System Helps Keep an Eye on Health

You can use your personal computer to keep track of just about everything else, why not use it to keep track of your health?

The Dynapulse from Pulse Metric Inc. in San Diego, at (800) 835-7815, is a professional-quality system to measure, graphically display and record blood pressure and pulse.

Two models are available, a home model priced at $180 and a professional model at $250. Each runs on any IBM or compatible computer with any graphics display monitor. It can be run either from a hard disk or floppy disk. A Macintosh-compatible model is expected to be ready early next year.

Both units can keep track of blood pressure and pulse records for 25 people. In addition, the professional model also provides a form to record a complete medical history of each person.

The Dynapulse system consists of software, a small plastic case housing the electronics, and a 5.5-inch-wide pressure cuff with attached hose, pump bulb and pressure release valve. It connects to the computer through a serial port, and adapters are provided for both nine-pin and 25-pin connectors.

It is considerably more sophisticated than the typical $50 home blood pressure testing device.

The software displays two graphs on the screen to depict each blood pressure measurement.

One graph, the “pulsation stream,” which looks something like an electrocardiogram, records the strength of your heartbeat measurement over a 30- to 40-second time span. The horizontal axis along the bottom of the graph depicts pressure, and arrows point out the locations of the systolic (high pressure), diastolic (low pressure) and the mean.

Irregularities in the pulsation graph may indicate merely that you moved while the measurement was being recorded, or it could signify an irregular heartbeat. The manual cautions that only your doctor is qualified to interpret the meaning of the pulse shapes. It also cautions that different people have different-shaped heartbeats, so you shouldn’t draw any conclusions from comparing your graph to someone else’s.

The graphs can be printed so that they can be shown to a physician.

A smaller graph profiles a single heartbeat over a time scale measured in hundredths of a second.

Yet another portion of the display summarizes the numbers for systolic, diastolic and mean blood pressures and pulse rate.

Each measurement can be saved, and a graph can also be displayed, and printed, that shows blood pressure and pulse trends over a series of measurements.

If, like me, you don’t know much about blood pressure and its measurement, you’ll probably find the introduction to the user manual quite informative. Written by Dr. J. Howard Wyatt of the Hypertension Research Center at Indiana University, it is a clear explanation of what is being measured and how.

When doctors and nurses take your blood pressure, they use a stethoscope to hear the blood flow through an artery. Dynapulse has no stethoscope, nor does it listen for sounds.

Instead, a sensor built into the arm cuff measures pressure differences directly.

Before you can be measured the first time, you must be identified as a user in the Dynapulse software. Confidentiality is maintained even when many people are using the same system through the use of identification numbers and passwords that must be entered before gaining access to the measurement procedure.

For home use, you can simplify the process by just giving each family member a single-digit identification number instead of the Social Security number suggested in the manual and use the same number as the password.

As soon as you have told the software who is being measured, you can jump to the measurement screen on the computer, where a graphic depiction instructs you to put on the arm cuff, close the air release valve and pump the bulb until a message tells you to stop pumping.

Then you just sit still for about 30 or 40 seconds while pressure is automatically and gradually released from the cuff by a mechanism in the control box. When the system has completed the measurements, the program beeps and tells you to release the rest of the pressure by opening the valve next to the pump bulb.

An instant later, the measurements and the graphs fill the screen. If you want to track your blood pressure trend, you must save the measurement by invoking a menu choice on the screen.

There also is a form built into the software where you can record the medical history of each user, a feature that reflects the Dynapulse’s heritage as a system originally designed for professional use.

Of course, a blood pressure measuring system is no better than its accuracy, which is advertised as within plus or minus 2%, so I took the Dynapulse to the company’s medical department for an evaluation.

The medical director found it to be accurate within the normally expected range of error and commented that its graphs could be valuable in helping a physician see the trends in a patient’s blood pressure.

The obvious customer for Dynapulse would be anyone with hypertension and a PC. But healthy people might also find it valuable in tracking heart function before and after exercise or over the course of dieting.

Computer File welcomes comments but regrets that the author cannot respond individually to letters. Write to Richard O’Reilly, Computer File, Los Angeles Times, Times Mirror Square, Los Angeles, Calif. 90053.