Smiths Medical
Neonatal Respiration Monitors
MR10 S, MR10 and GM 109 Sensitivity Test rig Instruction Leaflet Issue A
Instruction Leaflet
15 Pages
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Page 1
Smiths Medical Publications This publication has been compiled and approved by Smiths Medical for use with their respective products. It is supplied in this format to permit users to access the text and illustrations for their own use e.g. training and educational purposes. Users of the equipment must ensure that they have read and understood the contents of the complete manual including the warnings and cautions and have been trained in the correct use of the product. Smiths Medical cannot be held responsible for the accuracy and any resulting incident arising from information that has been extracted from this publication and compiled into the users documentation. This publication maybe subject to revision and it is the users responsibility to ensure that the correct version of manual/ text/illustration is used in conjunction with the equipment.
MR10 S, MR10 and GM 109 Sensitivity Test rig Instruction Leaflet
89/336/EEC Document Number 0512-0116
Issue A
Published by SIMS Graseby Limited. All possible care has been taken in the preparation of this publication, but SIMS Graseby Limited accepts no liability for any inaccuracies that may be found. SIMS Graseby reserves the right to make changes without notice both to this publication and to the product which it describes. ©
SIMS Graseby Limited 2000
No part of this publication may be reproduced, transmitted, transcribed, or stored in a retrieval system or translated into any human or computer language in any form by any means without the prior permission of SIMS Graseby Limited. SIMS GRASEBY LTD, Colonial Way, Watford, Hertfordshire, WD24 4LG TEL: (+44) (0)1923 246434 FAX: (+44) (0)1923 231595
www.graseby.co.uk REGISTERED IN ENGLAND COMPANY No. 995550
Graseby Medical Ltd.
Respiration Monitor Sensitivity
CONTENTS Page
Sensitivity Test Rig for MR20/30, MR10 S, MR10 and GM 109 Description... 1 Setting-up instructions ... 1 Stopcock settings ... 3 Sensitivity setting procedures ... 4 Introduction ... 4 MR10 S sensitivity setting ... 5 MR10 sensitivity setting... 6 Setting procedure ... 7 GM 109 sensitivity setting ... 8 Setting procedure ... 8 Test Rig Calibration... 9 Specification ... 9
Figures 1 2 3 4 5
Page
Part view of sensitivity Test Rig ... 2 Stopcock: vent open ... 3 Stopcock: vent closed ... 4 MR10 sensitivity setting link block ... 6 GM0 109 sensitivity setting link block ... 8
Instruction Leaflet
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Respiration Monitor Sensitivity
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Graseby Medical Ltd.
Instruction Leaflet
Graseby Medical Ltd.
Respiration Monitor Sensitivity
Sensitivity Test Rig for MR20/30, MR10 S, MR10 and GM 109 Description The Sensitivity Test Rig (0512-0114) displaces an accurate volume of air into the respiration monitor in order to test its sensitivity. A variable stroke, small diameter piston, sealed by a rubber ‘O’ ring is used to adjust the displaced volume from 0 to 1 microlitre. A given piston displacement results in an equal displacement of air into the respiration monitor. The volume of air in the piston chamber and connecting tube is critical, and the correct 1 meter of connecting tube (0.9 mm I.D.) must always be used, since a significantly larger diameter or length of tubing may affect the accuracy of the Test Rig. The piston displacement is achieved by the action of a cam, which is offset from the centre of rotation of a DC motor that is coupled to a reduction gearbox. Downward movement of the piston is restricted by a stop. Adjusting the stop downwards increases the displacement. Setting-up instructions A micrometer type scale fitted to the adjuster (see Figure 1) indicates the displaced volume of air. Each full turn of the adjuster adds 1.0 microlitre to the displacement. A reading is given by observing the position of the scale relative to the cursor. If desired the adjuster can be locked in any position by tightening the Allen screw in the side of the test unit. The cycle time can be adjusted by varying the input voltage to the motor from 0 to 3.5 volts DC. Attach two wires 0.5 metres long to the motor, observing the correct polarity, and fit the motor end cap with PVC tape (the cap side wall may need breaking out for large diameter wire) and cable tie to clamp the wires to protect the terminals. Connect to a variable regulated DC bench power supply capable of delivering 300 mA. Apply a voltage of between 1.9 and 3.5 volts and set the Test Rig adjuster to 0.25 µl.
Instruction Leaflet
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Respiration Monitor Sensitivity
Graseby Medical Ltd.
Figure 1 Part view of Sensitivity Test Rig
To determine the cycle frequency it will be necessary to count the number of complete motor revolutions over a one-minute period. Adjust the DC supply to achieve 60 revolutions in 60 seconds, i.e. 1 ±0.1 Hz. Once the correct cycle time has been established, by using either a stopwatch or an oscilloscope, the setting of the respiration monitor’s sensitivity can be carried out. For the MR10 S and the GM 109 the pulse rate reading can be used for setting the repetition rate. As the results of the sensitivity tests can be affected by vibrations of the Test Rig or, temperature variations during the tests, it is recommended that the following conditions are observed: 1. Prior to testing the respiration monitor it should be left to stabilise at a temperature of between 19 and 24° C for at least one hour. The Test Rig should also be run for at least one hour before use. Page 2 of 9
Instruction Leaflet
Graseby Medical Ltd.
Respiration Monitor Sensitivity
2. Avoid any drafts such as open windows, or doors being opened and closed, as this type of change in the environment could affect the results. 3. The Test Rig, capillary tube, or the respiration monitor must not be disturbed during the tests. It is recommended that the Test Rig and the capillary tube are firmly secured during the tests. 4. As the frequency setting is critical, regular monitoring by an oscilloscope or a stopwatch is required. Stopcock settings 1. Ensure that all connections are firmly fitted. 2. Fit the supplied stopcock between the free end of the capillary tube and the luer input of the respiration monitor. 3. Ensure that the Open vent on the stopcock (see Fig. 2) is not covered when it is inserted into the inlet of the respiration monitor. Monitor Slip luer ⇑ • ⇒ Vent open ⇓ Test Rig Figure 2 Stopcock: vent open
The vented stopcock is to prevent the transducer diaphragm being stressed, which would take the transducer several minutes to relax, and could cause the subsequent readings to be incorrect.
Instruction Leaflet
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Respiration Monitor Sensitivity
Graseby Medical Ltd.
Figure 3 shows the stopcock vent closed to outside air. Monitor ⇑ ⇐ • Vent closed ⇓ Test Rig Figure 3 Stopcock: vent closed
Sensitivity setting procedures Introduction Graseby Medical Ltd. recommend that only Technicians who have had the relevant technical training should carry out the sensitivity settings of the respiration monitors. The sensitivity of the respiration monitor is set by adjusting the wheel on the Test Rig until breath detection occurs, and the correct reading is obtained once reliable detection of pulses has been successfully monitored over a 1 minute period, without any pulses being missed. The Technical Service Manual for each respiration monitor describes the procedures for disassembling and assembling the case.
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Instruction Leaflet
Graseby Medical Ltd.
Respiration Monitor Sensitivity
MR10 S sensitivity setting The sensitivity setting for the MR10 S should be between 0.20 µl and 0.28 µl, and is set during the procedures given below to 0.25 µl. 1. Enter the Technician Mode of the respiration monitor as detailed in Chapter 2 of the Technical Service Manual (part number 00SM-0512). Press the button on the respiration monitor (as many times as required) until the following display appears: SET RESP
2. Press the button and the following display will appear: OK ?
3. Turn the graduated dial at the top of the Test Rig and set the output of the Test Rig to 0.25 µl. 4. Insert the output connector of the Test Rig into the respiration monitor’s input ( ) using a slight twisting action and observing the stopcock instructions. 5. When the button on the respiration monitor is pressed the abbreviated please wait display will briefly appear: PLS WAIT
While the calibration is taking place the display will show PASS followed by an incrementing number. When ‘breaths’ are detected the LED flashes and the calibration proceeds until 60 consecutive ‘breaths’ have been successfully detected. At completion of the calibration a display similar to the one shown below will appear: SET @ XX
where XX is a number between 1 and 64. Instruction Leaflet
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Respiration Monitor Sensitivity
Graseby Medical Ltd.
If the display LOW SIGNAL appears then the monitor is indicating that it is unable to detect the signal from the Test Rig. The cause could be one of the following: • the output from the Test Rig is not inserted correctly into the respiration monitor, • the stopcock is vented, • the respiration monitor is faulty, • the Test Rig is faulty. When the respiration monitor has been successfully calibrated, disconnect the Test Rig and switch all the relevant units off. MR10 sensitivity setting
The sensitivity setting for the MR10 should be between 0.23 µl and 0.37 µl. The printed circuit board situated inside the MR10 contains four links, each with two positions (see Figure 4). This gives 16 possible sensitivity settings, that are arranged in a binary sequence, and each setting alters the sensitivity by about 20%.
Figure 4 MR10 sensitivity setting link block Page 6 of 9
Instruction Leaflet
Graseby Medical Ltd.
Respiration Monitor Sensitivity
The four links, marked 8, 4, 2 and 1 can be set to 1 (ON) or 0 (OFF). To increase the sensitivity by a step, the links must be set to the next binary sequence. For example, the value shown in Fig. 4 is 1000 binary or 8 decimal. To increase the sensitivity by a step, the link on the right must be moved to its 1 position. To reduce the sensitivity by a step, i.e. to 7 decimal, the link on the left must be moved to the its 0 position, and the other three links must be moved to their 1 position. The decimal value of the settings can be established by adding the numbers associated with the ON links, i.e. 4 + 2 + 1 = 7 for the previous example.
Setting procedure Starting with the Test Rig giving a 0.6 µl pneumatic signal, find the minimum level for breath detection by slowly reducing the input amplitude until detection ceases, then slowly increasing the level until reliable detection occurs. The minimum level must be between 0.23 µl and 0.37 µl. Due to a time lag in the pneumatic response and the action of the filter housed in the MR10, the respiration monitor must be allowed to stabilise after an alteration to the amplitude of the input signal. Allow at least 60 consecutive ‘breaths’ after an adjustment before confirming the sensitivity at the new amplitude.
Instruction Leaflet
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Respiration Monitor Sensitivity
Graseby Medical Ltd.
GM 109 sensitivity setting
The sensitivity setting for the GM 109 should be between 0.2 µl and 0.28 µl. Set the Test Rig to 0.25 µl. The four links situated on the circuit board within the GM 109 (see Fig. 5) are very similar to the four links of the MR10 shown on page 6. Both sets of links alter the sensitivity of their respective respiration monitors. Link 6 is the Most Significant Bit (MSB) on the link board of the G109.
Figure 5 G 109 sensitivity setting link block Setting procedure
Starting with the Test Rig giving a 0.6 µl pneumatic signal, find the minimum level for breath detection by slowly reducing the input amplitude until detection ceases, then slowly increasing the level until reliable detection occurs. The minimum level must be between 0.20 µl and 0.28 µl. With the display on the respiration monitor facing the front, set the switch pattern as shown in Fig. 5. This is 0001, and gives a decimal 8 (not 1).
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Instruction Leaflet
Graseby Medical Ltd.
Respiration Monitor Sensitivity
If the monitor triggers move the links down in binary sequence, i.e. 1110, decimal 7, until the monitor is just on the threshold of triggering. If the monitor does not trigger move the links up in binary sequence, i.e. 1001, decimal 9, until the monitor is just on the threshold of triggering. Test Rig Calibration Graseby recommend that the Test Rig (0512-0114) is returned to their premises for frequent calibration. The frequency of calibration will depend upon the usage that the Test Rig has been put to. The recommendations are as follows: infrequent use ... at least annually, • frequent use ... at least every 3 months.
•
Specification Storage temperature:
-20 to +50° C.
Operating temperature:
+19 to 24° C.
Input:
1 to 3.5 V DC.
Approvals:
EMC: EN55022: 1994 class B Radiated Emmisons. Complies with EMC Directive 89/336/EEC.
Output level:
Microlitres air volume change, as defined by Graseby Medical calibration standards. 0.00 µl 0.20 µl 0.25 µl
±0.05 µl. ±0.03 µl. ±0.01 µl.
0.30 µl 0.40 µl
±0.03 µl. ±0.04 µl.
EC Declaration of Conformation Graseby Medical Ltd. of Watford, Herts, UK, WD2 4LG, declare under our sole responsibility that the Graseby Neonatal Sensitivity Test Rig Type 0512-0114 is in conformity with the EMC standard EN55022 (08/94) Class B following the provisions of the EMC Directive 89/336/EEC.
Instruction Leaflet
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IN AN EMERGENCY CONTACT:
SIMS Graseby Limited Colonial Way, Watford, Herts , UK, WD24 4LG Tel: (+44) (0)1923 246434 Fax: (+44) (0)1923 231595 Web: www.graseby.co.uk
Part No. 0512-0116 Issue A March 2000 © SIMS Graseby Ltd. 2000 PRINTED ON RECYCLED PAPER