The failure of synthetic polymeric medical devices - Durability and Reliability of Medical Polymers - page 189

length of remaining catheter proved to have been held in storage pinned to
black card, and the proximal end through which the epidural fed showed
signs of brittleness. Nurses had remembered having problems attaching the
proximal end to the drip, and had to tape the parts together. There were brittle
cracks present here, and at several other places along its length. in addition,
there appeared to be a slight yellowish tinge to the failed catheter.
The expert acting for Mrs K examined the failed end of this length in a
solicitor's office with a hand lens, not an ideal way of assessing the evidence.
He thought he could see traces of score marks running across the failed
end, perhaps created by the catheter being withdrawn over the sharp end of
the Tuohy needle. This should not have happened, because there are strict
guidelines given to hospital staff that the Tuohy needle should be taken out
first, and then the catheter withdrawn through the needle. In his opinion, the
staff had been negligent by withdrawing the catheter first, and thus damaging
the end.
9.3.3 Microscopic analysis of fractured catheter end
The dispute entered a new phase when experts were appointed to act for
the hospital and manufacturer. A joint meeting agreed that high-resolution
microscopy of the fractured catheter could help resolve the main issues,
whether to confirm or negate the score marks claimed by the claimant's
expert. This was one of the first uses of environmental scanning electron
microscopy (eseM); the distal catheter end is shown in Fig. 9.8. Although
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9.8 Fractured end of catheter showing bleed hole in section.