Medical Robot

A slot machine for blood pressure

Jeanette Williams, 73, a San Francisco housewife, used to see her doctor every week to make sure she was winning her battle against hypertension, or high blood pressure. Now she merely stops by a shopping center near her home, where she consults a curious-looking machine that resembles an armrest-equipped chair in a college lecture hall. Taking a seat, Mrs. Williams rolls up her sleeve, puts her arm into a vinyl cuff, deposits 50-c- in the slot and pushes a button. On the console in front of her, the words light up, TESTING--REMAIN STILL. The vinyl cuff tightens noticeably around her arm. Moments later her blood pressure flashes on the screen.

The robot blood-pressure machine --or sphygmomanometer--that has sharply reduced Mrs. Williams' dependence on her physician is one of the latest marvels of medical technology. Introduced in 1976 by Vita-Stat Inc. of Tierra Verde, Fla., and now produced by other firms as well, the coin-operated gadgets have appeared in some 1,300 shopping malls, drug and department stores, factories and hospital lobbies across the country. They are not only cheap and fast --a reading takes a little more than a minute--but impressively accurate. Comparing their results with those obtained by conventional means, Dr. Joseph Chadwick, director of the health-systems program at SRI International (formerly the Stanford Research Institute) in Menlo Park, Calif, concluded that the machines are "more consistent than a well-trained blood-pressure technician."

Like ordinary sphygmomanometers, they work by measuring the surge of arterial blood that occurs immediately after the tightened cuff is slightly released. The major difference is that the precise moment of maximum flow, when the heart is pumping hardest--represented by the upper, or systolic, blood pressure--and that of minimum flow, or diastolic reading, are not determined by a doctor or technician listening for the coursing blood with a stethoscope pressed against the forearm. Instead, that job is done by a tiny microphone in the cuff, which sends its signals to the machine's miniature "brain"--tiny silicon chips or microprocessors. Programmed to recognize the noises, the microprocessors not only instruct the machine when to pump up and deflate the cuff, but also determine the exact time for taking the two readings. If there are any disturbing outside sounds or arm movements, Vita-Stat's machine flashes three zeros on the screen and refunds the customer's money.

By referring to a chart fixed to the machine, users can tell whether their blood pressure is outside the normal range for their age. If so, that should be prodding enough for them to seek medical counsel. Hypertension is probably the leading cause of death in the U.S., yet can be easily treated, even in its most severe forms (TIME cover, Jan. 13, 1975).

For those who are already under treatment, like Jeanette Williams, the machine is an enormous convenience. Says her husband Eric, 74: "It's easy to use, easy to read, and we have confidence in it." -

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