Obstetric Emergencies Flashcards
What is cord prolapse?
Cord descends through cervix with (or before) presenting part of fetus. 0.1-0.6% of births but high mortality (~91 in 1000, as occurs more frequently in preterm babies [often breech and may have other congenital anomalies]). Occurs in presence of ruptured membranes.
- Occult (incomplete): cord descends alongside the presenting part, but not beyond it.
- Overt (complete): umbilical cord descends past presenting part and lower than the presenting part in the pelvis.
- Cord presentation: presence of umbilical cord between the presenting part and the cervix. This can occur with or without intact membranes.
Fetal hypoxia via 2 main mechanisms: occlusion (presenting part presses onto cord) + arterial vasospasm (exposure to cold atmosphere: umbilical arterial vasospasm, reducing blood flow to the fetus).
Risk factors for cord prolapse?
Breech presentation
Unstable lie (changes between transverse/oblique/breech), Artificial rupture of membranes (particularly when presenting part of fetus is high in pelvis)
Polyhydramnios
Prematurity
If >37 weeks and unstable lie, consider inpatient admission until delivery due to risk of cord prolapse
Diagnosis and management of cord prolapse?
Cord prolapse should always be considered if non-reassuring fetal heart beat + absent membranes. Can be confirmed by external inspection or digital vaginal examination. Fetal heart rate pattern can vary from subtle changes (e.g. decelerations with some of the contractions) to more obvious signs of fetal distress e.g. fetal bradycardia. Fetal bradycardia is strongly associated with cord prolapse (relating to the mechanism of occlusion of the cord by the presenting part). PV bleeding or heavily blood-stained liquor with ruptured membranes would suggest placental abruption or vasa praevia.
Management
- Call for help (obstetric emergency!)
- Avoid handling cord to reduce vasospasm
- Manually elevate presenting part by lifting off the cord (vaginal digital examination). If in community: fill bladder 500ml normal saline (warmed if possible) via urinary catheter & arrange immediate hospital transfer
- Encourage into left lateral position with head down & pillow placed under left hip OR knee-chest position: relieves pressure off the cord from the presenting part.
- Consider tocolysis (e.g. terbutaline): if delivery not imminently available, will relax uterus & stop contractions, relieving pressure from the cord. Particularly useful if there are fetal heart rate abnormalities while preparing for C-section: may also allow time for transfer to a location where delivery is feasible (e.g. operating theatre for C-section).
- Delivery usually via emergency C-section (if fully dilated and vaginal delivery seems imminent, encourage pushing or consider instrumental delivery). If at threshold for viability (23+0 – 24+6 weeks) & extreme prematurity, expectant management may be discussed due to significant maternal morbidity with C-section at this gestation & poor fetal outcomes.
What is shoulder dystocia?
Complications?
0.6-0.7% of all deliveries. After delivery of the head, anterior shoulder of fetus impacted on pubic symphysis, or less commonly, posterior shoulder becomes impacted on the sacral promontory. Defined by delay in delivery of the shoulders following the head with the next contraction after using normal traction. Leads to hypoxia in the fetus, proportional to the time delay to complete delivery.
Complications: 3rd or 4th degree tears (3-4%), PPH (11%), fetal humerus/clavicle fracture, fetal brachial plexus injury (2-16%), HIE.
Signs of shoulder dystocia?
Management?
Signs: difficulty in delivery of fetal head or chin, failure of restitution (head remains in OA position after delivery by extension), turtle neck sign (fetal head retracts slightly back into pelvis, so that the neck is no longer visible, akin to a turtle retreated into its shell.
1.. Call for help (senior obstetrician, senior midwife + paediatrician needed)
- Advise to stop pushing (can worsen impaction)! Avoid downward traction on fetal head (increases risk of brachial plexus injury – major cause for litigation): use only routine axial traction (keep head in line with spine) and do not apply fundal pressure (increases risk of uterine rupture).
• Consider episiotomy: won’t relieve obstruction but improve access for manoeuvres
First line manoeuvres: McRoberts manœuvre +/- suprapubic pressure (>90% success)
Second line (internal manoeuvres): Posterior arm, Internal rotation (Corkscrew)
- If fail – roll onto all fours and repeat (may widen pelvic outlet).
- Additional manoeuvres (cleidotomy, symphsiotomy, Zavenelli) very rarely used in UK
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Post-delivery: active management of 3rd stage recommended (PPH risk), PR exam to exclude 3rd degree tear. Debrief mother & birth partner and advise them of risk of recurrence. Consider physiotherapist review before discharge (increased risk of pelvic floor weakness, 3rd degree tear, musculoskeletal pain & temporary nerve damage). Paediatric review recommended before discharge to assess for brachial plexus injury, humeral fracture & HIE.
Retained placenta
Undelivered placenta >30 minutes (mean time 8-9 minutes, PPH risk doubles after 10 mins).. <3% of vaginal deliveries
Causes
• Separated but undelivered (bleeding, uterus shape, cord lengthening)
o Prevention by active management of 3rd stage
o Missed signs: uterus unable to retract, becomes broad & boggy, significant uterine bleeding follows
• Placenta partly or wholly attached
o Completely failed separation
o No bleeding as contrasted with Cornual implantation
• Partial separation
o Bleeding but fundus still broad
o Hour glass constriction
• Invasive placenta (rare but increasing incidence with C-section incidence)
o Includes accreta, increta or percreta
o Abnormal adherence of placenta to uterine muscle
o Partial of wholly attached placenta
o Risk factors: VBAC, placenta praevia, maternal age, high parity, prior placenta accreta
Management
• Monitor vital signs
• Large bore IV (16-18 gauge)
o Active management of Third Stage of Labour
• Brandt-Andrews Manoeuvre (cord traction)
o Umbilical cord pulled gently with one hand
o Other hand pushes uterus up from pubis (prevents uterine inversion)
o See-saw motion between two hands
• Umbilical vein uterotonics
• Consider obstetric consultation (placenta accreta, increta, percreta)
• Observe for signs of significant bleeding (PPH)
Manual extraction of placenta
• Conscious sedation or anaesthesia
• Fingers separate placenta from uterus (never grasp until separated)
• Abdominal hand presses fundus into placenta (prevents tearing of lower segment)
• Consider accreta if tissue plane not easily distinguished on manual placenta removal (especially if tissue plane not easily distinguished on manual placenta removal)
o Especially consider in VBAC, placenta praevia, advanced maternal age, high parity, prior placenta accreta
o High risk of life threatening PPH (may require hysterectomy)
• Placenta inspected for completeness (re-explore any possible retained products)
• Administer uterotonics & massage uterus
Amniotic fluid embolism (AFE)
Rare syndrome: acute hypoxia, haemodynamic collapse & coagulopathy. ?May be an anaphylactic reaction triggered by maternal exposure to fetal antigens. AFE incidence in UK: 2 in 100,000 pregnancies. Diagnosis: clinical (& finding of fetal squame cells & mucin in the maternal peripheral vasculature is of uncertain importance). May occur before onset of or during labour, during C-section or immediately postpartum. Mortality ~26% (5th largest cause of direct maternal deaths). In patients who survive the acute event, left ventricular failure may develop, in a clinical picture consistent with ARDS & DIC.
Characteristic clinical features:
• Sudden dyspnoea
• Acute hypoxia (dyspnoea, cyanosis, respiratory arrest)
• Acute hypotension or cardiac arrest
• Coagulopathy: will usually develop within 30 minutes
• Some cases: may present with generalised seizure activity
Risk factors:
• High parity
• Excessive or strong uterine contractions
• Induction of labour & use of oxytocic drugs (particularly single IV bolus syntocinon or Syntometrine)
• Overdistention of uterus e.g. polyhydramnios, multiple pregnancy
• Women >35 years of Indian ethnicity
There may be premonitory signs & symptoms (before collapse & haemorrhage occur) e.g. breathlessness, chest pain, restlessness, feeling lightheaded, respiratory distress, paraesthesia in fingers, nausea and vomiting. Senior Obstetric & Anaesthetic staff should be involved if there is any suspicion of these early warning signs.
Diagnosis: mainly based on clinical symptoms in presence of ruptured membranes. Important to differentiate from PE (potentially preventable cause of maternal mortality).
Clinical features of AFE compared to PE:
• AFE most likely to occur at delivery (PE any time)
• Early symptoms of AFE are dyspnoea, restlessness, panic, feeling cold, paraesthesia, less likely to have pain (PE: dyspnoea, cough, haemoptysis, pleuritic pain)
• Collapse highly likely in AFE (may occur in PE)
• DIC highly likely in AFE (absent in PE)
• CXR: AFE – pulmonary oedema, ARDS, right atrial enlargement, prominent pulmonary artery
• CTPA: negative in AFE, positive in PE
Management: 15L/min O2 via high-concentration reservoir mask (non-rebreathe), cardiovascular support with IV fluids & blood transfusion, correction of coagulopathy, effectiveness of replacement & supportive therapy continuously monitored by ABCDE approach. Once stable enough: managed on ITU.
Uterine rupture
0.2-0.3 / 10,000 deliveries in UK. Risk factors: previous C-section, previous uterine instrumentation (e.g. evacuation, D&C), myomectomy, cornual ectopic pregnancy, bicornuate uterus.
Symptoms / signs
• Hypotensive collapse
• FH rate abnormalities including bradycardia (may be 1st & only sign)
• Vaginal bleeding or blood-stained liqor
• Severe abdominal pain (often felt high in the abdomen if liquor or blood seeps up along paracolic gutters – beware right upper quadrant pain in woman with C-section scar & an epidural)
• Haematuria
• Cessation of contraction or dysfunctional uterine activity
• Sudden upward displacement of the presenting part of the fetus
• Scar tenderness or crepitus over the lower uterine segment
Management:
• 2 large bore IV cannulae
• Resuscitate with IV fluids and oxygen by facial mask
• Crossmatch 4 units
• Consent patient for laparotomy & explain that hysterectomy may be neccessary
• Inform obstetric consultant on call
Surgical management: careful assessment made in theatre, operation carried out will depend on size and site of rupture, degree of haemorrhage & patient’s future fertility wishes. Three options exist:
• Simple repair
• Subtotal hysterectomy
• Total hysterectomy
Maternal collapse
Causes: bleeding, eclampsia, sepsis, uterine rupture, amniotic fluid embolism, anaphylaxis, venous air embolism, neurological causes, cardiac causes, cardiac arrest.
Lay flat & ABDCE assess. Commence 15L/min O2 via high-concentration reservoir mask (non-rebreathe).
