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Related Manuals for CMA Dishmachines BLOOD PRESSURE SENSOR BT17i
Summary of Contents for CMA Dishmachines BLOOD PRESSURE SENSOR BT17i
- Page 1 BT17i LOOD RESSURE ENSOR ’ UIDE CENTRE FOR MICROCOMPUTER APPLICATIONS http://www.cma-science.nl...
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Page 2: Short Description
Short description The Blood Pressure sensor BT17i allows measuring arterial blood pressure. The sensor measures the pressure in the connected cuff caused by the interaction between the cuff and the blood flow through the brachial artery. The systolic and diastolic blood pressure can be calculated using the oscillometric method (non-invasive method). The Blood Pressure sensor consists of: • a pressure sensor with measurement range between 0 .. 375 mmHg, • a standard adjustable blood pressure cuff (size: 24 cm to 35 cm), • a bulb pump with a control valve. The blood pressure cuff consists of an inflatable bladder connected by one hose to a hand pump bulb and by a second hose to the pressure sensor box. The user can set the rate of cuff deflation manually with the control valve. The sensor produces an output voltage, which varies linear with the measured pressure. The special circuitry in the sensor minimizes errors due to temperature changes. The Blood Pressure sensor can be directly connected to the analog BT inputs of the CMA interfaces. The sensor cable BT - IEEE1394 needed to connect the sensor to an interface is not supplied with the sensor and has to be purchased separately (CMA Article BTsc_1). - Page 3 How the Blood Pressure Sensor works 1. About blood pressure During each heart beat the arterial blood pressure varies between two utmost values: the systolic and the diastolic pressure. The peak pressure in the arteries is the systolic pressure and the lowest pressure is the diastolic pressure. In between these is the Figure 1. Pressure course of the heart beat in Mean Arterial Pressure (MAP), which is the brachial artery.
- Page 4 The Accoson ambidex one-piece cuff has been developed to provide a blood pressure cuff which is easy to use, clean, multi-purpose and cost-effective. cuff is inflated around the upper arm for more than 5 minutes. The cuff has a unique soft edge which replaces the weld found on other cuffs, allowing the ambidex cuff to be applied to either the left or right arm with equal comfort for the patient.
- Page 5 6. Lay down the arm of the test person on the table with an open hand. Important: The test person must remain still during data collection—no movement of the arm or hand during measurements. 7. Start your measurement. 8. Quickly and repeatedly squeeze the bulb to inflate the cuff on the test person’s arm. Continue inflating the cuff to a pressure between 150 and 170 mm Hg. When this pressure is reached, set the bulb pump down onto the table. The built-in pressure release valve will slowly deflate the cuff. 9. After the measurement is finished, release the remaining air in the cuff by turning the valve. You should be able to hear air coming out of the cuff.
- Page 6 point below the mean pressure where the differences start to get small corresponds to the diastolic pressure. Systolic pressure around 115 mmHg Diastolic pressure around 65 mmHg Figure 2. A typical measurement with the Blood Pressure sensor. 1. Identify the largest pressure “pulse”. This is an estimation of the MAP. 2. Identify when the data begins forming rapid “pulses”. This is an estimation of the systolic pressure. 3. Identify when the data stops forming smaller “pulses”. This is an estimation of the diastolic pressure. 2. Determining the blood pressure using oscillometric method A more precise but laborious method to determine the blood pressure is the oscillometric method. The pressure pulses, when extracted from the cuff pressure, form an oscillating waveform. The peak-to-peak amplitudes of this waveform vs. pressure create a bell shaped “envelope curve” (see figure 5). Within the envelope, the pressure...
- Page 7 I. Determining the cuff (trend) pressure 1. From the data table determine the number of the measured points. In this description we assume that the measured data are stored in Run 1. 2. Right-click the graph and select Analyze/Process > Select/Remove Data. 3. Select under Run the option Run 1 and select under Selection method Point-by-point. 4. Mark the very first point, very last point and points where the pressure values are locally minimal. These points indicate the deflating pressure trend of the cuff (i.e. without the pulses).
- Page 8 more points. These are the pulse pressure data, you can rename this run into p_pulse. III. Determining the envelope curve 10. To be able to calculate the pressure difference first copy the pressure data from Run 3 p_trend into Run 5 p_pulse. • Select a data series (at the right side of the table) or select a cell in a column of the data series of Run 3. • When you start to drag a variable heading p the cursor changes into a graph icon. Continue dragging until you place the cursor over run number 5, at the left side of the table (to this run you are copying the data). • When the run number is selected (a blue frame appears) release the icon. A new variable column with the heading Copied of p(mmHg) will be added to Run 5. • The data points from the column p (mmHg) of Run 3 are now copied into a new column Copy of p (mmHg) of Run 5. You can see it by opening Run 5. You can rename the variables to reflect the above: p to p_pulse and Copy of p into p_trend.
- Page 9 Figure 5: A bell shaped “envelope curve” vs. the trend pressure. As blood pressure values are usually rounded to 5 mmHg we find a blood pressure of 120/80. A best-fit bell-shape envelope is drawn in the graph to find the maximum (MAP). Method 2 – via derivative graph 14. Right-click the p-difference vs. p-trend graph and select Analyze/Process > Derivative. 15. Select under Run the option Run 5. 16. Select under Variable the variable Fit of p_difference5 Select under Order First derivative and under Method Differences. 18. Click Plot. 19. Accept with OK. 20. Click a pane to place the Derivative graph. 21. Use the Scan function to read out the blood pressure values. - The pressure value of the intersection of the derivative with the horizontal axis corresponds to the MAP value. - The pressure value of the minimum of the derivative graph corresponds to the systolic pressure.
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Page 10: Reference Values
Reference values The table below indicates normal heart frequency and blood pressure values for boys and girls for ages between 10-19 years old. Heart frequency per Systolic pressure average ± Diastolic pressure average ± minute boys girls boys girls boys girls 10 jr 108±12 109±13 67± 9 64±11 11 jr 109±11 110±12... -
Page 11: Technical Specifications
Technical Specifications Sensor kind Analog, generates an output voltage between 0 and 5 V Measurement range 0 .. 375 mmHg Resolution 0.1 mmHg Calibration function p (mm Hg) = 83.34 * V (V) – 16.67 Max. pressure 1500 mm Hg Temperature compensated -0°C to 85°C Response time 1 ms Warming time 20 ms IEEE1394 connector for BT-IEEE1394 sensor cable. Connection Sensor cable not delivered with the sensor. Warranty: The Blood Pressure sensor BT17i is warranted to be free from defects in materials and workmanship for a period of 12 months from the date of purchase provided that it has been used under normal laboratory conditions. This warranty does not apply if the sensor has been damaged by accident or misuse. Note: This product is to be used for educational purposes only. It is not appropriate for industrial, medical, research, or commercial applications.
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