SwRI IRD 2004--Development of a Networked Blood Pressure Monitoring System, 10-9369

Background - Healthcare costs are expected to increase at double-digit rates in the coming years. Cardiovascular disease is the primary cause of death of males in the United States and consumes a large share of these healthcare dollars. Hypertension, also called high blood pressure, most commonly is the result of a narrowing or stiffening of the arteries. If untreated, hypertension can lead to heart attack or even death. If detected early, hypertension can often be reversed through a combination of diet, exercise, and pharmaceuticals, thus reducing the likelihood of catastrophic disease, hospitalization, and death.

Approach - The objective of this project was to develop and implement a simulated home-network environment at SwRI to monitor the arterial health of SwRI employees. The goal of this implementation was to establish an Institute capability for networking medical devices using the Internet and to investigate improving employee health through use of the developed network. The general approach was to network-enable an existing automated commercially available blood pressure measurement device to save blood pressure measurements automatically in an online database.

Accomplishments - A blood pressure measurement station was designed that consisted of a blood pressure measurement device and a control computer. A parallel port-controlled switch circuit was added to the blood pressure measurement device to prevent unauthorized use of the system. When a user logged into the web interface on the control computer, a custom written program running on the control computer identified the successful login and activated the switch, thus enabling the blood pressure device. Blood pressure measurements were sent from the blood pressure measurement device to the control computer via a serial port wired connection. The custom program automatically stored the blood pressure measurements on the project database server via the network. The project server was developed using open source operating system, web server, and database server packages.

A web-based portal interface to the database and other blood pressure reference material was developed using an open-source content management system. The portal allowed subjects to review their history of blood pressure measurements in tabular and graphical format. In addition, the portal allowed subjects to manually keep a history of their weight that was viewable in tabular format.

A total of eight blood pressure measurement stations were installed on the SwRI campus. A total of 109 SwRI employees were enrolled in the program, and a total of 1,705 blood pressure measurements were obtained during the 7.5-month period during which blood pressure stations were installed. The average blood pressure measurement was 124/74, which is slightly prehypertensive. The maximum systolic blood pressure recorded was 170 mm Hg, while the maximum diastolic blood pressure recorded was 101 mm Hg.

Example of the web portal interface displaying blood pressure measurements as time-based graphs with trend lines. The boxes are the individual blood pressure measurements. The total number of data points is displayed in the lower left corner of each plot. The upper right corner region labeled "BP System Statistics" displays a statistical snapshot of system usage.

Plot of all blood pressure data points obtained on the project. The colored lines indicate the boundaries of the JNC-7 blood pressure classifications. The normal range is located below and to the left of the green line. The Prehypertension range is located between the green line and the yellow line. The Stage 1 Hypertension range is located between the yellow line and the orange line. The Stage 2 Hypertension range is located above and to the right of the orange line.