16.9 Pre Eclampsia Flashcards
A 25-year-old woman who is 37 weeks pregnant and known to have pre-eclampsia is admitted to your
labour ward with a blood pressure of 160/110 mm Hg on several readings.
a) What is the definition of pre-eclampsia (1 mark) and which related symptoms should pregnant women
be told to report immediately? (2 marks)
Pre-eclampsia is new hypertension
(systolic greater than 140 mm Hg,
diastolic greater than 90 mm Hg)
presenting after 20 weeks’ gestation
with significant proteinuria.
(Significant proteinuria:
24-hour urine collection
greater than 300 mg protein
OR
urinary protein:creatinine ratio [PCR]
greater than 30 mg/mmol).
Symptoms to report immediately:
Symptoms to report immediately:
» Severe headaches.
» Visual disturbance, blurred vision, flashing lights.
» Sudden swelling of hands, feet or face.
» Upper abdominal pain or vomiting.
b) How should this patient be managed following admission to your labour ward? (12 marks)
Multidisciplinary management is required of this obstetric emergency, with
obstetric, midwifery, anaesthetic and intensive care input. Level 1 care as a
minimum.
Assess and manage the patient simultaneously following a systems-based
approach
> > Airway:
• Airway assessment –
anaesthesia for urgent delivery or
airway support may be necessary.
• Assess for voice change,
hoarseness, facial oedema –
laryngeal oedema and difficult intubation are more likely.
> > Respiratory:
• Pulmonary oedema may result in respiratory compromise.
• Assess oxygen saturations, respiratory rate.
• Auscultate chest.
• Supplementary oxygen if required.
• Consider fluid restriction to 1 ml/kg/h to a maximum of 80 ml/h
(although may need extra bolus if hydralazine is commenced).
> > Cardiovascular:
• Cannulate.
Start antihypertensive medication to target BP less than
150/100:
first line oral or intravenous labetalol;
second line intravenous hydralazine;
third line oral nifedipine.
• Monitor response with frequent blood pressure checks.
> > Neurological:
• Assess for hyper-reflexia,
severe headache,
visual disturbance.
May signify risk of eclampsia.
Consideration of magnesium treatment if
these symptoms are present or
if there is significant proteinuria.
> > Gastrointestinal:
• Keep nil by mouth and administer antacid in
view of likely imminent
delivery and possibility of seizure.
> > Haematological:
• Check full blood count for platelet level and coagulation screen.
> > Renal:
• Urinary protein:creatinine ratio and
urine dip for protein to assess
disease severity.
• Monitor urine output.
• Monitor renal function.
> > Hepatic:
• Check transaminases and bilirubin.
> > Obstetric:
• Continuous fetal monitoring with cardiotocograph,
especially once antihypertensives are initiated.
• Uric acid is a marker of disease severity.
• Plan for delivery:
baby is at term and ultimate cure for pre-eclampsia is
delivery of the placenta.
c) What changes would you make
to your usual general anaesthetic
technique for a pregnant woman
if this woman needed a general
anaesthetic for caesarean
section? (5 marks)
> > Airway:
• Increased awareness of risk of and preparation for difficult airway: assess for upper body or facial oedema and hoarseness that may indicate oropharyngeal and laryngeal oedema.
• Airway oedema may worsen over duration of surgery: deflate endotracheal tube cuff to check for leak before extubation.
> > Respiratory:
• Limit fluid input to 80 ml/h unless matching losses through e.g. haemorrhage.
• Higher airway pressures and PEEP may be required for oxygenation in the presence of pulmonary oedema – this may necessitate postoperative ventilation as well.
> > Cardiovascular:
• Consideration of intra-arterial blood pressure monitoring.
• Mitigate pressor response of intubation with short-acting opioid, e.g. alfentanil 10 mcg/kg.
• Consider pressor response of extubation if blood pressure remains high and labile. Consider short-acting beta-blocker, e.g. labetalol 10–20 mg intravenously.
> > Pharmacology:
• Caesarean section under general anaesthesia has an increased association with uterine atony. Ergometrine is contraindicated for this patient due to its hypertensive effect.
> > Neurological:
• Even more important to ensure adequate pain relief before waking due to impact of circulating catecholamines on blood pressure. Consider
transverse abdominis plane blocks and morphine.
• Magnesium prolongs the effect of depolarising and non-depolarising muscle relaxants: mandatory use of nerve stimulator, and anaesthesia may have to be prolonged to allow for this prolonged offset time.
> > Renal:
• Avoid NSAIDs due to the effect of pre-eclampsia on kidney function.
Incidence
Pre-eclampsia complicates about 7% of all pregnancies in the UK, and is part of a
spectrum of disease which includes HELLP syndrome, peripartum cardiomyopathy and
possibly acute fatty liver of pregnancy. It is the second commonest cause of maternal
death after thromboembolic disease.
Definition
: pre-eclampsia is a systemic disorder of the vascular endothelium which
has its origin in abnormal placental implantation.
