Medical power supplies differ greatly from average, domestic power supply units. Because of their application there are critical demands on medical power supply units for safety and reliability. Consequently, the units go through lengthy product testing before being certificated as being safe to use in a medical environment.
The amount of research and development involved in the manufacture and production of medical power supplies means that only a few producers actually tackle the field. One other aspect that tends to thin the herd is the possibility of product liability in the event of a power supply failure leading to a medical emergency or even, in a worst case scenario, a patient death.

Despite these concerns, a handful of power supply specialists are using their product development to provide units that can have medical applications. Their enthusiasm may be prompted by a small but steadily growing marketplace, as power supply units are required for more home-based medical equipment. A report issued by Frost & Sullivan in 2006 estimated that the world power supply market for medical applications would grow from $350million in 2005 to a projected $438.1million in 2012. This is just a fraction of the overall potential power supply market, and as new developments in medical treatments mean more patients can benefit from home care equipment, that forecast may be a little on the low side.

The rise of applications such as CAT scans, MRI devices, blood analysers and patient-monitoring systems for home care are also expanding the uses that medical power supplies can be incorporated into. In addition there are now specific requirements within hospital and medical centre applications that require power supply units that can give high power, reliable and efficient power delivery which are both cost effective and compliant with all legislation.

One of the concerns regarding compliance is that in some instances, end users are unaware that ordinary, commercial power supplies do not necessarily meet the required standard for application in medical equipment. Issues such as component spacing, insulation and leakage current can all cause a power supply to perform below standard, and in a medical situation where the life of a patient may depend on the power supply’s ability to cope with the application, this could prove fatal. The International Electronics Manufacturing Initiative (iEMI) addressed this in 2006 with a project that set out to develop reliability specifications for medical-grade electronic components, including medical power supplies. The ongoing project has so far achieved three objectives:

• Established draft protocol for acceptance testing based on a comprehensive Failure Mode Effects Analysis of failed devices. This protocol is currently being validated using components provided by different suppliers.
• Developed new optical inspection methods to screen components for macroscopic failures during testing. This automated system enables acquisition of large data sets quickly.
• Tracked reliability of parylene coatings (of neural recording electrodes) as a function of local chemistry and identified conditions of use that resulted in significant localized degradation at the probe tip.

It is essential for those who are looking to purchase medical power supplies that they ensure that the product they buy is fully compliant with all legislation that deals with medical equipment. It is critical that lives are not put at risk because of the desire to cut costs by employing unsuitable commercial power supply units that may not be able to cope with the demands put upon them by medical equipment. When choosing medical power supplies, the purchaser should always look for the highest quality product from a reputable supplier. They should also consider the end user – not the hospital, but the patient.