Electrical safety of medical electrical devices

 

Aplied-partIt can be assumed that not all people will understand the dangers associated with the exposure to electricity. It is this danger that has triggered several discussions relating to the safety of all members of the public. Regulatory bodies world-wide have acknowledged the dangers of electricity by producing legislation, standards and guidelines to control the design and test of electrical appliances in order to prevent any hazard to the general public. One environment where electric currents pose an acute threat is in the medical treatment and care of patients. Often, patients are physically connected to one or more electrical medical devices for a period of time. In these circumstances it is possible that patients are unaware of being exposed to electrical currents, especially if patients are treated under full or local anaesthetic. During invasive treatments, the human body’s natural protection organ, the skin, no longer provides the basic insulation against electrical currents.It is during these treatments that electrical currents as low as 50mA can float through the human body and cause the heart to fibrillate or paralyse the respiratory system. To govern the design of medical equipment, the International Electro technical Committee, the IEC has produced a standard to control all aspects of safety directly or indirectly relating to the handling, use or connection to, of medical equipment. This standard is referenced to as IEC 60601, or by many simply referred to as IEC 601. The IEC60601 was first published in 1977 (then referred to as IEC 601) and handles the electrical safety of both mechanical and electrical issues and is constructed from 2 parts;
Most Biomedical departments use the 60601 standard to test if medical equipment is safe during their preventive maintenance job and after any repair to a medical device.

A more and more accepted standard in the biomedical industry is the new IEC 62353. As its full name implies, IEC 62353 Medical Electrical Equipment – recurrent test and test after repair of medical electrical equipment, is proposed to define the requirements of ensuring the in- service electrical safety of electro medical equipment and systems. The IEC 62353 standard is an attempt to harmonize the various local standards and practices to ensure safe operation and testing of medical electrical equipment and ME systems. In meeting this requirement the IEC 62353 incorporates tests beyond those of type testing. Specifically it seeks to provide a uniform and unambiguous means of assessing the safety of medical equipment, whilst maintaining the relation to IEC 60601-1 and minimizing the risks to the person conducting the assessment. Importantly, the new standard recognizes that the laboratory conditions described in the IEC 60601-1 cannot always be guaranteed when in-service testing of medical devices is undertaken. As a result, test measurements that require certain environmental conditions may not always be applicable or consistent for the testing of equipment that is already in use. Another factor raised is that equipment could potentially be damaged by applying type test specifications when in service and could therefore represent a potential danger to users.

Please if you are interested in more information on medical electrical safety Logitecq Medical Services provides electrical safety analysers that both comply with the IEC 60601 and IEC 62353. Logitecq also provides training on the practical understanding and use of both regulations.

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