Blood Transfusions in Obstetrics Flashcards
How can the risk of transfusion be reduced?
Optimisation of haemoglobin in the antenatal period
Diagnosis
- Anaemia in pregnancy: in line with BCSH guidance.
first trimester Hb < 110 g/l,
second/third trimester Hb < 105 g/l, and
postpartum Hb < 100 g/l, - For normocytic or microcytic anaemia, trial of oral iron first step & further tests if no demonstrable rise in Hb at 2 weeks & compliance been checked.
- Pregnant offer screening for anaemia at booking and at 28 weeks.
- multiple pregnancies additional full blood count done at 20–24 weeks.
How can the risk of transfusion be reduced?
Treatment and management
- Oral iron preferred first-line treatment of iron deficiency.
- Parenteral iron: indicated when oral iron not tolerated or absorbed or patient compliance is in doubt or if approaching term and insufficient time for oral supplementation to be effective.
- receive information on improvement of dietary iron intake and factors affecting absorption of dietary iron.
- role of rHuEPO for non-end-stage renal anaemia: still
to be established & only be used in context of controlled clinical trial or expert advice of haematologist. - Active management 3rd stage of labour recommended to minimise blood loss.
- high risk of haemorrhage: advise deliver in hospital.
General principles of blood transfusion
Consent for blood transfusion
- Valid consent where possible prior to blood transfusion.
- In emergency, not feasible to get consent, information on blood transfusion provided retrospectively.
- reason for transfusion & note of consent discussion should be documented in patient’s case notes.
General principles of blood transfusion
Requirements for group and screen samples and cross-matching
- All woman blood group and antibody status checked at booking and at 28 wks
- Group & screen samples for provision of blood in pregnancy < 3 days old.
- at high risk of emergency transfusion, e.g. placenta praevia, & no clinically significant alloantibodies, group and screen samples should be sent once a week to exclude or identify any new antibody formation and to keep blood available if necessary.
- Close liaison with hospital transfusion laboratory is essential.
- Women have group and screen sample taken in line with clear locally agreed protocols for provision of blood.
General principles of blood transfusion
Blood product specification in pregnancy and the puerperium
- ABO-, RhD & Kell compatible red cell units transfused.
- If clinically significant red cell antibodies, then blood negative for relevant antigen cross-matched before transfusion; close liaison with the transfusion laboratory is essential to avoid delay in transfusion in life-threatening haemorrhage.
- CMV seronegative red cell and platelet components provided for elective transfusions during pregnancy.
What are the strategies to minimise the use of banked blood?
Is there a role for preoperative/predelivery autologous blood deposit?
Predelivery autologous blood deposit not recommended.
What are the strategies to minimise the use of banked blood?
Is there a role for intraoperative cell salvage (IOCS)?
- Cell salvage recommended where anticipated blood loss is great enough to induce anaemia or expected to exceed 20% of estimated blood volume.
- Consent for IOCS where possible and use in obstetric patients should be subject to audit and monitoring.
- Cell salvage only be performed by MDT who develop regular experience of IOCS.
- Where IOCS is used during CS in RhD-neg, previously nonsensitised women and where cord blood group is confirmed as RhD positive (or unknown), a minimum dose of 1500 iu anti-D immunoglobulin given following reinfusion of salvaged red cells.
- maternal blood sample taken for estimation of fetomaternal haemorrhage 30–40 minutes after reinfusion in case more anti-D is indicated.
Management of obstetric haemorrhage with blood components
- clear local protocol on how to manage major obstetric haemorrhage.
- protocol should be updated annually and practised in ‘skills drills’ to inform and train relevant personnel.
Are there mechanical strategies that can be employed?
Clinicians should familiarise themselves with mechanical strategies that can be employed to reduce postpartum blood loss.
What blood components can be used for obstetric haemorrhage?
When should red cells be used?
- no firm criteria for initiating red cell transfusion.
- decision to provide blood transfusion made on clinical and haematological grounds.
- In extreme situation and when blood group unknown, group O RhD-negative red cells (although may be incompatible for patients with irregular antibodies).
- Staff working in obstetric units should be aware of location of satellite blood fridge (where available) and should ensure that access possible for blood collection.
In what circumstances should fresh frozen plasma (FFP) and cryoprecipitate be used?
- FFP dose of 12–15 ml/kg for every 6 units of RBCs during major obstetric haemorrhage.
- Subsequent FFP transfusion guided by results of clotting tests if available in timely manner, aiming to maintain PT and APTT ratios less than 1.5 x normal.
- essential that regular full blood counts and coagulation screens (PT, APTT and fibrinogen) performed during bleeding episode.
- Cryoprecipitate at standard dose of two 5-unit pools administered early in major obstetric haemorrhage.
- Subsequent cryoprecipitate transfusion guided by fibrinogen results, aiming to keep levels > 1.5 g/l.
- FFP and cryoprecipitate ideally be of same group as recipient. If unavailable, FFP of different ABO group is acceptable providing that it does not havehigh titre of anti-A or anti-B activity.
- No anti-D prophylaxis is required if a RhD-negative woman receives RhD-positive FFP or cryoprecipitate.
When should platelets be used?
- Aim to maintain platelet count > 50 x 109 /l in acutely bleeding patient.
- platelet transfusion trigger of 75 x 109 /l recommended to provide margin of safety.
- platelets ideally be group compatible.
- RhD-negative women receive RhDnegative platelets.
Is there a role for near patient testing of coagulation?
Centres using thromboelastography (TEG®), or rotation thromboelastometry (ROTEM®), for guiding blood transfusion during major obstetric haemorrhage must ensure that their transfusion algorithm protocol has
been validated & quality assurance measures followed.
Pharmacological strategies for management of major obstetric haemorrhage
Is there a role for recombinant factor VIIa (rFVIIa) therapy?
- use of rFVIIa may be considered astreatment for life-threatening PPH, but should not delay or be considered substitute for live-saving procedure such as embolisation or surgery, or transfer to a referral centre
Pharmacological strategies for management of major obstetric haemorrhage
Is there a role for fibrinogen concentrate therapy?
- Fibrinogen concentrate is not licensed in UK for MX of acquired bleeding disorders.
- use in PPH considered only in context of clinical trials.
