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BCU Citrate Guideline v6 Nov 2015 (Approved by CCSC May ’15) 1

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CITRATE GUIDELINESCITRATE GUIDELINESCITRATE GUIDELINESCITRATE GUIDELINES (Approved May 2015)


BCU Critical Care Guideline for Renal Replacement Therapy using Citrate

Indication Regional anticoagulation in patients receiving CRRT.

Contraindications 1. Severe liver impairment.

2. Paracetamol overdose.

3. Metformin toxicity.

4. Patient already receiving systemic anticoagulation.

(All relative, discuss with consultant)

Before starting treatment 1. Check the daily blood results before the start of treatment:

TOTAL CALCIUM (not the corrected value), magnesium and potassium.

2. Check recent arterial blood gas including calcium (PATIENT IONISED CALCIUM).

3. Ensure patent vascular access (able to withdraw blood at rate of 20mLs/6sec).

(NB: APTT levels are not required to operate the treatment.)

Equipment needed • 1 Prismaflex Filter ST150.

• 1 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.

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 value 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)


Starting Parameters (NB: if this is not the first set for this patient, simply set calcium compensation and citrate at their previous rates)

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

1 - 1.11 mmol/L 110%

1.12 – 1.3 mmol/L 100%

Greater than 1.3mmol/L 90%

Table 1: Initial Calcium Compensation

INITIAL FLOW SETTINGS: Based on Weight. See table 2 below.

INITIAL SETTINGS WITH CITRATE DOSE of 3 mmols/L blood

Weight

(Actual in Kg)

(Round up to

nearest whole kg)

Blood Flow

mLs/min

Dialysis rate

mLs/hr

Replacement

(post filter) rate

mLs/hr

Actual Renal

Replacement

Dose

Up to 50 100 1000 200 37 mLs/kg/hr

51 to 60 110 1100 400 37 mLs/kg/hr

61 to 70 120 1200 500 35 mLs/kg/hr

71 to 80 130 1300 500 33 mLs/kg/hr

81 to 90 140 1400 500 31 mLs/kg/hr

91 to 100 150 1500 600 31 mLs/kg/hr

101 to 110 160 1600 700 30 mLs/kg/hr

111 to 120 170 1700 800 30 mLs/kg/hr

121 and up 180 1800 1000 30 mLs/kg/hr

Table 2: Initial Flow Settings

CONNECTION (see Picture 1)

1. Connect access line to patient VasCath (red).

2. Connect yellow line to effluent bag.

3. Connect calcium chloride line to available port on Y connector.

4. Disconnect Y connector from priming bag and attach to Vascath (blue).

5. Connect blue return line to the vacated port on the Y connector.

6. Tape together calcium and return line (near patient).

7. Unclamp lines (as per machine).

8. Press start treatment (note the time).

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.


Picture 1: Connecting Tubing to VasCath.


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 0.25-0.5 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 Hourly until

stable** 6 Hourly

PATIENT IONISED CALCIUM – ABG from arterial line*

Target 1.00 to 1.30 mmol/L Hourly until

stable** 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 Daily

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


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


0.25 – 0.5


<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

1.0 – 1.3

Citrate dose increased by

0.5mmols/L blood

‘Normal’

Ideal Values


0.5mmols/L blood

Patient Ionised

Calcium

> 1.3

Calcium compensation decreased

by 10%

Calcium compensation

decreased by 10%

Calcium compensation decreased by

10%

AND


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 0.4 – 0.5mmol/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.


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

Patient Acidaemic -

too much citrate (and the liver

can’t handle it)

Only generally seen in liver

dysfunction

CONSULTANT DISCUSSION

REQUIRED

See Section on total calcium to ionised calcium ratio

RECHECK BLOODS ONE HOUR AFTER ANY CHANGE

ALWAYS REVIEW UNDERLYING PATHOLOGY Table 6: Acid/Base


Frequently Asked Questions

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 0.1 – 0.2mls 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.


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 0.2 - 0.25mmol/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.


APPENDIX: FLUID INFORMATION

PrismoCitrate 18/0 Predilution anticoagulant (mmol/L) (white scale)

Citrate 18

Na 140

Cl 86

K 0

PrismOcal B22 Dialysate (mmol/L) (green scale)

Na 140

Cl 120

Lactate 3

HCO3 22

K 4

Glucose 6.1

Mg 0.75

Calcium None

Prismasol 4 Replacement (mmol/L)(purple scale)

Na 140

Cl 113.5

Lactate 3

HCO3 32

K 4

Glucose 6.1

Mg 0.5

Calcium 1.75


Who contact with questions/ queries regarding citrate therapy

CSIG superusers:

Dr John Glen 07968980925

For all Prismaflex machine questions/ queries:

Prismaflex Helpline 0808 1003539

Documents

North Wales Critical Care & Trauma North Wales …nwcriticalcare.com/wp-content/uploads/2016/04/Citrate-Guidelines-v...North Wales Critical Care & Trauma North Wales Critical Care