Transcript Aspen, Colorado

Anticoagulation in CRRT
Timothy E. Bunchman
Professor
Pediatric Nephrology & Transplantation
Anti-Coagulation
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What is best?
Can you run anticoagulation free?
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Having no anticoagulation shortens circuit life
Will you use Heparin?
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Patient bleeding
Platelet count (HIT)
Will you use Citrate?
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Citrate lock
Metabolic alkalosis
Anticoagulation free Protocols
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Classically occur in patients with MODS with
abnormal clotting parameters
Usually these patient are given ample
amount of platelet infusions and coagulation
factors
This excessive amount of volume adds to
greater need for ultrafiltration
Final affect is clotting
Heparin or Citrate
(Mehta data)
Saline Flushes
Filter Life (hours)
Citrate
Heparin
Mehta,RL. Regional Citrate anticoagulation for CAVHD in
critically ill patients . Kidney Int, 38; 976-978, 1990.
Heparin Protocols
Benefit and Risks
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Benefits
Heparin infusion prior
to filter with post filter
ACT measurement
Bolus with 10-20
units/kg Infuse at 1020 units/kg/hr
Adjust post filter ACT
180-200 secs
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Risks
Patient Bleeding
Unable to inhibit clot
bound thrombin
Ongoing thrombin
generation
Activates - damages
platelets /
thrombocytopenia
Citrate: How does it work
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Clotting is a calcium dependent mechanism;
chelating calcium within blood will inhibit
clotting
Adding citrate to blood will bind the free
calcium (ionized) calcium in the blood thus
inhibiting clotting
Common example of this is blood banked
blood
Citrate: Mechanism of Action
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(Thanks to Peter Skippen)
Relationship of Prefilter [Citrate] to Prefilter iCa
1.2
1
0.8
Prefilter iCa
mmol/L 0.6
0.4
0.2
0
0
1
2
3
4
5
Prefilter [Citrate] mmol/L
6
7
8
Citrate: Advantages
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No need for heparin
Commercially available solutions
exist (ACD-citrate-Baxter)
Less bleeding risk
Simple to monitor
Many protocols exist
(Ca = 0.4 x citrate rate
60 mls/hr)
(Citrate = 1.5 x BFR
150 mls/hr)
Pediatr Neph 2002, 17:150-154
(BFR = 100 mls/min)
Normocarb
Dialysate
Normal Saline
Replacement
Fluid
Calcium can be infused in 3rd
lumen of triple lumen access if
available.
ACD-A/Normocarb Wt range 2.8 kg – 115 kg
Average life of circuit on citrate 72 hrs (range 24-143 hrs)
Complications of Citrate:
Metabolic alkalosis
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Metabolic alkalosis due to
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citrate converts to HCO3 (1 mmol of citrate
converts to 3 mmols of HCO3)-major cause
Solutions contain 35 meq/l HCO3-minor cause
NG losses-minor cause
TPN with acetate component-minor cause
Rx metabolic alkalosis by addition of an acid
load = Normal Saline (pH 5.4)
Complications of Citrate:
“Citrate Lock”
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Seen with rising total calcium with either a
sustained or dropping patient ionized calcium
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Rx of “citrate lock”
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Essentially delivery of citrate exceeds hepatic metabolism
and CRRT clearance
Decrease or stop citrate for 10-30 minutes then restart at
70% of prior rate
Patients receiving multiple blood products receive
additional citrate that may not be accounted for!
What is the best anticoagulant
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None
Heparin
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Standard
Low molecular weight
Citrate
Citrate
Heparin
LM Hep
Hoffbauer R et al. Kidney Int. 1999;56:1578-1583.
Heparin or Citrate?
(M Golberg RN et al, Edmonton PCRRT 2002)
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Heparin circuits
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13 patients with 45 filters
29.4 + 23 hrs average length of circuit
Citrate circuits
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16 patients with 51 filters
49.1 + 26 hrs average length of circuit
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(p < 0.001)
Filter clot free survival at fixed time intervals according to method of
anticoagulation
1. 00
citrate
0. 75
0. 50
heparin
0. 25
0. 00
0
20
40
60
80
Ti m
e f r omst ar t of C
R
R
T ( hour s)
C
i t r at e
(data from Sheldon Tobe)
H
epar i n
100
120
ppCRRT- Anticoagulation
Center, Patient and Circuit Demographics
 Data collected from 1/1/01 through 10/31/03
 HepACG only:
3 centers (1 CVVH, 2 CVVHD)
 CitACG only:
2 centers
 HepACG changed to CitACG: 2 centers
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138 patients total
18208 hours of CRRT circuit time
 230 hepACG circuits (52%) (9468.hrs)
 158 citACG circuits (36%) (6545 hrs)
 54 noACGcircuits (12%) (2185 hrs)
ppCRRT: Anticoagulation
Cumulative Proportion Surviving (Kaplan-Meier)
Complete
Censored
1.0
Cumulative Proportion Surviving
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
20
40
60
80
100
120
140
Circuit Survival Time (hours)
(Brophy et al, submitted)
160
180
200
220
Hep
Cit
No
ppCRRT: Anticoagulation
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43/158 citACG vs 58/230 hepACG clotted (NS)
9 pts (hepACG) had systemic bleeding; 4 led to
hepACG discontinuation
1 pt (hepACG) developed Thrombocytopenia
leading to hepACG discontinuation
No systemic bleeding side effects were reported
with citACG; 4 pts developed alkalosis and 2 pts
with hepatic failure developed citrate lock.
No correlation between circuit survival and (1)
mean hepACG rate (2) #ACT/hour or (3) # ACT’s
less 180 seconds
Summary
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Many protocols exist for anticoagulation
All have risk and benefit
Heparin with protamine has been used but
adds to potential complications and work at
bedside
Conclusion
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Choice of anticoagulation is best decided locally
For the benefit of the bedside staff who do the
work come to consensus and use just one protocol
Having the “protocol” changed per whim of the
physician does not add to the the care of the child
but subtracts due to additional confusion and work
at bedside