Environmental stress cracking of polycarbonate catheter connectors

A catheter connector allows medical staff to supply a range of fluids to ill patients using a single intravenous line. In the case of premature babies, such a line provides nutrition in the form of a synthetic milk (TPN) and antibiotics to prevent infection. The connectors are made from several alternative polymers, but polycarbonate is used widely. However, the material is susceptible to environmental stress cracking (ESC) from a variety of fluids. The case study shows how the first versions of one design were poorly moulded and cracked during service, allowing bacteria to enter the line and so infect the baby. The baby contracted meningitis, but lived although suffering brain damage. Evidence was produced which showed that it was a widespread problem in the mid-1990s in UK hospitals. The investigation suggested that poor design and manufacture were the root cause of the problem.