New Low-Cost, Solar-Powered BP Device for Developing Countries

Lisa Nainggolan

June 18, 2009

June 18, 2009 (Milan, Italy) — A new, low-cost, solar-powered blood-pressure-monitoring device (Omron M1 Plus) has been shown to be accurate and easy to use and was well accepted by healthcare professionals and patients in Africa [1]. Dr Gianfranco Parati (University of Milano-Bicocca, Monza, Italy) presented the results of a field trial of the new device during a late-breaking trials session at the European Meeting on Hypertension 2009.

"These results in the field confirm the accuracy of this device in a low-resource setting. If you consider the low cost, this new device might prove to be suitable and reliable to improve the diagnosis of hypertension in men and women in low-resource settings," Parati said.

Chair of the late-breaking session, Dr Michael Alderman (Albert Einstein College of Medicine, Bronx, NY), told heartwire : "This is very exciting. There are a billion people with hypertension--soon to be a billion and a half. Most of those people are living in low-resource countries, where the ability to intervene is going to be dependent upon identifying patients, so this is a critical tool."

Device Tested in Urban and Rural Centers in Two Countries

Parati explained that high blood pressure is increasing in low-resource settings such as Africa, while BP monitoring and treatment remain poor. At the same time, mercury sphygmomanometers are gradually being withdrawn because of the toxicity of mercury, which is a nondegradable pollutant. So newer, automated, and affordable devices are needed for lower-income nations.

His study tested the Omron M1 Plus device in more than 700 patients attending three centers in southern Africa for various health problems: two were in Uganda--the Lacor Hospital, in Gulu, in the north of the country, and the Benedict Medical Center, on the outskirts of the capital, Kampala--and one was in a more rural area, the Mtendere Hospital, in Chirundu, Zambia.

Healthcare providers were trained in the use of the new device. In each subject, BP measurements were performed four times within eight minutes, twice with the new device and twice with a conventional mercury sphygmomanometer.

"The aim of the study was to assess the usability and robustness of the device, and its acceptability by healthcare personnel and also by patients in the settings where it's supposed to be used," Parati explained.

There was no significant difference between the average systolic and diastolic BP as measured by both means: 120.5/74.6 mm Hg with the mercury sphygmomanometer compared with 122.3/71.2 mm Hg with the OM1 device. There were 20% of subjects classified as hypertensive with the mercury sphygmomanometer compared with 19.9% with the new device.

There was, if anything, a slight overestimation of SBP and slight underestimation of DBP by the device compared with the mercury sphygmomanometer, Parati said.

You've Got to Find the People First

A questionnaire was used to evaluate the experience with the device. It was found to be clearly legible in 98% of cases, the cuff inflated and deflated appropriately in 96.7% of cases, and the on/off switch performed correctly 98.3% of the time. The solar-powered batteries performed well, and Parati noted that conventional batteries could be employed in the device as a backup, but this occurred only in a few cases.

As compared with the mercury sphygmomanometer, the OM1 device was rated as "good" in 82% and "preferred" in 95.1% of cases, mainly because of its ease of use and the availability of automated measures and solar power. The device was felt to be more comfortable to use and more reliable than the mercury sphygmomanometer, because there were lots of problems with Korotkoff sounds in these centers, said Parati. But the mercury sphygmomanometer was felt, in a subjective assessment, to be more durable, he noted.

Alderman concluded: "We've got cheap pills, and we've got ways to take care of people simply, and it has been shown that will make a big impact, but you've go to find the people who have it, and this might be that tool."