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Colloid Osmometer Model 4420 Operator & Service Manual

1. 6 OUTSIDE RNA PEO D IAS PONO Gu PENA du GEN QV PON du PNE 7 1 4 Controls and Connections 0 000 cece ees 8 159 S5 AAA 13 SECTION 2 G tting SII ed erica 15 2 T sdnstallnguied2 s es cemeterio ine 15 2 2 The Pressure Transducer sicie ceste A A ws dati te al dae a 17 2 3 5 MEDIIS 15r vu xs oo ns depu p rep acc eee es Seat pe red bd 19 2 4 Filling the Reference Chamber 0000 cece eee eee SIR 23 2 5 Membrane Performance 25 2 6 Preventive Maintenance 27 SECTION 3 Setup amp Calibration _ 29 3 1 Filling the Sample Chamber DR ECRIRE ee EES 29 3 2 Setting the Display ZERO de A ea al Sa os 30 3 3 Changing Displayed Units ata et est 30 3 4 Colloid Osmotic Pressure Calibration Control Solutions 31 3 5 Calibration Procedure Using the COP Calibration Solution 32 SECTION 4 Operating the Osmometer lee nnne 33 4 1 Injecting Samples daa AA 33 427 The Mandal MDGB 2 2e ote A Rhet ee Rt Rn RD Rn e 36 4 3 The Prompted Mode Lee dE E RR LACER RUE MOLAR AS EU tatas A UR 38 4 4 Storage Procedures 5 4 s nado d e abu E abu da ode uat 40 4 5 Disinfection Procedures 42
2. AWIASIO Alddns JIMOd JONVSO 3LIHM 039 3L1HM 34IM 34v8 YIONASNVAL JYNSSAYd S30Wld Z Id OOLy 7 O OQv 4e 603071 92026 SAYJOML3N 2 H ONIY NOS O 69 ELECTRONICS 500 N3NIA 93d 32v7d E Ole T N3HIA 93d 30d 2 SIO T WIT vui 31413345 ASIAN SINN H SOWEVIOBOIN Ni aav SSOLIOVAYO IE z SONvM31Ol Mi suOlsiS3H lv SWHO Ni 3uw sHOlsIS3H TYG qavogd NIVMW suy l essc SESS ISAS SSESINFESSISK L TWINAIVW 40 LSI SNOILYII319adS N lldIS2830 ON Lavd pus ALO 1 LOHPL ELSOHvE de Age v ioHgZ otn LA i 13 PLOHtL arin een ZHW rv ZA x 309 T dsqdd 7TTTTTT d S APPOEEOW an ALNAN HAONOSNYYL er ag ag anor 1 ASE ano Y WHOLNA hd Lo Lo eroon xe oz sy 2 ASE dno eLo ne to q w Be sa n UA o s ozewn zn u zu voouLa i ON lA E N xc ioHEL iOHvZ MOOL Zu aen NOLL IAOS 30 SNUISIA 39
3. However since the pressure transducer is highly sensitive and delicate it is susceptible to damage if you do not observe the following cautions 18 OPERATOR S MANUAL CAUTION 1 Do Not install membrane inject any sample standard or control solution into the instrument or attempt any operator functions unless instrument power is ON Do Not Apply Excessive Injection Pressure The most common cause of transducer damage is excessive injection pressure To help prevent this the instrument has an automatic alarm which sounds when the instrument senses excessive injection pressure Always use a 10 or 12 mL syringe for injecting saline and a 1 mL syringe for samples When injecting sample fluid into the sample chamber with a small lt 10 mL syringe you can generate sufficient fluid pressure to damage or destroy the pressure transducer This can occur even if you feel no resistance Under certain conditions such as injecting a sample very rapidly with a 1 mL syringe you can damage the transducer before the built in alarm can respond and sound the over pressure warning tone If the drain tube from either the reference chamber or the sample chamber becomes obstructed the osmometer cell will become a closed system Under such circumstances damage to the pressure transducer can occur if you attempt to clear the blockage in the drain tube by applying pressure with a syringe at the sample injection port or at the reference chamber
4. 1 Whenever you empty the waste container you may add 5 mL of undiluted bleach to the empty waste container to help inactivate contaminated fluids and prevent microbial growth 2 Asolution with a 50 50 mix of isopropyl alcohol distilled water and a contact time of 20 minutes will reduce contamination without causing significant damage to the materials used to manufacture the 4420 The solution can be wiped or lightly sprayed onto the affected surfaces for cleaning purposes Avoid getting liquid into the electronics of the instrument CAUTION Alcohol poses some fire hazard Use appropriate biohazard general health and fire hazard precautions 3 Other disinfectants may be used if you are certain that they will not damage materials used in the manufacture of the 4420 CAUTION Hydrogen peroxide can destroy aluminum Bleach can destroy acrylic plastic High concentrations of alcohol can destroy acrylic plastic 4 When higher level disinfection or preparation for shipment is required contact Wescor for current decontamination instructions and forms See Appendix C Customer Service for contact information THEORY OF OPERATION 43 SECTION 5 Theory of Operation This section describes the theory of measuring colloid osmotic pressure as applied in the Model 4420 Colloid Osmometer 5 1 Definition of Terms The science of osmometry as applied in clinical and research laboratories includes the measurement of osmol
5. 70 OPERATOR S MANUAL CUSTOMER SERVICE 71 APPENDIX C Customer Service Wescor is ready to help you resolve any difficulty with the operation or performance of your Colloid Osmometer If you cannot resolve a problem using the procedures in this manual please contact us Customers within the United States are encouraged to contact us by telephone Outside the U S many of our authorized dealers offer complete customer service and support If factory service is required instruments must be drained cleaned and decontaminated before being returned to Wescor You will receive complete instructions and forms for decontaminating and shipping your osmometer once return is authorized Phone 435 752 6011 Toll Free 800 453 2725 Fax 435 752 4127 E mail Wescor wescor wescor com E mail Wescor Service and Repair service wescor com Web www wescor com Mailing Address Wescor Inc 459 South Main Street Logan UT 84321 USA 72 OPERATOR S MANUAL BIBLIOGRAPHY 73 BIBLIOGRAPHY Carlson R W Schaeffer R C Michaels S G and Weil M H Pulmonary edema fluid Circulation 60 1161 1979 Cordasco E M Piedad O White R and Anderson C Noncardiac Pulmonary Edema New Aspects in Management J Inter Amer Med 2 2 1977 Kul F Editorial Review Mechanism of Osmosis Kidney Int 21 303 1982 Luz P L Shubin H Weil M H Jacobsen E and Stein L Pulmonary Edema Related to Changes i
6. beep tone The display will show a message similar to that 4420 COP in Figure 2 2 The default language for the display is English VERSION 2 3 Refer to Appendix B to change the language English If the POWER indicator does not light or you do not see this message recheck your power connections and the rear panel Figure niil noie as power switch po s switched o The display should remain for approximately two seconds and then you will see one of the following displays Figure 2 3 represents the normal display indicating the 4420 is now ready for preparation and that you can skip ahead to 0 0 mmHg Section 2 2 Figure 2 3 The normal display when the 4420 is in manual mode Units in mmHg kPa or cmH 0 according to your last selection 16 OPERATOR S MANUAL The message in Figure 2 4 appears when the batteries fail or when the osmometer has not been initialized after replacing batteries The batteries power the memory settings for units zero level and calibration data during power failure or disconnection BATTERY FAILURE Re calibration To clear the message and initialize the instrument press required ZERO as instructed The osmometer will then initialize itself Press ZERO and return to the normal display as shown in Figure 2 3 After initializing recalibrate before testing samples Fresh batteries Figure 2 4 Message that appears are installed at Wescor before shipment and should provide when batteries must be r
7. Section 4 2 lists the routine injection procedure as well Accurate measurements require complete displacement of any saline solution in the sample chamber by the injected sample It is essential to avoid dilution of the incoming specimen which would cause erroneously low COP indications In theory the advancing specimen fluid will displace saline from the sample chamber into the waste container but because of turbulence surface roughness and boundary layer effects the process is not 100 percent efficient To reduce dilution error you must inject specimen in discontinuous steps with pauses between steps to allow boundary layer saline to diffuse into the specimen In prompted mode the display instructs you to inject the specimen in a specific sequence This reduces dilution error and usually provides the quickest possible result with a nominal sample size of 350 uL We recommend that you routinely use the prompted mode sample size permitting since it reduces operator error and ensures a consistent sampling technique The prompted mode nominally requires 350 uL of specimen but may require one or more additional specimen injections of 50 uL before reaching a final result The time taken to actually inject the 50 uL should be approximately Y second 50 uL is a minimum injection The injection could be as much as 100 uL or more if you have plenty of sample NOTE Run samples in the same mode that the instrument was calibrated in Selecting
8. cut off 48 52 defects 25 26 installing 19 limitations 48 76 longevity 13 27 performance 22 25 58 plateau holding 25 26 58 rejection characteristic 48 removing 20 response time 13 25 26 scraper 20 61 specifications 13 storage 27 40 support structure 46 troubleshooting 58 ideal 48 Microprocessor 57 Non lonic Solutes 48 Normal Sample Volume 36 Oncotic Pressure 43 Operating Sequence 53 Organic Residues 40 Osmocoll 22 31 61 Osmolality 43 Osmometer Cell Assembly 51 Osmosis 43 Osmotic Pressure 43 Over Pressure Alarm 52 Physiological Membrane Systems 48 Plateau condition 7 38 holding ability 22 25 26 Pooled Serum Colloid Serum 36 Port Plugs 10 61 Power cord 15 55 entry module 57 indicator 8 15 55 63 mains 57 supply 61 63 switch 11 55 Pressure Transducer 17 52 57 61 Preventive Maintenance 27 Problem Solving 55 Prompt Language 65 Prompt Units Control Switch 8 Prompted Mode 7 8 30 32 34 35 38 aborting test 35 exiting 34 normal display 38 sample size in 34 selection 38 used in calibration 32 Protein Molecules 43 48 50 53 OPERATOR S MANUAL net electrical charge of 49 Recorder Output 12 13 circuitry 63 Reference Chamber 6 9 13 17 51 52 air bubbles 25 26 30 37 56 58 air leaks 26 58 drain tube 9 10 fill tube 9 filling 23 flushing 30 40 42 injection port 10 18 40 55 pinch valve 9 20 22 23 27 40 55 56 Removing Membrane 20 Replacement Parts 61 Ret
9. 3 human albumin for samples Other types of samples may adversely affect typical membrane performance GETTING STARTED 23 2 4 Filling the Reference Chamber Fill the reference chamber with saline solution 0 9 NaCl irrigation immediately after installing a new membrane in order to protect the membrane from drying out 1 Make certain that all drain and fill tubes are connected as shown in Fig 2 5 Instrument power should be on POWER indicator will be lit 2 Insert the tip of a 10 mL plastic syringe filled with normal saline solution into the reference chamber injection port Use a slight rotation to ensure a tight connection Figure 2 9 3 Open the reference chamber pinch valve by lifting and turning the pinch valve knob Sample Port Pinch Valve Knob Reference Chamber Injection Port Figure 2 9 Using a 10 mL syringe to inject saline solution into the reference chamber 4 Using smooth gentle pressure on the syringe inject 5 to10 mL of saline solution into the reference chamber CAUTION Watch the display and do not exceed 150 mmHg or equivalent If you observe bubbles in the lines continue to inject solution until no bubbles are visible Inject enough saline to fill the small inner cup in the waste collection bottle to prevent saline in the tubes from evaporating and leaving salt deposits in the lines The reference chamber drain tube should be inserted approximately 1 inch into the center hole of the w
10. Manual or Prompted Mode The default mode at power up is manual The instrument stays in the manual mode until you press PROMPT You must press PROMPT each time to begin a prompted test 0 0 mmHg After completing or aborting a test the instrument returns to the manual mode In the manual mode the display shows only the colloid osmotic pressure in the selected units as shown in Figure 4 2 Figure 4 2 A normal display in manual mode When entering the prompted mode the display instructs you to inject 200 microliters of sample as shown in Figure 4 3 If you press PROMPT again before injecting a sample the 0 0 mmHg instrument checks to see that the reading is at or near zero If not the display will prompt you to rinse the sample chamber with saline Figure 4 4 If the reading is at or near Zero or after you inject sufficient saline the display will revert to the manual mode display of Figure 4 2 Figure 4 3 The initial display in prompted mode Please inject 200 microliters OPERATING THE OSMOMETER 35 Once you begin a prompted test by injecting specimen the instrument remains in prompted mode until it reports a FINAL 12 8 mmHg RESULT To abort the prompted test press PROMPT The display will then direct you to flush the sample chamber with Flush chamber saline solution as in Figure 4 4 When complete the with saline instrument reverts to manual mode While in the prompted mode the UNITS switch ZERO sw
11. Osmometer the vascular and interstitial compartments of the body are represented by the sample and reference chambers respectively of the osmometer test cell assembly The synthetic membrane separating the two chambers simulates the vascular membrane The design of the instrument is based upon the concept illustrated in Figure 5 2 but with considerable refinement to satisfy the needs imposed by routine clinical testing where minimal sample volume ease of operation and simple maintenance are mandatory The osmometer has five major parts or assemblies that function together as an integrated system illustrated diagrammatically in Figure 5 5 The parts are separately detailed in the following petram ape Syringe Osmometer Cell Assembly _ Sample Waste Collection System N Nc e 2m Sample Chamber Membrane Pressure Transducer 7 Reference Chamber Injection Alarm Signal Processing and LCD Digital Amplification mE Display Electronics Power Supply Figure 5 5 The 4420 System 1 Osmometer Cell Assembly The osmometer cell assembly consists of two precisely machined cylinders having corrosion resistant surfaces 52 OPERATOR S MANUAL The reference chamber is machined in the face of the lower cylinder It consists of a shallow spiral groove that c
12. appendix CIRCUIT DESCRIPTION Power Supply and Regulation The power supply board converts the line voltage to a dual unregulated DC voltage typically this voltage would range from 12 to 21 volts depending on the actual line voltage Voltage regulation is performed by a total of four regulators located on the main board Most of the circuitry receives power from the main 5 volt regulators two separate regulators are used for the pressure transducer and microcontroller memory Pressure Transducer The pressure transducer is of the strain gauge type with the output signal magnitude proportional to the deflection of the diaphragm within the transducer The phase of the output signal is indicative of either a positive or negative pressure Signal Amplification and Conversion The output signal from the transducer is amplified by the main board to increase signal strength and reduce noise This signal is then split and sent to a second amplifier for the chart recorder output and conversion to a digital signal for use by the microcontroller A trim pot located on the main board provides correction of any zero offset of the transducer for the chart output but no gain adjustment is provided by this circuitry Digital User Interface The interface between the user and pressure transducer is provided by the microcontroller 68HC1 1 which is located on the main board The microcontroller accepts the inputs from the front panel control switches
13. converts the transducer signal into the proper units and displays the value It uses stored offset and gain values to compensate for errors within the signal amplification and transducer itself The microcontroller also detects injections and looks for the signal plateau by sensing the changing signal at the transducer output 64 OPERATOR S MANUAL Internal Batteries Two 3 volt lithium batteries are mounted on the main circuit board on the left side of the instrument behind the display They provide back up power to the microprocessor s RAM to maintain the stored calibration data language selection units and zero offset in the event the external AC power is interrupted Thus recalibration is not required whenever the instrument is disconnected from line power The batteries will normally last about five years When the batteries fail the osmometer s display will indicate BATTERY FAILURE Replacement batteries are available from Wescor under catalog number RP 131 two required You may also use any convenient source for Eveready CR 2025 or direct replacement To replace the batteries use the following instructions referring to Figures B 1 B 2 B 3 and B 4 Remove the saline syringe the sample syringe and the waste container before proceeding 1 Switch the rear panel power switch off O then disconnect line power by removing the power plug from the rear panel 2 Wait at least 30 seconds to allow the power supply s filter capacit
14. either inject the sample without introducing an air bubble see below or make sure you observe the air bubble see below or make sure you observe the air bubble leaving the sample chamber and moving toward the waste bottle Inject Saline Solution 1 Promptly after the sample has been measured remove the sample syringe from the injection port Insert a 10 mL syringe filled with saline into the sample injection port Inject 3 mL of saline through the sample chamber Wait for a stable reading Inject 1 mL of saline and wait for stable reading You should now read virtually Zero If you still have a small positive offset after certain samples flush another 1 mL of saline and wait for a stable reading The instrument should return to the zero reference level within 20 to 90 seconds after you inject the saline If the reading climbs after a few seconds inject more saline through the sample chamber Do not leave sample in the instrument Note Use standard biohazard safety precautions when operating maintaining or decontaminating the instrument 38 OPERATOR S MANUAL 4 3 The Prompted Mode The prompted mode offers convenient simple and consistent sample testing in routine situations such as in the clinical laboratory COP results are determined usually with no more than 350 microliters of specimen required Once you begin a test in prompted mode the UNITS ZERO and CALIBRATE switches will not function until the osmometer re
15. injection port You should be particularly cautious when using a syringe to apply pressure to a closed system This can happen if any outlet is left open to the atmosphere with saline solution in the cell Evaporation of water will leave salt deposits in the bore This can also happen if the pinch valve tubing remains pinched together after the pinch valve is open NOTE The negative reading on the instrument display when solutions are injected is an indicator of positive pressure generated in the cell Hence you can easily avoid pressures higher than 200 mmHg simply by injecting slowly and not driving the reading beyond 150 mmHg Do Not Freeze If the osmometer must be stored or shipped in freezing temperatures remove the membrane see Section 2 3 and all liquid from the cell assembly to prevent damage to the pressure transducer Do Not Ship the Colloid Osmometer to Wescor unless it has been drained cleaned and decontaminated see Appendix C Customer Service and Section 4 5 Disinfection Procedures GETTING STARTED 19 2 3 Membranes The membrane is the heart of the colloid osmometer measurement system This section explains procedures for installing a new membrane and removing a used membrane if in place This step must be completed before the colloid osmometer can be used INSTALLING A MEMBRANE The Colloid Osmometer is shipped from the factory without a membrane installed in the cell assembly Before first
16. is an impossibility since the crystalloid particles are comparable in size to water molecules and hence will pass through any membrane that is permeable to water The van t Hoff relationship can be used to calculate the osmotic pressure that will exist across a semipermeable membrane if the term c is modified so as to represent the differential osmolality of colloid constituents on opposite sides of the membrane Colloid Osmotic Pressure is a physicochemical phenomenon that occurs whenever two solutions having different concentrations of colloid particles are separated by a semipermeable membrane In general colloid osmotic pressure measurements are not made relative to pure water but rather with reference to normal saline solutions that more closely approximate the fluids present in the interstitial spaces of the body Colligative Properties are defined as those properties of a solution that bear a mathematically linear relationship to solution concentration or osmolality The four properties most frequently mentioned in this context are vapor pressure freezing point boiling point and osmotic pressure The first three are cardinal properties of the solvent that are modified in direct proportion to the number of solute molecules added per unit mass of solvent In general the colligative relationships apply only to non volatile solutes Solvent free energy is the fundamental basis of the measurement of colloid osmotic pressure and the mea
17. lid Air Vent I I Sample Chamber Outlet Waste Nipple S Container au Sample Chamber Reference Chamber Drain Tube Reference Chamber N Reference ea I Chamber Reference Chamber Pinch Valve Reference Chamber Fill Tube Injection Port Figure 1 3 Controls and Connections in the 4420 s interior bowl Sample Chamber The chamber that holds sample fluid after injection or normal saline between samples Its inlet is the sample chamber injection port As you inject additional sample fluid the existing fluid flows through the sample chamber drain tube and into the waste container The sample chamber must be filled with saline solution in order to set the ZERO offset see Section 3 It should be flushed with saline whenever a membrane is in the instrument and you are not actually testing a sample Reference Chamber The chamber that holds the reference fluid This chamber must be filled with normal saline solution 0 9 NaCl in order to test a sample and whenever a membrane is in the instrument see Section 2 3 The reference chamber is filled through the reference chamber fill tube Both the reference chamber fill tube and drain are controlled by the reference chamber pinch valve so that the reference chamber can be sealed during measurement and to prevent evaporation of the saline solution Reference Chamber Fill Tube Connects the reference chamber injection port to the reference
18. on the colloidal protein will augment colloid osmotic pressure as a result of the Gibbs Donnan Effect detailed in the next section We must also recognize the practical limitations of membranes Real membranes whether natural or synthetic will reject only solute molecules that are larger than the pore size of the membrane Solute molecules and ions that are smaller than the pores will pass freely through the membrane along with solvent molecules Furthermore real membranes do not have perfectly uniform pores but rather a distribution of pore diameters about a mean value Therefore even assuming globular solute particles there will not be a precise point in terms of molecular weight above which all particles are rejected by the membrane and below which all particles pass through the membrane Instead the membrane will exhibit a rejection characteristic that rises from 0 to 100 percent within a zone of increasing solute particle size By definition membrane cut off is the molecular weight at which the membrane will reject 90 percent of particles as depicted in Figure 5 3 With synthetic membranes used for osmometry suitability for a particular application requires that the cut off be well below the lowest molecular weight of colloid particles of interest and that the pore size distribution be as narrow as possible Membranes that meet these requirements will develop hydrostatic pressure and exhibit pressure holding ability approach
19. particles electrolytes and other small metabolites freely permeate the vascular membrane Semipermeable Membranes used in the Wescor Colloid Osmometer have relatively uniform pore size so as to reject any solute particles having molecular weights above a certain limit In physiological systems this limit has been taken to be 30 000 MW as noted above Osmotic Pressure can be a confusing term if used without qualification since it is identified as one of the colligative properties of a solution and is often used carelessly or by the uninformed as if synonymous with osmolality Unlike the other colligative properties that are all intrinsic characteristics of the solvent osmotic pressure is a relative characteristic of a solution with respect either to pure solvent or to another solution While it can be calculated from mathematical considerations it will arise as an actual pressure only when colloid particles are in differing concentrations in solutions separated by a semipermeable membrane 44 OPERATOR S MANUAL The theoretical osmotic pressure of a solution with respect to its pure solvent can be calculated from the van t Hoff equation T CRT where ri is the osmotic pressure c is the osmolality R is the universal gas constant and T is the absolute temperature This calculation assumes a hypothetical membrane having the ability to reject all solute particles while being freely permeable to solvent molecules Obviously such a membrane
20. sample chamber drain tube to drain used sample fluid to the waste container when fresh sample or saline rinse is injected INTRODUCTION AND SPECIFICATIONS 11 REAR PANEL CONTROLS and CONNECTIONS Power Switch Voltage Selector Tone Recorder Power Entry Transducer Output Module Figure 1 4 Controls and connections on the rear panel Power Switch Switches power mains for Colloid Osmometer on I or off 0 When the instrument is connected to proper voltage source and the switch is on l the front panel POWER indicator will be lit It is normal to leave instrument power on for extended periods Fuse Door Access the osmometer s main fuses by disconnecting the power cord and using a small screwdriver to open the fuse door Figure 1 5 Before replacing the fuses for any reason please refer to Section 6 2 for important safety precautions For continued protection against fire hazard replace fuses only with the correct type and rating 100 amp 115 units 1 8 Amp Type T time delay fuses two required 230 V units 1 16 Amp Type T time delay fuses two required Voltage Selector The selector is set at the factory to 100V 115V or 230V The voltage indicated may not agree exactly with your local source but it should be within a range For example the 115V selector is safe for sources between 110 and 120 volts The 230V selector is suitable for sources from 220 to 240 volts Do not connect the unit to a volt
21. switch down while the software version and language are displayed 66 OPERATOR S MANUAL 3 The display will change from the current language cycling through English Francais and Deutsch as you press and continue to hold the UNITS switch down 4 When the display indicates the desired language release the UNITS switch After two seconds the display will change to the current COP reading After this you cannot change the language again unless you start at step 1 If the line power is interrupted or is subject to heavy line noise the display may show scrambled characters or a foreign language If so reset the language to your preference by repeating steps 1 through 4 67 ELECTRONICS THINS S3HSINI3 3NIHOVW TI JIMS 3903 d vHS ONY SHunB 3AON3Y e S F O SXIONV wu S00 N3MI0 930 30Wld OLO F N3WIO 930 39d Z GLO F WIG Ov83 G3 3234S ISIMYIHLO SS3Nn dlO 1109 Ocvv MAIEV Aldd S SIMOS _ Z r HVIN Nv901 133815 NWN HINOS 6SF ASSY 1X3N 039v3138 NOILOMOOYA 035V3139 ONIVIINION 03323H9 66 YIONILIIS 8c00 33H929W aio 193r08d AB NMVEC OGS 300001 L IIT A0S 3n000 Zo SNOISIASY VOOVNI va vOOVNI ga FOOTNI ca vOOPNI ig OPERATOR S MANUAL 68 ie L kai d P Wwe Hin ADO LUIS MN HINOS 6c 031 0398 ISMAILO SESIWN NNOO SIN suf ee a mm 33r 139 jd 007v 1d QOL z El YOLOINNOO AYLNA JIMOd YY 9 L
22. 35 mmHg 0 1 mmHg 0 3 mmHg Assuming proper membrane function Osmocoll N Normal Level Colloid Osmotic Pressure Calibrator 4 line by 16 character alphanumeric liquid crystal display LCD Solid state microprocessor controlled 30 mmHg 2 mmHg Standard BNC connector 10 mv mmHg output impedance 500 ohms 115 to 120 Volt 50 60 Hz 220 to 240 Volt 50 60 Hz Factory Option 100 Volt 50 60 Hz 5 watts 3 V Lithium Cell Two Required Eveready CR2025 or equivalent 14 OPERATOR S MANUAL Fuses 2 Required 1 8 Amp Type T time delay for 100V or 115V P N 39 0136 1 16 Amp Type T time delay for 220 240V P N 39 0185 Size and Weight 19 cm 7 5 wide x 14 cm 5 5 high x 28 cm 11 deep 3 2 kg 7 Ib Waste Container Volume 120 mL 4 oz Standard Accessories AC 007 Membrane Scraper AC 012 Torque Indicating Screwdriver SS 025 Osmocoll N Normal Level Colloid Osmotic Pressure Calibrator SS 030 Wet Packed Pre mounted Membranes Operator s Manual Tuberculin Syringes 2 each 10 mL 25 each 1 mL Cotton Swabs 2 packs Saline Solution 500 mL 0 9 NaCl Irrigation USP Material Safety Data Sheet Return Forms Operator Warning Product Bulletin Power Cord Consumable not available for reorder from Wescor Inc Specifications are subject to change without prior notice SPECIFICATION OF SAFE USE Using this instrument in a manner not specified by Wescor Inc may impair the safety protection designed into t
23. 45 seconds Non parallel clamping of a good membrane can cause plateau decay in less than 5 seconds Occasionally a newly installed membrane exhibits a tendency to fall from plateau This will often stop when the membrane has been in the instrument for a few hours if at least three samples have been tested during this period If the osmometer fails to perform as described do not assume that the membrane is defective without first considering and eliminating all other possibilities As stated in Section 2 3 the most common cause of poor performance in a newly installed membrane is failure to properly tighten the osmometer cell screws Use the provided torque indicating driver to make certain that the screws are as evenly tightened as possible An air bubble in the reference chamber can produce erratic or unstable results To reduce this possibility use a 10 mL syringe to gently flush 3 or 4 mL of saline solution through the reference chamber Then repeat the test 26 OPERATOR S MANUAL Air leaks in the reference chamber will also cause failure to hold plateau reading If all of the above possibilities have been eliminated and the problem remains check for a defective or damaged membrane A properly installed membrane should work well for several hundred samples Resist changing zero or calibrate controls once the membrane has stabilized see Section 2 3 Small positive shifts in zero usually indicate air in the reference chamber which can
24. Colloid Osmotic Pressure 43 44 48 50 and critically ll patients 50 calculated 50 definition 44 differential 48 solutions 31 vs protein concentration 50 Colloid Particles 43 44 48 Crystalloid Particles 43 Definition of Terms 43 Differential Colloid Osmotic 48 Diffusible lon 48 Dilution Error 34 37 Disinfection Procedures 42 Display please wait display 38 negative reading 18 panel 8 Drain Tube Obstructions 18 59 Electroneutrality 49 75 INDEX Electronics 52 57 63 description 63 layout 63 69 troubleshooting 55 Electrophoretic Protein Pattern 50 English Language Display 65 Equilibrium 36 44 46 Equilibrium Hydrostatic Pressure 47 Filling the Reference Chamber 23 Final Result Display 32 35 38 Flush Sample Chamber Display 30 35 38 French Language Display 65 Front Panel Diagram 8 Fundamental Osmotic Pressure 45 Fuses door 11 ratings 11 14 57 German Language Display 65 Gibbs Donnan Effect 44 48 49 53 Gravimetric Effect 47 52 Heparinized Plasma 7 Human Albumin 22 31 Hydrostatic Pressure 45 47 Initialization 16 65 Injecting saline solution 23 24 36 samples 36 38 Injection Pressure Cautions 18 57 Injection Procedures 34 small sample volumes 34 37 Installation 15 Installing a Membrane 19 Interconnection Wiring Diagram 68 Interior Bowl Diagram 9 Language display 65 display problems 55 selecting 65 66 Manual Mode 7 36 and sample size 37 Measured COP 50 Membrane construction 13
25. SECTION 5 Theory of Operation De da le De es 43 5 1 Definito OFT GENIS curo pola el OG puspa Ob Oa ou CDAS IE Pans 43 5 2 Fundamental Osmotic Pressure 45 5 3 Physiological Membrane Systems 48 5 4 The Gibbs Donnan Effect 49 5 5 Calculated versus Measured COP 50 5 6 The 4420 Colloid Osmometer 51 5 7 Operating Sequence 53 SECTION 6 SolVIng Problems sa suce poro poro pro PEPE PEPE 55 6 1 Troubleshooting spas OS OS O E Gaeta ees 55 6 2 EIECTONICS wires dnc a Su Oke de ed deus Cac ete La de Eta Sarapas Ea akay AUR A 57 O 3 TransdUCEr 2 3 a rare td uu Tu iy hah puk 57 6 4 Membrane sco x oma AAA AAA D SAKSI S eee 58 6 5 FUDING OA 59 APPENDIX A Accessories Supplies amp Replacement Parts 61 APPENDIX B Electronics 63 INTRODUCTION AND SPECIFICATIONS SECTION 1 Introduction and Specifications Thank you for purchasing the Wescor Model 4420 Colloid Osmometer We believe it is the finest instrument of its type available anywhere Before you begin using the osmometer please study the first three sections of this manual which contain important information you must have
26. TACT TOUCH ONLY THE PLASTIC FRAME WHILE HANDLING THE MEMBRANE CAN NOT BE REUSED IF DRIED OUT REMOVED OR REORIENTED 10 NOTE A sudden slip while applying torque may affect the driver zero torque setting and require readjustment To readjust the zero Make sure the setscrew near the driver tip is tight then loosen the setscrew near the handle turn the plastic dial to the zero position and retighten the setscrew Install the sample chamber on the reference Holding the sample chamber down flat Remove the membrane from the deionized water bath and then place the membrane in position on the reference chamber with the red ring shiny side of membrane up Press down the membrane ring evenly into the chamber chamber Be sure to align the offset index pins to assure correct alignment of the parts replace the four socket head cap screws and tighten them until the screw heads just touch the cell top Back them off 1 8 turn Using the torque driver Figure 2 8 tighten each screw 1 8 turn following the pattern shown in Figure 2 7 Tighten each screw 1 8 turn following the same pattern you should feel some resistance at this point Make sure Figure 2 7 Pattern for tightening the socket head cap screws on the sample chamber the driver is completely seated in the socket head screw before tightening Tighten the screws following the pattern z shown in Figure 2 7 in stages first tighten all Figure 2 8 Tighte
27. Vascular Membrane 6 Voltage Selector 11 Volume of Sample 13 34 Waste Collection System 27 52 Waste Container 10 34 61 disinfection 42 emptying 27 volume 14 ZERO Control Switch 8 26 30 56 Zero Reference Level 37 39 TT
28. WESCOR Colloid Osmometer Model 4420 Operator amp Service Manual M2054 3A Copyright 1998 2000 2005 Wescor Inc All Rights Reserved Printed in USA WARNINGS Power source voltage for this instrument is indicated on the rear panel Be sure to connect to the correct voltage source To prevent fire or shock hazard do not expose this instrument to rain or any type of moisture IMPORTANT CAUTIONS The pressure transducer used in this instrument is sensitive and delicate Carefully read Section 2 2 for important information about the pressure transducer before attempting to operate the osmometer Never subject the instrument to freezing temperatures while liquid remains in the osmometer reference chamber cell Serious damage could result Never leave colloid solution in the sample chamber after testing Flush the sample chamber with saline after testing to promote membrane longevity Trademark Acknowledgment Wescor and Osmocoll are registered trademarks of Wescor Inc Other product names mentioned in this document may also be trademarks of their respective owners used here for information only U S Patent Number 4 150 564 U K Patent Number 2 018 430 Canadian Patent Number 1 122 033 TABLE OF CONTENTS SECTION 1 Introduction and Specifications _ 5 1 1 Operator s Manual Overview 5 1 2 Instrument Description
29. Weight Cutoff YM Series package of 3 SS 057 Membranes Wet packed Premounted 10 000 Molecular Weight Cutoff PM Series package of 3 SS 123 Membranes Wet packed Premounted 3 000 Molecular Weight Cutoff YM Series package of 3 Each Osmocoll lot has a specific control value and range Replacement Parts 30 0125 3 Volt Lithium Battery CR2025 2 required RP 028 Port Plugs RP 033 Reference Chamber Drain Fill Tube Assembly 2 pieces 1 white 1 red RP 034 Waste Container RP 072 Pressure Transducer RP 073 Cell Assembly RP 128 Electronics Module Exchange RP 129 Display Module RP 130 Power Supply Module 62 OPERATOR S MANUAL ELECTRONICS 63 APPENDIX B Electronics INSTRUMENT LAYOUT The electronic components of the model 4420 Colloid Osmometer have been designed and assembled in a modular fashion The main electronics module is mounted behind the instrument front panel This module contains the control switches power indicator microprocessor backup batteries memory signal processing and associated circuitry The power entry module is mounted on the instrument s inside rear panel along with the injection alarm tone transducer and chart recorder output connector The display module is mounted to the front panel between the case and the main electronics module The power supply is located on the case bottom directly beneath the bowl and cell area Schematic diagrams for the 4420 electronics are included at the end of this
30. ab as shown in Figure 4 1 2 Remove any excess liquid from the port area Figure 4 1 Cleaning the sample with a swab or a tissue injection port before injecting a sample 3 Use a fresh clean plastic syringe to inject samples The 1 mL size with a volume graduated scale will generally be most convenient Avoid excessive injection pressure Section 2 2 when using this type of syringe Locking type syringes require a plastic adapter Make certain the sample is free of bubbles and insert the tip of the syringe firmly with a slight rotation Plastic syringe adapters are available from Industrial Specialties MFG Inc 2741 W Oxford Unit 6 Englewood Colo 80110 303 781 8486 Part IFML CAUTION Never insert metal fittings into the sample port A plastic adapter can be used as an interface between the sample port and any metal fitting that must be used 4 Use smooth gentle pressure when injecting sample solution into the cell Note Use standard biohazard safety precautions when operating maintaining or decontaminating the instrument 34 OPERATOR S MANUAL Sample Volume and Injection Procedure With sufficient specimen volume at least 350 uL we recommend using the prompted mode described below and in Section 4 3 With minimal specimen volume but at least 125 pL use the special procedure below and in Section 4 2 to test the specimen s COP Also if you prefer to operate in the manual mode for any reason
31. age source outside the indicated range such as a 115V unit to a 230V source Serious damage could result OPERATOR S MANUAL Power Entry Module Provides connection for the standard IEC 320 type power cord included with the instrument Recorder Output Provides standard BNC connection for an external chart recorder One mmHg on the display is equal to 10 mV at the recorder output Tone Transducer Provides audible feedback for control operation and alarm for excessive injection pressure see Section 2 INTRODUCTION AND SPECIFICATIONS 13 1 5 Specifications COLLOID OSMOMETER Model 4420 Sample Volume Sample Loading Reference Chamber Standard Membrane Membrane Life Response Time Clinical Range Resolution Precision Calibration Readout Electronics Zero Offset Range Calibration Range Recorder Output Electrical Requirements Power Consumption Internal Batteries 350 microliters nominal for routine clinical measurements in prompted mode as little as 125 microliters using special manual technique Direct syringe injection flow through system Direct syringe injection flow through system Selectively impermeable to proteins exceeding 30 000 molecular weight Wet packed and pre mounted for easy replacement Wescor catalog SS 030 30 000 MW Greater than 1 000 samples in routine applications provided the membrane is properly maintained 3 to 7 minutes depending upon membrane condition 0 to
32. ality and of colloid osmotic pressure COP or oncotic pressure Since there is often a degree of confusion regarding these and associated terms used in osmometry it is appropriate to begin a theoretical discussion by reviewing the fundamental definitions and concepts Osmosis is the diffusion or more specifically the transudation of fluid through a semipermeable membrane that separates solutions of differing concentrations of solutes Fluid transudes from the region of lower concentration to the region of higher concentration Osmolality is an expression of the total concentration in mmol kg of solvent of dissolved particles in a solution without regard for the particle size density configuration or electrical charge Osmolality may be measured indirectly using laboratory instruments that determine either the vapor pressure depression of the solution or the freezing point depression of the solution By definition such measurements include both the so called colloid particles and crystalloid particles Crystalloid and Colloid Particles are terms coined by Thomas Graham in 1861 and refer respectively to solute particles that are smaller or larger than an arbitrarily decided particle weight which in the specific case of body fluid components is usually taken as 30 000 molecular weight MW Colloid particles e g plasma protein molecules are those that generally do not permeate the vascular membrane while crystalloid
33. ane installation 5 Remove the four socket head cap screws from the osmometer cell assembly using a standard 9 64 hex driver Do not use the AC 012 torque driver The shock of screws breaking free can alter the zero adjustment of the torque driver 6 Carefully lift the sample chamber straight up and away from the reference chamber The used membrane usually adheres to the sample chamber 7 Remove the old membrane frame from the sample chamber by separating it from the membrane as shown in Figure 2 6 HINT Use saline from a 10 mL syringe of saline solution to saturate the old membrane Let the membrane soak in the saline for about two minutes The membrane should lift off easily leaving very little residue 4 Qus WEM lt Em SS Figure 2 6 Removing old membranes with the scraping tool 8 Remove all residual membrane material from the sample chamber using the furnished plastic scraping tool For convenience you can do this while holding the sample chamber under running water GETTING STARTED 21 CAUTION USE ONLY A SOFT NON ABRASIVE IMPLEMENT TO AVOID DAMAGING THE PRECISELY MACHINED SURFACE 9 Remove stubborn membrane particles from the sample and reference chambers using a cotton swab or lint free tissue moistened with isopropyl alcohol followed by a pure water rinse Make certain that no membrane particles clog the inlet or outlet ducts CAUTION THE DELICATE MEMBRANE SURFACE CAN BE DAMAGED BY CON
34. aste container lid NOTE Solution should flow easily with gentle syringe pressure If obstructed do not attempt to clear the line by applying excessive pressure with the syringe This can damage the pressure transducer see Section 2 2 24 OPERATOR S MANUAL 5 Rotate and lower the pinch valve knob to seal the reference chamber 6 Remove the syringe from the reference chamber injection port Use a tissue or cotton swab to absorb any residual solution and prevent salt deposits around the plug Insert the saline syringe into the sample port and inject 1 mL of saline solution NOTE As a minimum we recommend that you flush the reference chamber with fresh saline before and after each day s use of the colloid osmometer GETTING STARTED 25 2 5 Membrane Performance Because the membrane is the heart of the osmometer s measurement system it is important that you can clearly recognize whether a membrane is performing its role in the determination of colloid osmotic pressure After injecting serum plasma or whole blood regardless of the actual COP of the sample the instrument response profile provides important diagnostic information This information can help you determine the condition of the membrane and its suitability for measurement Verifying appropriate membrane function is a prerequisite to calibration of the osmometer The two main factors of interest in assessing membrane performance are speed of response and plateau hold
35. ation Procedure Using the COP Calibration Solution A membrane should have previously been properly installed and the cells recently flushed with saline Use the information in Section 4 to inject the following sample using the prompted mode 1 Press PROMPT on the front panel to set the osmometer to prompted mode The 0 0 mmHg display should appear as shown in Figure Please 3 1 inject 200 microliters 2 Follow the prompts to inject COP standard until the display indicates FINAL RESULT Figure 3 1 The prompt to inject solution 3 Press CALIBRATE or until the display indicates the assayed value of the COP calibration solution Repeat the calibration procedure two or three times to ascertain repeatability if desired NOTE Calibration by this procedure is a simple one step operation However the operator must ascertain proper membrane function see Section 2 5 OPERATING THE OSMOMETER 33 SECTION 4 Operating the Osmometer SECTION 4 offers instructions for operating the Colloid Osmometer It describes procedures for using either manual Section 4 2 or prompted Section 4 3 mode 4 1 Injecting Samples The sample injection procedures in this section apply to both manual and prompted modes Sections 4 2 and 4 3 cover manual and prompted modes in detail When ready to test a sample 1 Remove the saline syringe do not be concerned if the zero reading drops slightly and clean the injection port using a cotton sw
36. be cured by flushing with saline Section 2 4 When the membrane begins to deteriorate its response time will tend to increase and the plateau level could decrease slightly requiring you to increase the CALIBRATE setting to maintain calibration These effects probably indicate a decrease in the number of pores available for transudation of fluid and an increase in the membrane cut off see Section 5 When you observe these changes you should replace the membrane Section 2 6 Preventive Maintenance offers some important information to help keep the instrument operating properly You can find instructions for calibrating the instrument in Section 3 and procedures for testing samples in Section 4 GETTING STARTED 27 2 6 Preventive Maintenance This section offers important preventive maintenance procedures to help you keep the Colloid Osmometer working well These procedures are part of the routine operation of the instrument and are not optional STORAGE BETWEEN USES When the osmometer is idle saline solution should fill both sample and reference chambers and the inner waste collection cup The sample chamber injection port should be closed with a saline syringe and the pinch valve must be in the closed position EMPTYING THE WASTE CONTAINER Empty the waste collection container whenever the liquid rises to a visible level Add a small amount of sodium hypochlorite to the container before reinstallation into the osmometer to help c
37. ce department for help or to determine if your osmometer needs factory service Refer to Appendix C Customer Service Note Do Not Ship the Colloid Osmometer unless it has been drained cleaned and decontaminated see Appendix C Customer Service 6 1 Troubleshooting This section will help you solve problems that you may encounter with the 4420 Try to locate a description of your problem in the left column then use the possible solution listed in the right hand column PROBLEM POSSIBLE SOLUTION POWER lamp is not lit display is blank Check the rear panel power switch power connector fuses line power outlet and source Power cord must be completely inserted into power module See Section 1 4 Figures 1 4 and 1 5 Make sure the source voltage matches the voltage indicated on the rear panel Voltage Selector Section 1 4 Figure 1 4 Scrambled language or messages Switch the power off wait 10 seconds appear on the display switch power on If the problem remains reset the language according to the instructions in Appendix B under heading Software Language Display indicates BATTERY FAILURE See Batteries in Section 6 2 Cannot inject saline into the reference Make sure the reference chamber pinch chamber injection port valve Figure 1 3 is open Check the tubing for salt deposits Squeeze the tubing gently along the area normally inside the pinch valve See Section 6 5 Cannot inject fluid into the sample Ch
38. chamber passing through the reference chamber pinch valve 10 OPERATOR S MANUAL Port Plug A pair of polyethylene plugs which seal the sample chamber injection port and reference chamber injection port Reference Chamber Injection Port Facilitates injection of saline solution into the reference chamber Accepts a standard non locking syringe A plastic adapter must be used when injecting with locking syringes or metal tips see Section 4 1 Reference Chamber Drain Tube Allows drainage of used saline solution from the reference chamber to the waste bottle Waste Container A container for temporary storage of used sample fluids and saline solution from the sample chamber and reference chamber Empty the waste container regularly to avoid the chance of a spill or overflow Air Vent A small air vent in the waste container lid allows the air volume in the waste container to be displaced by fluid volume from the sample and reference chambers Sample Chamber Drain Tube Drains used sample fluid from the sample chamber outlet nipple to the waste container Sample Chamber Injection Port Accepts a standard non locking tuberculin plastic syringe containing the sample fluid A plastic adapter must be used when injecting with locking syringes or metal tips see Section 4 1 Inject the sample according to displayed prompts in prompted mode or user discretion manual mode Sample Chamber Outlet Nipple Facilitates connection of the
39. ctronics THEORY OF OPERATION 53 5 7 Operating Sequence This section describes how the components of the instrument respond to your actions and work together to test a typical sample This information is intended only as an overview of how the osmometer operates For complete operating instructions refer to Section 4 Operating the Osmometer You must initially installa membrane and fill both the reference chamber and sample chamber with normal saline solution Normal saline is used in the reference chamber to produce approximately the same Gibbs Donnan Effect as would normal interstitial fluid Initial filling of the chambers calls for 10 cc of saline solution to fill the inner cup of the waste collection system as well thereby bringing that system into operational readiness After filling both the reference and sample chambers with saline press the ZERO switch on the front panel to clear any offset and adjust the display reading to zero Use a plastic syringe to inject sample solutions into the sample chamber Leave the syringe in place during measurement to close the input end of the system The sample chamber is vented to atmosphere at the waste collection end When a solution containing protein molecules is introduced into the sample chamber there is an immediate net migration of water molecules and diffusible solute ions from the reference chamber through the membrane and into the sample chamber This is caused by the osmotic eff
40. d sources for literature about colloid osmotic pressure measurement and applications The Index helps you quickly find the information you need 6 OPERATOR S MANUAL 1 2 Instrument Description The Model 4420 Colloid Osmometer is a compact user friendly instrument It measures the colloid osmotic pressure COP or oncotic pressure of high molecular weight blood solutes that are non diffusible through the vascular membrane The operating principle is based upon the movement of water molecules and diffusible solute particles through a synthetic semi permeable membrane a phenomenon known as transudation The membrane separates the specimen solution in the sample chamber from a reference solution in the reference chamber After a sample is injected fluid from the reference chamber moves through the membrane and into the sample chamber until an equilibrium hydrostatic pressure is reached This pressure is measured by a precise pressure transducer and associated electronic circuitry Results are digitally displayed on the instrument front panel If you would like to learn more about how the Colloid Osmometer operates refer to Section 5 for the theory of operation and additional descriptive detail OSMOMETER 4420 COLLOID Figure 1 1 The Wescor Model 4420 Colloid Osmometer INTRODUCTION AND SPECIFICATIONS 7 1 3 Features The Colloid Osmometer offers many useful features making it well suited for both routine clinical and r
41. e rubber grommet on the case bottom Do not try to force the case into position since you could damage the waste cup Also be sure that none of the internal wires will be pinched by any case parts and that the wire connectors are still properly seated on the main board connectors 11 Replace the four screws removed in Step 2 and reconnect line power You can now switch the instrument s power on After indicating the software version and language the instrument BATTERY FAILURE will display the message shown in Figure B 3 Re calibration required Press ZERO as prompted The instrument performs internal Press ZERO initialization You will briefly see the message shown in Figure B 4 Then the display shows the current COP reading Figure B 3 Display after new You must calibrate the instrument as described in Section3 batteries are installed You must B initialize and recalibrate the and in Section 4 before attempting to test samples osmometer Software Language The instrument is programmed to display prompts in your Initializing choice of English French or German To change the current language follow these instructions 1 Switch the power off O at the rear panel Figure B 4 Message that appears switch Wait at least five seconds so that Too ino d rd the internal voltage level can drop sufficiently for the microprocessor to reset 2 Switch the power back on and within one second press and hold the UNITS
42. eck the sample chamber drain system chamber for salt deposits or blockage Check the connections to the waste container Figure 1 3 See Section 6 5 56 Osmometer repeats a loud tone Osmometer sounds a loud tone when you inject sample or saline even though injection pressure is slight Instrument will not hold a plateau reading No pressure displayed or pressure does not change with sample injection Readings increase Pressing Zero does not zero display when in manual mode OPERATOR S MANUAL Check the display if it indicates Flush chamber with saline immediately flush the sample chamber Section 3 1 Check all tubing and waste container inner cup for salt deposits or blockage Check the tightness of the sample chamber screws see Section 2 3 Steps 11 12 and 13 and Figures 2 7 and 2 8 Check for air bubbles in the sample or reference chambers See the information in Sections 2 5 and 6 4 Be sure the pinch valve is closed Transducer may be damaged check the information in Sections 6 3 and 2 2 Contact Wescor for further assistance Empty waste container Membrane may be stabilizing Transducer may be damaged from excessive pressure Contact Wescor SOLVING PROBLEMS 57 6 2 Electronics Power Mains Electronic malfunctions or failures are unlikely with the 4420 Two Type T time delay fuses protect the power mains to prevent the risk of catastrophic current surge and associated dama
43. ect of the non diffusible protein molecules and the Gibbs Donnan Effect resulting from their electrical charge The resultant negative pressure in the reference chamber developed across the membrane is sensed by the pressure transducer The inverted signal from the pressure transducer is converted directly into either millimeters of mercury mmHg centimeters of water cmH2O or kilopascals kPa depending upon the UNITS selection you have made The pressure reading is displayed on the alpha numeric display The pressure difference will normally reach equilibrium within 30 to 120 seconds after the colloid solution is injected into the sample chamber After the necessary number of injections a final result or plateau is reached Higher values typically require longer times and more injections to reach a final result Flush the colloid solution from the sample chamber with fresh saline solution promptly after making a colloid osmotic pressure measurement When necessary the reference chamber can be easily flushed with fresh saline solution following the procedure outlined in Section 2 4 54 OPERATOR S MANUAL SOLVING PROBLEMS 55 SECTION 6 Solving Problems SECTION 6 will help solve routine problems encountered in operating the osmometer It includes troubleshooting procedures and additional information about the instrument electronics transducer membrane and tubing If these procedures fail to resolve a problem contact Wescor s servi
44. eplaced or approximately 5 years of service See Appendix B for more when the instrument is reset after new batteries are installed information about replacing the internal batteries If the instrument will not power up or if you do not see either of the displays shown above refer to Section 6 Solving Problems GETTING STARTED 17 2 2 The Pressure Transducer The pressure transducer is a vital component of the osmometer system It is integral with the reference chamber of the cell assembly As a sensitive measuring instrument the pressure transducer responds to minute pressure changes occurring within the reference chamber producing a corresponding electrical signal Reference solution in the chamber is contiguous with the transducer diaphragm that is coupled to a precision semiconductor strain gauge Pressure changes within the reference chamber deflect the diaphragm which changes the electrical signal from the strain gauge to the amplifier The cell assembly is designed to protect the pressure transducer which is completely enclosed within the instrument to minimize the risk of shock damage through handling The membrane can be installed and the reference chamber flushed without disassembling the transducer from the reference chamber In normal operation and maintenance the cell is always vented to the atmosphere to reduce the risk of inadvertent over pressure resulting from injecting fluids into a closed system
45. erence in liquid levels in the arms of the tube The osmotic pressure is equal to the level difference multiplied by the specific weight of the solution and will agree with the value calculated using the van t Hoff relationship Various theories have been postulated to explain the physicochemical mechanisms that come into play in the transport of water and diffusible solute molecules through membranes A number of these have been reviewed by Kul see bibliography While the open U tube apparatus allows a simple demonstration of osmosis it suffers from a number of practical shortcomings that prevent it from being a convenient laboratory instrument for routine testing applications Some of these shortcomings are apparent on inspection 46 OPERATOR S MANUAL 1 Because the apparatus relies upon gravity to create hydrostatic pressure a relatively large volume of solvent must transude the membrane into the solution side of the tube before equilibrium is attained This takes considerable time and has the undesirable effect of significantly altering the concentration of the solution during the process 2 Because of this dilution a calculation must be performed to find the osmotic pressure of the original solution 3 Since the membrane itself is structurally thin the hydrostatic pressure tends to balloon the membrane away from the high pressure side This increases the time necessary to reach equilibrium and may also cause spurious permeabil
46. esearch applications Some of the features are listed below co Minimal sample volume c Simple operation and maintenance c Choice of manual or prompted operation c Choice of English French or German language displays c Colloid osmotic pressure values can be displayed in mmHg cmH20 or kPa c Built in alarm helps prevent damage from excessive injection pressure c Reliability c Long membrane life c Built in battery backup maintains calibration data if instrument power is interrupted Manual or prompted mode are selected by pressing PROMPT on the front panel see Section 1 4 Controls and Connections In the prompted mode the instrument guides you through each sample injection with instructions on the alpha numeric display When the instrument detects a plateau condition it displays the final result The prompted mode works well for specimens such as heparinized whole blood heparinized plasma or serum In the manual mode you determine the timing and volume of sample injections You will make decisions based on the available sample size and by monitoring the display for plateau conditions The manual mode works well for specimens such as hetastarch or synthetic serums When available sample size is very small i e between 125 microliters and 350 microliters you can use a special manual procedure which is described in Section 4 The instrument can display the measured colloid osmotic pressure in millimeters of
47. ge in the event of an internal short circuit or malfunction The fuses are in the power entry module on the rear panel If a fuse fails it may indicate a serious internal problem You should always determine the cause of a fuse failure and correct the problem before replacing the fuse s and reconnecting the instrument to power The correct power source for your 4420 is indicated on a label on the rear panel The selected power source is shown in the power entry module window Be sure to connect the instrument to the correct power source to avoid serious damage or injury Internal Batteries The 4420 uses two 3 volt lithium batteries to maintain power to the microprocessor s memory in case the external power BATTERY FAILURE source is interrupted This eliminates the need to recalibrate Re calibration the instrument or set the zero reference if power is required interrupted The batteries are mounted inside the instrument Press ZERO case in a special module on the main circuit board You will know the batteries have failed when the 4420 displays the Figure 6 1 Time to replace the message shown in Figure 6 1 at power up 4420 s batteries Normal battery life is about five years Replacement batteries are available from Wescor under catalog number 30 0125 two required Eveready CR2025 or equivalent See Appendix B for instructions to replace the batteries If the batteries do fail you may see scrambled information or a foreign lan
48. guage on the display Refer to the troubleshooting chart in Section 6 1 for assistance 6 3 Transducer As discussed in Section 2 the pressure transducer in the 4420 is an expensive sensitive and delicate component The pressure transducer can be damaged by excessive injection pressure or improper cleaning procedures Please read Section 2 carefully for correct operating procedures that will minimize the risk of damage to the transducer Beyond the concerns listed above the transducer is well protected The cell assembly is designed to help protect the transducer from general shock or carelessness 58 OPERATOR S MANUAL 6 4 Membrane Most problems with the colloid osmometer arise from improper membrane installation and or improper preventive maintenance procedures The most common problem appears as a low response to a colloid osmotic pressure standard This can arise from a insufficient clamping pressure on the membrane refer to Section 2 3 b air leaks in the osmometer test cell assembly c air bubbles in the sample or reference chambers or d cell top not parallel with the cell bottom when tightened the most common cause of low response There is also a tendency for certain membranes when new to give unsatisfactory plateau holding performance In many cases the same membrane will perform normally after being left in the instrument overnight Please refer to Sections 2 4 2 5 and 2 6 for more information If after foll
49. h as a 1 4 watt resistor lead CAUTION USE GREAT CARE WHEN USING THIS TECHNIQUE TO CLEAR THE VERTICAL BORE HOLE AT THE CENTER OF THE REFERENCE CHAMBER SPIRAL THE PRESSURE TRANSDUCER DIAPHRAGM IS LOCATED DIRECTLY BELOW THE DUCT MAKE A SAFE CLEARING TOOL FROM A LENGTH OF WIRE BY BENDING IT TO FORM A SHOULDER AT A DISTANCE OF 3 MILLIMETERS 1 8 INCH FROM THE END See Figure 6 2 THE BEND WILL PREVENT DAMAGE TO THE SENSITIVE DIAPHRAGM OF THE PRESSURE TRANSDUCER Flood the plugged duct with distilled water and carefully probe the deposit until it dissolves and will flush away 3 mm Do not scratch the cell surfaces 1 8 Ya watt resistor lead or bent 1 paperclip Figure 6 2 A safe tool for clearing salt deposits from the reference chamber bore 60 OPERATOR S MANUAL ACCESSORIES SUPPLIES AND REPLACEMENT PARTS 61 APPENDIX A Accessories Supplies amp Replacement Parts Cat No Accessories AC 007 Membrane Scraper AC 012 Torque Indicating Driver Supplies SS 025 Osmocoll N Normal Level COP Calibrator Osmolality Control package of 6 1 mL vials Approximately 20 mmHg COP SS 038 Osmocoll HL High and Low Level COP Control References package of 6 1 mL vials 3 High 3 Low High Approximately 25 mmHg COP Low Approximately 15 mmHg COP SS 030 Membranes Wet packed Premounted 30 000 Molecular Weight Cutoff PM Series package of 3 SS 050 Membranes Wet packed Premounted 10 000 Molecular
50. he digital readout stabilizes typically within 60 seconds press ZERO The display will now read zero NOTE Small positive shifts in zero usually indicates air in the reference chamber If this is a problem try flushing with saline Section 2 4 A large negative offset 30 mmHg or more could indicate a problem with the transducer 3 3 Changing Displayed Units You can set the display to colloid osmotic pressure readings in Millimeters of Mercury mmHg Centimeters of Water cm H20 or Kilopascals kPa To change displayed units press UNITS The display will update each time you press UNITS Changing units does not affect the zero or calibration of the instrument Once you enter the prompted mode the UNITS switch is disabled until the instrument reports a final result or until you abort the test by pressing PROMPT At that time the instrument will ask you to flush the sample chamber with saline Once that is done the instrument returns to manual mode and you can again change the displayed units Ready for Calibration Once you have set the instrument zero and selected the desired units the instrument is ready for calibration Membranes may differ in response times Calibration is always required after installing a new membrane SETUP 8 CALIBRATION 31 3 4 Colloid Osmotic Pressure Calibration Control Solutions The objective of colloid osmometer calibration is to set the amplifier gain CALIBRATE control so the instrumen
51. he equipment and may lead to injury SAFE USE ENVIRONMENT This equipment is designed to be safely operated at 5 to 35 C maximum relative humidity 80 FUSES All fuses in this equipment are type T SLO BLO time delay EXPLANATION OF SYMBOLS FOUND ON EQUIPMENT E Alternating Current AC l Power On O Power Off GETTING STARTED 15 SECTION 2 Getting Started SECTION 2 familiarizes you with the Colloid Osmometer so that you can begin testing samples Section 2 1 contains directions for installing the instrument Sections 2 2 through 2 5 discuss the pressure transducer membranes and reference chamber Preventive maintenance is covered in Section 2 6 After completing Section 2 you will be ready to begin testing samples with your Colloid Osmometer Section 4 2 1 Installing the 4420 This section explains how to install the Colloid Osmometer in your lab and connect it to the correct power source It describes the messages you will see on the display when you switch the osmometer on 1 Locate the osmometer on a suitable laboratory bench or table with convenient access to the correct power source 2 Attach the included power cord to the power connector on the rear panel Figure 2 1 3 Connect the power cord to the correct power Figure 2 1 Connecting Power source as indicated on the rear panel 4 Turn ON I the power switch located on the rear panel The POWER indicator should now be lit followed by a short
52. imbs after a few seconds inject more saline through the sample chamber Do not leave sample in the instrument SPECIAL PROCEDURE FOR MINIMAL SAMPLE VOLUME If your specimen volume is limited reasonably accurate measurements can still be made on as little as 125 microliters of sample solution if you employ the following procedure 1 Before injecting the sample to be tested inject 300 uL of a colloid solution having a colloid osmotic pressure similar to the anticipated value of the solution to be tested a solution can be made up from pooled serum from the laboratory After injecting this solution pause until the displayed reading shows no change during a 10 second period OPERATING THE OSMOMETER 37 2 Use a fresh clean syringe to inject 125 uL of the test solution To prevent an air bubble between the initial colloid solution and the specimen use the syringe to fill the injection port level with the top of the sample chamber before inserting the specimen syringe Since the difference between the colloid osmotic pressure of the solution previously in the chamber and that of the solution being tested will be small dilution error that results from mixing of the two solutions will be correspondingly diminished With small volume samples it is particularly important to use a uniform volume for each test and to inject the sample at a uniform rate Also any air bubble in the system will tend to reduce the COP reading For a valid reading
53. ing ability Of the two plateau holding ability is more important to accuracy While rapid measurement is generally desirable the speed of response is influenced by many variables including both colloid and crystalloid solute makeup of the sample solution in addition to age and individual characteristics of the membrane itself Membranes that can t hold equilibrium pressure plateau may appear to give rapid response times but will show measurement inaccuracies When installed correctly wet packed membranes supplied by Wescor Cat No SS 030 should produce the following characteristic instrument response after injecting the COP calibration solution or human blood serum or plasma 1 As the sample is injected into the cell the readout will deflect sharply in the negative direction in response to the injection pressure refer to CAUTIONS Section 2 2 2 After releasing sample injection pressure the reading will immediately reverse direction rising past zero to some positive value The plateau will be reached typically between 30 and 120 seconds insignificant increases may occur with some membranes even beyond 120 seconds 3 The membrane should produce a rising display indication and stabilize at a plateau level for at least thirty seconds after sample injection Any fall off from plateau level within thirty seconds should be interpreted as marginal or submarginal performance A good membrane can show a plateau decay at approximately
54. ing that of an ideal membrane REJECTION PERCENT 100 lud a AS CUT OFF 80 60 40 100 1000 MOLECULAR WEIGHT THOUSANDS Figure 5 3 Membrane Rejection Characteristic THEORY OF OPERATION 49 5 4 The Gibbs Donnan Effect An important factor in biological systems is the contribution to colloid osmotic pressure from the net electrical charge of the protein molecules in the presence of charged membrane diffusible ions At normal blood pH levels the net protein charge will be negative Electroneutrality must be reached on either side of the membrane The presence of non diffusible negatively charged colloid particles requires that the concentration of positively charged diffusible ions must exceed that of the negatively charged diffusible ions on the colloid side of the membrane The diffusible ions redistribute across the membrane so that at equilibrium the product of the concentrations of diffusible ions on each side of the membrane is equal 40 ll DONNAN AUGMENTATION ll PROTEIN CONTRIBUTION COLLOID OSMOTIC PRESSURE mmHg 0 10 20 30 40 50 60 70 80 90 100 PROTEIN g L Figure 5 4 COP vs Protein Concentration Considering only the diffusible ions at equilibrium the concentration on the colloid side of the membrane will be slightly greater than that on the non colloid side producing an osmotic pressure difference that augments the pressure due to the concentration of the colloid particles per se which
55. is a linear function of the colloid concentration The pressure component of the Gibbs Donnan Effect is a function of the square of the electrical charge carried by the colloid component It follows that since the total measured COP is made up of both contributions it is non linearly related to colloid concentration This relationship is illustrated in Figure 5 4 50 OPERATOR S MANUAL 5 5 Calculated versus Measured COP In recent years there has been controversy among medical professionals as to the need for laboratory measurement of COP It has been demonstrated that a correlation exists between total measured protein and colloid osmotic pressure in normal blood samples This fact is often put forth as an argument against the need to measure COP The actual value of COP in a given blood sample will be influenced by the blood pH as well as variation in the relative transportation of plasma proteins as shown by the electrophoretic protein pattern of the sample The formulas used to calculate COP from total protein measurements have been derived empirically and are based on blood samples where pH and electrophoretic patterns are normal In the case of critically ll patients these conditions may not apply COP is becoming more widely recognized as a valuable laboratory test A bibliography of relevant technical publications can be found at the end of this manual THEORY OF OPERATION 51 5 6 The 4420 Colloid Osmometer In the Wescor Colloid
56. itch and CALIBRATE Figure 4 4 A prompt to rinse the switch are not active sample chamber when needed 36 OPERATOR S MANUAL 4 2 The Manual Mode This section describes recommended injection procedures for normal samples when using manual mode The UNITS ZERO and CALIBRATE controls are all active during manual mode operation NORMAL SAMPLE VOLUME at least 350 microliters Use a sample volume of 350 LL injected as follows 1 Inject 200 uL then pause for 90 seconds Immediately record reading and do Step 2 2 Inject 50 uL then pause for 45 seconds Immediately record reading and do Step 3 3 Inject 50 uL then pause for 30 seconds Record reading and repeat Step 3 When the previous reading is within 0 2 mmHg or equivalent of your current reading you have reached equilibrium plateau A typical sample requires 3 to 5 injections Inject Saline Solution 1 Promptly after the sample has been measured remove the sample syringe from the injection port 2 Inserta 10 mL syringe filled with saline into the sample injection port 3 Inject 3 mL of saline through the sample chamber Wait for a stable reading Inject 1 mL of saline and wait for stable reading You should now read virtually Zero If you still have a small positive offset after certain samples flush another 1 mL of saline and wait for a stable reading The instrument should return to the within 20 to 90 seconds after you inject the saline If the reading cl
57. ity changes or even physical damage to the membrane because of the induced stress The apparatus illustrated in Figure 5 2 is improved in practical ways to eliminate the major shortcomings of the open U tube It provides a direct rapid and accurate readout of the osmotic pressure of the solution In this configuration a permeable support structure reinforces the membrane to reduce ballooning to a negligible level The solvent arm of the U tube is closed with a sensitive pressure measuring device that is hydraulically coupled to the solvent The open arm of the U tube is filled with solution as before so that the initial pressure in the solvent chamber is zero A zero pressure condition in the solvent chamber is unnecessary if correction can be made for quiescent initial pressure Solvent molecules transude the membrane as in the previous example but in this case negative pressure develops rapidly in the solvent chamber Osmotic pressure indicated directly by pressure gauge M SOLUTION Solution initial level and equilibrium level are virtually the same Hydrostatic pressure builds quickly and the net volume of solvent that transudes the CLOSED membrane is SOLVENT negligible because of CHAMBER the closed solvent SUPPORTED chamber MEMBRANE Figure 5 2 A U Tube Osmometer with Closed Chamber and Direct Reading Pressure Transducer THEORY OF OPERATION 47 Theoretically if there is negligible ballooning of the me
58. ll be idle for several weeks and you want to preserve the membrane Flush both the reference chamber and the sample chamber with copious amounts of saline solution to remove any organic residues from the osmometer cell Empty and dry the waste collection bottle Remove the sample chamber drain tube from the sample chamber outlet nipple and connect the reference chamber drain tube in its place as illustrated in Figure 4 8 Leave the pinch valve in the open position Install plugs securely in the sample chamber injection port and the reference chamber injection port With the osmometer cell thus sealed the integrity of the membrane can be maintained over several weeks of storage CAUTION DO NOT EXPOSE THE INSTRUMENT TO FREEZING TEMPERATURES WHILE LIQUID REMAINS IN THE OSMOMETER CELL OPERATING THE OSMOMETER Figure 4 8 Long term storage with a membrane installed 41 42 OPERATOR S MANUAL 4 5 Disinfection Procedures Using the osmometer to measure an infectious sample contaminates the sample injection port the internal tubing the membrane and the inside of the waste container The saline syringe used for flushing the chambers also becomes contaminated when placed into the sample port and will in turn contaminate the saline when refilled from the saline container Treat the saline flushing solution and the saline syringe as biohazards and dispose of them properly We recommend the following procedures to disinfect the system
59. mbrane and if the walls of the solvent chamber are perfectly rigid then the volume of solvent that transudes the membrane to the solution side will be only that necessary to actuate the mechanism of the pressure indicator Assuming this is small so that the gravimetric effect of the increased liquid level in the solution arm is negligible then the equilibrium hydrostatic pressure as indicated by the negative reading on the pressure indicator is the true osmotic pressure of the solution 48 OPERATOR S MANUAL 5 3 Physiological Membrane Systems For the sake of simplicity in the previous discussion a single uncharged non diffusible colloid solute was considered Thus in this example the measured osmotic pressure is the colloid osmotic pressure of the solution with respect to pure solvent and is equal to the value given by the van t Hoff relationship where c is the osmolality of the solution In applying this measurement concept to real physiological systems we must take into account additional factors that influence the resultant measurement To begin the osmotic pressure of interest will generally be the differential colloid osmotic pressure between two solutions rather than the absolute colloid osmotic pressure of a solution referred to pure solvent water Both solutions will contain mostly diffusible ionic and non ionic solutes and a substantial number of colloid particles mainly protein molecules Furthermore electrical charge
60. mercury mmHg kilopascals kPa or centimeters of water cmH2O Select UNITS on the front panel you can set the current COP reading to be displayed in whichever unit of measurement you prefer 8 OPERATOR S MANUAL 1 4 Controls and Connections FRONT PANEL CONTROLS CALIBRATE Display Panel Control Switch 4420 COLLOID OSMOMETER POWER Indicator ZERO Control Switch Lamp PROMT UNITS Control Switch Figure 1 2 Front Panel Controls POWER Indicator Lamp Lights when the power is on Display Panel 4 line X 16 character alpha numeric display provides specimen results prompts and other useful information Display messages are described in Sections 2 3 and 4 PROMPT UNITS Control Switch A two way rocker switch lets you select the prompted or manual mode of operation PROMPT or set the displayed units of COP to mmHg kPa or cmH2O UNITS See Section 3 for more information ZERO Control Switch Resets the display to 0 clearing any offset Used when the sample chamber contains saline solution Refer to Section 3 2 for instructions CALIBRATE Control Switch A two way rocker switch to increase or decrease the instrument s reading allowing you to calibrate the osmometer to the COP standard See Section 3 for correct use of the CALIBRATE control INTRODUCTION AND SPECIFICATIONS INTERIOR CONTROLS and CONNECTIONS Sample Chamber Drain Tube Sample Chamber permanently connected Injection Port to waste container
61. n Colloid Osmotic and Pulmonary Artery Wedge Pressure in Patients after Acute Myocardial Infarction Circulation 51 350 1975 Rackow E C Fein I A and Lepp J Colloid Osmotic Pressure as a Prognostic Indicator of Pulmonary Edema and Mortality in the Critically Ill Chest 72 709 1977 Reiff T R Colloid Osmotic Hemeostasis in Humans J Theor Biol 28 1 1970 Sprung C L Isikoff S K Hauser M Eisler B R Comparison of Measured and Calculated Colloid Osmotic Pressure of Serum and Pulmonary Edema Fluid in Patients with Pulmonary Edema Crit Care Med 8 613 1980 Starling E H On the Absorption of Fluids from the Connective Tissue Spaces J Physiol 19 312 1896 Webster H L Colloid Osmotic Pressure Theoretic Aspects and Background Clinics in Perinatology 9 505 1982 74 OPERATOR S MANUAL INDEX Aborting a Prompted Test 35 Absolute Pressure 48 Accessories 14 61 Air Bubbles 25 37 Air Leaks 26 Air Vent 10 Assayed COP Calibration Solutions 31 61 Batteries 61 64 failure display 57 64 65 failure message 16 55 57 replacing 64 65 specification 13 Block Diagram 68 Blood pH and COP 50 Calculated vs Measured COP 50 CALIBRATE Control 8 26 31 32 35 36 Calibration procedures 29 31 32 with COP solutions 32 Cell Assembly 51 61 screws 20 21 25 Chart Recorder Output circuitry 63 Choosing Manual or Prompted Mode 34 Circuit Description 63 69 Colligative Properties of Solution 44
62. ning the sample the screws to level A then B then C and chamber screws with the AC 012 Torque Driver 22 OPERATOR S MANUAL finally to level D on the scale After all screws have been tightened to level D recheck each screw to make sure it does not advance further at torque C1 2 halfway between C and D This corresponds to 32 to 35 inch lbs NOTE Poor plateau holding performance or a low reading after injecting serum or colloid osmotic pressure standard into the sample chamber can indicate insufficient or uneven membrane clamping pressure due to improper screw tightening 13 Close the reference chamber pinch valve by turning the knob and lowering it into the closed position 14 Replace the sample chamber drain tube removed in Step 1 The osmometer is now ready for chamber filling as instructed in the following sections This should follow immediately to protect the newly installed membrane from drying out After installation sample components build up on the sample side of the membrane forming a stable layer that remains after flushing with saline This layer stabilizes in 24 to72 hours depending on how often samples are run During this time you will notice the zero and calibration slowly change Patient samples can be tested during this stabilizing period if you calibrate with Osmocoll N Section 3 4 just prior to testing This assumes that you are using an SS 030 membrane and are only running human blood Osmocoll N and 5 or
63. ommunicates through ducts to the pressure transducer mounting port and the reference chamber inlet and outlet ports An annular channel which receives the mounting frame of the membrane is also machined in the face of the lower cylinder The sample chamber has a spiral groove precisely matching that of the reference chamber It is machined in the face of the upper cylinder of the osmometer cell assembly The upper cylinder likewise has an annular channel to receive the membrane mounting frame Opposite ends of the sample chamber groove are connected by ducts to the sample chamber luer inlet port and to the sample chamber outlet nipple on the top surface of the cylinder The reference and sample chamber cylinders are assembled with the membrane between them Because the width of the grooves is small and the membrane is firmly held by the clamping action of the cylinders membrane displacement ballooning is negligible 2 Pressure Transducer The pressure transducer is interfaced to the reference chamber cylinder of the osmometer cell assembly Its sensing diaphragm is contiguous with the reference solution The pressure transducer converts minute pressure changes in the reference chamber into electrical changes that are measured and displayed 3 Membrane The standard membrane has a cut off of 30 000 MW and is only a few microns in thickness It is formed on a polymeric substrate that is approximately 0 2 millimeters thick A unique plastic moun
64. on diffusible colloid solute molecules Both solvent and solute molecules are in a state of constant random motion due to their thermokinetic energy Given time a number of the solvent molecules will traverse the pores of the membrane in both directions but there will be an initial net flow from the solvent side to the solution side of the membrane This causes a rise in the liquid level in the solution arm as the level in the solvent arm falls SOLUTION SOLVENT EQUILIBRIUM SOLUTION LEVEL Level difference creates hydrostatic pressure equal to the osmotic pressure ot the solution in equilibrium gt q4 INITIAL gt LEVEL lt EQUILIBRIUM SOLVENT LEVEL SEMI PERMEABLE MEMBRANE impervious to solute molecules Solvent molecules transude the membrane in both directions but the net flow is in direction of arrows until hydrostatic pressure across membrane Causes equal conterflow equilibrium Figure 5 1 An Open U Tube Osmometer As the difference in level between the two arms increases hydrostatic pressure builds across the membrane The pressure acts to increase the flow of solvent molecules from the solution arm to the solvent arm thus counteracting the osmotically induced flow The new flow reaches zero when solvent molecules transude the membrane equally in both directions In this equilibrium the solvent free energy difference or osmotic pressure can be determined simply by measuring the diff
65. ontrol bacterial growth After reinstallation be sure to inject sufficient saline solution through the sample chamber to fill the inner cup of the waste collection system This will prevent evaporation of water from within the osmometer cell that would otherwise allow the membrane to dry out and or result in salt blockage of the chamber ducts Make sure that the reference chamber drain tube is inserted approximately 1 inch into the center hole of the waste container lid MEMBRANE The membrane must be kept wet during its life Between uses keep the sample chamber filled with saline solution and closed with a saline syringe The reference chamber must likewise contain saline solution at all times The pinch valve must be closed These simple rules will promote membrane longevity NOTE Never leave a colloid solution in the sample chamber when you are not actually testing a sample Use standard biohazard safety precautions when operating maintaining or decontaminating the instrument 28 OPERATOR S MANUAL SETUP 8 CALIBRATION 29 SECTION 3 Setup amp Calibration This section offers procedures to prepare the osmometer for use and for calibrating it with the COP standard The osmometer must be properly calibrated to have reliable COP readings The system is very stable After proper calibration and membrane stabilization frequent recalibration is not required Before attempting the procedures in this section you should have read and foll
66. ors to discharge then remove the two screws from the bottom front and the two screws from the rear top of the instrument see Figure B 1 Back panel screws Bottom panel screws Figure B 1 The four screws to be removed after disconnecting the 4420 from line power 3 Gently lift the instrument s case top upward approximately one inch The bowl and internal components will remain attached to the case top 4 Now slide the case top assembly forward away from the case back about three inches 5 You should now be able to see the batteries in their holder on the left side of the main circuit board behind the display area ELECTRONICS 65 6 Remove the small plastic connector from the pins just below the battery holder labeled Battery Disconnect 7 Gently lift the small spring away from the batteries and slide both batteries out the side of the holder 8 Install two fresh batteries being sure to match the polarity The negative surface of both batteries must face in toward the circuit board The positive face of both batteries must face out toward the battery holder clip see Figure B 2 The battery holder clip must press against the top battery 9 Replace the battery disconnect jumper that you removed in Step 6 Figure B 2 Correct polarity of batteries 10 Lift the case top back into position and lower it carefully onto the case bottom The plastic nipple from the waste container cup must fit into th
67. owed the instructions in Section 2 Getting Started 3 1 Filling the Sample Chamber CAUTION Be sure instrument power is on before injecting solution or installing a membrane Before use you must install a membrane and fill the reference chamber with saline as described in Sections 2 3 and 2 4 Once you have completed both those steps you should fill the sample chamber with saline 1 Insert the tip of a 10 mL plastic syringe filled with normal saline solution into the sample port Use a slight rotation to ensure a tight connection 2 Using smooth gentle pressure inject saline solution to clear all bubbles from the sample chamber and drain tube typically about 2 mL Leave the saline syringe in place if you are going to ZERO the 4420 NOTE Solution should flow easily with gentle syringe pressure Do not attempt to clear an obstruction in the line by applying excessive pressure with the syringe This can damage the pressure transducer see Section 2 2 Use standard biohazard safety precautions when operating maintaining or decontaminating the instrument 30 OPERATOR S MANUAL 3 2 Setting the Display ZERO Before calibration you must set the instrument to ZERO Do this before entering the prompted mode since the ZERO switch will not function in the prompted mode The procedure is to flush the reference chamber if needed and then the sample chamber with normal saline solution 0 9 NaCl Irrigation USP After t
68. owing the procedures in this manual you cannot resolve a problem please contact Wescor see Appendix C to obtain prompt assistance CAUTION Do Not Ship the Colloid Osmometer unless it has been drained cleaned and decontaminated Contact Wescor for return authorization see Appendix C Section 4 5 and Section 2 2 SOLVING PROBLEMS 59 6 5 Tubing If saline solution evaporates from the sample chamber or the drain lines the resulting salt deposits can block the fluid ducts making it impossible to inject solutions into the chamber Proper preventive maintenance will preclude this but if it does occur remove the sample cell and membrane to allow safe removal of the obstructions If the instrument is idle for a long period with the pinch valve closed the tubing inside the valve may deform slightly It then can remain mashed when the valve is opened preventing fluid flow In this happens reshape the tubing by squeezing it gently from the sides along the length that lies inside the valve Salt deposits in the drain lines or in the spiral reference and sample chambers can be removed simply by rinsing with water Clearing the smaller ducts may be more difficult particularly in the reference chamber which ordinarily remains attached to the interior of the instrument These ducts can be cleared using a 0 038 inch diameter or smaller wire such as a straight section of paper clip wire It would be best to use soft copper wire suc
69. ports its final result or until you abort the prompted test by pressing PROMPT and flushing the sample chamber as prompted The procedure below describes a typical specimen test in prompted mode You may want to review Section 4 1 Injecting Samples before beginning your test Insert the sample syringe into the sample injection port before selecting prompted mode If the 4420 is in manual mode 0 0 mmHg only pressure shown on display press PROMPT to enter Please the prompted mode You will see a display like the one in inject Figure 4 5 200 microliters 1 Gently inject 200 uL of sample The display Figure 4 5 The initial display in will change to Please wait as the COP prompted mode reading rises toward the plateau see Figure 4 6 2 After a delay the osmometer chimes and the display will prompt you for a 50 uL 12 8 mmHg injection Please 3 Immediately inject 50 uL of sample The wait display will change to Please wait as the reading rises Figure 4 6 Waiting for a plateau condition after the first sample The instrument continues to prompt you for 50 pL injections jeenon until it detects and displays the peak reading and FINAL RESULT Figure 4 7 The microprocessor determines the final result when it detects a plateau condition on two consecutive 50 uL injections within approximately 0 2 mmHg A typical sample will require approximately three to five minutes to reach a final result in the prompted mode In some ca
70. ses it may take as long as seven minutes depending on the characteristics of the membrane Once FINAL RESULT appears on the display you can change the units of measurement by pressing UNITS You 18 8 mmHg can also change the instrument calibration by pressing FINAL RESULT CALIBRATE refer to Section 3 for proper calibration Flush chamber procedure Both UNITS and CALIBRATE are inactive in with saline prompted mode until the final result is obtained The ZERO switch remains inactive until you return to manual mode by Figure 4 7 Final result displayed rinsing the sample chamber with saline solution with a reminder to rinse the sample chamber The display will now prompt you to flush the sample chamber OPERATING THE OSMOMETER 39 with saline solution as in Figure 4 7 If you do not flush the sample chamber with sufficient saline within four minutes the osmometer will sound an alarm to remind you to flush the chamber As you flush the chamber with saline the COP reading gradually falls below zero the alarm will stop and the Flush chamber with saline prompt will be cleared from the display Inject Saline Solution 1 Promptly after the sample has been measured remove the sample syringe from the injection port 2 Inserta 10 mL syringe filled with saline into the sample injection port 3 Inject 3 mL of saline through the sample chamber Wait for a stable reading Inject 1 mL of saline and wait for stable reading You sho
71. surement of osmolality Solvent free energy is reduced whenever solute is added to the solvent This in turn gives rise to corresponding changes in the colligative properties of the solution that afford a means for the determination of osmolality i e vapor pressure depression or freezing point depression The measurement accounts for all solute particles without discrimination as it is referenced to free energy of the pure solvent On the other hand the measurement of colloid osmotic pressure is discriminatory with respect to solute particle size because of the semipermeable characteristic of the membrane Pressure results from the differential osmolality differential solvent free energy that exists at equilibrium between the solutions on opposite sides of the membrane Because of electrical charge on some colloid molecules diffusible charged particles present in solution will become involved in the development of colloid osmotic pressure even though they can permeate the membrane Known as the Gibbs Donnan Effect this phenomenon is discussed in Section 5 4 THEORY OF OPERATION 45 5 2 Fundamental Osmotic Pressure Osmotic pressure can be demonstrated quite simply in the laboratory Consider the classical experiment illustrated in Figure 5 1 The arms of a U tube are separated by a semipermeable membrane One arm is initially filled with pure solvent while the other arm is filled to the same level with a solution made up of solvent and n
72. t will accurately measure the true colloid osmotic pressure of the solution injected into the sample chamber Since the measurement depends upon membrane function calibration must involve an appropriate colloid solution whose colloid osmotic pressure has been accurately assayed Traditionally COP calibration solutions for clinical work have been based upon assayed solutions of human albumin a colloid material that is acceptable as a control A 5 solution of human albumin in saline prepared for IV infusion will typically have a COP of 19 3 1 4 mmHg Osmocoll N Normal Level Colloid Osmotic Pressure Calibrator is a calibration solution for all colloid osmometers Osmocoll is available from Wescor Cat No SS 025 and comes packaged in six 1 mL vials The colloid osmotic pressure osmolality range lot number and expiration date accompany each package The package also includes instructions for use and storage as well as product warranty information Osmocoll is also useful as an osmolality control reference Osmocoll HL high and low level Cat No SS 038 and Osmocoll HNL high normal and low level Cat No SS 039 are also available from Wescor Each lot has a specific assayed control value and range but will measure approximately 25 20 and 15 mmHg for high normal and low levels CAUTION Using standards or controls other than Osmocoll or human albumin can degrade membrane performance 32 OPERATOR S MANUAL 3 5 Calibr
73. time use you must install one of the membranes which are included with each new instrument Membranes are supplied in a disposable preassembled plastic frame and packed in a saline solution This method of packaging prolongs membrane shelf life Sample Chamber Drain Tube Sample Chamber ILA mbl hee permanently connected sse bly Injection Port to waste container lid Air Vent Sy I Ao E S a IE ETE lies ns l Sample Chamber Outlet 7 Nipple Waste Container Sample Chamber Reference Chamber Drain Tube Reference d Chamber X N Reference Chamber Reference Chamber Pinch Valve Reference Chamber Fill Tube Injection Port Figure 2 5 The cell assembly in the interior bowl NOTE Do not open the membrane package until preparing for installation Do not allow the membrane to dry out 1 Open the membrane wet pack by cutting one end with scissors Soak the membrane in a deionized water bath for at least 15 minutes You may continue with the following steps during this soaking period 2 Plugin the osmometer and turn the power on 3 Remove the sample chamber drain tube from the sample chamber outlet nipple shown in Figure 2 5 20 OPERATOR S MANUAL NOTE The sample chamber drain tube is permanently attached to the waste container lid 4 Open the reference chamber pinch valve lift and turn so the knob stays in the upper position to prevent any pressure buildup during membr
74. ting frame maintains flatness provides a safe and convenient means of handling and positions the membrane upon installation onto the reference chamber of the osmometer cell Packed in saline solution to provide maximum shelf life the membrane requires no preliminary preparation or conditioning prior to installation into the osmometer cell assembly 4 Waste Collection System The waste collection system is connected to the osmometer cell assembly and is an integral part of the sampling system of the osmometer It helps assure accuracy of measurements by a providing a constant gravimetric pressure in the sample and b eliminating capillary end tension effects that would otherwise induce variable back pressure with concomitant measurement error 5 Electronics Most of the instrument electronics are mounted on a single microprocessor controlled printed circuit module that contains the signal conditioning and amplification circuits zero calibrate and prompt unit selection controls The power supply the over pressure alarm transducer and the digital display are mounted on separate printed circuit modules In the unlikely event of a circuit component failure the normal field servicing procedure is simply to replace the entire module This can be accomplished in a matter of minutes Refer to Section 6 Solving Problems for more information on servicing the instrument Appendix B offers additional technical information about the instrument ele
75. to operate the instrument The remaining sections offer more detailed information and procedures that you will need to refer to later We have attempted to make this operator s manual easy to read and convenient to use so that you will want to refer to it often The following is a brief description of the information in this section Each section has a similar outline to help you quickly locate the information you need SECTION 1 contains an overview of this operator s manual 1 1 a description of the Colloid Osmometer 1 2 a list of the instrument s features 1 3 a description of the osmometer s operating controls and connections 1 4 and instrument specifications 1 5 1 1 Operator s Manual Overview This manual provides the information and procedures you need to set up and operate your Colloid Osmometer Section 2 contains important information about the pressure transducer and the installation and care of the semipermeable membrane Section 3 contains proper calibration procedures Section 4 contains proper operation procedures Section 5 contains information about the theory of operation Section 6 contains preventive maintenance information as well as solutions for routine problems you may encounter Appendix A lists available supplies accessories and replacement parts Appendix B contains detailed technical information about the instrument electronics The Bibliography lists authors cited in this manual an
76. uld now read virtually Zero If you still have a small positive offset after flushing out certain samples flush another 1 mL of saline and wait for a stable reading The instrument should return to the zero reference level within 20 to 90 seconds after you inject the saline Do not leave sample in the instrument Note Use standard biohazard safety precautions when operating maintaining or decontaminating the instrument 40 OPERATOR S MANUAL 4 4 Storage Procedures STORAGE BETWEEN USES When the osmometer is idle saline solution should fill both sample and reference chambers and the inner cup of the waste collection system The sample chamber injection port should be closed with a saline syringe and the pinch valve must be closed Empty the waste collection container after each use or whenever the liquid rises to a visible level We recommend that you add a small amount of sodium hypochlorite to the container before installation in the osmometer to help control bacterial growth After reinstallation be sure to inject sufficient saline solution to fill the inner cup of the waste collection system This will prevent evaporation of water from within the osmometer cell that would otherwise allow the membrane to dry out and or result in salt blockage of the chamber ducts Make sure that the reference chamber drain tube is inserted approximately 1 inch into the center hole of the waste container lid LONG TERM STORAGE If the osmometer wi
77. urn Authorization 71 Rinsing Sample Chamber 21 35 38 Salt Deposits blockage 27 40 clearing 59 preventing 23 24 Sample Chamber 6 9 21 27 34 drain tube 9 10 filling 29 injection port 10 27 40 outlet nipple 10 19 rinsing 21 35 38 turbulence 34 Sample Injection 33 procedure 36 Sample Volume 13 and injection procedure 34 and prompted mode 34 Schematic Diagrams interconnection wiring 68 main board 69 power supply 67 Scrambled Display 55 66 Screw Tightening Sequence 21 Selecting Manual or Prompted Mode 34 Selecting Units of Measurement 7 8 30 Semipermeable Membrane 43 Setting Language 65 Shipping Instructions 71 Signal Amplification 63 Small Sample Volume Procedure 36 Software Version Display 15 Solvent Free Energy 44 Solving Problems 55 Specific Weight of Solution 45 Specifications 13 14 INDEX Speed of Response 25 Storage in freezing temperatures 18 40 procedures 27 40 Supplies 61 Syringe Size 14 18 System Diagram 51 Thermokinetic Energy 45 Thomas Graham 43 Tone Transducer 12 flush chamber alarm 18 39 injection pressure alarm 18 repeating 56 Torque Driver AC 012 14 20 21 25 61 Transducer 17 52 57 Transudation 6 26 43 Troubleshooting 55 Tubing 59 obstructions 59 pinched 18 troubleshooting 59 U Tube and Osmosis 45 osmometer 46 shortcomings 45 46 UNITS Control Switch 8 30 35 36 Units of Measurement 7 selecting 8 30 van t Hoff Equation 44 45 48 Vapor Pressure Depression 43 44

Colloid Osmometer Model 4420 Operator & Service Manual

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Colloid Osmometer Model 4420 Operator &amp; Service Manual

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Colloid Osmometer Model 4420 Operator & Service Manual