Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Neuroanaesthesia PPT 3 Dvt Prophylaxis In Neuro Icu Lecture Notes
DVT Prophylaxis in Neuro ICU
What is DVT?
VTE= DVT+PE
Deep vein thrombosis is the formation of a blood clot in one of
the deep veins of the body, usually in the leg
History
Susruta (Ayurveda physician and surgeon, 600-1000B.C), Patients with a
"swollen and painful leg that was difficult to treat"
First description of pulmonary embolism by Giovani Battista Morgagni in
1761, described large blood clots in the pulmonary vessels of patients who
died suddenly
History
"Discovered" PE in 1846 ? "the detachment of larger or smaller
fragments from the end of a softening thrombus which are carried
along the current of blood and driven into remote vessels.
This gives rise to the very frequent process on which I have
bestowed the name Embolia
In 1856, Rudolf Virchow published a collection
titled "Collective Treatises on Scientific Medicine,"
which contained his detailed studies of embolization
following venous thrombosis.
Virchow's triad
Neurologically impaired patients-
moderate to high risk for VTE
Paresis/Paralysis Venous stasis
Prolonged duration of depressed consciousness/coma
Brain neoplasm/Rheumatological/inflammatory disorders Hypercoagulability
Prolonged duration of surgery
Aneurysmal SAH ? Vessel injury/ Endothelial activation
DVT in neurologically impaired patients
Large variation in the statistics- overall incidence of DVT
Incidence of DVT ranges from 21-34%- among pts who underwent cranial or
spinal surgeries without any DVT prophylaxis
Higher incidence seen (~50%)- in pts with spinal cord injury and ischemic
stroke
Incidence of DVT in aneurysmal SAH is 1.5-24%
Symptomatic deep vein thrombosis is
"tip of the iceberg"
The presence or absence of clinical symptoms of DVT is as unreliable
marker
Signs and symptoms of DVT
Pain or tenderness in the leg
Swelling of the leg or along a vein in the leg
Red or discoloured skin on the leg
Increased warmth in the area of the leg that's swollen or is in pain
Homan;s sign- pain in posterior calf with forced dorsiflexion of foot
Moses sign- gentle squeezing of the lower part of calf from side to side causes severe pain
Diagnosis of DVT
D- Dimer Assay
125-labelled fibrinogen test
Impedance plethysmography
Doppler ultrasound of femoral veins
Venography
DVT risk assessment score
DVT prophylaxis methods
Graduated
Pharmacological
compression
Neuromuscular
prophylaxis
stockings
electrical stimulation
Mechanical
Methods
UFH
LMWH Warfarin
Intermittent
pneumatic
Venous foot pump
compression
DVT prophylaxis methods
Early and frequent ambulation- historically used to prevent DVT
Not feasible for critically ill, neurologically impaired patients
Largest no. of thromboembolic events occurred after pts started to ambulate
Ambulation ?counteracts only one component of Virchow;s triad- venous stasis
Mechanical methods
Graduated compression stockings:
Graded circumferential pressure from distal to periphery
Greatest degree of compression at the ankle, with the level of compression gradually
decreasing up the garment
Pressure gradient ensures, blood moves from limb towards heart
Reduces diameter of veins
Improves venous flow velocity
Avoid venous stasis
Less efficacious in immobile patients
In CLOTS trial 1, symptomatic and asymptomatic deep vein thrombosis
occurred in 126 (10.0%) patients wearing graduated compression stockings
and in 133 (10.5%) not wearing them, for a nonsignificant absolute
reduction in risk of 0.5% (95% confidence interval [CI] ?1.9% to 2.9%).
Intermittent pneumatic compression:
Cycles of compression and relaxation of pumped air
Inflates first at ankle with higher pressure
Inflates last at thigh at lower pressure
Deep veins are compressed and displaces blood proximally
Vein refill from distal flow when cuff deflates
Simulating pulsatile blood flow
Useful as a solo measure in neurosurgical patients where anticoagulants are to be avoided
LIMITATIONS: Improper fitting/neurovascular compression/iatrogenic DVT
CLOTS-3 trial, concluded that with the use of thigh length sequential IPC, in
patients with acute stroke leads to signifcant reduction in the
development of DVT.
Venous foot pump:
An alternate to IPC/compression stockings
Higher compression force
Neuromuscular electrical stimulation:
Muscle contractions decrease stasis improve venous return
Comatose/neurologically impaired patient unable to contract muscle
Deliver pulses of electric current, via electrode on skin over selected muscle groups or
nerves to induce involuntary contractions
Pharmacological methods
Low dose unfrationed heparin (LDUH)- S/C heparin 5,000 IU 8 Hourly (high risk)or 12 hourly
(moderate risk)
Low molecular weight heparin (LMWH)- e.g. S/C enoxaparin 40mg daily when creatinine
clearance > 30ml/min or 30mg daily when creatinine clearance <30ml/min
Warfarin- high risk patient to keep INR between 2-3
Newer antithrombotic drugs
Agent
MOA/RA
Duration of action
fondaparinaux
Factor Xa inhibitor /S.C
36-48hr
Rivaroxaban
Direct factor Xa inhibitor/oral
2-3 day
Apixaban
Direct factor Xa inhibitor/oral
2-3 day
Edoxaban
Direct factor Xa inhibitor/oral
One day
Dabigatran
Direct thrombin factor/oral
2-3 day
Desirudin
Direct thrombin factor/oral
7-9 hrs
VTE prophylaxis for the patient who
underwent craniotomy
ACS-NSQIP data (2011-2012)- 10477craniotomy patients- VTE-3.2%
Smith et al-1148 patient who underwent craniotomy for brain neoplasm,
incidence of DVT- 14% and PE 3%
Risk factors for postoperative venous thromboembolism in neurosurgery
Its recommended to use IPC+LMWH or IPC+UFH after 24-48 hr following
craniotomy to minimize risk of VTE
Intracranial bleeding occurs in approximately 1-1.5% of craniotomy patients who
do not receive anticoagulant prophylaxis
The use of anticoagulant thromboprophylaxis may be associated with a small
increase in the risk of intracranial; haemorrhage
The timing of initiation of anticoagulant thromboprophylaxis appears to
influence postoperative bleeding risk
Bleeding risk higher in the patients where prophylaxis given prior or soon after the
craniotomy as compared to when administered after 24 hrs
Decision should be made based on patient's bleeding and thrombosis risk
VTE prophylaxis for patients with
aneurysmal SAH
Patients with a SAH are at increased risk of developing VTE,
Incidence of DVT ranges from 1.5 to 24% and the incidence of PE 1.2-2.0%
Worse clinical status at presentation, longer hospital stay and blood transfusion are
associated with higher risk of VTE in this patient population
Determining appropriate VTE pharmacoprophylaxis is challenging in presence acute bleed
Initiating IPC as VTE prophylaxis as soon as patient with aSAH is admitted
Initiating VTE prophylaxis with UFH at least after 24 hr after aneurysm has been clipped or
coiled.
LMWH has shown higher risk of bleeding in this patient group
VTE prophylaxis for patients with
traumatic brain injury (TBI)
Incidence of DVT in severe TBI patient ranges 13 to 17%
Initiating IPC within 24hrs of presentation of TBI or completion of craniotomy
Initiating LMWH or UFH after 24-48 hr of presentation with TBI and ICH
LMWH OR LDUH in combination of mechanical prophylaxis may be used however there
is increased risk of expansion of intracranial hemorrhage (Level-III evidence, BTF 2016)
Parkland's protocol
VTE prophylaxis for patient with spinal cord
injury
Spinal cord injury- independent risk factor for DVT
Reported incidences of DVT in paralytic spinal cord injuries ranges from 18 % to 100% within first
12 weeks of injury
Risk of DVT highest during first 2 weeks post injury
Initiating VTE prophylaxis as early as possible within 72hrs of injury or once bleeding is controlled
Mechanical prophylaxis alone in not enough
LMWH or LDUH with or without IPC is recommended
VTE prophylaxis for the patient who
underwent spinal surgeries
Generally at lower risk for VTE
Incidence ranges from 0.4% to 1.1%
Higher risk seen in patient with associated carcinoma, limited preoperative
/postoperative mobility, complex or multilevel and prolonged procedure and
advanced age
Almost 50% of thromboembolic events in spinal surgery occur after hospital
discharge
Early mobilization
Inhospital thromboprophylaxis startring with IPC followed by delayed use of
LMWH (after 24 hr)
Reported rates of epidural hematoma associated with thromboprophylaxis is
very low (~0.2%)
VTE prophylaxis in critically ill patients
with ischemic stroke
Pulmonary embolism accounts for 10% of deaths in AIS patients
With thromboprophylaxis there is concern of haemorrhagic transformation of
ischemic stroke
Various randomised trials and metaanalysis are in favour pharmacological
thromboprophylaxis
VTE prophylaxis should be started as soon as possible
Patients with AIS with restricted mobility, LMWH in combination with IPC
Stroke patients who undergo hemicraniotomy or endovascular procedure,
UFH/LMWH and/or IPC should be used in the immediate postsurgical epoch,
except when r TPA is administered, in that case it should be delayed for 24hr
VTE prophylaxis in critically ill patient
with intracranial haemorrhage
In few prospective studies incidence of DVT detected by venous
ultrasonography was 20-40%
Risk of VTE in patients with ICH has been estimated 2-4 times as high as
patients with AIS
Its recommended to use IPC/GCS over no prophylaxis at the time of
hospital admission
Using LDUH/LMWH to prevent VTE in patients with stable hematoma
without ongoing coagulopathy, after 48 h of admission
Mechanical prophylaxis can be continued once pharmacological
prophylaxis started
VTE prophylaxis in critically ill patients
with neuromuscular disease
Patients who are critically ill with neuromuscular diseases like GBS, MG are
at high risk of VTE
VTE prophylaxis is the key element of the care of these patients
LMWH or LDUH or Fondaparinaux as the preferred method of VTE
prophylaxis
Mechanical prophylaxis where risk of bleeding is significant
VTE prophylaxis should be continued for extended period, at a minimum
for th eduration of acute hospitalization or until the ability to ambulate
returns
VTE prophylaxis in critically ill patient
with intracranial haemorrhage
In few prospective studies incidence of DVT detected by venous
ultrasonography was 20-40%
Risk of VTE in patients with ICH has been estimated 2-4 times as high as
patients with AIS
Its recommended to use IPC/GCS over no prophylaxis at the time of
hospital admission
Using LDUH/LMWH to prevent VTE in patients with stable hematoma
without ongoing coagulopathy, after 48 h of admission
Mechanical prophylaxis can be continued once pharmacological
prophylaxis started
This post was last modified on 07 April 2022