Innovations in medical instrumentation

A new and elegant technique has been adopted in the design and fabrication of a digital blood pressure measuring instrument which inhibits the drawbacks of the conventional sphygmomanometer. In this instrument a pressure transducer, a Korotkoff sensor, an instrumentation amplifier, an analog to digital converter and display units have been used as building blocks. The circuit employs two separate seven-segmental, three-digit display units to indicate systolic and diastolic pressures respectively. A provision is also made to read the applied pressure to the artery at the time of inflation in the diastolic display unit. The circuitry offers a high degree of accuracy and resolution up to 1 mmHg at low cost and overcomes the possibility of parallax error where unskilled personnel are required to make measurements. The output of the Korotkoff sensor when processed in a signal analyzer corresponds to the heart-beat rate