Malfunction of medical equipment as a result of mains borne interference

Medical equipment has become more intelligent as the manufacturers have incorporated the latest microprocessor based technology. Many items of medical equipment are used in critical care situations where failure could lead to loss of life. There are many items of medical equipment in use in hospitals which do not claim compliance to any EMC standard and there have been occasional reports of failures which could be attributed to electrical interference. Surveys have shown that electrical mains supply in hospitals can carry considerable interference. Using a test protocol described previously (Currie et al, 1992) a wide range of medical equipment was removed temporarily from use and its immunity to electrical mains borne interference tested. The authors conclude that the benefits to be gained from microprocessor based technology must be weighed against possible problems from interference. It is to be hoped that these will be overcome by the implementation of the EEC Directive on EMC which will result in design improvements