8.2 Management of Anticoagulated patient Flashcards
Risk factors for the development of spontaneous haemorrhagic
complications after anticoagulation include:
5
1 elderly/females/low weight (< 100 lb): higher chance of inappropriately more anticoagulation than expected because of lower metabolic capacity or lower weight
2
intensity of anticoagulation
3
prolonged duration of therapy
4
concomitant therapy with multiple agents
5
history of gastrointestinal bleed.
Risk factors for development of spinal/epidural haematoma following
a neuraxial anaesthetic include:
Patient factors x5
Patient factors:
elderly,
females,
low weight,
hepatic or renal disease,
congenital or acquired spinal abnormality.
Risk factors for development of spinal/epidural haematoma following
a neuraxial anaesthetic include:
Anaesthetic factors:
Anaesthetic factors:
1
wide-gauge needles rather than finer gauge,
2
use of spinal/epidural catheters,
3
multiple attempts and
4
difficulty in needle placement.
Risk factors for development of spinal/epidural haematoma following
a neuraxial anaesthetic include:
Drug factors:
Drug factors:
preoperative anticoagulation,
type of drug being used
(maximum with thrombolytic drug),
combination of drugs
and early
post-operative drug therapy.
For a patient on heparin anticoagulation, the relative risk of a spinal
haematoma is in the following increasing order
neuraxial puncture after 1 hour
of unfractionated heparin administration
– least risk
neuraxial puncture within 1 hour of unfractionated heparin administration
patient on aspirin (along with heparin)
traumatic puncture – maximum risk.
Half-lives of vitamin K–dependent coagulation factors
What are they
VII 6
IX 24
X 25–60
II 50–80
Considerations for neuraxial block in anticoagulated patient
Long-duration warfarin therapy
Long-duration warfarin therapy
Action persists for 4–6 days after
stopping warfarin
(till new factors
are synthesised)
Monitor and document
INR before neuraxial block
Considerations for neuraxial block in anticoagulated patient
This patient is at a high risk of venous thromboembolic (VTE)
This patient is at a high risk of
venous thromboembolic (VTE)
complications
There is a need to continue
anticoagulation up to the day of
surgery
Start heparin after stopping
warfarin
(unfractionated/low
molecular weight)
Considerations for neuraxial block in anticoagulated patient
Elective case
Elective case
No indication for fresh frozen plasma
Use only vitamin K to
reverse warfarin or
postpone surgery if needed
Considerations for neuraxial block in anticoagulated patient
Postoperative venous
thromboprophylaxis after major surgery in a patient at high risk of VTE
Postoperative venous
thromboprophylaxis after major surgery in a patient at high risk
of VTE
Cannot give warfarin postoperatively (only used in patients with low risk of VTE) or Low molecular weight heparin in high therapeutic doses (only used in patients with minor surgery)
Use low molecular weight
heparin in low doses (prophylactic)
•
Regarding perioperative warfarin use
How long to reach therapeutic INR
Is a normal INR normal anticoagulant
It takes 3–5 days to achieve therapeutic with warfarin.
Return of INR to normal range
reflects adequate levels of anticoagulants,
hence should be sought before a neuraxial block
Regarding perioperative warfarin
ASRA recommended INR for Neuraxial
What % baseline factor level for haemostasis
ASRA recommends a value of INR < 1.5 before undertaking a neuraxial block.
Factor levels of 40% of baseline are adequate for haemostasis
Regarding perioperative warfarin
indwelling epidural catheter,
In those patients with an
indwelling epidural catheter,
if INR > 3 postoperatively,
then warfarin dose should be withheld
or
reduced to reduce chances
of neurological complications
Regarding perioperative warfarin
LA concentration for block
Dilute concentration of
local anaesthetics should be used to avoid
motor block
(which may interfere with neurological assessment).
Antiplatelet agent
How work
do need to stopped for spinal?
Antiplatelet agents irreversibly
inhibit platelet cyclooxygenase and
hence prolong surgical bleeding.
However, aspirin and NSAIDs have not been found to be a risk factor for bloody needle or catheter placement and they need not be stopped preoperatively (for a spinal anaesthetic).
Clopidogrel and ticlopidine stopped?
But clopidogrel and ticlopidine should be
stopped 7 days and 10
days before spinal anaesthetic,
respectively.
Platelet glycoprotein stopped
Platelet glycoprotein IIb/IIIa inhibitors
have to be stopped 8–48
hours before needling
Herbal remedies stopped?
Herbal remedies like garlic, ginkgo or ginseng may affect platelet aggregation, but no evidence suggests that they need to be
discontinued prior to surgery
UFH & LMWH
Unfractionated heparin (UFH) or low molecular weight heparin (LMWH) may both be used for venous thromboprophylaxis
Since doses needed for treatment are higher than the prophylactic
doses, one has to wait for a longer time if treatment doses are used.
LMWH Prophylaxis timing
needling cather removal
Rx dose
dose after removal
If LMWH is used for prophylaxis,
one needs to wait 12 hours before
needling/catheter placement/removal,
while if used for treatment,
the appropriate time frame is 24 hours.
The next dose of LMWH
should be given 4 hours after catheter removal
Regarding epidural haematoma:
incidence spinal / epi
Rare complication after a spinal (1 : 220 000) or an epidural
(1 : 150 000).
Regarding epidural haematoma:
a/w use
Mostly associated with the use of anticoagulants.
Highest risk with patients
receiving thrombolytic therapy
Epidural Haematoma
RF
Risk factors include old age, female sex, anticoagulant therapy and technical difficulty in performing the block.
Epidural Haematoma
Commonest at what level
Is most common at thoracic levels followed by cervicothoracic levels.
Epidural Haematoma
PC
Presents as a
severe, localised, dull back ache 24–48
hours after the epidural block.
Epidural Haematoma DDx
Epidural abscess,
anterior spinal artery syndrome,
surgical spinal cord damage,
and exacerbation of
underlying neurological diseases are
differentials.
Epidural Haematoma Imagining of choice
Magnetic resonance imaging (MRI) is the diagnostic imaging of choice
Epidural Haematoma
Definitive Rx
Surgical decompression
is the treatment of choice. Early exploration
(within 36 hours) has a favourable outcome.
