Solar powered blood pressure device is reliable tool for developing
23 Nov 2010
A new solar-powered device to measure blood pressure can
provide affordable and reliable blood pressure testing in low income
countries, according to research published in Hypertension: Journal
of the American Heart Association.
The solar powered device, which has 94% agreement with the
standard blood pressure testing method for systolic blood pressure,
is currently in field testing in Uganda
"The incidence of hypertension is rising dramatically in these
countries," said Eoin O'Brien, M.D., lead author of the study and
professor in Conway Institute of Biomolecular and Biomedical
Research at the University College Dublin in Belfield,
Dublin, Ireland. "Hypertension
leads to stroke and heart attack as the major cause of death around
the world. It is greater than malnutrition, cancer and AIDS."
Many low-income countries have a short supply of trained
medical personnel, he said. "We have been able to provide an
accurate, robust and inexpensive device to diagnose high blood
pressure. It's a start. If we can't measure blood pressure, we
certainly can't begin to treat hypertension."
The World Health Organization asked multiple companies to devise
a blood pressure measuring device that was accurate, easy to use and
solar powered. One device met their criteria. WHO then funded the
study to test the device in the field.
After initial testing showed the accuracy of the selected device,
it was used in two centres in Uganda
and one centre in Zambia. Staff,
trained on the fully automated device in about 15 minutes, took
blood pressure readings on about 716 participants, using the new
device and a standard one. They repeated the effort one month later.
Both patients and healthcare professionals preferred the new device:
- 85% of healthcare professionals rated the solar device as
good or very good primarily because of ease of use (88%) and the
automated features (85%);
- 79% considered the solar device an advantage over the
- the majority of healthcare providers rated it best for its
comfort, clearly legible readings, the cuff and the on/off
- after the first and final visit a month later for patient
blood pressure readings, 97% of healthcare professionals
favoured the new device and would recommend its use.
"Solar energy eliminates the need for expensive rechargeable
batteries in remote areas where electricity and the availability of
batteries might be scarce, but sunlight is plentiful," O'Brien said.
"It can be run on batteries, but it can also be left in the sunlight
to charge, making it ideal for rural areas and use out in the bush."
The device costs about US$32 (€25),
with significant savings from not having to provide and use
batteries regularly, he said.
While the device initially fulfilled accuracy criteria for the
European Society of Hypertension, it had less accuracy for diastolic
blood pressure (the pressure when the heart relaxes) on a second
testing and in the study. But it wouldn't be difficult for
manufacturers to correct the device, O'Brien said. Moreover,
systolic blood pressure (the pressure when the heart contracts) is
the major contributor to cardiovascular events. "Systolic blood
pressure is the blood pressure reading on which most decisions are
made," O'Brien said.
Manufacturers of other devices, such as those used to record or
measure blood sugar, cholesterol and electrocardiograms (ECG), might
also be encouraged to fulfill the requirements of low income
countries, he said. "We now hope to use the solar device to diagnose
hypertension in pregnancy as a step towards reducing the very high
maternal death rates from this illness in low income countries."