Medical

NON INVASIVE BLOOD PRESSURE MONITOR

ELECTRONICS IN THERAPEUTIC AND DIAGNOSTIC DEVICES (BMD 32203)

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Blood Pressure Monitor Principle - Is a measurement of the force applied to the walls of the arteries as the heart pumps blood through the body. - The pressure is determined by the force and amount of the blood pumped and the size and flexibility of the arteries. - Example for normal measured values for resting:

115/75 mmHg

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Systolic pressure is peak pressure in the arteries, which occurs near the end of the cardiac cycle when the ventricles are contracting. Diastolic pressure is minimum pressure in the arteries, which occurs near the beginning of the cardiac cycle when the ventricles are filled with blood.

1. 2. There are two basic methods: Indirect (non-invasive), manual and automatic, and Direct (invasive) method to measure blood pressure.

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Indirect methods are used to take instantaneous pressure values (usually systolic and diastolic) and they don't give information about the continuous pressure pulse, unlike the direct methods. bp basic.flv

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1. Non-invasive measurement Auscultatory and oscillometric measurements - Simpler and quicker - Require less expertise in fitting - Virtually no complications - Less unpleasant and painful a. Palpation method - minimum systolic value can be roughly estimated without any equipment. Example: Palpation of radial pulse = 80bpm

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b. Auscultatory method - Uses a stethoscope and sphygmomanometer. - Comprises an inflated cuff placed around the upper arm at roughly the same vertical height as the heart, attached to a mercury or aneroid manometer. - A cuff of appropriate size is fitted smoothly and snugly, then inflated manually by repeatedly squeezing a rubber bulb until the artery is completely occluded. - Listening with the stethoscope to the brachial artery at the elbow, slowly releases the pressure in the cuff. When blood just starts to flow in the artery, the turbulent flow...