THIS MONTH
A wireless future
One of the biggest problems for companies developing implantable medical devices is powering them. A spinout company from a New Zealand University says it has developed a solution.
New generation implantable devices coming to the market include treatments for diabetes, nerve stimulation devices for Parkinson’s disease and heart-assist units. Many require a reliable source of electrical power. Batteries may last several years for low power devices such as pacemakers, but eventually need replacing. In some cases such as left ventricular assist heart pumps the power required exceeds that which a battery can usefully provide. Recent advances in power electronics, particularly in semiconductor power switches, have made possible the transmission of power across an air gap using magnetic fields, known as inductively coupled power transfer. The important issue is the conversion from a low frequency system such as 50/60 Hz mains power to a much higher frequency system of 10–200 kHz. This allows power transfer to occur even when using small components, and up to 60 W is practical.
Telemetry Research, a spinout from the University of Auckland’s Bioengineering Institute in New Zealand has taken the technology further and developed several unique features for implantable medical devices. Power can be transmitted across greater distances, which removes restrictions in the surgical placement of devices, and without heating surrounding tissue. The company has established a relationship with ADInstruments, which produces software for the collection and analysis of physiological signals. It is seeking to work with medical device companies to develop implantable devices for specific human purposes. David Budgett of Telemetry Research says, “Technology partnering is the way forward to unify the expertise in wireless power delivery with the new generation of medical devices and hence eliminate the problem of providing energy.” For more details, contact Nigel Whittle, UK Department of Trade and Industry (DTI) International Technology Promoter, e-mail: nigel.whittle@pera.com Information supplied by the DTI’s Global Watch.
Blood pressure monitors on the rise
The home-use digital blood pressure monitor market, currently valued at US$800 million, is set to increase to US$1 billion by 2010. The predicted rise is linked to the increasing prevalence of hypertension in the ageing world population and the growing emergence of telehealth, according to a report by InMedica. It found that automatic upper-arm blood-pressure monitors accounted for over half of all monitors sold; their ease of use and consistent results make them the doctors’ favourite. These monitors are particularly recommended in the US so that patients can see the results of any lifestyle changes they implement and the effects of prescribed medication. www.in-medica.com
Germans top the doc list
According to a study conducted by the German sickness fund, Gmünder Ersatzkasse, Germans visit the doctor more than anyone else in the world. On average, each German visited the doctor 16.3 times during 2004. The cost of office-based outpatient care was e34.6 billion in 2004. Another statistic reports that the number of sick days in the German economy has reached its lowest figure in more than 10 years. In 2005, an average of 4.4% of employees took sick leave; in 2004, the figure was 4.5%. www.bvmed.de
Why the radiation standards were changed
Personal insights into the reasons behind the new content of the two radiation standards are now available. (EN) ISO 11137-1, Requirements For Development, Validation and Routine Control of a Sterilisation Process for Medical Devices, and (EN) ISO 11137-2, Establishing the Sterilisation Dose, were published in 2006 to replace the original standards, EN 552:1994 and ISO 11137:1995. The preparation of the new standards was the responsibility of a working group of ISO TC 198, which met on approximately 10 occasions over a period of five years. No official record was made of the discussions that occurred at these meetings and, as a result, the background to the changes and additions to the old standard is not documented. Two UK delegates to the working group, Dr Eamonn Hoxey and Professor Alan Tallentire, have written their personal record of the reasons for the changes. The article is designed to give users of the standards, and those who may be faced with revising them in the future, an understanding of why changes were made. Their article, Rationale Behind the Principal Changes To and Inclusions of New Elements in the Requirements of EN ISO 11137, can be downloaded from the Panel on Gamma and Electron Irradiation’s website: www.irradiationpanel.org
