"service manual"
Contents
1. APPENDIX A Instrument Specifications 2s er Rr Rx APPENDIX B Accessories Supplies and Replacement APPENDIX C Supplemental Information Cystic Fibrosis A Brief Description of the Disease Evolution of Sweat Test Methods Development of the Nanoduct Neonatal Sweat Analysis System ACA Vara a APPENDIX D Instrument Setup Menu APPENDIX E Pilocarpine lontophoresis Requirements and Risks APPENDIX F Serial Data HITS Sane SECTION 1 INIRODUCTION SECTION 1 INTRODUCTION 1 1 Customer Service Thank you for purchasing the Nanoduct Neonatal Sweat Analysis System We believe itis the best diagnostic sweat testing system for newborns available We are confi dent that you will be satisfied with our product Wescor is dedicated to assisting in every aspect of sweat testing theory and practice Wescor is the acknowledged world leader in the development of innovative systems for cystic fibrosis diagnosis by sweat testing This manual contains basic maintenance troubleshooting and service information Wescor is prepared to help you resolve any difficulty with the operation or perform ance of your Nanoduct Neonatal Sweat Analysis System If you are unable to solve problem using the procedures describe2. SECTION 2 SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test 20 B 12 Connect Sensor to the Red Sensor Connector NOTE With the sensor in the holder press the sen sor connector fully onto the red sensor so that the two electrode pins seat in the mating receptacles orientation is not important NOTE The sensor cable must be securely taped to the patient s arm approximately 2 inches from the strain relief Be sure to leave enough slack in the cable on the sensor side of the tape down to protect it from inadvertent tugging Make sure the tape down doesn t disturb the sensor s even con tact with the skin surface Make sure the black electrode cable is still securely taped down Activate Sweat Conductivity Analysis Immediately after the sensor is placed in the holder Press ENTER The instrument will then prompt you to choose to display readings during testing or to suppress the reading for recall at a later time Press SELECT to make your selection and then press ENTER A patient should produce sufficient sweat within 30 minutes after iontophoresis If the Nanoduct does not detect sufficient sweat to report Sweat at First Electrode within 30 minutes or 30 minutes has elapsed between seeing Sweat at First Electrode on the display and seeing sweat testing data appear on the display the test should be aborted due to insufficient sweat production Display with readings suppressed Dis
3. Using the data displayed in Fig 1 which show both sweat rate and conductivity variation with time after stimulation the Nanoduct averaged value over period C was obtained 46 mmol L This can be compared with the value 47 mmol L that would theoretically have been obtained using a Macroduct obtained mixed sweat yield over 30 minutes the standard collection time used in the clinical trial that provided the basic results for the selection of the currently established normal equivocal and CF diagnostic ranges It is clear that the Nanoduct results may confidently be eval uated with reference to these ranges for children under 16 years of age normal 0 to 60 mmol L equivocal 61 to 80 mmol L and CF above 80 mmol L equivalent NaCl In non CF adults the normal range is frequently extended into the equivocal levels but never suffi ciently to provide false positive diagnosis SECTION 3 INTERPRETING THE SWEAT TEST 3 4 Initial Sweating Rate One advantage of the unique continuous flow sensing device of the Nanoduct System is that it allows computation of the initial sweating rate The volume of the sensor channel from the first elec trode to the second electrode contact is precisely known as is the collecting surface area After the sensor is attached to the arm the time taken for this volume to be filled with sweat is measured by the Induction Analysis module Applying an algorithm with the fill time as the sole vari
4. With the development of this neonatal pro cedure the opportunity presented itself to make desirable modifications with the aim of improving the safety and shortening the time of iontophoresis and to provide the electrode gels with protection against acci dental freezing This method was first published in the Annals of Clinical Biochemistry in 2000 8 55 APPENDIX C SUPPLEMENTAL INFORMATION References 1 Gibson L E Cooke E Atest for concentration of electrolytes in sweat in cystic fibrosis of the pancreas utilizing pilocarpine iontophoresis Pediatrics 1959 23 545 9 2 Gibson L E The Decline of the Sweat Test Comments on Pitfalls and Reliability Clin Pediatr 1973 12 450 3 3 Rosenstein B J Langbaum T S Gordes E and Brusilow S W Cystic fibrosis prob lems encountered with sweat testing JAMA 240 1987 1978 4 Gibson L E Cooperative study comparing three methods of performing sweat tests to diag nose cystic fibrosis 5 Webster H L and Lochlin H Cystic fibrosis screening by sweat analysis A critical review of techniques Med J Aust 1 923 1977 6 Webster H L and Barlow W K New approach to cystic fibrosis diagnosis by use of an improved sweat induction collection system and osmometry Clin Chem 27 385 1981 7 Barlow W K and Webster H L A simplified method of sweat collection for diagnosis of cystic fibrosis Proceedings of the 9th International C
5. 62 Using the Self Test The Self Test allows testing of current output con ductivity and battery voltage To use the Self Test select Self Test in the Setup Menu see the far left column of displays CAUTION Do not run Self Test while the module is connected to a patient Using the Demo Mode The Demo Mode is used to simulate typical dis plays that are seen during normal operation This can be useful for demonstrating instrument func tion or to familiarize the user with the instrument No actual iontophoresis or sweat analysis occurs in this mode and only simulated results are shown In this mode the instrument functions much like it would when running on an actual patient The display screen and menu appears as it would during an actual test with the exception that Demo Mode appears at the top of the dis play and the Check Controls option is not avail able while in this mode The instrument must be operated in Normal Mode in order to check con trols or calibrate While running in this mode the ENTER key acts as a shortcut key and advances the instrument through the phases of the operation allowing yo to see the next display without waiting for the full instrument countdown APPENDIX E PILOCARPINE IONTOPHORESIS REQUIREMENTS AND RISKS APPENDIX E PILOCARPINE IONTOPHORESIS REQUIREMENTS AND RISKS In common with all sweat test procedures for the diagnosis of cystic fibrosis since the ince
6. SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test WARNING IMPORTANT NOTE Due to the remote possibility of ignition never attempt iontophoresis on a patient receiving oxy gen enriched respiratory therapy in an enclosed space With medical approval remove the patient from that environment during iontophoresis Check calibration before each session of use by using the instructions in Section 4 4 m Sensor Cell and Sensor Cell Connector DA Pilogel lontophoretic Discs 1 Assemble Equipment and Supplies alibration Plate Make certain you have everything on hand for the complete procedure e Sweat induction analysis module Two holders Two holder straps with strap retainer posts e Two Pilogel discs Analysis One sensor DOT Electrode cable for connecting the ion tophoretic electrodes or the sensor to the induction analysis module Sensor Cell Connector You will also need a supply of deionized Holders amp Straps water alcohol cotton balls or gauze pads and cotton swabs and a roll of 1 inch wide plastic surgical tape 3M Transpore rec ommended Make sure that the battery for the sweat inducer analysis module is not dead and that the gel discs are rubbery translucent and not cracked or otherwise damaged lontophoretic Electrodes Electrode Cable Assembly Strap Retainer Posts 2 Inspect Electrodes Leads and Cables a Clean the
7. In addition if a new calibra tion is completed the new date time and calibration value will be transmitted to the printer or computer The Nanoduct serial port uses a DB9 connector on the instrument front panel This port is for asynchronous serial communication with a printer or computer It uses standard non return to zero NRZ format at RS 232 voltage levels SERIAL OUTPUT TECHNICAL DATA Output voltage level Nominal 9 volts Maximum 15 volts Minimum 5 volts Data protocol 9600 bps 1 Start bit 8 Data bits No parity 1 Stop bit By entering Self Test Mode the following serial output can be sent DATE TIME PRINT TEST This can be used for testing the printer and cable 69 APPENDIX D SERIAL DATA OUTPUT Pin Diagram mn CEN 72 Mnemonic Description 000090 1 N C No Connection 2 Heceive Data output 6 7 8 9 3 TXD Transmit Data input 4 N C No Connection 5 GND Signal Ground passive 6 N C No Connection 7 N C No Connection 8 N C No Connection 9 N C No Connection The serial port is configured as Data Communications Equipment DCE This enables the Nanoduct to be connected directly to most computers which are usually configured as Data Terminal Equipment DTE Most printers are configured as DCE in which case a null modem cable is required Data output is in ASCII characters Reading format of output _ _ DATE TIME READING mmol L eq NaCl Calibration format of output CAL DATE
8. L and display 80 mmol L eq NaCl when completed Optionally for checking control values connect the sensor cell connector to any of the 3 control values The selected value will show corresponding mmol L eq NaCl 1 Refer to the following page to see how this procedure is followed using the dis play screen prompts SECTION 4 TROUBLESHOOTING AND PREVENTIVE MAINTENANCE 4 4 Calibration and Checking Control Values Date and time indications are in the format yyyy mm dd hh mm Dates times and other data shown are for example only Actual data during use will vary Shows date and time of last cali bration for a few seconds Sends data to serial port Connect the sensor cell connector to the 80 mmol L connector on the calibration plate Sends data to serial port APPENDIX A SPECIFICATIONS APPENDIX A SPECIFICATIONS Readout 128 x 64 dot graphic Supports up to 8 lines of 18 charac ters or numerals with multi lingual support bs Alert and Alarm signals Keyboard ON OFF SELECT and ENTER keys Electrode Connection 6 pin locking medical connector to mate with induction con ductivity cell cable Serial Connection 9 pin connector compatible with RS232 Electrical One 9 0 Volt Lithium battery Alkaline b
9. TIME 80 mmol L eq NaCl 70 INDEX Accessories 47 Alkali Accumulation during ion tophoresis 8 Anodic Acidification 8 Automatic Averaging 21 25 27 Battery low 10 18 33 replacement 10 37 Buffer see Trisodium Citrate Burns Under lontophoresis 65 66 Cable Assembly 9 13 18 Cable Connector Socket 9 Calibration 38 39 Citrate Buffer see Trisodium Cit rate Conductivity automatic average 9 21 25 cell 10 measurement 9 10 21 25 26 27 Units of 10 21 25 26 Configure Option 59 60 Current DC 6 flow indicator 18 Customer Service 3 Cystic Fibrosis CF 6 54 Diagnostic Ranges 28 Display 9 10 21 language settings 61 suppressed readings 10 60 Environmental limits 4 Electrode s anodic positive 7 14 18 cable assembly 7 13 cathode negative 7 14 cleaning 34 color coding 8 flanges 7 inspection 13 installing 16 17 iontophoresis 7 reference 7 First Sample Phenomenon 27 Fault Condition 9 low battery 9 10 33 open electrode 9 33 circuit 9 33 Flanges 17 Glycerol 8 High Resistance 14 33 Holder s 7 13 14 22 straps 13 14 15 rings 16 17 Induction Analysis Module 6 7 9 10 13 20 22 lontophoresis 6 9 13 16 18 61 62 current 6 18 61 62 time 18 Initial Sweating Rate 9 21 29 Keypads ON 9 18 OFF 9 22 9 18 21 SELECT 9 21 Latching Flanges 17 LCD Readout See Display Low Battery Indicator 10 18 33 Microconductivity cell see c
10. are secure and cable is con nected to control unit Inspect cable for any damage The patient s sweat rate may be very low Wait sufficient time to allow sweat to flow Not to exceed 30 minutes Orifice on sensor cell blocked Set Clock menu is displayed when instrument is turned on Battery for clock is dead Replace clock battery NOTE This instrument is designed and tested to meet EN61326 standards for electromagnetic compatibility for laboratory equipment However if you suspect electromagnetic susceptibility or interference reorient or relocate the equipment to correct the problem 33 SECTION 4 TROUBLESHOOTING AND PREVENTIVE MAINTENANCE 4 2 Cleaning the Instrument When needed the induction analysis mod ule surfaces and accessories should be wiped down using a soft cloth dampened with mild detergent or 1096 household bleach solution Electrodes must be cleaned following each iontophoresis procedure as follows 1 Remove any remaining gel from electrodes 2 Use a cotton ball or swab moistened with purified water to clean each electrode thor oughly 3 If the electrode appears dirty after an extended idle period or will not clean with steps 1 and 2 use a small round piece of light duty cleaning pad such as 3M Scotch Brite 7445 to buff the electrode surface CAUTION Never use harsh abrasives such as steel wool sanapaper or emery cloth to clean electrodes Never scrape electrodes with metal
11. electrodes if necessary see Section 4 2 Check the lead wires and insu lation for damage b Connect the electrode cable assembly to the electrode socket 13 SECTION SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test 2 3 JANODUCT m NOTE WESCOR Calibrate and Check Control Values Turn the power on Check for low battery condition on the display The arrow on the display should indicate Check Controls on the menu We recommend checking control values using the built in calibration plate before each session See Section 4 4 for details Selecting the FORCE CAL option will bring up the Check Controls operation whenever the instrument is turned on See Appendix D Clean Selected Skin Areas Select the anodic positive skin site for the greatest density of sweat glands The site must be well removed from the wrist where movement of tendons or ligaments could possibly affect the stability of the attached units In neonates the optimum site is the flexor aspect of the forearm approximately half way between wrist and elbow The cathodic negative electrode site is not as critical place it an inch or two from the anode in the direction of the elbow WARNING 14 Never place electrodes across the chest or on opposite limbs Even though the DC iontophoretic current is extremely low there is a very remote risk of interference with cardiac rhythms Inspect the selected site
12. presentation to an instrument for analysis would clearly not be feasible because the potential for serious error would be very difficult if not impossible to control ouch limitations could be avoided if no attempt was made to collect the minute sweat yield Instead the sweat is chan neled from the sweat duct openings in such a way that it passes directly and anaerobically into a conical collecting interface just as it does in the Macroduct device and thence to a microbore tube within the collector that is equipped with APPENDIX C SUPPLEMENTAL INFORMATION Development of the Nanoduct Neonatal Sweat Analysis System electrodes and becomes a conductivity cell for analysis of electrolyte concentra tion Research and development at Wescor provided evidence that this approach was feasible and sweat tests using the prototype equipment illustrated the simplicity and ease of operation of the method and the speed at which definitive results could be obtained In effect the apparatus called the Nanoduct Neonatal Sweat Analysis System incorporates a flow through con ductivity cell that provides in situ continu ous readings as the sweat enters it from the sweat ducts This type of data has not been available in any test method to date making the Nanoduct unique All other methods involve analysis of a mixed sam ple obtained over the whole collection period The sweat is not seen nor is it col lected as a visible sample
13. 6 At the cathode the increased pilocarpine a good buffer at moderately alkaline pH also reduces iontophoretic accumulation of alkali This buffering prevents skin burns due to pH change in the gel Each of these features contribute to the safety of the procedure See Appendix E for important information about pilocarpine ion tophoresis Sensor Cell Color coded red the sensor has two external flanges as with the electrodes for latching to the red holder The base of the sensor is a shallow concavity leading at its center to an entry port and from there to an internal fine channel passing by two analyzer micro electrodes forming a microconductivity cell The sensors pass through stringent quality con trols before shipment to the customer To be accepted sensors must be highly consistent throughout each batch SECTION 1 INTRODUCTION 1 5 System Description INDUCTION ANALYSIS MODULE The battery operated electronic induction analysis module controls the Nanoduct system The mod ule performs 6 separate functions Provides a timed and controlled current for iontophoretic sweat stimulation Measures electrical conductivity of the excreted sweat during the analysis phase Automatically averages the conductivity reading over defined 5 minute period computes the initial sweating rate Displays the above information on the LCD readout and reports sweat test and calibra tion results to the serial por
14. NANODUCT Neonatal Sweat Analysis System Instruction Se 57 0803 01A COPYRIGHT 2006 WESCOR INC O 2006 Wescor Inc All rights reserved Printed in the United States of America Wescor Nanoduct and Pilogel are trademarks of Wescor Inc Other trade names used in this manual may be trademarks of their respective owners used here for information only U S Patent Number 6 198 953 All information in this document is subject to change without prior notice TABLE OF CONTENTS section 1 INTRODUCTION 11 Customer Service erre rne bert aan 3 1 2 Important User Information 4 1 3 System DESCHONOMN een 5 section SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat 13 section 3 INTERPRETING THE SWEAT TEST 31 Units of Conductivity en 25 3 2 Automatic Averaging sse 27 9 9 Diagnostic 5 REC Rt ti EE E ee 28 3 4 Initial Sweating 29 ii TABLE OF CONTENTS section 4 TROUBLESHOOTING MAINTENANCE 4 1 Troubleshooting EA 585550885482 4 2 Cleaning the Instrument 4 3 Battery Replacement 4 4 Calibration and Checking Control
15. PPENDIX B ACCESSORIES SUPPLIES amp REPLACEMENT PARTS APPENDIX B ACCESSORIES SUPPLIES amp REPLACEMENT PARTS ACCESSORIES Calibration Plate AC 081 Nanoduct Patient Simulator AC 111 SUPPLIES Nanoduct Supply Kit for 6 sweat tests 55 043 Nanoduct User s Manual RP 360 REPLACEMENT PARTS Nanoduct Control PCB Assembly Factory Service Only Electrode Cable Assembly HP 359 Strap Retainer Post HP 353 Positive Red Electrode and Sensor Cell Holder RP 357 Negative Black Electrode Holder 358 Holder Attachment Strap Small 1 each 354 Holder Attachment Strap Medium 1 each 355 Holder Attachment Strap Large 1 each 356 Case Latch 1 each 347 Clock Battery 1 each 238 47 APPENDIX C SUPPLEMENTAL INFORMATION APPENDIX C SUPPLEMENTAL INFORMATION Cystic Fibrosis A Brief Description of the Disease Cystic fibrosis of the pancreas or muco viscidosis is due to one of the many known inborn errors of metabolism that are fundamentally the result of aberrations in the structure of the genetic material It is classed as lethal because of the ver
16. PPLEMENTAL INFORMATION The sweat test has traditionally involved three separate sequential procedures stimulation of the sweat glands collection of their secretion and sweat analysis Early stimulation procedures involved total body heating followed by placing the patient in a bag or later by heating fol lowed by collection from a limited area of skin covered by a hermetically sealed absorptive pad Both of these methods endangered the infants and proved unsat isfactory The heating was eventually avoided by using pilocarpine iontophoresis to induce the glands to sweat maximally Following this the sweat was collected in a pre weighed pad and re weighed eluted and analyzed The method is usually known as the Gibson and Cooke pad absorption sweat test or the QPIT quantitative pilocarpine iontophoresis test This procedure has persisted over the years and is still being performed particularly by CF centers It is time consuming and tedious requiring many manipulations where human error may intervene and in one particular step offers technical difficulties that virtually ensure some degree of error particularly when the sweat sample size is very small Laboratorians in CF centers who special ize in this method develop the requisite skill to maintain reasonably accurate results but this is generally not the case in outlying clinics and hospitals where the test is only occasionally requested leading to unacceptably
17. TION AND ANALYSIS 2 1 Performing the Sweat Test 15 Remove Holders and Sensor and Clean Electrodes Disconnect the cable from the sensor remove the sensor from the holder and dis card the used sensor Disconnect the cable plug from the socket of the Sweat Induction Analysis module and turn OFF the power Remove the holders from the patient and gently wash and dry the entire skin areas involved in the test Wash and dry the electrode plates wash amp dry metal plates 16 Recall the Display Reading If you selected SUPPRESS READINGS or if the control unit powers off the last reading can be recalled by selecting RECALL READ ING on the display menu and pressing ENTER Recall Reading also outputs the last read ing to the serial port where it can be printed if a serial printer is connected to the port 22 SECTION 3 INTERPRETING THE SWEAT TEST SECTION 3 INTERPRETING THE SWEAT TEST 3 1 Units of Conductivity Electrical conductivity essentially an electrical measurement should properly be measured in siemens cm However we use conductivity to indi rectly measure electrolyte concentration Since medical professionals are more familiar with stan dard chemical units such as mmol L for concen tration the siemens cm units have not been used for conductivity values in the practice of clinical chemistry to prevent confusion Wescor has retained the mmol L equivalent NaCl unit used by other swea
18. Time Bar shows the remain ing time Current will then decrease to zero indicated by a short beep The display will show IONTOPHORESIS COMPLETE Compilere C Press ENTER to return to the main menu 9 Remove the Red Electrode While applying pressure to the red electrode with the index finger rotate the upper ring approximately 90 clockwise until the cut outs align with the electrode flanges Then remove the electrode CAUTION Do not disturb or remove the red holder It must remain in place during analysis In addition leave the negative black electrode gel holder and tape downs in position to provide a ground con tact for initial sweat rate determination 18 SECTION 2 SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test 1 Clean and Dry the Skin in the Collecting Area Use a cotton swab to absorb any surface moisture from the entire skin area inside the holder followed by clean dry swabs to completely dry the area Without delay proceed to the next step NOTE Ifthe sensor is not inserted immediately repeat the cleaning and drying procedure just before attaching the sensor 11 Insert Sensor Into Positive Holder Insert the sensor without being attached to the wiring harness into the holder red locking ring as described in steps 7a and 7b taking care not to disturb the holder or touch the bottom of the sensor Confirm that the Induction Analysis module is ON 19
19. able allows a display of the initial sweating rate in the conventionally accepted units of grams per square meter of skin surface per minute This datum is available when the first reading is dis played on the continuous record of conductivity 29 SECTION 4 TROUBLESHOOTING AND PREVENTIVE MAINTENANCE SECTION 4 TROUBLESHOOTING AND PREVENTIVE MAINTENANCE 4 1 Troubleshooting SYMPTOM CAUSE SOLUTION High resistance fault during iontophoresis High skin or electrode to skin resist ance Inspect the electrodes and clean if nec essary Place a drop of deionized water directly on the clean skin beneath the pilogel disk Make sure the electrodes are secured with adequate tightness to the patients limb Open loop fault during lontophoresis Loose electrode or broken cable Be sure both electrodes are inserted into the holders and that the cable is connected to the control unit Over current fault during iontophoresis Control unit may be damaged Do not continue to run or use the con trol unit Contact Wescor for further instructions Control unit immediately shuts off Battery voltage too low Replace bat tery Control unit failure Contact Wescor for further information Low battery display Low battery voltage Replace battery Display remains blank when turned on Dead battery Replace battery Display does not change from Waiting For Sweat No sweat detected Check expiration date on Pilogel Check that straps
20. ally The diagnostic range is therefore different from that established for chlo ride The electrolyte selected for calibration reference happens to be sodium chloride but it could have been any other salt The chemical nature of the calibration solution is immaterial because the ref erence ranges for sweat conductivity will be based upon comparison with the calibration value and will be valid whatever electrolyte is used as a ref erence For example if lithium nitrate had been selected as the reference salt it may have pro duced a possibly different but equally reliable and effective reference range Conductivity values would then have been expressed as mmol L equivalent LINO3 Though such an alternative calibration option is not recommended it would have had the advantage that since no mention of sodium or chloride is made the results would not be mistakenly seen as representing actual sweat sodium or chloride levels 26 SECTION 3 INTERPRETING THE SWEAT TEST 3 2 Automatic Averaging Automatic Averaging Examination of the data showing the relationship between sweat conductivity and time after attach ing the sensor obtained on all the subjects in the Original test of the system and typically shown in Fig 1 allowed the selection of optimal settings for the averaging circuitry After a variable lapse of time Period A Fig 1 during which the sweat is gradually filling the channel in the sensor it reach es the secon
21. aramount among the sys tem s several unique features was the innovative MACRODUCT disposable sweat collector 53 APPENDIX C SUPPLEMENTAL INFORMATION Development of the Nanoduct Neonatal Sweat Analysis System During almost twenty years of successful deployment of the Macroduct Sweat Chek System it began to be realized that a truly neonatal sweat test was needed one that preserved the error free anaerobic han dling of the sweat sample employed in Macroduct yet at the same time was par ticularly designed to meet the special requirements of the newborn infant during the first two weeks of life In the interests of effective early manage ment of newborn CF patients it is highly desirable that a definitive laboratory diag nosis be made as early as possible allow ing prompt initiation of appropriate medical procedures especially those correcting malnutrition due to pancreatic deficiency and those protecting the infant from airway problems The frequency of insufficient sweat or sweat reports from labora tories has been unsatisfactorily high throughout the history of sweat testing on very young infants Recent years has seen increasing emphasis on screening tests to newborns particularly the combination of immuno reactive trypsin assays and genotype analysis Both of these have been very useful but have not reached the status of a definitively diagnostic pro cedure as has the sweat electrolyte test The rea
22. attery may be used 100 milliwatt power use during operation Typical solid state over current circuit protection 3 0 Volt lithium coin cell for real time clock Sweat Induction Control Current profile controlled for use with Pilogel amp lontophoretic disks with multiple fail safe circuits to limit current Nominal current is 0 5 2 02 mA for 2 5 minutes 02 Sec Maximum fail safe current limited to 5 mA Sweat Analysis Conductivity with readout in mmol L equivalent NaCl Range 3 to 200 mmol L equivalent NaCl Error 1 or less from 25 to 150 mmol L equivalent NaCl Initial sweating rate reading O to 50 g m2 min Single point automatic cali bration 80 mmol L equivalent NaCl Real Time Clock 2 minutes per year Operating Temperature 15 to 30 degrees C Storage and Transport Temperature 0 to 60 degrees Regulatory an dodo dew GRO A Meets EN 61326 Standards for EMC compatibility Meets IEC 60601 standards for safety Manufactured under Wescor s quality system ISO 13485 2003 Bears the CE mark as a Class lla medical device Certificate issued by BSI 0086 ed sob dido eco pa a eb Housed in portable carrying case Storage compartment for supplies Handle for ease of carrying HEION MP T m 16 cm eae ge a es RUP S X E SOROR an ge ee US 23 cm Bro SM 33 cm esencias peas Less than 2 25 kg 43 A
23. d electrode thereby completing the conductivity cell circuit and producing a displayed conductivity reading During the next 3 minutes Period B Fig 1 this reading usually falls sharply and then assumes a steady rate of decrease that is maintained thereafter Fig 1 Rate of Sweating g m min This initial rapid change has been termed the first sample phenomenon and the reason for it is not 0 5 10 15 20 25 30 35 yet clear In the steady phase of decrease of con ductivity the average rate of decrease is about 1596 per 10 minutes during the period 10 to 20 A Conductivity v Time minutes after the first reading The best time peri od for averaging commences after the initial rapid Rate of Sweating v Time fall stabilizes that is at 3 minutes from the first reading thus avoiding the first sample phenome non It then continues for the next five minutes Period C Fig 1 during which the sweating rate is still near maximal The induction analysis module is therefore pro grammed to make an average conductivity assessment by noting the time at which the first conductivity result is displayed allowing a time lapse of 3 minutes and then commencing a 5 minute averaging period after which the mean value is displayed 2 SECTION 3 INTERPRETING THE SWEAT TEST 3 3 Diagnostic Ranges Normal 0 to 60 mmol L Equivocal 61 to 80 mmol L CF above 80 mmol L equivalent NaCl 28
24. d in this manual please contact us Customers should contact Wescor by telephone fax or e mail Outside the U S many of our authorized dealers offer customer service and support TELEPHONE 435 752 6011 Extension Operator 171 Orders 172 Service 173 Product Information amp Pricing TOLL FREE US and Canada 800 453 2725 Extension 0 Operator 171 Orders 172 Service 173 Product Information amp Pricing FAX 435 752 4127 E MAIL service wescor com WEBSITE WWW Wescor com biomedical MAILING ADDRESS Wescor Inc Biomedical Products Division 459 South Main Street SECTION 1 INTRODUCTION 1 2 Important User Information This manual describes the complete procedure for the laboratory diagnosis of cystic fibrosis particularly in the early neonatal period through examination of sweat electrolyte concentration using measurement of electrical conductivity Section 1 gives a brief description of the system and its components Section 2 describes the procedure for stimulating and analyzing sweat Section 3 gives needed information on the analysis of sweat In addition instructions for troubleshooting and maintenance of the system are provided in Section 4 A detailed description of the development of the Nanoduct System is presented in Appendix C INTENDED APPLICATION AND CLASSIFICATION APPLICATION The Nanoduct System is intended for laboratory use by qualified personnel to provide laboratory diagnosi
25. der precisely over the cleaned skin site selected for sweat stimulation and hold it down while drawing the free end of the strap down and around the arm Pull the strap to tighten stretching slightly and affix it to the retainer post 15 SECTION 2 SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test NOTE 16 Grip the holder and lift it briefly above the skin to equalize strap tension on each side of the holder then replace it on the skin sur face Adjust strap tension as needed to ensure correct contact Attach the strap firmly but avoid excessive tightness Correctly applied the holder should grip the skin firmly enough to resist moderately forceful attempts to change its position The surrounding skin areas should move with the holder when it is moved Draw the skin back around the holder to remove any underlying wrinkles Position the negative black holder on the same limb in the same manner 6 Insert Pilogels Into the lontophoretic Electrodes Insert a gel into each electrode assembly Press lightly and rotate to ensure an air free and moist interface between electrode plate and gel 7 Insert Each Electrode Into Its Holder Fit the red positive anode into the hold er with the red locking ring and fit the black negative cathode into the holder with the black locking ring as follows SECTION 2 SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test 2 a Rotate the holder
26. ence of allergic sensitivity to the drug Wescor gel drug reservoirs are quality controlled to meet these requirements in Pilogels manufactured in house using spectrophotometric procedures to check the pilocarpine content of the gels in each batch Burns Under lontophoresis Minor skin burns have been an unwel come adverse side effect of pilocarpine iontophoresis from the beginning Unusual sensitivity to pilocarpine has sometimes been assumed to be the cause of burns but there is no firm evidence for this con tention Majority opinion seems to support the proposition that some types of stimu lating apparatus are prone to cause burns particularly when associated with proce dural error Such burns are extremely rare with Wescor sweat stimulating systems They use a sophisticated microprocessor con troller and a very low total delivery current 0 5 milliamperes in the Nanoduct System Pilocarpine is contained in unique gel reservoirs The gels also include compounds that further protect the patient from skin damage by preventing acid accumulation by minimizing the risk of gel breakage and by substantially reducing the time of electrical drug trans port These features markedly reduce but do not entirely eliminate the possibility of skin burns 65 APPENDIX E PILOCARPINE IONTOPHORESIS REQUIREMENTS AND RISKS Most individuals exhibit a mild erythema redness at the skin stimulation site In some cases one or m
27. eric read out displays all func tions and results as they occur including ion tophoresis status and analysis results plus the time and date of the last procedure The user responds to prompts on the display to activate various functions The instrument emits a short beep tone at the start and end of each operation The instrument displays conductivity measure ments in mmol L equivalent NaCl during analy sis If desired display readings can be suppressed 50 readings are not visible but can be recalled at a later time LOW BATTERY Indicator If the battery voltage drops below a preset level as the instrument is turned on Low Battery appears on the display When this indicator first appears you can usually complete 1 to 2 tests before a dead battery If battery power is too low to com plete a test the module will automatically shut off and iontophoresis cannot be started You must replace the battery to continue See Section 4 3 for information Note The inducer analyzer is powered by one 9 Volt cell which should provide a minimum of 100 tests with a standard alkaline battery or 200 tests with a lithium bat tery SERIAL PORT Connector The RS232 compatible connector can be used to print out results of sweat tests with a time and date stamp Do not connect a line powered printer or computer when the instrument is attached to a patient See Appendix F for details SECTION 2 SWEAT INDUCTION AND ANALYSIS SECTION 2
28. et of symptoms that were not as yet associated with a specific illness It should be noted here that CF sufferers may differ quite widely in the degree to which they exhibit the various symptoms Some may be rela tively less affected in the respiratory air Ways others may show more serious pan creatic problems A feature of the inheri tance is that carriers do not exhibit the symptoms of CF In 1953 it was found that children afflicted by the disease are prone to acute hypona tremia during hot weather Investigations on the cause of the loss of sodium showed that the eccrine sweat of children with CF contains 3 to 4 times as much salt as that of unaffected subjects Subsequent work showed that this salt increase is not observed in presumed carriers This was the first intimation that a laboratory test for the disease was conceivable The sweat test was born and remains to this day the principal laboratory diagnostic test for this disease In recent years the discovery of the CF gene promised a new laboratory diagnostic approach Intensive studies of this gene have revealed hundreds of vari ants that may or may not produce the typical CF symptoms There is no doubt that this research will in the future illuminate the effects of different genetic abnormalities on the biochemical patterns of the individual However the sweat test will remain the definitive labora tory diagnostic test for some time yet 51 APPENDIX C SU
29. f inducing sweat by pilocarpine iontophoresis The pilocarpine is introduced into the skin of the patient using controlled DC electrical cur rent from the Nanoduct induction analysis module This is followed by continuous flow analysis using the unique sensor Storage Container Results appear quickly on the display During the process the operator installs and then removes the various components that fit in the holders described later A description of the various components of the Nanoduct system follows lt Sensor Cell Connector Holders lontophoretic Electrodes SECTION 1 INTRODUCTION 1 5 System Description Holders Two plastic holders are attached to the patient with comfortable but secure non latex elastic straps These holders accept the electrodes and later the sensor holding them securely against the patient s skin Holders are color coded one red to accept the positive anode and subsequently the red sensor the other black to accept the nega tive cathode Strap retainers are pushed through the holes in the strap to maintain the correct ten sion lontophoretic Electrodes Two color coded electrodes one red for the anode positive and the other black for the cathode negative are otherwise identical both having a small stainless steel disc as the electrode plate These electrodes are part of the electrode cable assembly see below that also includes the sen sor cell co
30. h either the hours or minutes flashing Select hours first and enter the correct hour and press ENTER Then select Minutes and enter the correct minute Then press ENTER Setting Year Month and Day 1 Select Set Date and press ENTER 2 While the year position is flashing press SELECT to adjust the year Then press ENTER 3 While the month position is flashing press SELECT to adjust the month Then press ENTER 4 While the day position is flashing press SELECT to adjust the day Then press ENTER Press EXIT to return to the previous MENU 60 APPENDIX D USING THE SETUP MENU Setting or Adjusting Options 1 While in the Configure Menu select Set Options and press ENTER 2 To either display or suppress the results of the sweat test select either Suppress Readings or Display Readings and press ENTER 3 The Calibration Option menu allows you to automatically go to the Check Controls menu on power up of the instrument Choose Force Cal for this option or Cal Optional to calibrate only when you need to Press ENTER when you have made your selection Setting Language Options 1 You can set the display language in the con figure menu Select Change Language and then press ENTER 2 Select the desired language and then press ENTER Select and press ENTER to return to the SETUP MENU 61 APPENDIX D USING THE SETUP MENU Self Test displays Minn Demo Mode displays
31. high risk of false results While the iontophoretic transport of pilo 22 Evolution of Sweat Test Methods carpine into the glands has remained the universally preferred method of sweat stimulation to this day the need for a sim pler method of collection and analysis spawned the development of alternative procedures during the late 60 s and early 70 Principally among these were the cup collection systems which used electri cal conductivity for analysis and the direct skin chloride electrode system These methods were highly innovative procedurally simpler than the Gibson and Cooke method and were initially commer cially successful They nevertheless failed in their objective to eliminate false diag nostic results The adoption of these new procedures on a wide scale exacerbated the problem evoking a storm of criticism in the professional literature with calls for a return to the original pad absorption which was now regarded as the reference method 3 4 In fact CF referral centers in the United States operating under accreditation of the Cystic Fibrosis Foundation were forbidden to use any sweat test method other than the QPIT These early attempts to simplify the sweat test failed for two principal reasons 1 error intrinsic to the method of collection and beyond the control of the operator or 2 extreme susceptibility to variations in operator technique The direct skin chlo ride electrode though offeri
32. lkaline bat tery ANSI NEDA 1604 4 Push the battery pack back into the instru ment until the retaining latch engages 5 Dispose of the spent battery according to battery manufacturer s instructions and local regulations NOTE fthe instrument will be unused for an extended time remove the battery Batteries can leak and damage terminals if left unused for extended periods 21 SECTION 4 TROUBLESHOOTING AND PREVENTIVE MAINTENANCE 44 Calibration and Checking Control Values 38 LI Patient Simulator Wescor offers the Patient Simulator for those who wish to measure unknown sam ples as part of a proficiency study or to veri fy or validate the function and accuracy of the Nanoduct instrument Contact Wescor for more information NOTE This instrument uses an extremely stable single set point calibration The calibration plate is provided to verify that the instrument is functioning properly and to allow for re calibration when necessary The calibration plate has one calibration value 80 mmol L equivalent NaCl and three control values 40 60 and 120 mmol L equivalent NaCl Instructions Select Check Controls on the menu and press ENTER Connect the electrode cable assembly to the electrode socket and connect the sensor cell connector to the 80 CAL connection on the calibration plate Select Calibrate and press ENTER The instrument will now cali brate to 80 mmol
33. locking ring to align cut outs with those of the underlying holder the arrow indicator should be at Position 1 shown at left Match the latching flanges of 1 the electrode with the cut outs and insert the gel fitted electrode into the holder Locking Ring Electrode b Lightly press the electrode down against the skin and maintain pressure while rotating the locking ring counter clockwise until the arrow indicator is in line with the holder strap holes Position 2 at left Release pressure on the electrode and continue to slowly rotate the locking ring counter clockwise until the electrode clicks into the detent Position 3 at left Latching Flange NOTE Electrode wires must be securely taped to the patient s arm to prevent disturbing the gel to skin contact during iontophoresis Use 1 inch surgical tape to secure wires firmly to the skin about 2 inches from each strain relief Leave slack between taped area and electrodes to pre vent strain to the electrode assembly 17 SECTION 2 SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test 5 Activate lontophoresis a X After completing Check Controls the arrow on the display should indicate lontophoresis on the menu b Press ENTER to start iontophoresis The dis play will show INCREASING CURRENT Once current has reached the full 0 5mA the dis play will show FULL CURRENT and that level is maintained for 2 minutes Once full current is achieved the
34. ng unrivaled simplicity was very prone to operator vari ability in manual skill and gave poor results due mainly to great difficulties experienced in the control of evaporation error APPENDIX C SUPPLEMENTAL INFORMATION Evolution of Sweat Test Methods The cup collection method was examined for potential intrinsic error by Webster who found that the phenomenon of con densate formation on the walls of the plas tic cups was the principal cause of the trouble His quantitative measurements of the degree to which this occurred in unheated plastic cups showed that the error was always significant and very often reached proportions sufficient to produce false positive results The error was avoid ed by using a metal collector cup that was maintained at above skin temperature throughout sweat collection condensation was prevented and the error disappeared In 1978 Wescor introduced the Model 3500 Webster Sweat Collection System that employed an electrically heated metallic collector cup It was the first simplified sweat collection system worthy of comparison with the Gibson and Cooke method it enjoyed considerable success and was free from any criticism by users and related professionals It was however burdened by a problem common to all cup collection systems that is the need to harvest the sweat accumulated beneath the cup during collection Wescor s determined commitment to resolve this problem eventually led to
35. nnector to attach the separate sensor cell Both electrodes have projecting flanges for securing the electrodes in the holder rings Electrodes provide current from the module through Pilogel discs during iontophoresis The black cathode electrode also serves as an electri cal reference to detect sweat flow to the sensor cell during the analysis phase Electrode Cable Assembly This dual purpose cable assembly includes the red anode and black cathode iontophoretic elec trodes and also the red sensor cell connector The cable connects to the Induction Analysis Module at the electrode connection socket SECTION 1 INTRODUCTION 1 5 System Description Pilogel lontophoretic Discs Pilogel lontophoretic Discs Pilogel discs are small surface area 2 5 cm ion tophoretic discs that are inserted into the elec trode assemblies prior to iontophoresis These discs are designed especially for neonates and have a pilocarpine concentration of 1 5 96 for opti mum stimulation of the sweat gland and to reduce iontophoresis time to approximately 2 5 minutes Pilogel discs contain sufficient glycerol to provide substantial protection of gels against damage from accidental freezing Cracked discs due to freezing can contribute to burns See Appendix E for more information Pilogels contain trisodium citrate an excellent buffer in the acid range of pH This reduces anod ic acidification of the gel during iontophoresis by 909
36. on ductivity cell ON Switch see Keypads Open Loop Fault 33 Patient Simulator 38 47 Pilogel lontophoretic Discs 8 13 16 33 65 Pilocarpine lontophoresis See iontophoresis Pilocarpine 8 65 66 Power Supply 43 Quality Control 8 Recall Reading 22 Replacement Parts 47 Self Test Option 62 INDEX Sensor 8 13 18 20 21 27 cable 20 connector 7 13 20 flanges 8 socket 9 Setup Menu 59 Skin condition 14 65 66 electrical impedance of 14 Specifications 43 Supplies 47 Suppress Reading 22 Sweat analysis 6 9 10 analysis results 10 chloride in 26 contamination of 14 flow 7 glands 14 61 sodium levels 26 stimulation 9 61 rate 7 21 33 test 21 Trisodium Citrate in Pilogels 8 Troubleshooting 33 Units of Conductivity Measure ment 10 21 25 26 73
37. ore blister like welts may also form These are often mistaken for burns but are more likely to be a tem porary reaction to the passage of electrical current Such blisters invariably disap pear within 2 or 3 hours leaving no after effects Based on current data and reported events the apparent burn rate using Wescor instruments is less than 1 in 50 000 The low rate is due to Wescor s insistence on proper test procedures together with built in equipment safety pro visions that minimize the risk of even mild skin injury It is highly unlikely that patients will suffer a burn during the stimulation phase of the sweat test We realize these statistics will be of scant comfort to the parents of a child who has the misfortune of suffering the 1 burn in 50 000 However experience has shown that when burns do occur the injury is minor with little or no scarring 66 APPENDIX F SERIAL DATA OUTPUT APPENDIX F SERIAL DATA OUTPUT Data is automatically sent out on the serial port whenever Recall Reading or Check Controls is selected from the main menu If a printer is correctly connected to the serial port the data can be printed or the data can be captured with the use of a computer The output from the Recall Reading selection will be the date time and result from the last sweat test completed The output from the Check Controls selection will be the date time and calibration value from the last calibration
38. play with readings shown SECTION 2 SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test 14 Record the Result With the sensor in place the display usu ally indicates sweat contact with the first electrode within a few minutes After another 2 to 6 minutes all timing is approximate the conductivity display should begin to show continuous data if DISPLAY READINGS has been selected Simultaneously the initial sweating rate in g m2 min is displayed If the black elec trode is removed and the Initial Sweat Rate is reported as invalid the result from the sweat test remains valid The continuous data remains on display and after 3 minutes the display shows that averaging has commenced The time bar at the bottom of the display indicates remaining time once sweat reaches the second electrode The mean sweat con ductivity is displayed after another 5 min utes This value is compared with the estab lished conductivity ranges for children under 16 years normal 0 to 60 mmol L equivocal 61 to 80 mmol L and CF z above 80 mmol L for a diag nostic appraisal and becomes the report ed test result A typical final display is shown at left See Section 3 for complete information Once the test is completed the display flashes COMPLETE and the control mod ule emits a short beep The date and time the test was completed is displayed Press ENTER to return to the main menu 21 SECTION 2 SWEAT INDUC
39. ption of the sweat test sweat must be induced in order to be analyzed In modern medical practice the sweat glands in a limited area of the skin are stimulated by local application of choliner gic drugs particularly pilocarpine These substances are introduced to the glands by iontophoresis in the case of pilo carpine These drugs act by mimicking the action of the natural physiological gland stimulator acetylcholine which is liberated at the gland by signals from the autonomic nervous system The ion tophoretic procedure depends upon the application of a small and brief direct cur rent to the skin via electrodes the anode of which being positive drives the posi tively charged pilocarpine from the reser voir of drug sufficiently to reach the glands The requirements for Pilocarpine as defined in the Wescor Quality Procedures are primarily that the form and source of the drug be pilocarpine nitrate and the purity being that specified by the United States Pharmacopeia USP Grade The concentration of aqueous pilocarpine nitrate solution should be sufficient to initi ate a maximal sweat yielding response from the glands The Wescor concentra tion for Nanoduct meets this requirement at a minimal level of 1 5 Where positive ly charged salt ions acting as iontophoret ic transport competitors are absent from the drug solution the requirement may be met by 1 096 pilocarpine The literature on pilocarpine shows no evid
40. s The skin should be free of fissures and any structural abnor mality There should be no inflammation or signs of eczema Apart from exacerbating the complaint there is always the possibility of contamination of the sweat by serous exudates SECTION 2 SWEAT INDUCTION AND ANALYSIS 2 1 Performing the Sweat Test To minimize the electrical impedance resis tance of the skin remove as much dead epithelial material dirt and fatty substances as possible by swabbing the area vigorously with surgical alcohol followed by plenty of distilled or deionized water Then totally remove the excess water 5 Attach the Holders NOTE Wescor provides perforated non latex elastic straps of different lengths to fit infants older chil dren and adults To save time pre arrange strap holder assemblies to fit varying sizes of patients Select the red holder and attach a rubber strap of appropriate size as follows a Attach the strap to one side of the holder by inserting it from below through the holder slit and down to form a small loop Align two perforations in this loop and push a strap retainer post through the aligned holes such that the post points away from the patient s arm In use the flat retainer base should rest against the skin of the patient b Run the free end of the strap through the opposite slit from below Hold this loop open as you run the arm of the patient up through the loop C Place the hol
41. s of cystic fibrosis Anyone operating Nanoduct must be thoroughly familiar with the procedures and cautionary informa tion detailed in this manual before attempting a sweat test Abbreviated instructions printed elsewhere are provided for reference only Do not use them as a substitute for the complete information contained in this manual CLASSIFICATION This equipment is classified as Type BF Medical Equipment Internally Powered SPECIFICATION OF SAFE USE Using this equipment in a manner not specified by Wescor may impair safety protection and may lead to injury Do not use where flammable anesthetic is present or in any oxygen enriched environment Do not connect the serial port to external sources while the Nanoduct is connected to a patient STATEMENT OF ENVIRONMENTAL LIMITS This equipment is designed to be safely operated at 15 to 30 C maximum relative humidity 80 EXPLANATION OF SYMBOLS FOUND ON EQUIPMENT BF equipment complying with Medical Equipment Safety Standard 60601 1 SECTION 1 INTRODUCTION 1 5 System Description SECTION 1 INTRODUCTION 1 5 System Description Nanoduct is a complete integrated system for inducing and analyzing sweat for cystic fibro sis CF diagnosis all while attached to the patient This reduces the possibility of intrinsic error and enables pristine samples to be obtained from neonates and analyzed in situ Nanoduct incorporates the classic method o
42. son for sweat test failures is well understood by those professionally charged with sweat test performance The size of iontophoretic electrodes and collec tion paraphernalia is usually inappropriate ly large for effective use on the extremely small and frail limbs of the newborn Many technologists are wary of attempting this daunting task due to the distinct possibility 54 of causing a burn and also because of the risk of producing a false result in the pad absorption test by inability to control evap oration and condensation errors particu larly when handling tiny infants and deal ing with low sweat yields The Macroduct oystem which employs the smallest elec trodes and collector of all methods used up to 1998 is nevertheless frequently found to be inappropriately sized for tests with neonates It is obvious that any attempt to devise a sweat test for newborn babies must involve as a fundamental requirement equipment for iontophoresis and collection that is scaled down to mini mal dimensions enabling their effective application to extremely small limbs It is also evident that this approach taken alone would merely aggravate the prob lem by limiting even further the number of sweat glands involved and thereby reduce the sweat yield to as little as 3 6 micro liters in 15 minutes collection In such cases the traditional methods for gathering the sample storing it in a sealed contain er and taking aliquots for
43. t Provides time and date display for cali bration and test results CONTROL AND CONNECTIONS Electrode Socket The electrode socket on the front panel of the induction analysis module connects the elec trode sensor cable assembly to provide electrical current for sweat stimulation and to receive sensor signals to the induction analysis module during the analysis phase Keypads ON keypad controls power to the module This must be on during iontophoresis and analysis OFF keypad terminates all operations and turns power to the module off Electrode Socket Note To preserve battery power leave power off except while performing a test In addition during idle periods the instrument shuts down automat ically after 10 minutes and must be turned on again to complete testing or retrieve a result SELECT ENTER Used to select options and start the iontophoresis OFF ENTER and analysis phases of the sweat test A warning ES tone sounds if a fault condition occurs such as an open electrode or circuit fault The fault condition is displayed and reset by pressing ENTER Front Panel Keypads INTRODUCTION 1 5 System Description Display NOTE Date and time indications are in the format yyyy mm dd hh mm Dates times and other data shown in this manual are for example only Actual data during use will vary Serial Port 10 DISPLAY The LCD alphanum
44. t conductivity instruments in the past Unfortunately this unit has also produced confusion in some quarters It is therefore important to define and explain the meaning of this expression The readout both as displayed continuously and as the electronically averaged value is expressed in mmol L equiva lent NaCl This means that the sweat sample has an electri cal conductivity that is equivalent to that of an NaCl solution of the displayed mmol L concentra tion at the same temperature THE READINGS IN SUCH UNITS DO NOT REPRESENT THE ACTUAL CON CENTRATION OF EITHER SODIUM OR CHLORIDE IN THE SWEAT The level of electrical conductivity is a function of the molar concentration of ionized molecules in a solution Sweat samples are made up of sodium potassium and a small contribution by ammoni um as the cation contribution The anions balanc ing these are mainly chloride with lactate and bicarbonate Thus the conductivity can be seen as a measure of the total electrolyte in mmol L Clinical trials have amply demonstrated that sweat total electrolyte and sweat chloride are equally effective analyses in the diagnosis of CF As there are other ions contributing to the conductivity other 25 SECTION 3 INTERPRETING THE SWEAT TEST 3 1 Units of Conductivity than sodium and chloride the mmol L equiv NaCl value of a sweat sample will always exceed the actual molar sodium or chloride concentration as analyzed specific
45. the invention of the MACRODUCT Sweat Collector This innovation completely sup planted the heated cup while retaining its advantages by the use of a collector that anaerobically collected sweat by using the hydraulic pressure of the sweat glands to pump the secretion directly from the ducts into a fine bore capillary tube This system has been very successfully employed both in the US and internationally since 1983 Vested in Wescor s scientific and engi neering staff is a combination of many years experience in laboratory sweat test ing and in the development of modern electronic instrumentation The Wescor aim in the field of sweat testing has always been to provide quality instrumen tation to meet a number of criteria 1 Elimination of all intrinsic sources of error concomitant to previous collection methods 2 Ensuring impeccable accuracy in the diagnostic result by reducing human error potential to the low est possible level 9 Maximization of patient safety and comfort 4 Maximization of operator con venience within the strictures imposed by objectives 1 2 and 3 These objectives have led to considerable innovative improvements in all aspects of sweat testing iontophoretic safety meas ures collection methods and also in the analytical phase of the test With the intro duction of the Model 3600 MACRODUCT oweat Collection System in 1983 all of the comprehensive objectives had been accomplished P
46. tools If the electrode surface is scratched or pitted it will not perform as specified and must be replaced 34 SECTION 4 TROUBLESHOOTING AND PREVENTIVE MAINTENANCE 4 2 Cleaning the Instrument Use the following options to clean Nanoduct straps holders and attachment strap retain ers or any other parts that come into contact with a patient Option A 1 ooak the straps for 30 minutes in a freshly prepared 1096 dilution of household bleach 2 Rinse soaked straps thoroughly in tap water 3 Allow to air dry Option B 1 Autoclave the straps for 30 minutes at 121 CAUTION Do not autoclave the Nanoduct holders red or black or the attachment strap retainer post Autoclaving will destroy these parts 53 SECTION 4 TROUBLESHOOTING AND PREVENTIVE MAINTENANCE 4 2 Cleaning the Instrument Option C Treat straps as disposables 1 Discard straps after each use 2 Purchase new straps from Wescor See Appendix B for complete information Contact Wescor for current prices and order ing information 36 SECTION 4 TROUBLESHOOTING AND PREVENTIVE MAINTENANCE 4 3 Battery Replacement 1 The battery compartment is on the bottom of the induction analysis module Turn the unit on its side to access the battery compart ment Use a flat bladed screwdriver or simi lar tool to lift the battery pack out of its receptacle 2 Remove the spent battery from the holder 3 Replace with a 9 volt lithium or a
47. y poor prognosis afforded to sufferers The inheri tance is autosomal recessive so that an affected child must inherit one defective gene from each of the parents to be homozygotic Such parents must then at the least be carriers heterozygotes The distribution of the genetic anomaly varies with racial types It is predominantly asso ciated with Caucasians in whom it occurs in about 1 in every 1500 to 2000 live births The symptoms of the disease are mani fold however they are not strictly specific and hence physicians often have difficulty in distinguishing CF from other childhood diseases on the basis of medical diagno sis alone The most serious clinical fea tures are the pulmonary problems stem ming from abnormally viscous exudates in the lungs requiring urgent physiotherapy and antibiotic treatment to offset the ever present risk of pneumonia The pancreas is also affected by over viscous secretions that reduce its output of digestive enzymes thus the child tends to fail to thrive because the food ingested passes through the alimentary canal without the normal enzymic breakdown necessary for absorption of nutrients Fortunately the latter problem is relatively easily corrected by the addition of animal pancreatic extracts to the diet The use of pancreas in the disease name arose because of the identification in 1938 of pancreatic abnor malities during post mortem examination of children that had died with a s
48. ystic Fibrosis Congress Brighton England June 9th 15th 1984 Lawson D ed John Wiley amp Sons New York 1984 204 8 Webster H L Quirante C G Micro flowcell conductometric sweat analysis for cystic fibro sis diagnosis Ann Clin Biochem 2000 Vol 37 399 407 56 APPENDIX D USING THE SETUP MENU APPENDIX D USING THE SETUP MENU Press Simultaneously The Setup Menu allows you to configure the instrument for your use to run an instrument self test or to operate the instrument in a demonstra tion mode Accessing the Setup Menu 1 While pressing and holding down the SELECT and ENTER keypads press the ON keypad After a few seconds the display will show SETUP MENU Make selections by pressing ENTER when the pointer is next to your choice Select Exit to return to the main operation menu Using the Configure Option The Configure Option allows you to set the clock change the display language set options such as default status for suppressing or displaying test results and forcing a Calibration Check when the instrument is turned on 1 Select Configure from the Setup Menu and press ENTER 20 APPENDIX D USING THE SETUP MENU Setting or Adjusting Time and Date Display Setting Time 1 To set or adjust the time on the clock select Set Clock in the CONFIGURE MENU and press ENTER Then select Set Time and press ENTER 2 The display shows the Set 24 Hour Clock menu wit
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