inflicting bladder trauma characterized by loss of epithelium, oedema, haemorrhage, and neutrophil tissue infiltration. No significant trauma was identified when using MHZC.

Conclusions: Considerable mucosal bladder trauma is inflicted by CECs which may be an overlooked risk factor for urinary tract infection. Catheters can be designed to minimize mucosal suction and reduce associated trauma. This may be a solution to reduce infection frequency and increase user comfort. Furthermore, the study demonstrates the potential of pigs as an attractive animal model for investigating urinary catheter performances.

Keywords: bladder trauma; intermittent catheter; large animal model; microhole zone catheter; mucosal suction; pig; urinary catheter.

FIGURE 1

Intraluminal pressure measured inside the catheter at first flow stop (A) and as the highest pressure peak within each drainage (B). A lower negative pressure means a larger pressure impact for the respective catheter type. CEC, conventional eyelet catheter; MHZC, microhole zone catheter. ****P < 0.0001.

FIGURE 2

Catheter‐associated mucosal lesions observed by cystoscopy. All bladders appeared normal at baseline (row 1). Significant lesions were observed in the bladder mucosa after the drainage procedures using conventional eyelet catheters, determined by cystoscopy (A–D, rows 2 and 3, yellow arrows) or gross pathology (A–D, row 4, arrows). Lesions were not detected in the bladders from pigs drained by microhole zone catheters (E and F) nor in two of the six pigs drained by conventional eyelet catheters (from two different catheter manufacturers; not shown in the figure).

FIGURE 3

Histology and immunohistochemistry of bladder tissue exposed to repeated catheterizations. (A) Bladder mucosa from a pig catheterized with a microhole zone catheter showing no apparent pathologies. Haematoxylin and eosin stain, 200× magnification. (B) Bladder mucosa from a pig catheterized with conventional eyelet catheter showing loss of bladder epithelia, haemorrhage (h), and massive oedema (e) of the mucosa. Haematoxylin and eosin stain, 200x magnification. (C) Close up of picture (B). Massive neutrophil infiltration (red cells, arrows) is seen across the mucosa. Immunohistochemistry, 400× magnification. (D) Close up of picture (C). Neutrophils within and outside vessels (red cells, arrows). Immunohistochemistry, 600× magnification.