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
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:
BLOOD PRESSURE
Labetalol typically first-line
20mg orally
IV 50mg Bolus
followed by titrated infusion
Nifedipine MR 20mg PO
IV hydralazine
Aim for SBP 140mmhg
Bringing down too fast can cause hypoperfusion to the uterus (foetus)
REDUCING RISK OF SEIZURE
presence of neuro complaints (headache, blurred vision) = increasede risk of seziure
Start Magnesium = 4g loading dose bolus IV
will likely make them feel sick/hot/unwell but will pass quickly when bolus ends
Then infusion of 1g/hour for at least 24 hours
FLUID RESTRICTION
1ml/kg/hr up to a max of 85ml/hr
take labetalol and magnesium off the total volume
use hartmanns to make up the rest
ensure output ok and measure U&E’s along with FBC and LFT’s
DELIVERY - pre-eclampsia will only resolve when baby and placenta are delivered
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