SOUE News Issue 10

Resource-Constrained Digital Health Care

A synopsis of a 2011 Open Day talk given by Dr Gari Clifford

Dr Clifford started his talk by observing that data analysis in health care has currently not moved far beyond simply digitising a paper process. Technology can sometimes interfere with the data recording, producing a system that is slower than the pen: meanwhile, time delays in analysis can lead to "clinically significant" errors. An example was given of nurses sampling blood pressure at regular times, with intervals that might be up to 120 minutes, tending to over-estimate the readings and sampling at a very low rate (below Nyquist), which can lead to hypotensive (low B.P.) episodes being missed altogether, with serious diagnostic consequences. It is impractical to sample more frequently, so irregular sampling is needed; additionally, using direct personal monitoring avoids human transcription errors.

World Health Organisation figures make it clear that quality of health care is not a function of per-capita spending: the USA comes 37th on the quality list, just below Costa Rica, despite spending more per capita on public health care than the UK. The UK is 18th on the list, which is topped by France.

But while money is not so important for quality as might be expected, lack of trained health care workers in resource-poor regions means poor infrastructure: but Coca-Cola still gets there - as do mobile phones. The Chinese access the Internet largely through mobile phones: it is estimated that 950 million people will be using mobile phones for Internet access by 2020. (The figure rose by 18% in six months recently.)

The mobile phone infrastructure can be used to capture and transmit medical notes, images, videos etc. The phone itself is a physical object with a password, giving automatic security; and modern phones are also often equipped with accelerometers, cameras etc. that can provide rich diagnostic capture, and can automatically monitor patient activity; they can also play a vital role in prompting patients to carry out necessary tasks, e.g. checking blood sugar levels.

Using mobile phones in this way is known as "mHealth". Dr Clifford gave an example of an Oxford trial monitoring COPD (chronic obstructive pulmonary disease), which combines monitoring of sleep, ECG, heart sounds, pulse oximetry, respiration and blood pressure. Heart monitoring can be performed using a hands-free kit mounted in an egg cup to provide a cheap mobile stethoscope; and a mobile phone blood pressure monitor can be produced for just £5, using a cheap cuff with a manual inflation ball, a £3 silicon chip to measure pressure, and a USB connection to the phone - an app running on an Android phone gives exact instructions to the patient on what to do, and measures the pressure fluctuations directly. Heart rate can be determined by Fourier analysis of the pressure variations during the measurement.

Dr Clifford made a convincing case for the ability of the mobile phone to transform health care, particularly in resource-poor regions.

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