The document discusses pulmonary embolism (PE), including its causes, diagnosis, risk factors, and treatment. It highlights the process by which blood clots from the venous system can travel to the lungs and cause serious complications. Various diagnostic methods, including imaging techniques and tests such as D-dimer and ultrasound, are outlined, along with the symptoms and potential indicators associated with PE.

1. Pulmonary EmbolismPulmonary Embolism

2. Learning OutcomesLearning Outcomes
 CausesCauses
 DiagnosisDiagnosis
 Risk FactorsRisk Factors
 TreatmentTreatment

3. Blood flow to the lungsBlood flow to the lungs
 Venous system fromVenous system from
upper and lower partsupper and lower parts
of the body drains intoof the body drains into
the right atrium andthe right atrium and
then pumped into thethen pumped into the
right ventricleright ventricle
 The right ventricleThe right ventricle
pumps blood to thepumps blood to the
lungslungs

4. The Clot TravelsThe Clot Travels
 So if a clot occurs in anySo if a clot occurs in any
vein it will eventually (if itvein it will eventually (if it
breaks free) end up in thebreaks free) end up in the
right side of the heartright side of the heart
 The heart then pumps itThe heart then pumps it
into the pulmonaryinto the pulmonary
arteriesarteries
 As the pulmonary arteryAs the pulmonary artery
becomes smaller, thebecomes smaller, the
blood clot will becomeblood clot will become
caught in the lungs. Thiscaught in the lungs. This
is a Pulmonary Embolismis a Pulmonary Embolism

5. Lung Blood FlowLung Blood Flow
 Typically there isTypically there is
more flow to the lowermore flow to the lower
area of the lungs, duearea of the lungs, due
to gravityto gravity
 PEs can occurPEs can occur
anywhere in the lung,anywhere in the lung,
but more are seen inbut more are seen in
the lower portion thanthe lower portion than
upper portionupper portion
 No preference toNo preference to
which side it occurswhich side it occurs

6. Saddle EmbolusSaddle Embolus
 This is where a clotThis is where a clot
occurs at the point ofoccurs at the point of
the pulmonary arterythe pulmonary artery
branchingbranching
 This can be fatal, dueThis can be fatal, due
to the large amount ofto the large amount of
blood flow that isblood flow that is
inhibitedinhibited

7. Incidence of PEIncidence of PE
 In the UK, PE occurs in 3-4 per 10 000In the UK, PE occurs in 3-4 per 10 000
peoplepeople
 This could be possibly higher as this isThis could be possibly higher as this is
only based on clinical dataonly based on clinical data
 Between 2005-2008 it was mentioned onBetween 2005-2008 it was mentioned on
the death certificates of 12 - 13 000the death certificates of 12 - 13 000
peoplepeople
 It is thought that this figure could be asIt is thought that this figure could be as
high as 60 000 per year in the UKhigh as 60 000 per year in the UK
(NICE 2013)(NICE 2013)

8. DiagnosingDiagnosing
 A large number ofA large number of
patients arepatients are
misdiagnosed andmisdiagnosed and
only found to have aonly found to have a
PE on autopsyPE on autopsy
 We can test for themWe can test for them
but results can comebut results can come
back as negative (orback as negative (or
inconclusive)inconclusive)

9. DiagnosingDiagnosing
 Most PEs come fromMost PEs come from
Deep VenousDeep Venous
Thrombosis (DVT)Thrombosis (DVT)
 Most DVTs (75%) comeMost DVTs (75%) come
from the legs,from the legs,
 20% of clots embolise20% of clots embolise
with higher incidencewith higher incidence
above the knee ratherabove the knee rather
than belowthan below
 The emboli travel via theThe emboli travel via the
Inferior Vena Cava (IVC),Inferior Vena Cava (IVC),
to the heart, to the lungsto the heart, to the lungs
PEPE

10.  In the lungs the blood clotIn the lungs the blood clot
gets lodged in thegets lodged in the
pulmonary artery, sopulmonary artery, so
there is no morethere is no more
perfusion to that area ofperfusion to that area of
lung, thus ventilationlung, thus ventilation
occurs without perfusionoccurs without perfusion
forming a dead spaceforming a dead space
 The blood that shouldThe blood that should
have gone to that area ishave gone to that area is
then diverted to otherthen diverted to other
areas of the lung, thisareas of the lung, this
causes a V/Q Mismatchcauses a V/Q Mismatch

11. Lung InfarctLung Infarct
 There is also an increaseThere is also an increase
in resistance to bloodin resistance to blood
flow, this can cause aflow, this can cause a
cardiac arrestcardiac arrest
 The lungs may infarct, butThe lungs may infarct, but
this is difficult due to thethis is difficult due to the
dual blood supply, fromdual blood supply, from
both the pulmonary arteryboth the pulmonary artery
and also from the aorta,and also from the aorta,
as it sends branches toas it sends branches to
the lungthe lung

12. Risk FactorsRisk Factors
 Orthopaedic Procedure – THR, TKR, #sOrthopaedic Procedure – THR, TKR, #s
Lack of mobilisationLack of mobilisation
 No thrombo-prophylaxis – TEDS, Flowtrons,No thrombo-prophylaxis – TEDS, Flowtrons,
Dalteparin , WarfarinDalteparin , Warfarin
 Abdo / Pelvic surgery - especially for CaAbdo / Pelvic surgery - especially for Ca
 ObesityObesity
 Women >30yrs on oral contraceptive who smokeWomen >30yrs on oral contraceptive who smoke
 Hyper-coaguable state – Protein C & S deficiencies,Hyper-coaguable state – Protein C & S deficiencies,
Factor V LeidenFactor V Leiden
 PregnancyPregnancy

13. SymptomsSymptoms
 May be normalMay be normal
 TachycardiaTachycardia
 AFAF
 Reduced chest movementReduced chest movement
(due to pain)(due to pain)
 TachypnoeaTachypnoea
 Pleural rubPleural rub
 Haemoptysis (especially inHaemoptysis (especially in
lung infarction)lung infarction)
 Low grade feverLow grade fever
 Signs of DVTSigns of DVT
 PP22 Sound,Sound,
 Right Heart failure-Right Heart failure- CO,CO,
JVP,JVP, BP and PerfusionBP and Perfusion
PressurePressure

14. DiagnosisDiagnosis
 ABG –ABG – pH /pH /  pCOpCO22//  pOpO22 (or lower normal range)(or lower normal range)
 Respiratory AlkalosisRespiratory Alkalosis
  pOpO22 due to V/Q Mismatchdue to V/Q Mismatch
  pCOpCO22 due to tachypnoea (trying to make room for Odue to tachypnoea (trying to make room for O2)2)
 Alveolar-arterial oxygen (A-a) gradientAlveolar-arterial oxygen (A-a) gradient
 PPAAOO22 - P- PaaOO22
 Alone they are not diagnostic of pulmonary embolismAlone they are not diagnostic of pulmonary embolism
(PE), but they may be useful in excluding the diagnosis(PE), but they may be useful in excluding the diagnosis
of PE if their values fall within the normal rangeof PE if their values fall within the normal range

15. Alveolar-arterial oxygen (A-a)Alveolar-arterial oxygen (A-a)
gradientgradient
 PPAAOO22 - P- PaaOO22 should equal (Age (years) / 4) + 4should equal (Age (years) / 4) + 4
 PPAAOO22 = [(F= [(FiiOO22) x (760 – 47)] – (P) x (760 – 47)] – (PaaCOCO22 / 0.8)/ 0.8)
Barometric Pressure = 760mmHgBarometric Pressure = 760mmHg
Water Vapour Pressure = 47mmHgWater Vapour Pressure = 47mmHg
Respiratory Coefficient = 0.8Respiratory Coefficient = 0.8
UseUsePPaaOO22 andandPPaaCOCO22 in mmHg not KPain mmHg not KPa
Eg 40 Yr old,Eg 40 Yr old,
FFiiOO22 0.60.6
PPaaCOCO22 32.5 mmHg32.5 mmHg (4.27KPa)(4.27KPa)
PPaaOO22 65 mmHg (8.55KPa)65 mmHg (8.55KPa)
PPAAOO22 =(0.6 x 713) – 40.6 = 387.2=(0.6 x 713) – 40.6 = 387.2
PPAAOO22 - P- PaaOO22 = 387.2 – 65 = 322.2= 387.2 – 65 = 322.2
(40/4) = 10 (+4) = 14(40/4) = 10 (+4) = 14
Therefore 322.2 > 14Therefore 322.2 > 14
So if the A-a gradient > 14 it may be indicative of a PESo if the A-a gradient > 14 it may be indicative of a PE

16. Chest X-rayChest X-ray
 Chest X ray – most common finding with aChest X ray – most common finding with a
PE is a normal x-rayPE is a normal x-ray
 But they are useful as X-rays help to ruleBut they are useful as X-rays help to rule
out pneumonia and pneumothorax asout pneumonia and pneumothorax as
causes of dyspnoea etccauses of dyspnoea etc
 Possible signs indicating a PE are asPossible signs indicating a PE are as
followsfollows

17. Hamptons HumpHamptons Hump
 Not always seenNot always seen
 Wedged shapedWedged shaped
pleural based lesionpleural based lesion
 PE in one areaPE in one area
(Bottom arrow) and(Bottom arrow) and
everywhere else iseverywhere else is
infarctinfarct
 Causes pleurisy,Causes pleurisy,
irritationirritation

18. Westermark SignWestermark Sign
 On this X-ray PE is inOn this X-ray PE is in
Left lungLeft lung
 Increase in blood flowIncrease in blood flow
to right side.to right side.
 Minimal blood flowMinimal blood flow
seen to Left lungseen to Left lung
 So the side that looksSo the side that looks
clearer is the sideclearer is the side
with reduced bloodwith reduced blood
flow, therefore the clotflow, therefore the clot

19. ECGECG
 SSIIQQIIIIIITTIIIIII
 Can be seen in anyCan be seen in any
cor-pulmonalecor-pulmonale
syndrome wheresyndrome where
pulmonary arterypulmonary artery
systolic pressure issystolic pressure is
elevatedelevated
 Eg Normal PQRSTEg Normal PQRST

20. ECGECG
 LeadLead II
 Exaggerated S waveExaggerated S wave
 LeadLead IIIIII
 Exaggerated Q waveExaggerated Q wave
 T Wave inversionT Wave inversion
 Not specific to PE, butNot specific to PE, but
gets you to possibly thinkgets you to possibly think
of the diagnosisof the diagnosis

21. ECG – Precordial LeadsECG – Precordial Leads
 Peaked T wavesPeaked T waves
 V1-V4V1-V4
 Makes you think about :-Makes you think about :-
Right Heart Strain,Right Heart Strain,
PE, Cor-pulmonalePE, Cor-pulmonale
 Tachycardia nearlyTachycardia nearly
always seen in PE butalways seen in PE but
also most other problemsalso most other problems
so non-specificso non-specific

22. D-dimerD-dimer
 By-product of fibrinBy-product of fibrin
degradationdegradation
 As clot degraded byAs clot degraded by
enzymes, Fibrinenzymes, Fibrin
Degradation ProductsDegradation Products
(FDP) are released, one(FDP) are released, one
of these is the D-dimerof these is the D-dimer
 Little clots in body releaseLittle clots in body release
D-dimers, therefore if testD-dimers, therefore if test
+ve - do not know if it is+ve - do not know if it is
from a PE,from a PE,
 But test is so sensitiveBut test is so sensitive
that if no D-dimer ( –ve)that if no D-dimer ( –ve)
you can rule out PEyou can rule out PE

23. UltrasoundUltrasound
 Non-invasiveNon-invasive
 Looks at lower limbsLooks at lower limbs
 Doppler USS looks atDoppler USS looks at
vein for flow andvein for flow and
compressibilty to seecompressibilty to see
if clot presentif clot present

24. USS ResultsUSS Results
 If +ve for DVT and patient hasIf +ve for DVT and patient has
respiratory distress symptomsrespiratory distress symptoms
you can rule in a PE, since theyou can rule in a PE, since the
DVTs can embolise easily andDVTs can embolise easily and
enter the lungs causingenter the lungs causing
respiratory problemsrespiratory problems
 If -ve for DVT, unsure whetherIf -ve for DVT, unsure whether
there is a PE or not, as a clotthere is a PE or not, as a clot
from other part of body mayfrom other part of body may
have embolised the lung, or ahave embolised the lung, or a
whole DVT may have travelledwhole DVT may have travelled
to the lungto the lung
 So a –ve result does not give aSo a –ve result does not give a
thorough answer, whilst a +vethorough answer, whilst a +ve
result may rule it inresult may rule it in

25. ECHOECHO
 Sometimes beneficialSometimes beneficial
 The right ventricleThe right ventricle
pumps blood to lungspumps blood to lungs
 If clot is present theIf clot is present the
pressure at site of clotpressure at site of clot
increases and soincreases and so
does the pressure indoes the pressure in
the right ventriclethe right ventricle

26. ECHOECHO
 The severity of this PulmonaryThe severity of this Pulmonary
Artery Pressure (PAP) and theArtery Pressure (PAP) and the
severity of the clot, is found byseverity of the clot, is found by
looking at the tricuspid valvelooking at the tricuspid valve
and noting how much regurgeand noting how much regurge
occurs (Tricuspid jet)occurs (Tricuspid jet)
 If tricuspid jet is high then PAPIf tricuspid jet is high then PAP
differential between RA anddifferential between RA and
RV is great and the clot burdenRV is great and the clot burden
is largeis large
 All these tests may help in theAll these tests may help in the
possible diagnosis of a PE, butpossible diagnosis of a PE, but
are not definitive testsare not definitive tests

27. VQ ScanVQ Scan
 Nuclear medicine scanNuclear medicine scan
 Looks at perfusion and ventilationLooks at perfusion and ventilation
 In pneumonia for example, you would getIn pneumonia for example, you would get
decreased perfusion and decreased ventilationdecreased perfusion and decreased ventilation
due to the purulent material present this is adue to the purulent material present this is a
“Matched Deficit”“Matched Deficit”
 In a PE there is decreased perfusion of the lungIn a PE there is decreased perfusion of the lung
in the area but ventilation remains the same thisin the area but ventilation remains the same this
is an “Unmatched Deficit”is an “Unmatched Deficit”
 Does Not affect patient in renal failureDoes Not affect patient in renal failure
 Impaired view if patient has pneumonia etcImpaired view if patient has pneumonia etc

28. VQ ScanVQ Scan
 The patients ventilation isThe patients ventilation is
assessed by themassessed by them
breathing in Xenonbreathing in Xenon
 For perfusion the patientFor perfusion the patient
is injected with Technigasis injected with Technigas
(T(Tcc99mMAA)99mMAA)
 Use Gamma Camera (aUse Gamma Camera (a
glorified Geiger counter)glorified Geiger counter)
to measure the nuclearto measure the nuclear
materialmaterial

29. Probability of PEProbability of PE
 Normal - Full ventilationNormal - Full ventilation
and perfusion seenand perfusion seen
 Low Pobability for PE –Low Pobability for PE –
(<20%)(<20%)
 Intermediate probabilityIntermediate probability
for PE-for PE- V andV and P inP in
same areasame area
(Matched deficit) (20-(Matched deficit) (20-
80%)80%)
 High Probability for PE –High Probability for PE –
Normal V andNormal V and P (Un-P (Un-
Matched deficit) (>80%)Matched deficit) (>80%)

30. CTPACTPA
 Contrast injected into body,Contrast injected into body,
 CT Scan obtained as this isCT Scan obtained as this is
occurringoccurring
 Vessels viewed on end andVessels viewed on end and
seen if they light up withseen if they light up with
contrast.contrast.
 If only partially light up withIf only partially light up with
contrast there may be a bloodcontrast there may be a blood
clot present stopping flowclot present stopping flow
 Do not use if in renal failureDo not use if in renal failure
((Creatanine) (could useCreatanine) (could use
HCOHCO33 cover to stopcover to stop
nephrotoxic effect of contrast)nephrotoxic effect of contrast)
 Unlike VQ Scan if patient hasUnlike VQ Scan if patient has
a pneumonia it will not affecta pneumonia it will not affect
resultsresults

31. CTPACTPA
 In 2006 ‘The Christopher Study’ showed that ifIn 2006 ‘The Christopher Study’ showed that if
you perform a CTPA that was negative for ayou perform a CTPA that was negative for a
blood clot with a –ve D-dimer result, it wasblood clot with a –ve D-dimer result, it was
shown to be safe to withhold anticoagulation,shown to be safe to withhold anticoagulation,
this supports the reasoning that you should notthis supports the reasoning that you should not
do a repeat CT scan if first found to be –ve for ado a repeat CT scan if first found to be –ve for a
clotclot
 The CTPA is the test of choice for diagnosis ofThe CTPA is the test of choice for diagnosis of
PE, if unable to perform this due toPE, if unable to perform this due to
Creatanine, the next choice would be a VQCreatanine, the next choice would be a VQ
Scan.Scan.
 BUT, these are not the ‘Gold Standard’BUT, these are not the ‘Gold Standard’

32. Gold StandardGold Standard
 Pulmonary Angiogram –Pulmonary Angiogram –
Most accurate test, butMost accurate test, but
not always best fornot always best for
patient (most invasive)patient (most invasive)
 Catheter inserted intoCatheter inserted into
right side of the heart,right side of the heart,
dye is injected directlydye is injected directly
into pulmonary artery,into pulmonary artery,
observed underobserved under
fluoroscopyfluoroscopy
 Dangerous,Dangerous,
 mortality rate,mortality rate,
especially in patients withespecially in patients with
PEPE

33. TreatmentTreatment
 AnticoagulationAnticoagulation
 Eg Warfarin / HeparinEg Warfarin / Heparin
-Blood thinning-Blood thinning
-Prevent new clots-Prevent new clots
Non-thrombolyticNon-thrombolytic
treatmenttreatment
 ThrombolyticsThrombolytics
-Dissolve Clot,-Dissolve Clot,
-not solely used for-not solely used for
PE treatmentPE treatment
 DVT Treatment 3-6 monthsDVT Treatment 3-6 months
 PE Treatment 6-9 monthsPE Treatment 6-9 months

34. IVC FilterIVC Filter
 If anticoagulationIf anticoagulation
treatmenttreatment
contraindicatedcontraindicated IVCIVC
FilterFilter
If clot travels it getsIf clot travels it gets
caught in IVC Filtercaught in IVC Filter

35. IVC FilterIVC Filter
 It is possible for blood clot to be caught andIt is possible for blood clot to be caught and
develop in IVC filterdevelop in IVC filter
 Cochrane Collaboration recommends IVC forCochrane Collaboration recommends IVC for
1.1. Recurrent PE despite use of anticoagulation,Recurrent PE despite use of anticoagulation,
or in absolute contra-indication toor in absolute contra-indication to
anticoagulationanticoagulation
2.2. Proximal DVT with massive pulmonaryProximal DVT with massive pulmonary
thrombosis – next one could kill patientthrombosis – next one could kill patient
3.3. Trauma Patient – needing operationTrauma Patient – needing operation

36. AnticoagulationAnticoagulation
 Ideally start Fast acting and slow acting anticoagulants,Ideally start Fast acting and slow acting anticoagulants,
when slow acting anticoagulants at desired level, stopwhen slow acting anticoagulants at desired level, stop
fast actingfast acting
 Fast acting -Heparin productsFast acting -Heparin products
Heparin (IV) orHeparin (IV) or
Low Molecular Weight Heparin (S/C)Low Molecular Weight Heparin (S/C)
 Slow acting – Vitamin K AntagonistsSlow acting – Vitamin K Antagonists
WarfarinWarfarin

37. Fast ActingFast Acting
 Heparin productsHeparin products
IV HeparinIV Heparin
Aim for therapeutic APTTAim for therapeutic APTT
Can be startedCan be started
immediatelyimmediately
Quick AnticoagulationQuick Anticoagulation
actionaction
If bleeding occurs canIf bleeding occurs can
stop it and reducedstop it and reduced
effects occur within feweffects occur within few
hours as it has a shorthours as it has a short
half life (45-60min)half life (45-60min)

38. Heparin InducedHeparin Induced
ThrombocytopaeniaThrombocytopaenia
Can cause highest incidence of HITCan cause highest incidence of HIT
-Usually occurs 5-14 days after starting-Usually occurs 5-14 days after starting HeparinHeparin
(even if discontinued) or sooner if previously had(even if discontinued) or sooner if previously had
heparinheparin
-Immune response to heparin-Immune response to heparin
-Antibodies combine with heparin and platelets-Antibodies combine with heparin and platelets
causing platelet activation of microparticles whichcausing platelet activation of microparticles which
initiate the formation of blood clots; the plateletinitiate the formation of blood clots; the platelet
count falls as a result, So,count falls as a result, So,
-Platelet count drops by >50%-Platelet count drops by >50%
-Get hyper-coaguable state, get more clotting-Get hyper-coaguable state, get more clotting
even though platelet count loweven though platelet count low
-If this occurs change from heparin products-If this occurs change from heparin products

39. Fast ActingFast Acting
 Low Molecular Weight Heparin (SC)Low Molecular Weight Heparin (SC)
Eg clexane, dalteparin, fondaparinuxEg clexane, dalteparin, fondaparinux
Give twice per day dependent on Creatanine Clearance (CrCl)Give twice per day dependent on Creatanine Clearance (CrCl)
(20-29ml/min)(20-29ml/min)
Or if CrCl ≥30ml/min give once a dayOr if CrCl ≥30ml/min give once a day
Problem is if given, anticoagulation is present for next 12 orProblem is if given, anticoagulation is present for next 12 or
24hrs (as half life is four times as long as heparin, about 4 hrs)24hrs (as half life is four times as long as heparin, about 4 hrs)
Incidence of HIT is lower than IV HeparinIncidence of HIT is lower than IV Heparin
Easy and quick to administerEasy and quick to administer
 Also available is rivaroxaban, a fast acting oral medication, TheAlso available is rivaroxaban, a fast acting oral medication, The
effects lasts 8 to 12 hours, but factor Xa activity does not return toeffects lasts 8 to 12 hours, but factor Xa activity does not return to
normal within 24 hours so once-daily dosing is possible.normal within 24 hours so once-daily dosing is possible.

40. To work out CrClTo work out CrCl
 Takes into accountTakes into account
Patients Age, Gender,Patients Age, Gender,
Ideal Weight (Kg) SerumIdeal Weight (Kg) Serum
Creatanine (μmol/L) fromCreatanine (μmol/L) from
last 24hrslast 24hrs
 Use the equationUse the equation
((140-Age) x (ideal weight) /((140-Age) x (ideal weight) /
Cr) x1.23(male) = CrClCr) x1.23(male) = CrCl
((140-Age) x (ideal weight) /((140-Age) x (ideal weight) /
Cr) x1.04(female) = CrClCr) x1.04(female) = CrCl
Use STH treatment ofUse STH treatment of
Thromboembolic DiseaseThromboembolic Disease
Dalteparin PrescriptionDalteparin Prescription
ChartChart

41. ExamplesExamples
Eg Age 67 yrsEg Age 67 yrs
Gender - MaleGender - Male
Ideal Weight 85KgIdeal Weight 85Kg
Cr 73 μmol/LCr 73 μmol/L
Eg (140-67 = 73)Eg (140-67 = 73)  73 x 85 = 620573 x 85 = 6205  6205/ 73 =856205/ 73 =85 85 x 1.23 = 104.ml/min85 x 1.23 = 104.ml/min
So, 18 000 iu Dalteparin once per day as CrCl > 30ml/minSo, 18 000 iu Dalteparin once per day as CrCl > 30ml/min
Age 85 yrsAge 85 yrs
Gender – FemaleGender – Female
Ideal Weight 60KgIdeal Weight 60Kg
Cr – 160 μmol/LCr – 160 μmol/L
(140-85 = 55)(140-85 = 55)  55 x 60 = 330055 x 60 = 3300  3300 / 160 = 20.63300 / 160 = 20.6  20.6 x 1.04 =20.6 x 1.04 =
21.24ml/min21.24ml/min
So, 5000iu Dalteparin am and 5000iu Dalteparin pm as CrCl 20-29ml/minSo, 5000iu Dalteparin am and 5000iu Dalteparin pm as CrCl 20-29ml/min
If patient weighed more than 100Kg split dose if CrCl ≥30ml/minIf patient weighed more than 100Kg split dose if CrCl ≥30ml/min

42. Slow ActingSlow Acting
 Slow – Vitamin K antagonistsSlow – Vitamin K antagonists
eg warfarin 5mg po odeg warfarin 5mg po od
Affects factors 2, 7, 9, 10, C and SAffects factors 2, 7, 9, 10, C and S
If started on 10mg po od can get a drop inIf started on 10mg po od can get a drop in
protein C and S (shortest acting vitamin Kprotein C and S (shortest acting vitamin K
dependent factors), which can cause adependent factors), which can cause a
hyper-coaguable statehyper-coaguable state
Takes 2-3 days to reach desired level shownTakes 2-3 days to reach desired level shown
by INR of 2-3by INR of 2-3
If any medication changes, check INR as canIf any medication changes, check INR as can
be affectedbe affected

43. PreventionPrevention
 Bilateral Lower ExtremityBilateral Lower Extremity
Sequential CompressionSequential Compression
DevicesDevices
TEDs and FlowtronsTEDs and Flowtrons
When the legs areWhen the legs are
squeezed the veins release asqueezed the veins release a
factor which thins the bloodfactor which thins the blood
stopping clot formation,stopping clot formation,
the rhythmic motion copiesthe rhythmic motion copies
that of leg movementthat of leg movement
 ThromboprophylaxisThromboprophylaxis
DalteparinDalteparin

44. Genetic Blood TestsGenetic Blood Tests
 25-50% of patients with VTE have an inherited disorder25-50% of patients with VTE have an inherited disorder
 There are genetic causes of metabolism which may be tested forThere are genetic causes of metabolism which may be tested for
- Factor V Leiden – causes increased clotting as variant cannot beFactor V Leiden – causes increased clotting as variant cannot be
inactivated by Factor Protein C (5% of popinactivated by Factor Protein C (5% of popnn
and 20% of pts withand 20% of pts with
thrombus)thrombus)
- Factor Protein C Deficiency – results in normal cleaving of FactorFactor Protein C Deficiency – results in normal cleaving of Factor
Va and Factor VIIIaVa and Factor VIIIa
- 20210 (prothrombin) Mutation – 2-3 times risk of clot formation20210 (prothrombin) Mutation – 2-3 times risk of clot formation
- MTHMFR affects regulation of homocysteineMTHMFR affects regulation of homocysteine
- Lupus anticoagulant- prothrombotic agent which can causeLupus anticoagulant- prothrombotic agent which can cause
inappropriate clottinginappropriate clotting
- Anti phospholipid antibody – confused autoimmune responseAnti phospholipid antibody – confused autoimmune response
If any of these are positive and patient has a clot then may needIf any of these are positive and patient has a clot then may need
treatment for longertreatment for longer

45. So, RememberSo, Remember