Education Pack and Workbook for Citrate Anticoagulation via Prismaflex

Transcription

1 Education Pack and Workbook for Citrate Anticoagulation via Prismaflex Name Completion Date Assessed by (Superuser) Signature of Assessor Citrate Workbook v6 Nov

2 Contents Introduction 3 CSIG Members 3 Part 1 Continuous Renal Replacement Therapy - Overview 4 Anticoagulation of the Circuit 5 Citrate Anticoagulation - Overview 5 Citrate Advantages vs Disadvantages 6 Setting up and priming circuit 7 Assessment Part 1 9 Part 2 Starting CVVHDF using Citrate Anticoagulation 11 Treatment Monitoring 12 General Care of the RRT Patient 14 Troubleshooting Acid/Base disturbances 15 Assessment Part 2 16 Frequently asked questions 18 Reading List & Useful Websites 20 Certificate 22 Citrate Workbook v6 Nov

3 Introduction This booklet is designed to enable you to update your knowledge regarding the care of patients requiring Renal Replacement Therapy (RRT). It will help you gain the knowledge and skills to help you achieve competency in Citrate anticoagulation therapy using the Prismaflex. It is yours to keep as a resource and as a record of your learning. The experience of staff using Citrate in other hospitals is overwhelmingly positive. It is best for patients as they have fewer bleeding events and get more reliable RRT. Staff find that circuits last much longer and there are fewer problems to troubleshoot. You can work through the booklet at your own pace, using various resources. These include the Citrate Special Interest Group (CSIG): this is a group of medical and nursing superusers in BCU who are happy to be approached. The library contains useful reference books (see Further Reading), and the internet contains a number of useful sites (See Useful Websites). The Gambro Prismaflex Manual is a good resource, as is the Citrate Setup Guidelines attached to every machine. In order to gain the necessary experience and skills to become competent in Citrate therapy using the Prismaflex machine you are required to complete this workbook and have it assessed by a CSIG Superuser. CORE CSIG members: Wrexham Maelor Hospital Glan Clwyd Hospital (YGC) Bangor Hospital (YG) (WM) 1. Campbell Edmondson 1. John Glen 1. Alison Ingham 2. Graham Mayers 2. Richard Pugh 2. Janice Cadywould 4. Jennifer Smyth 3. Mark Williams-Jones 3. Pierre Peyrasse 5. Stewart Tasker 4. Phillip Rathbone 4. Sharon Evans 5. Uttam Chouhan CSIG Superusers: Wrexham Maelor Hospital (WM) Glan Clwyd Hospital (YGC) Bangor Hospital (YG) Stewart Tasker Louisa Erica Melissa Price Rachael Evans Karen Austin Kate Coleman Anwen Willams Naomi Jenkins Boyet Potunova Jon Pico Sion Thomas Jo White Kerry Angus Sharon Lynch Shona Hollins-Davies Janice Cadywould Glenn Sanderson Louise Lloyd Ceri Twigge Nerys Elias Jaydee Castillo Ferdinand Vitug Garcia Marites Clare Jones Linda Leech Acknowledgements We are grateful to the Intensive Care Staff at the Royal Marsden Hospital for allowing us to adapt their Citrate guidelines and learning materials. Citrate Workbook v6 Nov

4 CITRATE - PART 1 Continuous Renal Replacement Therapy (CRRT) - Overview This is a supportive therapy used in Critical Care patients who have developed an acute kidney injury (AKI). AKI is characterized by a rapid deterioration in kidney function resulting in a failure to maintain fluid, electrolyte and acid-base homoeostasis. There are a number of systems used to define and stage AKI, including RIFLE and KDIGO for more information on these visit the websites listed in the reading list. The end result, irrespective of which definition you use, is a patient with gross biochemical abnormalities and (often) fluid overload. The aim of therapy is to normalize this abnormal biochemistry as far as the technology will allow. This means: Relieving hypervolaemia and maintaining fluid balance. Removing excess urea and creatinine. Correcting and maintaining metabolic and electrolyte balance This continuous technique was developed for critically ill patients with AKI who had previously been treated with conventional dialysis. Those patients frequently became unstable during dialysis due to its short, intense nature. CRRT by contrast allows fluid and waste products to be removed more gradually over a 24 hour period, which may give greater cardiovascular stability. Of course this has been questioned, and many units run dialysis without a problem. Technique Using a double lumen Vascath and an extracorporeal circuit, blood is continuously removed from, and returned to, the patient. The circuit incorporates a blood pump and a filter containing a semi-permeable membrane. A pressure gradient within the circuit forces fluid and solutes across the membrane to form filtrate (or effluent). In addition, dialysis fluid on the other side of the membrane causes molecules to move across with their concentration gradient. The processes involved here are termed: Ultrafiltration: Water forced across a semipermeable membrane by pressure. Convection: Also called solvent drag solutes moving along with the water because they are dissolved in it. Osmosis: Water moving across a semipermeable membrane with its concentration gradient. Diffusion. Solute moving across the membrane with its concentration gradient. Fluid removed by ultrafiltration is replaced using replacement fluid we use Prismasol 4, which has a similar electrolyte composition to normal blood. Of course not all the fluid removed is replaced in this way: some of the patient s fluid will come from other sources like nutrition and drugs, and it may be desirable to remove fluid from the patient without replacing it at all. The net fluid removal aim is set by medical staff on the morning/ evening ward round. Citrate Workbook v6 Nov

5 Anticoagulation of the circuit Blood passes through the extracorporeal circuit, which has a colossal surface area. The large surface area leads to a reduction in blood velocity which leads to platelets beginning to stick to the sides of the circuit. This in turn activates the clotting cascade. Extra anticoagulation is therefore usually required to maintain the circuit and stop it from clotting off altogether. The aim of any anticoagulation medication is to anticoagulate the circuit, not the patient. There are three ways to anticoagulate CRRT circuits in BCU. The main method is (about to be!) regional Citrate, on which this booklet concentrates. The other two methods are to use heparin (for example, when Citrate is contraindicated), and to use Epoprostenol (when both citrate and heparin are contraindicated). The anticoagulant being used will determine which Pre Blood Pump (PBP), Dialysis and Replacement Fluids to use. For Heparin and Epoprostenol (Flolan) anticoagulation we can simply use Prismasol 4 on all three scales. Citrate is a bit more complicated, and requires 3 different fluids, as well as a Calcium replacement syringe (see below). Citrate Anticoagulation - Overview Citrate binds ionized calcium in the extracorporeal circuit, which prevents the formation of blood clots. This has no effect on the patient s systemic coagulation, which means that it is safe to use on patients with bleeding risks, (such as recent surgery or traumatic brain injury) and it is also safe to use in patients with Heparin-Induced Thrombocytopenia (HIT). The majority of citrate is cleared by dialysis as complexed calcium citrate. This means that the patient loses some of their calcium. Calcium must therefore be given back to the patient at the end of the circuit, or they will become hypocalcaemic. This is done via a 50mLs syringe attached to the Prismaflex machine. The rate of calcium given to the patient is calculated by the Prismaflex machine, based on the rate of citrate administration and the flow of effluent. The remaining citrate which returns to the patient is metabolised by the liver, skeletal muscle and kidney into bicarbonate. Because we don t want the calcium to be present in the circuit, we have to use Calcium-free Dialysate (Prism0cal B22). The Citrate itself is given in the Pre-Blood Pump (Prismocitrate 18/0). We can give the usual Replacement (Prismasol 4). Citrate Workbook v6 Nov

6 Citrate Advantages/Disadvantages Advantages Safe to use on patients with active bleeding, recent bleeding or who are at risk of bleeding, e.g. recent surgery. Safe to use with patients at risk of Heparin Induced Thrombocytopenia (HIT). Citrate acts as a buffer, being metabolized into 3 molecules of bicarbonate. This may be beneficial in cases of severe metabolic acidosis. Disadvantages In patients with SEVERE liver disease, citrate metabolism may be inadequate, resulting in citrate accumulation, metabolic acidosis and hypocalcaemia. Close monitoring of Calcium, ph, HCO 3 and electrolytes is required. Citrate intolerance in a small number of patients. Equipment needed 1 Prismaflex Filter ST bag of 5L PrismoCitrate 18/0 (Citrate used as pre-dilution). 1 bag of 5L Prism0cal B22 (Dialysate, calcium-free). 1 bag or 5L Prismasol 4 (post-dilution replacement fluid). 2 bags of 0.9% 1000mLs Sodium Chloride (priming solution - No Heparin required). 1 CA250 calcium line. 1 50mL Luer lock syringe. 30mmol calcium (as calcium chloride) made up to 50ml with 0.9% Saline Citrate Workbook v6 Nov

7 Setting up and priming circuit 1. Select New Patient. 2. Input actual body weight. 3. Input haematocrit. This is found on the full blood count. Unlike in treatment with heparin, haematocrit is important. Update the haematocrit every morning. 4. Choose CVVHDF. 5. Choose Citrate Anticoagulation via Prismaflex Pump. 6. Follow the installation steps on the screen: Install PrismoCitrate 18/0 on the white scale (PBP = pre blood pump). Install Prism0cal B22 on the green scale. (Dialysate). Install Prismasol 4 on the purple scale (Replacement). 7. Install the calcium chloride in the Prismaflex integral syringe pump. 8. Prime the circuit with 2 X 1L of 0.9% Sodium Chloride (as per on screen instructions) Notes on the above: a. Circuit Installation Throughout this process a series of Bullet Points appear on the left hand side of the screen; these are useful to press as they highlight exactly which parts of the machine or circuit need to be looked at next. They will help you to correctly install both the circuit and the syringe. Setting up and priming circuit - continued Citrate Workbook v6 Nov

8 b. Priming the circuit Circuits must be primed with 2 litres 0.9% Sodium Chloride to flush out the ethylene oxide used in the sterilizing process. Once primed the circuit must be used within 30 minutes otherwise you need to do it again. c. Calcium Replacement A 50mLs BD Plastipak syringe with 30mmol calcium (as calcium chloride) made up to 50mLs with 0.9% sodium chloride (final concentration 0.6mmol/L) is inserted into the Prismaflex syringe driver before you start the prime (see Install Calcium Syringe screen). The Calcium syringe is connected to Calcium line and a Y connector in order to administer Calcium to the patient via the return port of the Vascath. You need to attach these before the prime begins. The shorter line in the filter set (used for other methods of anticoagulant) should be clamped. d. Getting ready to start Once the set has been primed it will ask you to check the circuit and then Prime Test. Once the prime test has been completed, go no further. Now is the time to check the adequacy of the Access and Return ports of the Vascath. Withdraw 5mLs blood from each port and discard. Connect a 10mLs syringe to the Access port, draw back until full over 3 seconds: this will confirm patency of the port. Repeat on the Return line. If resistance is felt, line reposition may be required. The 10mLs of blood can be immediately returned before finally flushing both ports with 5mLs Saline. Do not proceed with therapy in presence of poor access pressures, it is sure to fail. NB: avoid swapping lines unless absolutely necessary. If lines are swapped, ensure the lines are clearly labelled, and the reason for the change is documented. Citrate Workbook v6 Nov

9 Part 1 Assessment Using this booklet and any other resource you choose, complete the following questions. Assessment Question 1 On the setup screen, what would you select for Regional Citrate? Heparin via the Prismaflex syringe driver. Anticoagulation via external syringe driver. Citrate via Prismaflex pump. Citrate via external syringe. Assessment Question 2 List the disposable equipment required to administer CVVHDF using Citrate. (not including fluids or calcium) (3 items). Assessment Question 3 What must the bedside nurse regularly monitor in order to ensure appropriate citrate dosing (2 items)? Assessment Question 4 What do you do if, during setup, you encounter resistance in the flow of the Vascath? Assessment Question 5: tick the correct answer from below. In Citrate anticoagulation, Calcium Chloride is adminstered: (1 point) Directly to the patient? Directly into the filter? Via the PBP scale? Assessment Question 6: tick the correct answer from below. Citrate is Administered: As a Dialysate? Directly to the patient? Via the PBP scale? Assessment Question 7: tick the correct answer from below. What is a potential side effect of citrate anticoagulation? Hyperphosphataemia Hypocalcaemia Hypercoagulability Assessment Question 8: Citrate Workbook v6 Nov

10 Haemodialysis, haemofiltration and haemodiafiltration are terms used to describe the removal of waste products and water from the blood through a semipermeable membrane or filter. This is achieved through certain physiological principles. Briefly describe each of the physiological principles listed. Osmosis Diffusion Ultrafiltration Convection Assessment Question 9: Fill in the blanks below: Mechanism Advantages Disadvantages Citrate Binds Calcium Heparin Epoprostenol Assessment Question 10: tick the correct answer from below. Citrate PBP Fluid (Prismocitrate 18/0) Contains: Citrate, Calcium, and Potassium. Citrate, Sodium and Potassium. Citrate and Sodium only. Assessment Question 11: tick the correct answer from below. Dialysis Fluid (Prism0Cal B22) Contains: Calcium, Glucose and HCO₃ (22mmol/L) Potassium 4mmol/L, Glucose and HCO₃ (22mmol/L) Glucose, HCO₃ (22mmol/L), and Phosphate Assessment Question 12: tick the correct answer from below. Replacement Fluid (Prismasol 4) Contains: Potassium, Calcium, HCO₃ (32mmol/L) Potassium 4mmol/L, Phosphate 1.2mmol/L and HCO₃ 30mmol/L No Potassium, no HCO₃, no Lactate CITRATE - PART 2 Citrate Workbook v6 Nov

11 Starting CVVHDF Using Citrate Anticoagulation. Citrate (Prismocitrate 18/0) is administered pre-filter (White scale - PBP) so that the chelating process begins before the blood has a chance to clot. The initial Citrate dose is always 3mmol/L. (If this is not the first circuit for this patient, then restart with the previous Citrate dose and Calcium Replacement rates from when the treatment last finished.) Setting the Flow rates: For Citrate a slower blood pump speed is usually adequate (between 100 to 180mLs/hr). This is much slower than you will be used to with heparin or epoprostenol. Follow the instructions below. MODE: CVVHDF FLUID REMOVAL: as advised by doctor CITRATE DOSE: 3 mmol/l. CALCIUM COMPENSATION: Depends on initial PATIENT IONISED CALCIUM level see table 1 below. Patient Ionised Calcium Starting Calcium Compensation (%) Less than 1mmol/L 110% AND give 10mls calcium chloride 10% over 30 mins before starting mmol/l 110% mmol/l 100% Greater than 1.3mmol/L 90% Table 1: Initial Calcium Compensation INITIAL FLOW SETTINGS: Based on Weight. See table 2 below. Weight (Actual in Kg) (Round up to nearest whole kg) INITIAL SETTINGS WITH CITRATE DOSE of 3 mmols/l blood Blood Flow mls/min Dialysis rate mls/hr Replacement (post filter) rate mls/hr Actual Renal Replacement Dose Up to mls/kg/hr 51 to mls/kg/hr 61 to mls/kg/hr 71 to mls/kg/hr 81 to mls/kg/hr 91 to mls/kg/hr 101 to mls/kg/hr 111 to mls/kg/hr 121 and up mls/kg/hr Table 2: Initial Flow Settings Citrate Workbook v6 Nov

12 Treatment Monitoring Low PATIENT IONISED CALCIUM values should ALWAYS be attended to as a priority as it will have the biggest impact on patient physiology and stability. If at any time during treatment the patient s ionised calcium is less than 0.7 mmol/l, administer 10mL calcium chloride 10% through peripheral or central line. The PATIENT IONISED CALCIUM from the patient s arterial line* is used to ensure that enough calcium chloride is being given to the patient to replace the calcium used up in the reaction with the citrate. A PATIENT IONISED CALCIUM of >1 is required TO KEEP THE PATIENT SAFE from the effects of hypocalcaemia. The calcium replacement, initially estimated by the Prismaflex machine, may need to be changed based on these results. The FILTER IONISED CALCIUM (from the blue port on the Prismaflex [i.e. post filter]) is checked on the blood gas machine to ensure that enough calcium is being removed by the citrate infusion via the pre-blood pump. A FILTER IONISED CALCIUM concentration of mmol/l is required TO PREVENT FILTER CLOTTING. The citrate dose, initially based on patient weight, may need to be changed based on these results. So, once treatment is initiated and blood flow established, wait 60 minutes then check the: PATIENT IONISED CALCIUM from the patient s arterial line*. FILTER IONISED CALCIUM (from blue port on Prismaflex). The table below gives the timings of the FILTER IONISED CALCIUM and PATIENT IONISED CALCIUM checks (as well as other blood tests which will be needed). Parameter Initial check And then FILTER IONISED CALCIUM ABG from blue port on circuit Target 0.25 to 0.50 mmol/l PATIENT IONISED CALCIUM ABG from arterial line* Target 1.00 to 1.30 mmol/l Hourly until stable** Hourly until stable** 6 Hourly 6 Hourly TOTAL CALCIUM yellow tube sent to lab Target 2.20 to 2.50 mmol/l After 6 hours Daily TOTAL CALCIUM to PATIENT IONISED CALCIUM ratio Target ratio <2.5 After 6 hours U&E 6 hourly 12 hourly when stable FBC/haematocrit Daily Daily Magnesium/phosphate Daily Daily Glucose As per protocol As per protocol Table 3: Frequency of blood tests. *Or central line, or peripheral venesection: the point is that it comes from the patient, not the machine. ** Stable = No changes required for 2 consecutive hours Daily Citrate Workbook v6 Nov

13 Treatment Monitoring continued Adjust the Calcium Compensation and Citrate Dose based on the table below. Adjustments are made through the Anticoag screen. Filter Ionised Calcium >0.50 Filter Ionised Calcium Filter Ionised Calcium <0.25 Patient Ionised Calcium < 1.0 Citrate dose increased by 0.5mmols/L blood AND Calcium compensation increased by 10% Calcium compensation increased by 10% Citrate dose decreased by 0.5mmols/L blood Patient Ionised Calcium Patient Ionised Calcium > 1.3 Citrate dose increased by 0.5mmols/L blood Calcium compensation decreased by 10% Normal Ideal Values Calcium compensation decreased by 10% Citrate dose decreased by 0.5mmols/L blood Calcium compensation decreased by 10% AND Citrate dose decreased by 0.5mmols/L blood RECHECK ONE HOUR AFTER ANY CHANGE Table 4: Adjusting Calcium and Citrate Dose With the exceptions given in the table above, aim to make only one adjustment at a time. Then recheck for desired effect in one hour. Making multiple changes to citrate dose, calcium compensation, blood flow or dialysis flow simultaneously will make the interpretation of actions and subsequent troubleshooting difficult. Total calcium to ionized calcium ratio monitoring A high total calcium to ionized calcium ratio is a surrogate marker of citrate toxicity. To obtain the value, perform the following calculation manually TOTAL CALCIUM PATIENT IONISED CALCIUM. Note that it is the total calcium and not the corrected calcium that is used in the equation. After 6 hours of treatment commencing, request a total calcium from the lab (yellow tube, best sent with U&Es). However, increasing calcium compensation in the preceding hours could indicate citrate accumulation. In these circumstances, a total calcium level may be checked before the 6 hour mark. Ratio Action <2.5 Check ratio daily >2.5 Consult medical staff. Stop the PrismoCitrate for 20 minutes and restart afterwards with 70% of prior citrate dose. Leave the calcium unchanged. This should result in a slightly higher filter ionised calcium. (0.4 to 0.5 acceptable) If ratio remains above 2.5 despite filter Ionised calcium of mmol/L then consider: 1. Doubling baseline dialysate flow (will increase citrate clearance) 2. Reducing blood pump speed (will reduce total administered citrate dose). 3. Stopping citrate and using an alternative anticoagulant (or no anticoagulant) Table 5: Citrate Accumulation. General care of patient undergoing Citrate CRRT Citrate Workbook v6 Nov

14 Remember that it is the PATIENT IONISED CALCIUM which will affect your patient first. This is the priority for action if you have abnormal blood tests. If calcium compensation is increasing and patient ionised calcium continues to decrease (by >50% of starting value) then consider citrate accumulation. Seek help. Immediately after connecting and commencing therapy, check the fluid level in the deaeration chamber and adjust appropriately. This will need to be monitored each hour and documented. Throughout the therapy monitor patient s general condition for changes in hemodynamic stability. On commencement of therapy it is not unusual for a patient s blood pressure to fall. Sometimes a fluid bolus is required. Once therapy has been commenced, it is important to calculate appropriate fluid removal. The target fluid balance should be indicated on the medical prescription. It is important to take into consideration any fluids being administered in the form of feed, drug volumes and drinks etc. and any fluids that are being passed or removed by other means. Patient s temperature will need to be monitored throughout treatment and the blood warmer attached to the return line if required. Most patients will require a Bair Hugger to maintain normothermia (>36 O C). The Prismaflex operates within fixed pressure ranges, and will stop if pressures are outside certain parameters. These can be found on the side of the machine. Because lower blood flow rates are required with citrate, pressurerelated issues are unlikely unless you have a Vascath problem. Citrate Workbook v6 Nov

15 Troubleshooting Acid/Base Disturbances BLOOD GASES POSSIBLE REASON POTENTIAL SOLUTIONS TO CONSIDER ph > 7.45 and BE > +5 Too much citrate (metabolised by the liver to bicarbonate). Boost citrate removal in dialysis by increasing dialysis flow by 500mLs/hr. Maximum dialysis dose of 3000mLs/hr. Or: Consider reducing citrate dose to patient by reducing blood flow rate in 20mLs/min increments. Or: Consider accepting higher post filter ionised calcium by reducing citrate dose by 0.5mmol/L ph < 7.35 and BE < -5 Total calcium and patient ionised calcium normal NB: NORMAL LIVER FUNCTION Metabolic acidaemia more citrate may help Reduce dialysis dose to reduce clearance of citrate, thus increasing citrate buffer load to patient. Or: Consider increasing blood flow rate, which will increase citrate dose. Or: Consider systemic sodium bicarbonate infusion. ph < 7.35 and BE < -5 Total calcium increased; patient ionised calcium normal or decreased Ratio of total Ca/ionised Ca > 2.5 Table 6: Acid/Base Acidaemic - too much citrate (and the liver can t handle it) Only generally seen in liver dysfunction CONSULTANT DISCUSSION REQUIRED RECHECK BLOODS ONE HOUR AFTER ANY CHANGE ALWAYS REVIEW UNDERLYING PATHOLOGY See Section on total calcium to ionised calcium ratio Citrate Workbook v6 Nov

16 Part 2 Assessment Using the booklet and any other resource you choose, complete the following questions. Assessment Question 13: The normal pressure ranges for the Prismaflex machine are: Pressure Normal Range Limit Access Return Filter Effluent Assessment Question 14: a) What does a rising Transmembrane Pressure indicate?. b) What does a rising Pressure Drop indicate?... Assessment Question 15: What parameters are monitored to check adequacy of anticoagulation? What else needs to be monitored for safety? Citrate Blood Test for Adequacy Blood Test for Safety Assessment Question 16: Name the site the bedside nurse should take blood from to check: a) Circuit Ionised Calcium?... b) Patient Ionised Calcium?... Assessment Question 17: What Blood Flow Rate will you start with for a 76kg male patient? 100mLs/h 130mLs/h The maximum the vascath will allow (please tick) Assessment Question 18: What settings would you use for a 97kg woman? (please tick) 150mLs PBP, 1500mLs dialysate, 600mLs replacement 111mLs PBP, 1000mLs dialysate, 500mLs replacement 100mLs PBP, 2000mLs dialysate, 500mLs replacement Citrate Workbook v6 Nov

17 Assessment Question 19: a) How often (if no changes to Citrate and Calcium compensation have been made) should you take blood?... b) If you have to adjust your citrate dose at the first check, when must you next check?... c) You have to adjust your calcium compensation at the first check, when must you next check?... d) You have just started CVVHDF using Citrate anticoagulation on your patient and find that on the first check the post filter ionised calcium is 0.6mmol/L. What should you do?... e) On the next check, the post filter Ca ++ is stable and the citrate dose is within the ideal range. i. What is the ideal range?... ii. When would you next check Ca ++?... f) At the next check, you find that the patients Ionise Calcium is 1.45mmol/L. What do you do?... g) As you have just started Citrate therapy, when should we check the patient s Total Calcium?... Assessment Question 20: a) Your patient s ABG shows a worsening metabolic alkalosis with a high Sodium with no obvious pathology to explain. What do you think may be the cause?... b) How might you resolve this?... c) The patient has a rise in Total Calcium. Their bilirubin is also elevated. What might be the reason?... d) How might you resolve this?... Frequently Asked Questions Citrate Workbook v6 Nov

18 Q. Is heparin used to prime the circuit? No. However patient s lines should be hep-locked at the end of treatment. Q. My patient is septic, and I want to increase my dose of RRT. How can I do this? Increase the replacement by 10ml/kg/hr. For example, if you have a 70kg patient receiving a total RRT dose of 35ml/kg/hr, and you want to up it to 45, then increase their replacement by 700ml/hr. Q. What do I do if I want to increase clearance? Depending on solute to be removed, either increase replacement flow or dialysate flow or alternatively move patient up to the next weight bracket. Changes to blood flow and dialysate flow rates will affect the citrate and calcium doses delivered. So change flow rates with caution. Increases to post filter replacement flow should not have a demonstrable effect on patient ionised calcium or citrate requirements. Increasing replacement rates to increase effluent dose does NOT require a change in dialysis flow UNLESS the blood flow rate is changed also. Q. How quickly does a change in citrate dose have its effect? Changes to citrate dose will have a rapid effect on post filter calcium concentration, usually within 5 to 10 mins. Q. The protocol says to reduce the citrate dose, and now the overall effluent dose has dropped. What should I do? Should the protocol stipulate that the citrate dose be reduced, pre-blood pump flow and hence total effluent dose will also fall. If the total effluent dose falls below 30mls/kg/hr as a result, increase the replacement flow until a dose of 30mls/kg/hr is achieved. Q. My calcium compensation is very high. Is that normal? There are lots of reasons why a patient s calcium needs can increase, but if calcium compensation is above 150% this could indicate citrate accumulation (citrate is not being metabolised and calcium is not being released). Check patient total calcium/patient ionised calcium ratio if >2.5 follow protocol guideline above. Q. What do I do if my bicarbonate is consistently low? This could be a sign of citrate accumulation. Check calcium ratio. If within normal levels, consider giving bicarbonate. Q. My calcium levels remain high, or are suddenly very low. What s going on? If post filter ionised calcium remains high with increasing citrate doses then check that the correct arrangment and type of fluid has been installed on the replacement and dialysis lines. A sudden and unexplained drop in the patient ionised calcium value and high post filter calcium should signal to check the PrismoCitrate bag has been installed correctly on the pre blood pump and not the replacement line! Q. Should I recheck bloods if the calcium chloride (CaCl) infusion adjusts by a very small amount? Sometimes the calcium chloride infusion will adjust by mls when the Prismaflex attempts to compensate for downtime when pumps have been stopped. No checks are required at very small levels if you are happy that there have been recent reasons for pumps being stopped (e.g. for bag changes). Q. How should citrate be re-started following a circuit change? If a new circuit is started in less than an hour after stopping, then start at the previous levels of citrate and calcium compensation. If more than an hour, then start all over again as if with a new patient. Citrate Workbook v6 Nov

19 Q. Why do I keep getting calcium line clamped alarm?? Before filling syringe, pump the plunger up and down in the barrel of the syringe to improve movement. After making up your syringe, discard some of the volume so that syringe volume is below 50mls. If alarm still persists consider moving calcium line to patient s central line. Q. How can I avoid machine interruptions? Ensuring machine interruptions are kept to a minimum will maintain continuous blood circulation and therefore seamless therapy. The following will help: Do not persist with therapy if ve access pressure (>200mmHg) unresolved within 5-10 minutes (contact Superuser/Consultant for advice immediately) Recirculate blood in set ASAP in order to give time (60 mins) for Vascath manipulation (as required) or other lengthy procedures that reduce Vascath patency. Ensure movement of fluid bags is kept to a minimum. Q. The filter has clotted early despite following the protocol. What should I do? If the patient demonstrates early filter clotting (less than 72 hours) then consider a lower target of FILTER IONISED CALCIUM of mmol/L by increasing the citrate dose by 0.2mmols/L from the previous dose. Be aware of risks of citrate accumulation and metabolic alkalosis. Q. Does citrate affect drug pharmacokinetics or clearance? Not appreciably. Citrate Workbook v6 Nov

20 Reading List: Ahmad, S (2009) Manual of Clinical Dialysis, 2nd edition, New York: Springer Science and Media Inc. Davenport, A. And Tolwani, A. (2009) Citrate anticoagulation for continuous renal replacmeent therpay (CRRT) in patient with acute kidney injuty to the intensive care unit, Nephrology Dialysis Transplantation Plus, 2, p Hetzel GR et al (2011),Regional Citrate versus systemic heparin for anticoagulation in critically ill patients on continuous venovenous haemfiltration: a prospective randomized mutlicentre trial, Journal of Nephrology Dialysis Transplant, 26, (p ). Kellum, J.A., Bellomo, R. And Ronco, C. (2010) Continuous Renal Replacement Therapy, New York: Oxford University Press. Kutsogiannis, D.J., Gibney, N., Stollery, D. and Gao, J. (2005). Regional citrate versus systemic heparin anticoagulation for continuous renal replacement in critically ill patients. Kidney international, 67(6), p Useful Websites Uptodate is a fantastic resource to which BCU subscribes. It is a continuous rolling review of the literature, written and kept current by eminent physicians at prestigious American institutions. It covers just about everything. You can get access to it via the library. Citrate Workbook v6 Nov

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