Topic 8 - Obstetrics Flashcards
Amniotic Fluid Embolism - Features
Sudden profound and unexpected maternal collapse associated with:
- Hypotension
- Hypoxemia
- DIC
Amniotic Fluid Embolism - Pathophysiology - Entry and Phase 1
Can enter through placental implantation but most commonly through the endoservix
PHASE 1 - An anaphylactoid biochemical mediator response causing peripartum hypoxia, hemodynamic collapse and coagulopathy. Lasts about 30 minutes
Amniotic Fluid Embolism - Phase 2
PHASE 2 - occurs in patients that survive phase 1 – L ventricular failure, DIC and pulmonary edema
Amniotic Fluid Embolism - Causes of Cardiac dysfunction
- Cardiac dysfunction is due to ischemia and the presence of endothelin (potent vasoconstrictor), histamine, PGs, Serotonins, Thromboxanes and leukotreins from the fluid
- Vasospasm and shunting causes ARDS
- Fluidalso contains coagulation factors and sloughed fetal skin which cause DIC without significant blood loss
Amniotic Fluid Embolism - Presentation
Breathlessness, cyanosis, hypotension, dysrhythmia, DIC, seizures, profound fetal distress
Amniotic Fluid Embolism - Mx
- O2 –CPAP or PEEP
- Fluidsand vasopressors
- Coagulants
- Fastdeliver of baby
Shoulder Dystocia - Principle
Disproportion between bisarcomial diameter of the fetus and anteroposterior diameter of pelvic inlet - confirmed if no delivery 60 seconds after head presents with normal downward traction
Around 1% of all vaginal births
C-section usually planned if >5kg or in instance of gestational diabetes
Shoulder Dystocia - Risk Factors (Weak)
- Previous shoulder dystocia
- Advanced maternal age
- Malebaby
- Macrosomia
- Maternal diabetes
- Maternal obesity
- Prolonged 1st and 2nd stages of labor
Turtle’s Sign
Positive sign for shoulder dystocia - chin retracts into perineum
Aim of Emergency Manouvers in Shoulder Dystocia
- Increase functional size of bony pelvis
- Decrease bisacromial diameter of the fetus
- Change relationship of bony pelvis with bisacromial size of fetus by rotation
McRoberts manouvre goal
- Increases width of birth canal by reducing lumbosacral lordosis
- Avoid fundal pressure
Chord management in shoulder dystocia
- Avoid cutting chord early if possible – increases risk cerebral palsy and asphyxia -
- Delay chord clamping if it has had sustained traction on it – increased transfer of blood to placenta may have occurred
- If chord must be immediately divided – try milking chord quickly
Documentation in shoulder dystocia
- Time of head birth
- Maneuvers performed and timing
- Direction baby is facing and which shoulder is impacted
- Time of delivery
- Staff in attendance
- Condition of baby
Complications for mother in shoulder dystocia
- 3rd/4th dergree tears
- PPH
- Uterinerupture
- Futureissues
- Physcological obstetric effects
Complications for baby in shoulder dystocia
- Brachial plexus injury
- Fractured hummers/clavicle
- Hypoxia (pH drops .04 per minute)
- Death
Umbilical cord prolapse
· Chord below or beside presenting part
· Life threatening:
- Chord compressed – vessels within cord spasm
- O2 can be prevented from reaching the fetus
- Mx is complicated due to ongoing contractions - more compressive force
Cord prolapse management
- Immediate transport
- May only survive 10 min – no O2
- 15L/minO2
- Positioning ‘knee-to-chest’ of mother to reduce cord pressure
- If cord not pulsating or fetal distress present – push presenting part off chord
- Cover cord with sterile moist towel/dressing – avoid handling
Nuchal cord
- Up to 25% birth
- Can be looped up to 4 times
- If cord is needed to be cut – time criticaldelivery
Breech birth types
Breech birth risk factors
Most significant factors are preterm labour and gravida however also:
- Previous breech
- Low-lying placenta/praevia
- Pelvic masses
- Bicornuate uterus
- Polyhdraminios
- Oligohydraminios
- Fetal abnormalities
- Twins or higher multiples
- Grand multiparty
Breech management
- Loveset’s
- Marceau-Smellie-Viet
- Burns–Marshall method
- Not recommended
Hematomas during delivery
Vulvul - usually varicose veins
Vaginal - potential space for 2 liters of blood
Broad Ligament - level of shock is out of proportion with the amount of blood seen
Uterine rupture
A tear in uterus usually associated with:
- Previous caesarian section
- Other uterine surgery
- Grand multiparity
Managment of uterine rupture
- O2
- Appropriate positioning
- Fluid
- Pain relief
- Notification receiving hospitaland urgent transport
Classifications of uterine rupture
ACUTE - less than 24 hours post delivery
SUBACUTE - from 24 hours to 4 weeks
CHRONIC - 4 weeks onwards
INCOMPLETE - fundus reaches servic
COMPLETE - fundus passes through cervix
PROLAPSE - uterus visible from vulva
Uterine prolapse
- Occurs spontaneously or following excessive traction being applied to the umbilical cord
- Severe abdo/pelvic pain due to excessive traction on the broad ligament and ovarian ligaments
- Hemorrhage if placenta is partially separated
- Manifestations of shock are more common with complete uterine inversion
Management of uterine inversion
- Cover uterus with sterile dry drape –minimize infection
- Help women achieve a position of reasonable comfort
- Administer pain relief as appropriate
- Treat for hypervolemia
- Transport to definitive care
- Notify
Secondary PPH
- 24hrs to 6 wks
- High association with maternal morbidity –85% require admission
Aetiology:
- Unknown in one third of cases
- Subinvolution of the uterus – does not return to normal size
- Retained products
- Endometriosis
Characteristics of secondary PPH
- Ongoing vaginal bleeding
- Pallor from recent blood loss
- Change in lochia – regression to bright red and increasing amounts – if infection, smell may be offensive
- Uterus may be larger than expected –failure to contract
- Pyrexia
- Tachycardia – indicates infection or hypervolemia
VTE risk factors
- >35
- Obesity
- Parity >4
- Family Hx
- Gross varicose veins
- Major concurrent illness
- Prolonged bed rest >4 days
- Long-haul travel
- C-section
- Prolonged labor
VTE diagnosis
VTE management
- Transport critical
- O2 Analgesia
- IVresus. as required
- Positioning to prevent mobilisation of clot
Risk factors for prolapse
- Abnormla fetal presentation
- Multiparity
- Low birth weight
- Prematurity
- Polyhydramnios
Complications to anticipate durring shoulder dystocia (for mother and baby)
MOTHER:
- PPH
- Perineal trauma
- Psychological trauma
BABY:
- Birth trauma
- Hypoxia
APGAR
Pertinant extra history questions in obstetric cases
- How many weeks pregnant (?/40)– Due date
- Need to ascertain G and P
- Previous obstetric history (ifany) especially in relation to birthing problems and/or premature births.
- Has the patient had antenatal care/assessment and/or recent scans
- Any identified risks such as breech, malposition, placental abnormalities
- Enquire about foetal movements, show, amniotic fluid presentation (presence of meconium)
When do ectopic pregnancies generally rupture?
Rupture usually occurs between 6 and 8 weeks of gestation: Can occur as early as 5 weeks or as late as 14-16 weeks
Risk factors for ectopic pregnancy
- In virto fertilisation
- STIs
- Use of intrauterine devices
- Advanced maternal age
- Smoking
- Previous Hx of ectopic pregnancy
Pre-eclampsia
- > 140mmHg SBP with protenuria and altered liver function
- Most likely due to vasospasm due to:· Increased resistance to blood flow leading to multi-system organ damage
- Usually after 20 weeks
- Hypertension in pregnancy = 140/90
Triad of pre-eclampsia
- Hypertension
- Proteinuria
- Generalized edema
Management for pre-eclampsia
- Seizure management (ICP)
- Reduce external stimuli
- Transport to an appropriate facility
Abruptio placentae types
PV bleeding may only present in partial abruption
Abruptio placentae presentation
- Pain
- Bleeding
- Shock
- Abdominal rigidity
- Difficulty hearing fetal heart sounds
Common causes of abruptio placentae and risk factors
Usually abdominal trauma - increasingly frequent as pregnancy progresses
Risk factors may include gestational hypertension, previous Hx of abruption, Hx of c-section, intrauterine infection and tobacco and cocaine use
Complications from abruptio placentae
- Death
- Maternal hypovolemia
- Acute renal failure
- Coagulopathies
Placenta previa and risk factors
- Abnormal placental implantation
- Risk factors include:
- Parity
- C-section
- Maturing age
- Smoking
- Previous placenta previa
Placenta previa grades
Presentation features of placenta preavia
- Vaginal bleeding – usually bright red/profuse
- Signs of shock
- No abdominal pain - unprovoked by bleeding or intercourse
- In contrast with abruption hemorrhage is uncontrolled, principal problem is hypervolemia rather than fetal hypoxia however fetal hypoxia will ensue maternal hypotension
Postpartum hemorrhage defintions
500 mls or more (arbitary quantity) or a loss that if left untreated can lead to maternal shock and death. Occurs within the first 24 hours but usually 20-60 minutes of birth
4 most common causes of postpartum hemorrhage
- Auterine Atony (tone) (70-90%) - failure of adequate myometrial contraction after placenta expulsion. Related to overstretched uterus, previous hemorrhage and use of muscle relaxants as risk factors
- Retained placental tissue (tissue) - risk factors include multiparity, previous uterine surgery or infection
- Trauma to genital tract (trauma) (uterine rupture or inversion, cervical laceration and previous eclampsia)
- Coagulation disorders (thrombin)
Feotal viability in maternal cardiac arrest
5 minutes in arrest and fetus is potentiallyviable – consider emergency hysterectomy
Not before 23 weeks – will not improvemothers heamodynamic condition
HELP Syndrome
- Haemolysis, elevated liver enzymelevels, and low platelet count
- Classic triad of:
- Abnormal vascular tone
- Vasospasm
- Coagulation defects
- Vision changes are also common
HELP syndrome pathogenesis
- Haemolysis causes platelet aggregation and microvascular endothelialdamage – leads to Haemolytic anaemia
- Hepatic Damage – hepatic restriction to blood flow cause RUQ pain
- Platelet aggregation causes thrombocytopenia
Trauma in pregnancy - key considerations
- Motheroften remains hemodynamically stable whilst shunting blood away from fetus
- O2 disassociation moved to left fetus§ Increased blood volume and CO means signsof shock are late and are severe when present
- Fundal height important to determine fetalviability (likely if above umbilicus)- If it increases – is also a sign of concealed abruption
- If <20 weeks treat as if not pregnant
- In burns – larger SA and more important to maintain normotension
Gestational diabetes
- Thought to be related to inability of mother to metabolize carbohydrates
- Eitherdeficiency in insulin or hormones that block maternal insulin (resistance)
Stages of labour
- Onset of regular contractions to completecervical dilation
- Expulsion of newborn
- Placenta delivery
Regular contractions lasting 45-60s every 1-2 minutes = no time to transport
Ductous venous, foraman ovale and ductus arteriosus
Ductous venous - Empties directly into inferior vena cava, bypassing the immature liver
Formaram ovale - Shunts 1/3 of blood from R atrium to L atrium, bypassing pulmonary trunk
Ductous Arteriousus - Pumps blood that does enter pulmonary trunk directly into aorta
Primary PPH management
Spontaneous abortion w/ fetal presentation
- Spontaneous loss of pregnancy before 20 weeks (or 400grams)
- Cut/clamp chord and wrap
- Resus is futile <23 weeks or <400g
Pre-eclampsia diagnostic criteria
- Systolic BP >140mmHg or Diastolic >90mmHg
+
- Neurological problems
- Proteinuria
- Renal insufficiency
- Liver disease
- Hematological disturbances
- Fetal growth restriction
Spontaneous abortion management
- Cut and clamp chord
- Wrap feotus
- If gestational age <23 weeks or birthweight <400grams
- Manage for sepsis and hemorrhage
