Download Regional anesthesia on anticoagulants MGMC

Regional anesthesia on
anticoagulants
Dr S. Parthasarathy MD DA DNB PhD
FICA , Dip software based statistics
Tank of the 1990s
• When I read MD – it is
an useless topic
• Then a few people had
drugs ( antiplateletsaspirin)
• Clopidogrel ticlopidine
tirofiban were not
invented
• Why should we know ??
• The risk of spinal hematoma
• Means both intrathecal and epidural
• The incidence cited in the literature is estimated to
be ,1 in 150000 epidurals and ,1 in 220000 spinal
anaesthetic
Thrombo embolic episodes
•
•
•
•
Epidural in childbirth - less
Old age - more
Hip surgery - more
Where is the source ?
• Venous or arterial –
• the delay in symptoms – points to a venous
source
What is the treatment of refractory
PDPH ??
Epidural blood patch
We did not bother
• Usually the bleeds are less than the volume of
an epidural blood patch !!
The amount does not matter
• The ongoing coagulopathy ??
Now I see !!
• almost one in ten of my
obstetric cases are
receiving heparin
• ACL test = start heparin !!
Why more bother ??DVT prophylaxis awareness
Drugs
• Antiplatelets
•
•
•
•
NSAIDs
aspirin
Clopidogrel
Ticlopidine
Not used for thrombo
prophylaxis –
but patients on such
drugs
• NSAIDs – ibuprufen, diclofenac, ketoroloc
• COX 2 inhibitors
No problem
• Aspirin – irreversible inhibition of platelets
• Cox 1 is more than cox 2 ::
• 7 days to resume activity – stoppage – 15 % increase in
vascular events
•
No major problem for neuraxial anesthesia but
surgeons especially dental ??
• Cervical and thoracic epidural - better stop aspirin
Dipyridamole
• Dipyridamole is a pyrimidopyrimidine derivative that
has both antiplatelet and vasodilating actions.
• It is usually used in combination with aspirin in the
management of cerebrovascular disease.
• Phosphodiesterase inhibition
• Not used nowadays
Clopidogrel
• The thienopyridines include ticlopidine and
clopidogrel.
• Both act to reduce platelet aggregation by the
selective, irreversible inhibition of the P2Y12
ADP receptor on the platelet surface (one of
three ADP receptors).
Clopidogrel
• Similar to aspirin, platelet inhibition can be overcome
only by platelet transfusion (in the absence of active
drug) or by the generation of new platelets
• Stop before seven days of neuraxial blocks
• epidural catheters be removed to be performed 5
days, and
discontinued
not
7
days,
after
clopidogrel
is
• If a neuraxial injection is to be performed in a patient
on clopidogrel before 7 days of discontinuation, a
P2Y12 assay, a new assay of residual antiplatelet
activity, can be performed;
• Stop ticlopidine for 10 to 14 days before a neuraxial
injection.
prasugrel
• quicker onset,
• 60 mg
• A 7-10 day interval is recommended before a
neuraxial injection
IIb/IIIa receptor antagonists- ACS
• abciximab eptifibatide, and tirofiban inhibit platelet
aggregation by interfering with platelet–fibrinogen
binding
and
subsequent
interactions. Discontinuation
• from 8 h (eptifibatide, tirofiban)
• 48 h (abciximab).
platelet–
platelet
Neuraxial block and antiplatelets
•
•
•
•
•
•
•
NSAIDs – no problem
Aspirin – OK ?? !!
Clopidogrel – 7 days
otherwise assay P2Y12
Ticlopidine – 10-14 days
Tirofiban - 8 hours
Abciximab – 48 hours
There is no wholly accepted test, including the
bleeding time, to guide antiplatelet therapy.
Careful preoperative assessment of the patient is
important in identifying conditions that might lead to
increased risk of bleeding.
Oral anticoagulants
• Warfarin exerts its anticoagulant effect by interfering
with the synthesis of the vitamin K-dependent clotting
factors (VII, IX, X, and thrombin)
• Start action after 5 days
• Stop for five days before block
• But we can restart on the day of surgery
• Can we remove catheter on day 2 = ok ? !
• The current ASRA guidelines recommends an INR
value of ≤1.4 as acceptable for the performance of
neuraxial blocks.
• The value was based on studies that showed
excellent perioperative hemostasis when the INR
value was ≤1.5.
• The concurrent use of other medications, such as
aspirin, NSAIDs, and heparins increases the risk of
bleeding complications without affecting the INR.
Heparin
• Heparin is a complex polysaccharide that exerts its anticoagulant effect by binding to antithrombin III.
• The conformational change in antithrombin accelerates
its ability to inactivate thrombin, factor Xa, and factor
IXa.
• Subcutaneous heparin – 1-2 hours but IV is faster
• Half life is 1 – 1.5 hours
Intravenous heparin
• therapeutic anticoagulation is achieved with a
prolongation of the aPTT to >1.5 times the
baseline value.
• See aPTT here but in warfarin it is INR and PT
• 1 hour stoppage for IV dose for blocks
• 2 – 3 hours later remove catheter
Subcutaneous heparin
• In patients who are on LMWH, needle/catheter placement should
be performed at least 12 hours after the last prophylactic dose of
enoxaparin or 24 hours after higher doses of enoxaparin (1 mg/kg
every 12 hours), and 24 hours after dalteparin (120 U/kg every 12
hours or 200 U/kg every 12 hours) or tinzaparin (175 U/kg
daily).
• 5. The LMWH can be administered 2 hours after the epidural
catheter is removed.
•
monitoring of anti-Xa level is not recommended
On bypass !!
• Neuraxial procedures should be avoided in patients with known
coagulopathy.
• Surgery should be delayed 24 h in the patient with a traumatic tap.
• The time from the neuraxial procedure to the systemic heparinization
should exceed 1 h.
• Heparinization and reversal should be monitored and controlled tightly.
• The epidural catheter should be removed when normal coagulation is
restored, and the patient should be monitored closely for signs of spinal
hematoma
LMWH
• The administration of other anticoagulant medications
with LMWHs may increase the risk of spinal hematoma.
• The presence of blood during needle placement and
catheter placement does not necessitate postponement
of surgery.
• However, the initiation of LMWH therapy should be
delayed for 24 hours postoperatively.
• Can we monitor ??
Heart attack – cellulitis - spinal ??
• Plasminogen activators, such as streptokinase and
urokinase, dissolve thrombus and affect circulating
plasminogen leading to decreased levels of both
plasminogen and fibrin.
• No clear cut guidelines
But ten days later
. Measurement of fibrinogen levels may be helpful in
guiding a decision about removal of the catheter.
Fondaparinux
• Fondaparinux produces its antithrombotic
effect through factor Xa inhibition.
• The plasma half-life of fondaparinux is 21 h,
allowing for single daily dosing,
• with the first dose administered 6 h after
operation
• 36 hours and 12 hours ??
• But go for other drugs for DVT
• Recombinant
hirudin
derivatives,
such
as
desirudin (Revasc), lepirudin (Refludan), and
bivalirudin (Angiomax), inhibit both free and clotbound thrombin. Argatroban
• The most recent ASRA guidelines recommend
against the performance of neuraxial techniques
in patients who received thrombin inhibitors.
Herbal Therapy
• garlic inhibits platelet aggregation and its
effect on hemostasis appears to last 7 days.
• Ginkgo biloba inhibits platelet-activating
factor and its effect lasts 36 hours.
• Is there a risk ?
• Do we need to discontinue ??
• Presently NO
Peripheral nerve blocks
• Spontaneous hematomas have been reported
in patients who took anticoagulants.
• Abdominal wall hematomas, intracranial
hemorrhage, psoas hematoma, and
intrahepatic hemorrhage have occurred after
LMWH
• For patients undergoing deep plexus or deep
peripheral block, recommendations regarding
neuraxial techniques should be similarly
applied
• Superficial blocks USG – no vessels- risk Vs
benefit – OK
Mixture ??
• Aspirin + heparin
• Clopidogrel + aspirin
• Clopidogrel aspirin +
LMWH
• No clear cut
recommendations –
• play safe
• Another mixture
• Play safe
• Thank you