Obstetric haemorrhage Flashcards
Why is obstetric haemorrhage important
Major cause of death in developing countries
Cause of up to 50% maternal deaths globally
What are the 3 classes of obstetric haemorrhage
Antepartum
Primary postpartum
Secondary postpartum
What is antepartum haemorrhage
Bleeding from genital tract from 24 weeks pregnancy, prior to birth
Usually caused by placenta praevia or abruption
Significant cause of maternal +fetal morbidity + mortality
Minor <50ml
Major 50-1000ml
Massive >1000ml
What is primary postpartum haemorrhage
Loss of 500ml or more blood from genital tract within 24 hours of birth
Major >1000ml
What is secondary postpartum haemorrhage
Abnormal/excessive bleeding from birth canal 24h-12 weeks postnatally
What are the blood volume changes in pregnancy
70ml/kg to 100ml/kg
Plasma vol increases 40-50%
Red cell mass increases 20-30%, relative anaemia
Why is increased blood volume in pregnancy beneficial
Facilitates maternal and fetal exchanges of respiratory gases, nutrients + metabolites
Reduces impact of maternal blood loss at delivery
What are the changes in clotting during pregnancy
Relatively hypercoagulable Decrease in fibrinolytic activity Prevent excessive bleeding at delivery Fibrinogen increased Clotting factors increased (2, 7, 8, 10, 11, 12) Platelet numbers increased DDimer levels elevated
What are the compensatory changes during pregnancy
Heart rate increases, beats more forcefully
Blood vessels constricted, increased vascular resistance
Less urine secreted so lose less fluid
What are the causes of obstetric haemorrhage
Tone
Tissue
Trauma
Thrombin
Describe tone in obstetric haemorrhage
Abnormalities of uterine contraction
Risk factors for atonic bleeding = prolonged labour, overdistended uterus
Describe tissue in obstetric haemorrhage
Retained products of conception
Retained placenta
Placenta praevia
Morbidly adherent placenta
Describe trauma in obstetric haemorrhage
Uterine trauma- inverted uterus, ruptured uterus, scars, surgical damage
Genital tract trauma- vaginal tears
Describe thrombin in obstetric haemorrhage
Abnormalites of coagulation
Acquired coagulopathy in pregnancy- Sepsis, preeclamspia, placental abruption, retained dead fetus
Platelet abnormalities- gestationsal thrombocytopenia, HELLP syndrome, idiopathic/immunological thromboctopenic purpura
What are the minimal staff that should be present in theatre for obstetric haemorrhage
Midwife, labour ward coordinator, neonatal team, 2 obstetric surgeons, 2 anaesthatists, 2 theatre nurses, 2 anaesthetic nurses, support worker
What equipment is used in obstetric haemorrhage
Rapid infuser
Red cell salvage
Point of care testing
What is a rapid infuser
Rapidly infuses + warms crystalloid, colloid blood
Ability to keep up with rapid blood loss
What is red cell salvage
Collects + processes maternal blood from surgica site
Centrifuges, washes + returns red cells to patient
What is point of care testing
ROTEM thromboelastometry tests whole blood clotting
Blood gas analyser guides resuscitation + blod
What are the main uterotonic agents
Syntocinon
Ergometrin
Carboprost
Misoprostol
What pharmacological treatments are there for obstetric haemorrhage
Uterotonic agents
Uterine atony treatment
Tranexamic acid for reduction of fibrinolysis
What are surgical treatments for obstetric haemorrhage
Tone- uterine massage, B lynch suture, bakri baloon insertion
Tissue- removal of retained products, manual removal of placenta
Trauma- surgical repair
What are the haematological treatments for obstetric haemorrhage
Replace circulating volume
Replace blood- cell salvage/allogenic
Correct coagulation with blood products
How are blood products produced
Donated blood centrifuged, supernatant removed, frozen within 8 hours- fresh frozen plasma
FFP contains all clotting factors
Cryoprecipitate prepared from FFP- higher concentrations of clotting factors
How are platelets produced
Centrifuging blood more slowly, pooling together from multiple donors
Given 1 bag at a time
How is fibrinogen produced
Cryoprecipitate contains 100iu factor 8, 250mg fibrinogen
Also von willebrands factor, factor 13
Given as pooled units
What is the major haemorrhage protocol
Aide memoire, reduce omission + human errors
Guide blood product replacement, aims for therapy
What are the aims for haematological parameters
Gm >8g/dl, normal 10-15 Haematocrit >0.3, normal 0.28-4 Prothrombin time <1.5 normal (12-13s) Platelets >75x10^9, normal 150-400 Fribrinogen >2g, normal 3.7-6.2
What bedside tests can be done
Serial blood gases, Hb/hct, lactate/ph/hco3
ROTEM (clotting)
