Five patients had a silicone-rubber catheter that broke during attempted
removal. Mechanical testing was performed to determine the tensile strength
of silicone-rubber as well as of polyvinyl chloride catheters.
Silicone-rubber catheters were found to have a low tensile strength. The
pull-out force of ten indwelling silicone-rubber catheters was also
measured. The pullout force measured from a patient who had a cast was
close to 40 per cent of the strength of the silicone-rubber catheters.