Download DVT

Thromboembolic disease
• -remains the third leading cause of direct
maternal death
• -The pregnant woman increased risk of
developing venous thromboembolism
(VTE) compared with the non-pregnant
which rises in the puerperium
Thromboprophylaxis in pregnancy
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Risk f a ct o r s f o r v e no us t hr o m bo e m bo lism
Pre-existing factors
– Previous VTE
– Family history of VTE (e.g. deficiency of protein C or S, antithrombin
deficiency, prothrombin gene variant, Factor V Leiden)
– Known thrombophilia
– Lupus anticoagulant
– Medical co-morbidities (e.g. sickle cell disease, cardiac disease, proteinuria >3
g/day)
– Age >35 years
– Obesity (BMI >30 kg/m2)
– Parity >3
– Smoking
– Intravenous drug user
– Varicose veins
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Obstetric factors
– Pre-eclampsia
– Dehydration/hyperemesis
gravidarum
– Multiple pregnancy
– Caesarean section or forceps delivery
– Prolonged labour
– Postpartum haemorrhage
Transient factors
– Systemic infection
– Paraplegia or immobility
– Recent surgical procedure
– Ovarian hyper stimulation syndrome
– Travel >4 hours
• Midwife assessment on
the following occasions:
• initial meeting with the
woman (booking visit)
• any hospital admission
• following the birth of
the baby.
• -If this assessment identifies women at risk of
developing VTE, the midwife should promptly refer
her to an expert in thrombosis in pregnancy
• - commenced on subcutaneous injections of low
molecular weight heparin (LMWH), as this does not
cross the placental barrier with consequential effects
on the fetus.
• -midwife educate the woman in self-administration
of the heparin, alerting her to carry a medical alert
card containing such details with her at all times.
• -provided with a sharps bin for safe disposal of the
injection devices.
• -Gradient compression stockings or TED stockings are
likely to be prescribed,are available in two lengths,
below the knee or thigh, and are designed to give a
pressure gradient from the ankle to the knee or thigh
• -Midwives should be trained in their use to be able
to instruct the woman how to wear them correctly
and monitor their use
• -For hygiene purposes, stockings should be removed
daily, but this should be no more than 30 minutes.
• -The legs should be inspected and measured by the
midwife every three days to detect any changes in
size or tissue damage
• -advice about avoiding dehydration, ceasing smoking
and eating a healthy diet .
• pregnant woman is expecting to travel long
distances, especially by air, she will benefit by
wearing loose fifing clothing and flight socks (TED
stockings), drinking plenty of water, avoiding alcohol
and remaining ambulant for as long as
possible/performing leg exercises when at rest .
• -During labour, encourage mobility with regular
changes of position and passive leg exercises when
the woman is at rest.
• hydration is maintained and frequent examination of
the woman's legs.
• - If the woman has been prescribed LMWH in
pregnancy, this should be omitted at the onset of
contractions and regional anesthesia avoided within
12 hours of the last administered dose.
• -There should be active management of the third
stage of labour with the oxytoxic drug being
administered IV.
• -perineal suturing is required, avoid the woman being in the
lithotomy position for a prolonged time, as this further
increases the risk for deep vein thrombosis (DVT).
• - If surgery is necessary, intermittent calf compression will be
required in theatre.
• -The postnatal period presents further risk to the woman for
both DVT and pulmonary embolism (PE), and early
mobilization should be encouraged.
• postnatal observations, respiration rate and the development
of any leg swelling.
• - If either condition is suspected the woman must be referred
urgently to a haematologist, or if at home she must be readmitted to hospital.
Deep vein thrombosis
• -A blood clot formed within a blood vessel is termed
a thrombus, which can become detached and lodge
in another blood vessel and partially or wholly
occlude it.
• -Virchow's triad -In pregnancy, Virchow's triad is
affected by the physiological changes to the
hematological system
• -Despite pregnancy presenting a state of
hypervolaemia, by term hypercoagulability also
develops to compensate for the demands of the
forthcoming labour and maintenance of
haemostasis.
• - venous stasis reaching its peak at 36 weeks
and declining to pre-pregnancy values by 6
weeks following the baby's birth
• the physical effect of the gravid uterus exerts
pressure on the pelvic veins and the inferior
vena cava, increasing the woman's risk of
developing a DVT in the veins of the calf, thigh
and pelvis
• -In pregnancy, 90% of DVT occur in the left leg
compared with 55% in the non-pregnant
woman due to compression of the left iliac vein
by the lt iliac artery in pregnancy
• -The complications of DVT are pulmonary
embolism (PE) and post-thrombotic syndrome
• arising from damage to the venous valves that
result in a backflow of blood, venous hypertension,
oedema and tissue hypoxia.
• -The midwife needs to be aware of the signs of DVT
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pain in the area of the clot
swelling (usually one-sided)
red discoloration
difficulty in weight-bearing on the affected leg
low grade pyrexia
lower abdominal or back pain.
-If the leg appears swollen a tape measure should be used to
assess the circumference of both legs at the affected area for
comparison.
• - A DVT is potentially life threatening and the midwife must
refer the woman immediately to hospital for medical
examination, investigation and treatment.
• The classic diagnostic use of dorsiflexion of the foot (Homan's
sign) is considered unreliable in pregnancy and the presence
of severe lower back pain has greater significance
• Doppler ultrasound and serum investigations might be
performed
• Venography is generally avoided in pregnancy due to the small
radiation risk to the fetus.
• -Treatment of DVT in pregnancy is with LMWH administered
12-hourly by subcutaneous injection to sustain the levels, and
which should continue for at least 6 months after the
diagnosis.
• -Gradient compression stockings should be prescribed
• -The woman will need to wear one on the affected leg for two years to
reduce the risk of post-thrombotic syndrome
• Anticoagulation therapy should continue for at least 6 months aher the
diagnosis
• -The woman should be seen by the anaesthetist prior to labour to discuss
the risks that thromboembolic disorders have on the administration of
regional/general anaesthesia.
• - As soon as labour commences, heparin should be omitted and
compression stockings should be worn.
• - As regional anaesthesia carries a risk of spinal bleeding, this should be
avoided within 12 hours of administration of heparin.
• -Although general anaesthetic is itself a thrombotic risk, it may have to be
considered for caesarean section.
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encouraged to remain mobile
passive leg exercises
maintain hydration.
drugs given IV instead of intramuscularly (IM).
Prolonged use of the lithotomy position should be avoided, as this is a DVT
risk.
• - The third stage of labour should be actively managed with the oxytoxic
drug being administered IV to prompt haemostasis.
• - If perineal suturing is required, it should be undertaken promptly to limit
the length of time the woman is in the lithotomy position
-potential for PE during the postnatal period.
• - woman who has had a previous DVT condition, encouraging early
ambulation and hydration.
• - Heparin is recommenced ,2 hours after a vaginal birth or longer if the
woman had an epidural and/or caesarean section, and should continue
until at least the 6-week postnatal appointment, at which point a decision
to change to warfarin
• -Oestrogen-based contraceptive pills are contraindicated so depo-provera
or barrier methods of contraception should be discussed with the woman
and her partner.
Pulmonary embolism
• occurs when a DVT detaches and becomes mobile, known as an embolus.
• - A large embolus might lodge in the pulmonary artery and smaller ones
can travel distally to small vessels in the lung periphery, where they may
wholly or partially occlude the blood vessel
• impaired gaseous exchange
• -After some hours, surfactant production by the affected lung ceases, the
alveoli collapse and hypoxaemia results.
• - Pulmonary arterial pressure rises and there is
a reduction in cardiac output.
• -The area of the lung affected by the
embolism may become infracted
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-In the case of a small embolism, there is likely to be:
dyspnoea
discomfort
pain in the chest
haemoptysis
low grade pyrexia, all of which can be misdiagnosed as a chest infection.
Cardiovascular examination is usually normal
• -A larger embolism that occludes a major vessel will result in a more acute
presentation, because of sudden obstruction of the right ventricle and its
outflow . There is :
• severe central chest pain due to ischaemiaPallor
• sweating as shock develops. Tachycardia occurs and a gallop rhythm of the
heart may be heard on examination.
• Hypotension develops as peripheral
shutdown occurs.
• Syncope may result when cardiac output is
suddenly reduced
• -Admission to an intensive care unit is highly
likely as there is a significant risk of death if
treatment is delayed.
• -Pulmonary embolism is a medical emergency
and urgent referral to hospital is indicated.
• Diagnosis :clinical probability score and
radiological imaging.
• Heparin, usually LWMH, is commenced at
presentation with subsequent anticoagulation
treatment and management in labour and the
postnatal period being similar to that for a
woman presenting with DVT
Disseminated intravascular coagulation (DIC)
• - DICdamage to the endothelium (lining of blood
vessel walls) arising from pre-eclampsia, placental
abruption, major haemorrhage, embolism,
intrauterine fetal death or retained placenta results
in thromboplastins being released from the damaged
cells, causing the extrinsic pathway to mount a
coagulation cascade.
• -Blood clotting occurs at the original site and then
small clots (micro-thrombi) formed
• -Large quantities of fibrinogen, thrombocytes
(platelets) and clotting factors V and VIII are
consumed.
• The micro-thrombi produced can occlude small
blood vessels, resulting in ischaemia, hence some
organ tissue dies and releases more thromboplastins
and the cycle re-commences.
• - All clotting factors and platelets are subsequently
consumed and bleeding results. There is widespread
blood clotting and a clotting deficiency. Bleeding
occurs, petechiae develop in the skin and, if
untreated, major haemorrhage can result