ANTICOAGULATION PCRRT 2008 Orlando Patrick Brophy MD Director Pediatric Nephrology University of...
-
Upload
emmeline-whitehead -
Category
Documents
-
view
217 -
download
0
Transcript of ANTICOAGULATION PCRRT 2008 Orlando Patrick Brophy MD Director Pediatric Nephrology University of...
ANTICOAGULATIONPCRRT 2008 Orlando
Patrick Brophy MDDirector Pediatric NephrologyUniversity of Iowa- Children’s Hospital
Normal CoagulationContact Phase (intrinsic)Contact Phase (intrinsic)
XII activationXII activationXI IXXI IX
Tissue Factor (extrinsic)Tissue Factor (extrinsic)TF:VIIaTF:VIIa
THROMBINTHROMBIN
fibrinogenfibrinogen
prothrombinprothrombin
XX XaXa Va Va VIIIa VIIIa CaCa++++ plateletsplatelets
CLOTCLOT
platelets / monocytes / macrophages platelets / monocytes / macrophages
Sites of Thrombus Formation
Any blood surface interface Hemofilter Bubble trap Catheter (Especially
Pediatrics) Areas of turbulence
resistance Luer lock connections / 3
way stopcocks
Anticoagulants
Saline Flushes Heparin ### Peds Citrate regional anticoagulation
### Peds Low molecular weight heparin Prostacyclin Nafamostat mesilate Danaparoid* Hirudin/Lepirudin Argatroban (thrombin
inhibitor)*
* No antidote known
Heparin
Sites of Action of HeparinContact Phase (intrinsic)Contact Phase (intrinsic)
XII activationXII activationXI IXXI IX
Tissue Factor (extrinsic)Tissue Factor (extrinsic)TF:VIIaTF:VIIa
THROMBINTHROMBIN
fibrinogenfibrinogen
prothrombinprothrombin
XX XaXa Va Va VIIIa VIIIa CaCa++++ plateletsplatelets
CLOTCLOT
platelets / monocytes / macrophages platelets / monocytes / macrophages
UF HEPARINUF HEPARIN
LMWHLMWH
LMWH: Theoretic advantages
Reduced risk of bleeding Less risk of HIT
LMWH
No difference in risk of bleeding No quick antidote Increased cost No difference in filter life
Heparin Protocols Heparin infusion prior to filter with post
filter ACT measurement and heparin adjustment based upon parameters
Bolus with 10-20 units/kg Infuse heparin at 10-20 units/kg/hr Adjust post filter ACT 180-200 secs Interval of checking is local standard and
varies from 1-4 hr increments
Heparin Protocols Benefit and Risks BenefitsBenefits Heparin infusion prior
to filter with post filter ACT measurement
Bolus with 10-20 units/kg Infuse at 10-20 units/kg/hr
Adjust post filter ACT 180-200 secs
RisksRisks Patient Bleeding Unable to inhibit clot
bound thrombin Ongoing thrombin
generation Activates - damages
platelets / thrombocytopenia
Citrate
Sites of Action of CitrateCONTACT PHASECONTACT PHASE
XII activationXII activationXI IXXI IX
TISSUE FACTOR TISSUE FACTOR TF:VIIaTF:VIIa
THROMBINTHROMBIN
fibrinogenfibrinogen
prothrombinprothrombin
XaXa
Va Va VIIIa VIIIa CaCa++++ plateletsplatelets
CLOTCLOT
monocytemonocyte/ / platelets / platelets / macrophagemacrophage
FIBRINOLYSIS ACTIVATIONFIBRINOLYSIS ACTIVATION
FIBRINOLYSIS INHIBITIONFIBRINOLYSIS INHIBITION
NATURAL NATURAL ANTICOAGULANTANTICOAGULANT(APC, ATIII)(APC, ATIII)
XX
Phospholipid Phospholipid surfacesurface
CaCa++
++CaCa++
++CaCa++
++CaCa++
++CaCa++
++CaCa++
++
CITRATECITRATE
How does citrate work
Clotting is a calcium dependent mechanism, removal of calcium from the 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
How is citrate used?
In most protocols citrate is infused post patient but prefilter often at the “arterial” access of the dual (or triple) lumen access that is used for hemofiltration (HF)
Calcium is returned to the patient independent of the dual lumen HF access or can be infused via the 3rd lumen of the triple lumen access
Citrate: Technical Considerations Measure patient and system iCa in 2 hours then
at 6 hr increments Pre-filter infusion of Citrate
Aim for system iCa of 0.3-0.4 mmol/l Adjust for levels
Systemic calcium infusion Aim for patient iCa of 1.1-1.3 mmol/l
Adjust for levels
Citrate: Advantages
No need for heparin Commercially available solutions
exist (ACD-citrate-Baxter) Less bleeding risk Simple to monitor Many protocols exist
Advantages of Citrate
Has zero effect upon patient bleeding as opposed to heparin which effects system and patient bleeding
Easy to monitor with ionized calcium assay Activated Clotting Time (ACT) nor PTT needed Programs report less clotted circuits = less disposable
cost and less overtime nursing hours Bedside surveys demonstrate less work of machinery
allowing more attention to patient
Citrate: Problems
Metabolic alkalosis Metabolized in liver / other tissues
Electrolyte disorders Hypernatremia Hypocalcemia Hypomagnesemia
Cardiac toxicity Neonatal hearts
Complications of Citrate:Metabolic alkalosis
Metabolic alkalosis due to citrate conversion to HCO3 Solutions with 35 meq/l HCO3 NG losses TPN with acetate component
Treatment Solutions with 35 meq/l HCO3
Decrease bicarbonate dialysis rate and replace at the same rate with NS (pH 5) to allow for the total solution exposure to be identical (ie no change in solute clearance) yet this will give less HCO3 exposure and an acid replacement
NG losses Replace with ½-2/3 NS
TPN with acetate component Use high Cl ratio
Complications of Citrate: “Citrate Lock”
Seen with rising total calcium with dropping/Stable patient ionized calciumEssentially delivery of citrate exceeds hepatic
metabolism and CRRT clearance Treatment of “citrate lock”
Decrease or stop citrate for 1 hr then restart at 70% of prior rate or Increase D or FRF rate to enhance clearance
Citrate or Heparin: literature
Hoffbauer R et al. Kidney Int. 1999;56:1578-1583.Hoffbauer R et al. Kidney Int. 1999;56:1578-1583.
Citrate Unfractionated Heparin
Anticoagulation In adults: Monchi M et al. Int Care Med 2004;30:260-65
Median filter life was 70 hr Citrate, 40 hr Heparin Fewer PRBC transfused in Citrate group (surrogate of
bleeding per study) 0.2 units/day of CVVH Citrate vs 1 units/day of CVVH Heparin
Heparin or Citrate?. single center - 209 adults regional anticoagulation : trisodium citrate vs standard heparin
protocol ( customized calcium-free dialysate)
CitACG was the sole anticoagulant in 37 patients, 87 patients received low-dose heparin plus citrate, and 85 patients received only hepACG.
Both groups receiving citACG had prolonged filter life when compared to the hepACG group.
significant cost saving due to prolonged filter life when using citACG.
Morgera S, et.al. Nephron Clin Pract. 2004; 97(4):c131-6.
Comparison of CRRT circuit life for PRISMA circuits with: no anticoagulation (filled squares), heparin anticoagulation (filled circles) or citrate anticoagulation (filled triangles). Mean circuit survival was no different for circuits receiving hepACG and citACG but was significantly lower for circuits with noACG (P<0.005).
Brophy et.al. NDT 2005 Jul;20(7):1416-21
None
Cit
Hep
Circuit Functional Survival (Hours)
Cum
ulat
ive
Prop
ortio
n Su
rviv
ing
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 20 40 60 80 100 120 140 160 180 200 220
None
Citrate
Heparin
ppCRRT ACG Side Effects Heparin
11 cases of systemic bleeding on heparin5 cases no ACG used secondary to bleeding1 case of HIT
Citrate19 cases of metabolic alkalosis
1 change to heparin for hyperglycemia 1 change to heparin for alkalosis
3 cases of citrate lock
Reference Tools
Adqi.net-web site for information on CRRT Crrtonline.com-web site for info on Dr Mehta’s
meeting www.PCRRT.com Pediatric CRRT with links to
other meetings, protocols, industry 5th International Conf on Pediatric CRRT June
19-21, 2008 Orlando, Florida PCRRT list serve (contact Bunchman)
Thanks
ppCRRT members Bedside ICU and Dialysis Nurses Mary Lee Neuberger Dr. Noel Gibney (for the slide master) patients