Episode 39: Obstetrics Part 2

Author: Eoghan Colgan  @eoghan_colgan
Special Guest: Marcus McMillan @1949LAN

23/10/19


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Guest Bios

Marcus McMillan

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Marcus McMillan is a consultant obstetrician in Princess Royal Maternity in Glasgow. He has a special interest in abnormally invasive placentas and coordinates care for people with this in Glasgow. He works with the Scottish Multiprofessional Maternity Development Programme for teaching obstetric emergencies and management to maternity staff and other departments.


Show Notes

Marcus McMillan is a consultant obstetrician in Princess Royal Maternity in Glasgow. He has a special interest in abnormally invasive placentas and coordinates care for people with this in Glasgow. He works with the Scottish Multiprofessional Maternity Development Programme for teaching obstetric emergencies and management to maternity staff and other departments. Eoghan and Marcus discuss obstetric emergencies, and in this episode they focus on eclampsia/pre-eclampsia, Ante-Partum Haemorrhage and Chest Pain iun Pregnancy.


TAKE-HOME POINTS

Pre-eclampsia

  • High BP in late pregnancy is an obstetric emergency

  • 3 things to think about:

    • Blood Pressure (>150SBP is bad, >160SBP is really bad)

    • Risk of seizure (eclampisa)

    • Fluid balance - increased risk of fluid leak incluiding into the lungs

  • Check for proteinura which is diagnostic in this setting

  • TREATMENTS:

    1. BLOOD PRESSURE

      1. Labetalol typically first-line

        1. 20mg orally

        2. IV 50mg Bolus

        3. followed by titrated infusion

      2. Nifedipine MR 20mg PO

      3. IV hydralazine

      4. Aim for SBP 140mmhg

      5. Bringing down too fast can cause hypoperfusion to the uterus (foetus)

    2. REDUCING RISK OF SEIZURE

      1. presence of neuro complaints (headache, blurred vision) = increasede risk of seziure

      2. Start Magnesium = 4g loading dose bolus IV

        1. will likely make them feel sick/hot/unwell but will pass quickly when bolus ends

      3. Then infusion of 1g/hour for at least 24 hours

    3. FLUID RESTRICTION

      1. 1ml/kg/hr up to a max of 85ml/hr

      2. take labetalol and magnesium off the total volume

      3. use hartmanns to make up the rest

      4. ensure output ok and measure U&E’s along with FBC and LFT’s

    4. DELIVERY - pre-eclampsia will only resolve when baby and placenta are delivered

      1. everything up to then (and afterwards) is supportive

  • HELLP Syndrome

    • Haemolysis; Eleveate LFT’s, Low Platelets

      • indiviual elements can occur without the others

    • Unclear why it happens

    • doesn’t really change management

    • platelets <50 likely need transfusion (remember other clotting factors can be deranged and need replaced) pre-delivery to avoid PPH

  • Proteinuria when asytmptomatic:

    • when >24/40, even if normal BP:

      • proteinuria +1 = suspicious of pre-eclampsia

      • proteinuria +2 = very suspicious of pre-eclampsia

      • proteinuria +3 = admit until can prove they don’t have it

  • DECIDING ON WHEN TO DELIVER:

    • think:

      • is mum unwell enough to deliver; or

      • is baby unwell enough to deliver

    • it is then a balance of benefits to mum/baby versus the risks of prematurity

    • if >36/40 then foetal outcoimes good so easy decision to deliver

    • earlier = will try and push pregnancy along a bit

ECLampSIA

  • Pre-eclampsia + seizures

  • most seizures are self-limiting in eclampsia; but they don’t get better and will continue/get worse unless baby delivered

  • Do ABC’s, get IV access, catheterise (proteinuria is diagnostic in setting of late pregnancy and seizures)

  • Start supportive therapy (as for pre-eclampsia)

    • control BP

    • start magnesium

    • fluid restriction

  • Antiseizure therapy = magnesium

    • if insufficient: continue magnesiums but could try diazemuls/phenytoin

  • Seizures can occur before/during/after delivery

    • commonest to occur after delivery, typically within 5 days but can be up to 10-14 days

    • could have a normal BP, but would expect patient to have proteinuria

Ante-partum haemorrhage

  • if mum or baby is compromised then deliver

  • if bleeding heavy and not stopping then deliver

  • Main Causes:

    • Placental Abruption

      • placenta separates from uterus before delivery

      • can be revealed (blood evident), or concealed

      • typically painful with tender, often firm, abdomen

    • Placenta Praevia

      • placenta covers cervix

      • painless bleeding classically, but not always

  • Do basics well:

    • ABC

    • IV access X 2 (large)

    • Bloods and X-Match

    • Give tranexamic acid - thought to be safe

    • Replace bloods and blood products

      • O-Neg, group-specific, x-match

      • make sure labs know that patinet is pregnant so they will look for additional things e.g. Kell antigens

        • if exposed, kell antibodies are bad for future pregnancies (haemolysis and foetal death)

    • Anti-D: give if mum resus negative and has a sensitising event

      • can be given up to 72 hours after sensitizing event so don’t need to worry in ED

  • FOETAL MONITORING:

    • only do it if there is an intervention that can be enacted on back of the monitoring

    • Best way to have a well baby is to have a well mum

      • concentrate on mum

      • always prioritise mum over baby in an emergency situation

Chest pain in pregnancy

  • SOB and chest pain in pregnancy

    • tend to think of PE first but cardiac causes are the number one cause of death of pregnant women in the UK

      • Listen to heart and lungs

      • ECG +/_ CXR +/_ ECHO

      • If cardiac symtpoms such as orthopnoea, involved cardiology eafrly for an ECHO

  • Cardiac Conditions:

    • Congenital (formerly the commonest)

    • Acquired (now the commonest) e.g. Ischaemic Heart Disease, Peripartum Cardiomyopathy

  • Standard Causes: things that can happenb ouitside of pregnancy

    • chest infections

    • exacerbation of asthma

    • pneumothorax etc

  • SOB in pregnancy can be normal

    • diaphragm splinting (harder to draw breathe)

    • PO2 has to be maintained to oxygenate mother and baby

    • nomrla biochemistry is reset

      • mother runs slightly alkalotic (blows off CO2)

      • this allows baby to dump their CO2 into maternal circulation

      • this gives a subjective feelking of SOB

    • Gradually worsening SOB over a few weeks is less concerning than an acute onset

  • PULMONARY EMBOLISM

    • Sudden SOB - PE should definitely be considered

      • it is the No. 1 cause of death directly related to pregnancy

      • mother is 4-5x more likely to have a PE when pregnant

      • 20x more likely to have a PE post-partum than when not pregnant

    • Standard workup:

      • history, obs, bloods, gas, imaging

    • D-Dimer: they do not use as will be +ve in 2nd/3rd trimester

      • studies on trimester-adjusted D-Dimers have not convincedthem to adopt them

    • Risk Stratification: they do not use tools that stratify based on sympotoms

      • they consider the presence of risk factors, e.g. smoking, DM, FH, obesity

      • they go by general suspicion but appreciate that they will overinvestigate

        • only 2-5% of suspected cases turn out to be PE’s

        • absolute risk if only 1/1000 so small overall

    • IMAGING:

      • do a CXR (without any worries) - and it will be required for V/Q

      • then V/Q scan if indicated (can do perfusion part without ventilation part)

      • is above is suspicious then do a CTPA

  • RISK TO FOETUS FROM RADIATION

    • modern machines with reasonable shielding will cause no harm to foetus

    • you can do prettyt much anything if needed

    • a CT PELVIS has about 1/10th the dose of radiation needed to causes significant harm to foetus

    • don’t do any tests unnecessarily but equally do a test if you think they need it

      • do whatever you would do for the patinet if they were not pregnant

  • TREATMENT:

    • even in tertiary centre it can take 24-48 hours to get a diagnostic test

    • start LMWH at treatment dose until test done

    • Enoxaparin 1mg/kg BD or 1.5mg/kg OD

    • it doesn’t cross placenta so is completely safe


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