An abdominal wall simulator for testing suprapubic urinary catheters.

ABSTRACT

Urinary catheters (drainage tubes) are in widespread use. The most common type of long-term catheter is the Foley, which is made from natural or synthetic rubber. Foley catheters are passed into the bladder via the urethra or the suprapubic puncture channel (through the abdominal wall). A simulator for the abdominal wall has been developed to simulate aspects of the interaction between it and a suprapubic catheter. The simulator is based on a slab of ultrasoft elastomer with tensionable reinforcing polyamide filaments. The behaviour of the simulator has been compared with data published. A soft membrane (contact pressure) transducer (SMT) was used and novel instrumented 'tongs' for lateral indentation of the puncture track giving indentation stiffness. Slab materials were used with shear moduli of 0.1 and 0.021 MPa. Two filament-tensioning methods were used by clamping to a winding mechanism and by weights. The combination of the softer slab material and tensioning by weights gave good conformity to physiological data; other combinations did not.