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G3+, G7+, 6+, Glu, Crea Cartridges
PRINCIPLE:
The i-STAT Portable Clinical Analyzer, in conjunction with the i-stat Test Cartridges,performs blood analysis at the point of care. Just 2-3 drops of fresh whole blood is all that isrequired, and the portable, battery-powered analyzer displays quantitative test results inapproximately 2 minutes. Portable printers and infrared communication devices allow allpatient information obtained at the bedside to be printed on demand and transmitted tocentralized information systems for record keeping and billing.
Quantitative determination of Sodium (Na+), Potassium (K+), Chloride (Cl-), Glucose (Glu),Urea Nitrogen (BUN), and Hematocrit(Hct) in whole blood is performed using the6+cartridge. Hemoglobin is mathematically derived based on the hematocrit value. The 6+cartridge is used in the ED, CCU, ICU, OR, and the CATH Lab.
The G cartridge for glucose only is used in the OR and the CATH LAB, for patients with glucose >200 mg/dL and Hematocrit <25 %.
Quantitative determination of Creatinine is performed using the Creatinine cartridge inthe ED and Radiology.
Arterial Blood Gas testing is performed using the EG7+ cartridge in the ED, ICU, CCU, SCN,OR, PACU, and the CATH LAB. The parameters that may be measured are: Sodium(Na),Potassium(K), Ionized calcium(iCa), pH, pCO2, pO2,and HCT. TCO2, HCO3, BE, sO2 andHemoglobin are calculated results.
Arterial Blood Gas testing is performed using the G3+ cartridge in the EmergencyDepartment, SCN CCU, ICU, OR, the CATH LAB and on the patient service/ nursing units.
The parameters that may be measured are: pH, pCO2,and pO2. TCO2, HCO3, BE, and sO2are calculated results.
i-STAT ordersAll i-STAT orders must be written on the patient’s chart. DO NOT PERFORMAN ARTERIAL BLOOD GAS WITHOUT A WRITTEN ORDER. Check the patient’s chart for anticoagulant therapy or diagnosis which would indicate thenecessity for increasing the pressure holding time on the puncture site.
B.
Patient Preparation:-Verify patient identification by checking the patient’s name and social security number and/or patient account number on the arm band.
-Explain the purpose of the test and the steps of the procedure to the patientprior to performing the test.
-The operator’s hands must be washed before and after testing.
-Because of the hazardous nature of handling blood products, it is required thatdisposable latex gloves or an acceptable substitute be used when collecting specimensand test procedures. Standard precautions shall be observed for all blood specimensand they should be handled at Biosafety Level 2 as recommended for any potentiallyinfectious material in the Centers for Disease Control/National Institutes of Healthmanual, Biosafety in Microbiological and Biomedical Laboratories, 1988 or in theNational Committee for Clinical Laboratory Standard Document M29, Protection ofLaboratory Workers from Infectious Disease Transmitted by Blood, Body Fluids, andTissue, 1991.
Sample volume (size): 65 uL for 6+ and G, cartridges Fresh whole blood from venous, arterial puncture, skin, or in- Venipuncture:
Observe the following precautions:
-Avoid drawing from an arm with an IV line. IV solutions will dilute thesample and may interfere with the tests.
-Avoid localized stasis which can increase potassium and pH results and decrease ionized calcium results. If a tourniquet is applied for more than oneminute while looking for a vein, release and reapply after two to threeminutes.
-Allow the tourniquet to remain in place until all blood is withdrawn to prevent changes in ionized calcium and pH results.
-Avoid extra muscle activity, such as clenching and unclenching the fist, which -Avoid hemolysis by allowing residual alcohol to dry over the puncture site.
Hemolysis will cause an increase in potassium results and a decrease in -If the cartridge cannot be filled immediately, collect a sample into an evacuated blood collection tube or a syringe containing heparin ( sodium, lithium orbalanced) anticoagulant. For ionized calcium measurements, balancedheparin or <10 IU/ml of sodium or lithium heparin is recommended.
Balanced heparin or low volume heparin is used in some commercially available blood gas syringes. Becton-Dickenson’s lithium heparinevacuated tubes contain approximately 15 IU/ml when filled to capacity.
-Fill evacuated tubes and syringes with anticoagulant to capacity. Incompletefilling will cause higher heparin to blood ratios which will decreaseionized calcium results and may affect other results.
-Gently mix blood and anticoagulant immediately to avoid clotting: invert anevacuated tube 5 to 10 times and roll a syringe between the palms for at least five seconds in two directions.
-Collect vacuum tubes in the prescribed sequence to avoid interference due tocarry over of anticoagulant from one tube to the next: blue, red, gold, green,lavender, grey. If a blue stoppered tube is drawn, draw a 1 ml bluestoppered discard tube before drawing the blue stoppered tube.
-For the most accurate results, test samples immediately after draw. If testing is delayed, remix evacuated tubes by gentle inversion and syringes by rollingbetween the palms for 5 seconds. Test samples within 10 minutes afterdraw.
Arterial :
Observe the following precautions:
-Evacuated tubes are not recommended for blood gas analysis.
-Follow the directions carefully when using pre-prepared blood gas kits andsyringes. Fill syringes to the recommended capacity or use the leastamount of liquid heparin anticoagulant that will prevent clotting.
Under filling syringes which contain liquid heparin will decrease results due to dilution and will decrease ionized calcium results due to binding.
-For ionized calcium, use balanced or low volume heparin blood gas syringes.
-Wait 15 minutes before specimen collection when there has been a change inventilator setting or the FIO2.
-Mix blood and anticoagulant by rolling between the palms for at least 5 seconds. Then invert the syringe repeatedly for at least 5 seconds.
-Do not expose the sample to air when testing for ionized calcium , pH, pCO2or pO2.
-Avoid or remove immediately any air drawn into the syringe and maintainanaerobic conditions.
-For the most accurate results, test samples immediately after draw. If testing is delayed, remix. Test samples within 10 minutes.
-Fill the cartridge before icing the sample for transportation. Icing will
increase potassium and will affect oxygen levels in samples collected in plastic
In-Dwelling Line :
-Withdraw slowly three to six times the volume of the catheter, connectors, and needle to remove intravenous solution, heparin, or medications that maycontaminate the sample. Samples collected without anticoagulant should betested within 3 minutes. Samples collected in lithium heparin syringes should tested within 10 minutes and well mixed before use.
Evacuated tubes (for Venous samples only)
-with lithium heparin anticoagulant).
Syringes
-without anticoagulant-with lithium heparin anticoagulant -balanced or low heparin-Blood Gas Syringe Kit 3 minutes
-evacuated tubes or syringes without anticoagulant 10 minutes
-for evacuated tubes or syringes with anticoagulant(Maintain anaerobic conditions when using syringes) (Evacuated tubes andsyringes must be well mixed before testing) If the i-STAT cartridge is not filled immediately after collection, the blood must bethoroughly mixed. Mix tubes by gentle inversion 7 times. Mix syringes by rollingbetween the palms 5 times in three directions.
-Specimens collected in anticoagulant other than lithium heparin.
-Syringe for pH, PCO2, and PO2 with air bubbles in sample.
-Other sample types such as urine, CSF and pleural fluid.
-Samples not collected according to the specimen type precaution guidelines.
Blunt End Dispensers
-To avoid the use of needles when transferring a blood sample from an evacuatedtube, a dispenser can be used. Do not use dispensers because that would introduce airinto the sample when ionized calcium, pH or pCO2 are being measured.
Unless the specimen is analyzed immediately after collection and then discarded, thespecimen container must be labeled with the following information.
-Patient's name-Patient's social security number-Time and date of collection-Phlebotomist/collector ID The i-STAT Test Cartridge is a self contained testing system. Each cartridge isconsidered a "run", with no reuse of reagents or carry-over of specimen.
The 6+ cartridge contains the following tests: The Arterial Blood Gas Cartridge, EG7+, performs the following tests: The Arterial Blood Gas Cartridge, G3+, performs the following tests: The Glucose cartridge performs only glucose.
The Creatinine cartridge performs only creatinine.
Each i-STAT Test Cartridge contains a buffered calibrant containing knownconcentrations of each analyte; a sample handing system; an array of unauthorizedsensors; and conductive pads to make electrical contact with the analyzer. Thesensors are electrodes which are micro-fabricated onto silicon chips. Sensingfunctionality is imparted to the electrodes by coating of chemically sensitive filmssuch as ion-selective membranes and enzyme layers. Each sensor is connected to acontact pad by a signal line.
Test cartridges are stored in their sealed foil pouches at 2-8o C. Do not allow thecartridge to freeze. Cartridges are usable until the expiration date printed on the foilpouch if stored at 2-8o C.
Cartridges may be stored at room temperature (18-30o) for a maximum of fourteen(14) days. If the cartridges are stored at room temperature, use the calendar on thecartridge box to indicate the room temperature expiration date. Do not use the cartridges if the 14 day time has expired. Do not store cartridges at temperaturesexceeding 30oC.
6+ and Glucose cartridges do not require thermal control and may be used after
standing just 5 minutes at room temperature. An entire box should stand at room
temperature for one hour.
EG7+ and G3+,and Creatinine cartridges require thermal control (37
used after standing just 5 minutes at room temperature. An entire box should stand atroom temperature for one hour.
DO NOT RETURN CARTRIDGES TO THE REFRIGERATOR ONCE THEY HAVE COME TO ROOM TEMPERATURE. Cartridges must be usedimmediately after they have been removed from the foil pouch.
Disposables (as appropriate for sample application) Venipuncture Supplies (Needles, Syringes) Arterial Blood Gas Supplies (Needles, Syringes, lowvolume heparin blood gas syringes Calibration is performed internally each time a test cartridge is inserted into the i-STAT analyzer with no intervention required on the part of the operator. Each cartridge includes a sealed foil pack which contains a calibrant solution with a knownconcentration of each analyte. During the first part of the testing cycle the calibratoris automatically forced out of the foil pack and over the sensors. The signalsproduced by the sensors in response to the calibrant solution are stored. If thecalibration fails, the i-STAT analyzer will give a code and results will not becalculated.
Calibration verification is performed by the Laboratory Department every six months.
Linearity is performed by the Laboratory Department initially on each analytetested.
Quality control (QC) is the process designed to ensure that a test system is workingproperly. The i-STAT system daily quality control is an electronic simulator. Liquidcontrol and calibration verification solutions for verification of cartridges are tested bythe laboratory for each new lot number of cartridges received.
The Electronic Simulator is a stable electronic device whichverifies the electrical measurement circuits by producing signals attwo levels to check the accuracy and integrity of the circuits and the electrical isolation between individual measurement channels.
The results of the Electronic Simulator are "PASS" or "FAIL".
External Electronic Simulator is used to verify a failed internalsimulator test.
 Remove the external Electronic Simulator from storage.
Insert the external Electronic Simulator into the cartridge
door to the i-STAT instrument. CONTRACTING
CARTRIDGES will be displayed.
Wait 70 seconds. PASS or FAIL will be displayed at the endof the simulator test. The acceptable limits for the simulatorare set internally; FAIL will be displayed if the limits areexceeded.
If PASS is displayed, patient testing may be initiated.
If FAIL is displayed on the analyzer screen: Repeat theprocedure with the same external Electronic Simulator. IfPASS is displayed use the analyzer as required. If FAIL isdisplayed repeat the procedure with a different externalElectronic Simulator.
If PASS is displayed with the second external ElectronicSimulator: Use the analyzer as required. Deliver the questionable external Electronic Simulator to the LaboratoryDepartment.
If FAIL is DISPLAYED with the second external ElectronicSimulator: DO NOT analyze patient samples with theanalyzer. Transmit the results to the Central Data Station.
Deliver the faulty analyzer to the laboratory. The Point ofCare Coordinator will record the failure along with the actiontaken.
Remove the external Electronic Simulator after the lockedmessage “LCK” is no longer displayed and return to The results of the external Electronic Simulator, the date,time and operator ID will be transmitted by a RespiratoryTherapist to the Central Data Station via the infrared cradlefor review and record keeping. Radiology and the CATHLAB will transmit their i-STAT analyzer each day at the endof 1st shift.
Perform the Electronic QC in the following situations: When an internal Electronic Simulator fails.
When an analyzer is brought from a coldenvironment to a hot, humid environment to insurethat any moisture that may have condensed on theinternal connector has evaporated before performingpatient tests.
When the analyzer's batteries are changed.
The internal Electronic Simulator is selected on an 8/24 hourschedule. The internal Electronic Simulator will run every 8hours for pH, pCO2, pO2, hematocrit and ACT channels andevery 24 hours for all other channels.
QC Lockout is enabled on all analyzers. This settingprevents analyzers from running a cartridge after a failedinternal Electronic Simulator test.
An internal Electronic Simulator is a circuit in the Analyzer which verifies the performance of each Analyzer by testing signals consistent with both very low and very highconcentrations of each of the analytes. The software in the analyzer and module measurethese signals as it would measure signals from a cartridge. The software checks the measurements against predetermined thresholds and indicates their acceptability to the usevia a PASS/FAIL message. ACT analyte has quality control tested every 8 hours.
The internal Electronic Simulator is triggered by inserting a cartridge.
If the software detects that the specified time has elapsed since thelast Electronic Simulator test (internal or external), it willautomatically perform the internal test before the sample is tested,adding about 15-20 seconds to the testing cycle. A failed Simulatortest stops the cycle, the FAIL simulator result will be displayed on thescreen, and the sample will not be analyzed. If the test passes, thecartridge cycle continues to completion and the cartridge results aredisplayed.
What to do if the Electronic Simulator Fails:
Rerun the cartridge in the same Analyzer to ensure the FAIL was notdue to a one-time spike of electrical noise. If the test fails again,rerun the cartridge in another Analyzer if immediately available.
Note that the cartridge should not be run if there is more than a threeminute delay from the time it is filled. If the cartridge fails in morethan one Analyzer, use another cartridge. In all cases, an externalElectronic Simulator can be used to verify proper performance ofAnalyzer. Failed analyzers are to be brought to the laboratory forreplacement.
Verification of newly received cartridges (performed by theLaboratory Department) Verify that the transit temperatures of each shipment weresatisfactory using the four window temperature indicator stripaffixed to the cartridge box.
From each lot of cartridges received, analyze three levels ofi-STAT and Meter Trax Controls each in duplicate, using anyverified analyzer.
From each new lot number of cartridges received, analyzei-STAT calibration verification solutions one, three, and fiveto ensure that patient reference ranges (or reportable ranges)are acceptable from lot to lot. Hematocrit calibrationverification is performed as a separate procedure at aminimum every 6 months (see i-STAT CalibrationVerification Procedure).
Perform a parallel reagent check by comparing the qualitycalibration verification ranges from the previous lot numbers.
Perform QC on the old cartridge lot number along with thenew cartridge lot number and record results.
Verify that the cartridges stored in the designatedChemistry refrigerator are all within the expirationdate printed on the boxes. Deliver any expiredcartridges to the Laboratory Point of Care office.
Verify that the Chemistry refrigerator did not exceedthe limits of 2-8oC (25-46oF).
Chemistry will document the refrigerator temperaturedaily.
If the temperature of the cartridge storage refrigeratoris within the range of 2-8oC (35-46oF) use cartridgesas required.
If the temperature is outside the range of 2-8oC (25-46oF) quarantine the cartridges in the storagerefrigerator. Notify the Point of Care Coordinator,Laboratory Manager, or Supervisor immediately.
DO NOT USE the cartridges from the out-of-controlrefrigerator. Record the QC failure with the actiontaken via a Laboratory Incident report form.
Verify that all boxes of cartridges at roomtemperature have been out of the refrigerator lessthan two weeks. Deliver any expired cartridges tothe Laboratory Point of Care office.
If the measured temperature of the room has beencontinuously below 30oC (86oF) use cartridges asrequired.
If the measured room temperature has exceeded 30o(86oF) for any period of time: Quarantine thecartridges. Notify the Laboratory Point of CareCoordinator, Laboratory Manager, or Supervisorimmediately. DO NOT use the cartridges. Recordthe out of control event and the action taken via aLaboratory Incident report form.
Comparison of test methods for Sodium, Potassium, Chloride, BUN, Glucose,Hematocrit, and Creatinine is performed by the Laboratory Point of Care office every6 months. (See Comparison of Test Methods procedure).
Proficiency Testing is performed on 6+, Creatinine and EG7+ cartridge using CAP’sAQ2 Survey. Laboratory Point of Care performs 6+ proficiency testing andRespiratory Therapy performs EG7+ proficiency testing. Proficiency testing samplesare shipped three times during the year and include five challenges for each analyte ortest. Samples are tested exactly like patient samples and the results are returned toCAP within 10 working days of receipt for grading.
If any QC result is not within range, take corrective action before any patient samplesare tested.
If QC is within range, patient testing may proceed.
If QC is not within range, DO NOT PERFORM PATIENT TESTING.
The Point of Care Coordinator will notify i-STAT Technical Service.
Corrective action taken is recorded in the i-STAT Central Data Station and noted onthe i-STAT System QC Log.
V. PROCEDURE
6+ Cartridge is used for stat Electrolytes, BUN, Glucose, and Hematocrit testing in ED, CCU, ICU, OR and the CATH Lab.
Creatinine cartridge is used for stat Creatinine in ED and Radiology.
EG7+ Cartridge is used for ABG in Critical Care areas: ED, ICU, CCU, SCN, OR,PACU, and the CATH LAB.
G3+ Cartridge is used for ABG in SCN, ED, ICU, CCU, OR, PACU,the CATH LABand on nursing floors/patient care units.
Glucose Cartridge is used in the Operating Room, and CATH LAB for patients withglucose concentrations above 200 mg/d and hematocrits below 25%.
The cartridge should be handled as follows to avoid difficulty in filling or -Do not contaminate the contact pads with finger prints or talc from gloves as the analyzer may not be able to make proper contact with the cartridge.
-Do not exert excessive pressure over the central area of the label as the calibrant pack underneath could burst prematurely.
-Do not block the air vent as the sample will not be able to flow to the fill mark and the calibrant solution will not be able to flow to the sensors.
-Do not use a cartridge on which blood or any other fluid is spilled, as theanalyzer’s connector may be contaminated.
Remove the cartridge from the protective foil pouch after it has come to roomtemperature.
Place cartridge on a flat surface or hold it horizontally. Do not hold cartridgebetween the fingers if using a syringe with needle to fill the sample well.
Direct the pipette tip, capillary tube, or needle into the sample well.
Dispense sample slowly and steadily until it reaches the FILL TO mark (tiltcartridge slightly if necessary). Avoid the introduction of air bubbles into thesample well.
Fill the sample well 1/3 to 2/3 full.
Once the cartridge is full, complete the procedure without delay.
Fold the plastic snap closure over the sample well.
Press on the rounded end of the closure until it snaps into place.
Failure to seal the cartridge will prevent patient testing.
Insert Test Cartridge into the i-STAT Analyzer Hold the analyzer firmly in one hand. Grasp the test cartridge by the sides,label facing up, with the other hand.
Push the cartridge slowly and smoothly through the cartridge door until it willgo no further.
The cartridge activates the analyzer. The analyzer displays "CONTACTINGCARTRIDGE" then a time-to-result bar, the cartridge type, "LCK" prompt,and an area in which to enter operator and patient identification numbers.
Do not attempt to remove a test cartridge while the "LCK" prompt isdisplayed indicating that the cartridge should not be removed. The forcenecessary to remove the cartridge would damage the analyzer and invalidatethe results.
Enter your assigned operator identification number. Respiratory Therapistsuse your LIS numerical Tech Code. All other operators use the first 6 digitsof your social security number. Use the numerical keypad to enter thenumber. Press the "CLR" key to backspace and erase a wrong number. Pressthe "ENT" key to enter the completed number.
After the ENT key is pressed, the prompt "Repeat #, ENT" appears in the box.
Repeat the operator identification number as above and press ENT to signalthe analyzer that the last digit has been entered.
Enter the patient's account number, not the patient social security number, inthe same manner as the operator ID number.
If either the operator identification or the patient identification numbers arenot entered correctly in duplicate, the message "ID DID NOT MATCHSTART AGAIN" will display. Re-enter the ID number that was in error.
Operating rooms and “codes” present a unique testing situation in that tests are
run repeatedly on the same patient. Pressing the DIS key when
prompted
for Patient ID will recall the last Patient ID entered into the analyzer. The
repeat request for Patient ID may also be entered by pressing the Display key.
After the patient identification number is entered, the PAGE key is activated allowingaccess to an additional data entry screen. (If results are already displayed, press thePAGE key twice to access the data entry screen).
The cursor will be flashing at the first input area. Use the numbered keys to inputinformation and press the ENT key to advance to the next input area (or to return tothe first area from the last input area). Invalid numbers will be ignored, and incorrectinputs can be corrected using the CLR key as a backspace.
Enter the patient’s temperature in degrees Fahrenheit or Centigrade.
Use the * key to enter a decimal point. The analyzer will interpretnumbers between 50.0 and 110.0 as degrees Fahrenheit andbetween10.0 and 45.0 as degrees Centigrade.
FIO2
Enter the FIO2 value as a whole number from 0 to 100,representing the number of liters or a percentage of the oxygen the patient is receiving. Use the * key to enter a decimalpoint.
4= CPAP5= trach6= mask7= vent8= croup tent Enter the number corresponding to the sample type: When 6(CPB) is chosen as the sample type, a special algorithm for hematocritvalues is used. The algorithm infers a total protein level, assuming the pumppriming solution dilutes the hematocrit and total protein equally. An adjustedhematocrit value is reported Hct,CPB on both the analyzer display and printout.
After data entry is completed the free fields may be edited until the results are printedor transmitted to the Central Data Station or until a new cartridge or externalElectronic Simulator is run.
The Portable Clinical Analyzer will display test results once the cartridge has beenunlocked and the LCK prompt disappears. Results will be displayed for 45 seconds .
Results can be recalled to the display screen by pressing the display key.
Results should either be transcribed onto the patient’s medical record or transmitted to the portable printer or the Central Data Station Remove the cartridge any time after the "LCK" prompt disappears from thedisplay screen. Discard the cartridge in an appropriate Biohazard Wastereceptacle.
The analyzer display will deactivate after 45 seconds to save the battery. The last results can be recalled by pushing "DISPLAY".
Once a cartridge is removed, even if results are still displayed, the analyzer is The i-STAT Portable Clinical Analyzer contains a microprocessor that performs allcalculations required for reportable results.
The i-STAT Analyzer will produce an audible beep as soon as the results are displayed. Theresults are displayed in numerical and bar graph forms. Results may be recorded on thepatient's chart directly from the i-STAT LED display or printed and the printout placed on thepatient's chart until the patient's laboratory cumulative summary is charted. The i-STAT willaccumulate a total of 50 test records (patients, control material, and electronic simulator tests).
All information will be transmitted to the Central Data Station, located in the Laboratory, viathe IR Cradle.
Test results are displayed showing numerical concentration values. Bar graphs which depictthe values in relation to reference ranges are also displayed. Blood gas results are notdisplayed with reference ranges. The reference range is marked on the bar by tick marks.
When all test values are within their reference ranges, the tick marks will be aligned. The bar graphs can be used as a visual cue for distinguishing between “normal” and“abnormal” results.
The reportable range for i-STAT constituents are as follows: If a "<" or ">" sign precedes a value or if a "< >" sign is displayed, thevalue exceeded the linear range of measurement for that particular test.
Report the “< or >” result immediately to the patient’s attending physicianor nurse. 6+cartridge results must be repeated by laboratory analysis.
A lithium heparin (green stoppered) tube must be collected for Electrolyte,BUN , and Glucose verification. An EDTA (lavender stoppered) tube mustbe collected for Hematocrit verification. The test to be repeated must beordered in SMS as STAT. The patient will be credited by Laboratory Pointof Care for all verification repeats.
Test results are displayed in numerical concentrations and on the bar graph.
Results are direct readout; no calculation is necessar y. There are fourexceptions to the direct readout when the results are not reportable: [****] is displayed in place of one or more results when a signal froma sensor is uncharacteristic. This may be due to a defective sensor oran interferant in the sample. If [****] is displayed repeat the test witha fresh cartridge. If [****] is still displayed on the 6+cartridge result,the physician may request a repeat by laboratory analysis. Followsteps VIII, A, 2 for repeating an i-STAT result by laboratory analysis.
Results Which Exceed Critical Limits (Alert Values) Results which exceed the laboratory established "AlertValues" represent an emergency condition.
If critical test result for venous Electrolytes or Hematocrit is
within the i-STAT Analyzer's reportable range repeat the test
for verification with a fresh test cartridge and report the
result.
Glucose >350 mg/dL must be verified by repeat in thelaboratory except for OR patients. The physician willdetermine if repeat verification is to be done. Follow stepVIII, A,2 for repeating an i-STAT result by laboratoryanalysis.
ABG alert values are NOT repeated. Arterialelectrolytes, ionized Calcium, and Hematocrit are NOT All results which exceed Critical Limits must be brought tothe physician or RN responsible’s attention immediatelyeither by phone call or direction notification. Physician orRN notification of the Alert Value must be documented onthe patient's chart. Respiratory Therapists will give all resultsdirectly to the physician or RN. Physician/RN notification isentered into the i-STAT analyzer and reported on the ABGpatient report.
Alert values repeated by i-STAT only will have a CriticalValue Documentation Verification form sent to the nursemanager or designee. The form must be completed andreturned to Laboratory Point of Care.
The established Alert Values are as follows: Any neonate glucose result below 45 mg/dL or above 150mg/dLshould be followed up according to the Neonate Blood GlucoseTesting procedure located in the Nursing unit procedure manual.
Test cycle not completed due to problem with the sample, calibrantsolution, sensors, mechanical or electrical functions of the analyzer:take the action displayed with the message that identifies the problem.
Refer the problem to the Laboratory Point of Care Coordinator ifnecessary.
To recall a stored test record to the display screen, press the MENU soft keyand select STORED RESULTS by pressing the "2" key, from the STOREDRESULTS menu, select DISPLAY A RESULT by pressing the "1" key.
Select the record to be displayed by pressing the key (1 to 5) on the pages (1to 10) corresponding to the test record. The list of stored results can be listedwith Cartridge Type or Date/Time. Use the DIS key to toggle between thesedisplay modes.
Place the analyzer in the printer cradle. Turn the printer on (printer lightgreen) or press the paper advance key to reactivate.
To print the displayed test record, press the PRT key on the analyzer. Themost recent test record can be printed only if a patient identification numberhas been entered or actively bypassed.
Do not move the analyzer while "Printing" is displayed. Note: Resultsprinted on thermal paper will fade with time and, therefore, not acceptable aspermanent chartable record.
Write the patient's name on the Pt name line, the physician's name on thePhysician line, and the Sample type on the Sample type line.
A stored test record can be printed without recalling the results to the screen.
Press the MENU soft key, select STORED RESULTS by pressing the "2"key. From the STORED RESULTS Menu select PRINT RESULTS bypressing the "2" key. Use the soft keys to page up or down through the 10pages of stored test records, press the 1 to 5 keys to select the desired recordson each page. When a key is pressed, the number selected will reserve video(dark background, light lettering). To deselect a record, re-press the key, thenumber will return to light background, dark lettering.
The list of stored results can be listed with Cartridge Type or Date/Time.
Use the DIS key to toggle between these display modes. When all the testrecords desired are selected, press the PRT key. The message"PRINTING." will be displayed while the records are transmitted to the printer. Each record will take about 45 seconds to print.
To stop printing before all test records are printed, press the * key.
A test record cannot be printed from a position displaying INVALID or NODATA, an Electronic Simulator test or an error code.
Transmitting Results to the Central Data Station i-STAT operators will transmit Arterial Blood Gas (ABG) resultsimmediately after completion of each ABG test.
Respiratory Therapy will transmit all results from each analyzer that ABGsare performed on at the beginning of each shift.
Radiology will transmit all results at the end of first shift, Monday throughFriday.
The Cardiac Cath Lab will transmit all results at the end of each case.
Place the analyzer in the IR Interface cradle. The IR Interface light must begreen.
To transmit all stored test records, press the * key or access STOREDRESULTS from the menu. Press the "3" key on the analyzer to transmit alltest records.
Do not move the analyzer while "Transmitting" is displayed.
During transmission the IR Interface light will blink alternately red and green.
If transmission is successful, the interface will emit a single high pitchedbeep, and the light will return to green. An unsuccessful transmission isindicated by three low tone beeps. In this case repeat the transmissionprocess. If unsuccessful the second time, notify the Laboratory Point of CareCoordinator.
Transmitting Results from the Central Data Station to the Lab Computer.
Test records will be routinely transmitted to LIS automatically via an AME interface.
The Laboratory Point of Care Office will transmit results manually from the CentralData Station to the Laboratory Information System when AutoSend is off: Use the up and down arrow keys on the Central Data Station to highlight thepatient test record to be transmitted.
"_ _ _" indicates that the record is in queue.
". . ." indicates the record is being transmitted.
A check mark in the Central Data Station SENT column indicates that theresults have been transmitted.
Activate the Auto Send "on" to resume automatic transmission.
The i-STAT Reference Ranges have been derived from the literature and areprogrammed into the i-STAT Analyzer. The reference ranges are as follows: The reference ranges listed below are those used by Durham Regional Hospital Laboratory(serum/plasma samples for chemistries). Sodium, Potassium, Chloride, BUN, Glucose, Hematocrit,Hemoglobin, and Creatinine values have been established by in-house normal range studies andavailable literature. Arterial Blood Gases and ionized Calcium have been derived from the literature.
Clinical Significance
Sodium
Test for sodium in the blood are important in the diagnosis and treatment of patients suffering from
hypertension, renal failure or impairment, cardiac distress, disorientation, dehydration, nausea and
diarrhea. Some causes of increased values for sodium include dehydration, diabetes insipidus, salt
poisoning, skin losses, hyperaldosteronism and CNS disorders. Some causes for decreased values for
sodium include delusional hyponatremia (cirrhosis), depletional hyponatremia and syndrome of
inappropriate ADH.
Potassium
Tests for potassium in the blood are important in the diagnosis and treatment of patients
from hypertension, renal failure or impairment, cardiac distress, disorientation, nausea and diarrhea. Some causes of increased values for potassium include renal glomerular disease,adrenocortical insufficiency, diabetic ketoacidosis (DKA), sepsis and in vitro hemolysis. Some causesof decreased values for potassium include renal tubular disease, DKA, hyperinsulinism, metabolic alkalosis and diuretic Chloride
Tests for chloride in the blood are important in the diagnosis and treatment of patients suffering from
hypertension, renal failure of impairment, cardiac distress, disorientation, dehydration, nausea and
diarrhea. Some causes of increased values for chloride include prolonged diarrhea, renal tubular
disease, hyperparathyroidism and dehydration. Some causes for decreased values for chloride include
prolonged vomiting, burns, salt-losing renal disease, overhydration and thiazide therapy.
Urea Nitrogen/BUN
An abnormally high level of urea nitrogen in the blood is an indication of kidney function impairment
or failure. Some other causes of increased values for urea nitrogen include
(e.g. shock), postrenal azotemia, GI bleeding and high protein diet. Some causes of decreased valuesof urea nitrogen include pregnancy, severe liver insufficiency, Glucose
Glucose is a primary energy source for the body and the only source of nutrients for the brain issue.
Measurements for determination of blood glucose levels are important in the diagnosis and treatment
of patients suffering from diabetes and hypoglycemia. Some causes for increased values of glucose
include diabetes mellitus, pancreatitis, endocrine disorders (e.g. Cushings syndrome), drugs (e.g.
steroids, thyrotoxicosis), chronic renal failure, stress, or I.V. glucose infusion. Some causes of
decreased values of glucose include insulinoma, adrenocortical insufficiency, hypopituitarism,
massive liver disease, ethanol ingestion, reactive hypoglycemia, and glycogen storage disease.
Hematocrit
Hematocrit is a measurement of the volume of red blood cells. This is a key indicator of the body'sstate of hydration, anemia or severe blood loss, as well as the blood's ability to Some causes of increased values of hematocrit include dehydration,burns, impaired ventilation andrenal disorders. Some causes for decreased values of hematocrit include hemolytic anemias, irondeficiency, marrow depression or blood loss.
Creatinine
Elevated levels of creatinine are mainly associated with abnormal renal function and occur whenever
there is a significant reduction in glomerular filtration rate or when urine elimination is obstructed.
The concentration of creatinine is a better indicator of renal function than urea or uric acid because it
is not affected by diet, exercise or hormones.
Ionized Calcium
Although most of the calcium in blood is bound to protein or complexed to smaller anionic species,
the biologically active fraction of calcium is free ionized calcium. Through its role in a number of
enzymatic reactions and in membrane transport mechanisms, ionized calcium is vitally important in
blood coagulation, nerve conduction, neuromuscular transmission and in muscle contraction.
Increased ionized calcium (hypercalcemia) may result in coma.Other symptoms reflect neuromuscular
disturbances, such as hyperreflexia and/or neurologic abnormalities such as neurasthenia, depression
or psychosis. Decreased ionized calcium often results in cramps (tetany), reduced cardiac stroke work
and depressed left ventricular function. Prolonged hypocalcemia may result in bone demineralization
(osteoporosis) which can lead to spontaneous fractures. Measurments of ionized calcium have proven
of value under the following clinical conditions: transfusion of citrated blood, liver transplantation,
open heart surgery, neonatal hypercalcemia, renal disease, hyperparathyroidism, malignancy,
hypertension, and pancreatitis.
pH
pH is an index of the acidity or alkalinity of the blood with an arterial pH of <7.35 indicating an
acidemia and >7.45 alkalemia.
PO2
PO2 (partial pressure of oxygen) is a measurement of the tension or pressure of oxygen dissolved in
blood. Some causes for decreased values of PO2 include decreased pulmonary ventilation, impaired
gas exchange between alveolar air and pulmonary capillary blood, and alteration in the flow of blood
within the heart or lungs.
PCO2
PCO2 along with pH is used to assess acid-base balance. PCO2 (partial pressure of carbon dioxide),
the respiratory component of acid-base balance, is a measure of the tension or pressure of carbon
dioxide dissolved in the blood. Causes of primary respiratory acidosis (increase in PCO2 ) are airway
obstruction, sedatives and anesthetics, respiratory distress syndrome, and chronic obstructive
pulmonary disease. Causes of primary respiratory alkalosis (decreased PCO2) are hypoxia due to
chronic heart failure, edema and neurologic disorders, and mechanical hyperventilation.
HCO3 (bicarbonate)
HCO3 (bicarbonate) is an indicator of the buffering capacity of blood. Regulated primarily by thekidneys, HCO3 is the metabolic component of acid-base balance. Causes of primary metabolicacidosis are ketoacidosis , lactate acidosis, and diarrhea. Causes of primary metabolic alkalosis arevomiting and antacid treatment.
TCO2 (total carbon dioxide)
TCO2 (total carbon dioxide) is a measure of carbon dioxide which exists in several states: CO2 in
physical solution or loosely bound to proteins. Bicarbonate ions make up all but approximately
2mmol/L of the total carbon dioxide of plasma. Measurement of TCO2 as part of an electrolyte
profile is useful chiefly to evaluate HCO3 concentration. TCO2 and HCO3 are useful in the
assessment of acid-base imbalance (along with pH and PCO2) and electrolyte imbalance.
Base Excess/BE
Base excess remains virtually constant during acute changes in the PCO2 and reflects only
nonrespiratory component of pH disturbances.
Limitations of Procedure
Proper venipuncture technique must be followed to avoid hemolysis of the sample or tissue fluidcontamination.
Interferences:
Hydroxurea
(Droxia, Hydrea)
Hydroxyurea can cause significant errors in the measurement of Glucose, and Creatinine with the
i-STAT system. An alternate method must be used to measure Glucose and Creatinine when
patient’s have been administered hydroxyurea.
Hemodilution of the plasma by more than 20% associated with priming cardiopulmonary bypass
pumps, plasma volume expansion or other fluid administration therapies using certain solutions may
cause clinically significant error on Sodium, Chloride, Ionized Calcium, and pH
results. These errors are associated with solutions that do not match the ionic characteristics of
plasma. These errors can be avoided if when hemodiluting by more than 20%, physiologically
balanced multi-electrolyte solutions containing low-mobility anions (e.g. gluconate) such as
Normosol-R (Abbott Laboratories). Plasma-Lyte-A (Baxter Healthcare Corporation), and
Isolyte-S (B Braun Medical) are used.
Thiocyanate
Thiocyanate is a degradation product product of nitroprusside treatment and also a product ofthiosulphate treatment of cyanide poisoning.
It may cause falsely elevated Chloride results, or may cause chloride results to be suppressed (“star
out”).
It can cause falsely decreased BUN/urea, and Glucose results. Preliminary studies indicated that
140mg/dL (24mmol/L) thiocyanate decreased BUN/urea results approximately 21%, and decreased
Glucose results approximately 23%.
37.5 mmol/L bromide will increase Sodium results by 5 mmol/L, and decrease Glucose by 30mg/L.
12.5mmol/L (100mg/dL) bromide will increase Chloride results by 30 mmol/L, and will increase
Creatinine by 0.8mg/dL (71 umol/L) from an initial creatinine concentration of 1.0 mg/dL (88
umol/L).
20 mmol/L lactate will decrease Sodium results by 5 mmol/L, and decrease Ionized Calcium results
by 0.05 mmol/L.
11 mmol/L (100 mg/dL) lactate will increase Chloride results by 3.5 mmol/L.
B-hydroxybutyrate
16 mmol/L (166 mg/dL) B-hydroxybutyrate will decrease Sodium results by 5 mmol/L, and will
increase Chloride results by 3 mmol/L.
20 mmol/L B-hydroxybutyrate will decrease Ionized Calcium results by 0.1 mmol/L.
Salicylate
4 mmol/L salicylate will increase Chloride results by 5 mmol/L.
4.34 mmol/L salicylate will decrease Ionized Calcium results by 0.1 mmol/L.
Magnesium
1.0 mmol/L magnesium above normal will increase Ionized Calcium results by 0.04 mmol/L.
Ascorbate
11 mmol/L ascorbate will cause a 0.7 mg/dL increase in Creatinine.
The use of blood collection tubes containing sodium heparin as an anticoagulant mayincrease sodium results up to 1 mmol/L.
If heparanized whole blood is allowed to stand before testing, potassium values will firstdecrease slightly, then increase over time. Potassium will increase in iced specimens.
Potassium values from anticoagulated samples are preferred to serum values because 0.1 to0.7 mmol/L potassium can be released from platelets and red blood cells during the clottingprocess. Potassium values obtained from skin puncture samples may vary due to hemolysisor an increase in tissue fluid from improper technique during the collection procedure.
Glucose values will decrease in whole blood samples over time. Venous blood glucose is asmuch as 7 mg/dL less in capillary blood glucose as a result of tissue utilization.
Values below 7.4 at 37 Cdecrease results by approximately0.9 mg/dL (0.05 mmol/L) per 0.1 pH units. Values above7.4 at 37 Cincrease results by approximately 0.8 mg/dL (0.04 mmol/L) per Oxygen levels of less than 20mmHg (2.66 kPa) at 37 C maydecrease results.
Grossly elevated WBC counts may increase results.
High Hematocrit results can be caused by settling of red blood cells in the sample.
Low hematocrit results can be caused by contamination from flush solutions in an arterial orvenous line.
Hematocrit results are affected by the level of total protein as follows:For HCT values below 40%PCV: For Total Protein values below 6.5g/dL, HCT decreased by 1% PCV for each For Total Protein values above 8.0g/dL, HCT increased by 1% PCV for each For Total Protein values below 6.5g/dL, HCT decreased by 0.75% PCV for each For Total Protein values above 8.0g/dl, HCT increased by 0.75%PCV for eachincrease of 1g/dL TP.
Abnormally high lipids may increase results. Interference from lipids will be abouttwo thirds the size of the interference from protein.
The sample electrolyte concentration is used to correct the measured conductivityprior to reporting hematocrit results. Factors that affect sodium will therefore alsoaffect hematocrit.
Venous stasis (prolonged tourniquet application) and forearm exercise mayincrease ionized calcium due to a decrease in pH caused by localizedproduction of lactic acid. Exposing the sample to air will cause an increasein pH due to the loss of CO2 which will decrease ionized calcium.
Heparin binds calcium. Each unit of heparin added per mL of blood willdecrease ionized calcium by 0.01mmol/L. The correct ratio of heparinanticoagulant to blood must be achieved during sample collection.
Intravenous injection of 10,000 units of heparin has been shown inadults to cause a significant decrease of ionized calcium of about Affect of Freezing: Cartridges should be stored between 2 and 8 C. Freezing should beavoided. Freezing will cause the ionized calcium in the calibrant fluid to precipate, whichwill cause sample results to be falsely elevated. To help avoid freezing, do not storecartridges against the walls of the refrigerator. If freezing is suspected, test a sample of thecartridges using i-STAT controls.
Venous stasis and forearm exercise may decrease pH due to localized productionof lactic acid. Exposing the sample to air will cause an increase in pH due to theloss of CO2. pH decreases on standing anaerobically at room temperature at arate of 0.03 pH units per hour.
Exposure of the sample to air will cause an increase in PO2 when values are below
150 mmHg and a decrease in PO2 when values are above 150 mmHg (approximate PO2
Standing anaerobically at room temperature will decrease pH at a rate of 0.03 per hour, will increase PO2 by approximately 4mmHg per hour and will decrease PO2
at a rate of 2-6 mmHg per hour.
Do not ice samples before testing-PO2 results may be falsely elevated in cold samples. Donot use a cold cartridge.-PO2 results may be falsely decreased if the cartridge is cold.
sO2 values calculated from a measured PO2 and an assumed oxyhemoglobin
dissociation curve may differ significantly from the direct measurement.
PCO2, TCO2,HCO3
Exposing the sample to air allows CO2 to escape which causes PCO2 to decrease
and pH to increase and HCO3 and TCO2 to be under-estimated.
Allowing blood to stand (without exposure to air) before testing allows PCO2 to
increase and pH to decrease which will cause HCO3 and TCO2 to be over-
estimated due to metabolic processes.
For Creatinine values below 2 mg/dL:For PCO2 values above 40, creatinine values are increased by 6.9% for every 10mmHgFor PCO2 values below 40, creatinine values are decreased by 6.9% for every 10 mmHg.
For Creatinine values above 2 mg/dL:For PCO2 values above 40, creatinine values are decreased by 3.7% for every 10mmHgFor PCO2 values below 40, creatinine values are increased by 3.7% for every 10mmHg.
A creatine level of 5 mg/dL will cause a 0.20 mg/dL increase in Creatinine. Creatinemay be elevated in patients using creatine supplements, experiencing muscle traumaor other primary or secondary myopathies, taking statins for hyperlipidemia control, orin patients with hypothyroidism or a rare genetic defect of the creatine transporterprotein.
i-STAT Cartridge and Test Information Sheets for Sodium, Potassium,Chloride, Glucose, BUN, Hematocrit, revised November 1996. The i-STATCorporation, Princeton, New Jersey.
i-STAT System Manual, revised October 2003. The i-STAT Corporation,Princeton, New Jersey Tietz, Norbert W., Clinical Guide to Laboratory Tests, pp. 446-447, pp 398-399, pp. 110-111, pp. 230-231, pp. 492-493, pp. 258-259, W. B Saunderscompany, Philadelphia, PA., 1983.
Procedure Written By: Kathryn Winston, 10/04 Procedure Revised By: Kathryn Winston, 10/94, 11/95, 8/96, 6/97, 10/97,5/98,7/98,11/98,11/99,2/00,3/00,10/00,1/01,6/01,11/01, Susan Montsinger 4/04, 5/05 Director of Arterial Blood Gas Laboratory

Source: http://poct.duhs.duke.edu/wysiwyg/downloads/Istabg.pdf