Hypertensive disorders of pregnancyHypertensive disorders of pregnancy Dr Mark Porter FRCA Fluids in severe pre-eclampsia Monitor, control and limit Listen to the chest regularly Limit

Hypertensive disorders of pregnancy Dr Mark Porter FRCA

Hypertensive disorders of pregnancy

Regional FRCA teaching

Coventry | 4 September 2019

Dr Mark Porter | consultant obstetric anaesthetist


What we are going to cover today

FRCA syllabus requirements

Sources Incidence and

mortality

Definitions Pathophysiology Recent news

Enhanced maternal care

Anaesthesia management

MBRRACE recommendations


FRCA syllabus

•Discusses common causes of maternal morbidity and mortality, including national reports

Knowledge

•Demonstrates satisfactory assessment of pregnant woman presenting for anaesthesia / analgesia including those with concurrent disease

Skill


Written exam questions

Autumn 2009

• a) What are i) diagnostic and ii) other clinical features of severe pre-eclampsia? (30%)

• b) What are the indications for magnesium therapy in severe pre-eclampsia/eclampsia and which administration regimen(s) should be used? (20%)

• c) What are the signs and symptoms of magnesium toxicity and how should it be managed? (40%)

September 2010 – again

• a) What are i) diagnostic and ii) other clinical features of severe pre-eclampsia? (30%)

• b) What are the indications for magnesium therapy in severe pre-eclampsia/eclampsia and which administration regimen(s) should be used? (20%)

• c) What are the symptoms and signs of magnesium toxicity (25%) and how should it be managed? (15%)



September 2015: 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 160/110mmHg 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)

•b) How should this patient be managed following admission to your labour ward? (12 marks)

•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)

March 2018: A 25-year-old pregnant women at 35 weeks gestation is admitted to labour

ward with a blood pressure of 180/110 mmHg. She is known to have pre-eclampsia

and there is a plan to deliver her baby within the next 24 hours.

•a) What is the definition of pre-eclampsia? (1 mark)

•b) What symptoms may this woman complain of due to her pre-eclampsia? (4 marks)

•c) What are the important priorities in her management when she arrives on the labour ward? (10 marks)

•d) A decision has been made to proceed to Caesarean section (CS) and the patient insists on having a general anaesthetic (GA). Explain potential changes to your normal GA technique for CS due to her pre-eclampsia. (5 marks)



September 2015: pass rate 16%.

• The poor pass rate for this important subject is of concern as pre-eclampsia is a common condition that all candidates should have encountered. Severe pre-eclampsia is an emergency for which the principles of management should be known.

• Surprisingly few candidates could give an acceptable definition of pre-eclampsia and even fewer knew that control of systolic hypertension is of prime importance in preventing intracerebral bleeding in women with severe pre-eclampsia.

March 2018: pass rate 60%

• A common theme from previous exams is that obstetrics seems to be poorly understood, with candidates demonstrating only superficial knowledge of the common obstetric complications.

• Some did not appreciate the difference between pre-eclampsia and eclampsia and were weak on definitions. Many candidates will have a great deal of practical knowledge of obstetric anaesthesia from their time on call for delivery suite, but seem to lack theoretical knowledge to back it up.


Selection of sources



Incidence and mortality

Pre-eclampsia affects up to 6% of

pregnancies in the UK

Severe pre-eclampsia develops in around 1-2% of UK pregnancies

8-10% of all preterm births result from

hypertensive disorders, including pre-

eclampsia

All direct and indirect deaths 2014-16 – 10.12

deaths per 100,000 maternities

Pre-eclampsia and eclampsia – 0.38

deaths per 100,000 maternities (9 deaths)


Typology of pre-eclampsia

Pre-eclampsia

Hypertension

Oedema

Proteinuria


Typology of hypertensive disorders

Hypertensive disorders of pregnancy

Chronic hypertension

Gestational hypertension

Pre-eclampsia


Basic definitions

Hypertension

•Blood pressure of 140mmHg systolic or higher, or 90mmHg diastolic or higher [2019]

Chronic hypertension

•Hypertension that is present at the booking visit, or before 20 weeks, or if the woman is already taking antihypertensive medication when referred to maternity services

• It can be primary or secondary in aetiology

Gestational hypertension

•New hypertension presenting after 20 weeks of pregnancy without significant proteinuria

Severe hypertension

•Blood pressure over 160 mmHg systolic or over 110 mmHg diastolic

Pre-eclampsia

•New onset of hypertension (over 140 mmHg systolic or over 90 mmHg diastolic) after 20 weeks of pregnancy and the coexistence of 1 or more of the following new-onset conditions…

This seminar does not cover outpatient management


Definition of pre-eclampsia ISSHP 2018 (International Society for the Study of Hypertension in Pregnancy)

NICE 2019 (National Institute for Health and Care Excellence)

New onset of hypertension (over 140 mmHg systolic or over 90 mmHg diastolic) after 20 weeks of pregnancy and the coexistence of one or more of the following new-onset conditions:

1. proteinuria (urine protein:creatinine ratio of 30 mg/mmol or more or albumin:creatinine ratio of 8 mg/mmol or more, or at least 1 g/litre [2+] on dipstick testing) or

2. other maternal organ dysfunction:

• renal insufficiency (creatinine 90 micromol/litre or more, 1.02 mg/100 ml or more)

• liver involvement (elevated transaminases [alanine aminotransferase

or aspartate aminotransferase over 40 IU/litre] with or without right upper quadrant or epigastric abdominal pain)

• neurological complications such as eclampsia, altered mental status, blindness, stroke, clonus, severe headaches or persistent visual scotomata

• haematological complications such as thrombocytopenia (platelet count below 150,000/microlitre), disseminated intravascular coagulation or haemolysis

3. uteroplacental dysfunction such as fetal growth restriction, abnormal umbilical artery doppler waveform analysis, or stillbirth

New gestational hypertension +

proteinuria ⌵ maternal organ dysfunction ⌵ uteroplacental dysfunction


More definitions

Eclampsia

• A convulsive condition associated with pre-eclampsia

Severe pre-eclampsia *

• Pre-eclampsia with severe hypertension that does not respond to treatment or is associated with ongoing or recurring severe headaches, visual scotomata, nausea or vomiting, epigastric pain, oliguria and severe hypertension, as well as progressive deterioration in laboratory blood tests such as rising creatinine or liver transaminases or falling platelet count, or failure of fetal growth or abnormal doppler findings

HELLP Syndrome

• Haemolysis, elevated liver enzymes and low platelet count


Pathophysiology of pre-eclampsia

Soluble factors released from placenta as response to oxidative stress of syncytiotrophoblasts:

•disrupt maternal endothelial function

•cause a systemic inflammatory response

Early-onset subtype – uteroplacental malperfusion secondary to defective remodelling of uterine spiral arteries:

•failing to reduce velocity and pulsatility of inflowing maternal blood (similar to FGR)

Late-onset subtype – acute atherosis:

•interaction between placental senescence and maternal genetic predisposition to inflammation, high BMI ⌵ hypertension

Histology:

•placental infarcts, fibrin deposition, focal syncytiotrophopblastic necrosis

Placental soluble factor reduces bioavailability of Vascular Endothelial Growth Factor

•impairing endogenous nitric oxide production

•AND increasing sensitivity to pro-inflammatory cytokines

Profound endothelial swelling and basement membrane disruption in the kidney

•this is not simply an unmasking of a hypertensive tendency

Definitions are syndromic: based on non-specific or arbitrary features


Diagrammatic representation of the effects of spiral artery remodeling on the inflow of maternal

blood into the intervillous space in normal and pathological pregnancies.

Graham J Burton et al. BMJ 2019;366:bmj.l2381 ©2019 by British Medical Journal Publishing Group


What’s in the news?

Screening and diagnosis

• Traditionally based on empirical detection of new-onset hypertension and proteinuria

• High-income countries now use biomarkers or Doppler ultrasound assessment of uteroplacental circulation for early-onset disease

• Increased sFlt-1/PlGF is a marker of the placental component of pre-eclampsia

PARROT trial results 2019

• PlGF assay availability significantly reduced time to diagnosis and maternal adverse outcomes…

• …without changing perinatal outcomes or gestation at delivery

• But – adverse outcomes went from 5% to 4%

• NICE recommends use from 20 up to 35 weeks in women with chronic hypertension

Where are we now?

• Combined assessment of demographic and clinical factors

• Prevention with aspirin ± calcium supplements

• Maternal mortality has dramatically reduced in high-income countries with careful monitoring and timely delivery

• Nothing is available to reverse pathology while placenta remains inside mother – all treatment is palliative


Management with enhanced maternal care The primary aims in the

management of pre-eclampsia are:

To deliver the fetus in optimum

condition

To control maternal

hypertension

To prevent eclampsia and the

other complications

Anaesthetists may become involved for:

Epidural analgesia in labour

Urgent control and reduction of

arterial blood pressure

Invasive monitoring of arterial blood

pressure

Anaesthesia for caesarean section

High dependency care initiation

Severe pre-eclampsia must be managed in a

high-dependency environment

Multiprofessional team

Appropriate senior involvement

Specialised level 2 care

CTG monitoring

Aortocaval decompression

and VTE prophylaxis

Symptoms of severe pre-eclampsia requiring immediate admission and treatment:

•Severe headache

•Visual problems such as blurring or flashing

•Severe pain just below the ribs

•Vomiting

•Sudden swelling of face, hands or feet

•Difficulty in breathing

•Suspected fetal compromise


Immediate actions

Apply monitoring of blood pressure with an arterial line, pulse and oxygen saturation

Administer supplemental oxygen if SpO2 < 96%, usually

through nasal cannulas

Check that the laboratory samples have been sent

•FBC, coagulation screen, crossmatch, biochemistry including liver function tests – all repeated at least every 12 hours; group and screen)

Start the HDU observations chart

Auscultate the patient’s chest for pulmonary oedema and

repeat this examination regularly every four hours;

ensure that the respiratory rate is being recorded

Patient on monitored sips of water only with ranitidine 150 mg given at six-hourly

intervals

Neurological assessment using AVPU (alert, responding to voice, responding to pain,

unresponsive)

Thromboprophylaxis with antiembolism stockings, encouragement of leg

movement and (if delivery is not indicated) enoxaparin


Antihypertensive treatment in pregnancy

Oral nifedipine or intravenous labetalol or hydralazine (methydopa)

Oral labetalol if these are unavailable – ISSHP

BP > 140/90 should be treated; keep BP below 150 mmHg; NICE has new target 135/85 for all forms of hypertension

Women with proteinuria and severe hypertension, or with hypertension and neurological symptoms, should receive magnesium sulfate for convulsion prophylaxis

Arterial line monitoring for severe hypertension or intravenous vasodilators


Fluids in severe pre-eclampsia

Monitor, control and limit Listen to the chest regularly Limit to 80 mL h-1 in severe hypertension, plus losses

Do not use volume expansion prior to antihypertensives (except for IV hydralazine)

Do not give aggressive or challenge treatment for oliguria

•These are not elderly patents with shock

•The oliguria arises from glomerular pathology

•No diuretics

Do not pre-load for low-dose epidural analgesia, or co-load

for CSE

Co-load or vasoconstrictor infusion for spinal?


Magnesium sulfate treatment

CET (1995) showed that this is the best available primary treatment and secondary prevention of eclampsia

Eclamptic seizures are self-limiting but may be lethal if

left untreated

MAGPIE trial (2002) showed some benefit in severe pre-eclampsia but NNT 60-120

(halves the rate)

Primary mode of action is to relieve cerebral vasospasm; also reduces oxidative stress

In practice: use for women with proteinuria and severe

hypertension, or hypertension with neurological signs or

symptoms, or (NICE) severe pre-eclampsia

CET / Oxford protocol:

Bolus 4 g (+ 2 g if necessary)

+ 1 g h-1 ongoing

continue 24 hours after initiation or last seizure

Complications – heat and flushing, obstetric

haemorrhage, muscle relaxant potentiation, oliguria,

weakness and cardiac dysrhythmia to arrest

Same dose used for fetal neuroprotection before 30 weeks, preventing cerebral palsy (max 24 hours or till

delivery), consider up to 34 weeks


Indications for maternal and fetal referral

Adverse indicators of serious

harm

ongoing or recurring

severe headaches

visual scotomata

nausea ⌵

vomiting

epigastric pain oliguria

severe hypertension

progressive blood derangements

↑ creatinine

↑ transaminases

↓ platelet count

These women should be followed in a centre with maternal high dependency or intensive care unit capacity for mother and baby.


HELLP syndrome

Diagnosis

Haemolysis (present)

Elevated liver enzymes

(transaminases >70)

Low platelets (<100)

Clinical features

Epigastric pain

Right upper quadrant

tenderness

Nausea and vomiting

Signs and symptoms of pre-

eclampsia

Complications

DIC

Abruption

Renal failure

Pulmonary oedema

Pleural effusion

Death


Epidural analgesia in pre-eclampsia

Indicated to reduce blood

pressure elevations

Improves uteroplacental

perfusion

Watch that recent platelet count > 75

and not falling

Beware fluid overload

Use vasopressors with caution

Watch for concomitant

vasodilator use


Delivery strategy

Serial fetal surveillance if FGR (fetal indication)

Deliver if 37+0 weeks gestation

(term) or if any of:

Repeated episodes severe

hypertension

Progressive thrombocytopenia or liver or kidney

dysfunction

Pulmonary oedema

Abnormal neurological signs

Placental abruption

Non-reassuring fetal status

Do not use serum urate or

proteinuria levels

Requirement to discuss with

anaesthesia team


Anaesthesia for caesarean section in pre-eclampsia

Perioperative monitoring of direct arterial pressure and

control of hypertension

Regional

Check platelets Use vasopressors for spinal hypotension -

variable effect

Ergometrine is safe and effective in small

IV doses

GA (coagulopathy, ongoing seizures, fetal

compromise)

Control exaggerated hypertensive response

to laryngoscopy

Alfentanil 20 mcg kg-1 with Mg2+; 30 mcg kg-1

without, or other appropriate technique

Check for dysphonia or facial oedema

Prepare for potential use of small

endotracheal tubes in laryngeal oedema. [MBRRACE 2017]

Caution with non-depolarising muscle

relaxants after magnesium

Rigorous fluid volume control to protect

against postoperative pulmonary oedema

Withhold NSAIDs e.g. diclofenac


The postpartum period in pre-eclampsia

Patient considered high-risk three days with four-hourly checks and VTE prophylaxis

Antihypertensive treatment withdrawn slowly or converted to long-term treatment

• enalapril

• or nifedipine or amlodipine if black

Continue fluid balance control

Avoid NSAIDs unless other analgesia does not work

• Whether NSAIDs cause any harm remains controversial

• Effective analgesia required

• Dihydrocodeine 30 mg QDS

Be aware of significant long-term cardiovascular risk for such women, and the need

for long-term follow-up


MBRRACE key messages 2016

Mortality from pre-eclampsia is reducing but aspects of care can still be improved.

New onset hypertension or

proteinuria needs prompt referral with

clear communication between health professionals.

Monitor blood pressure and

urinalysis at each antenatal

attendance. Keep blood

pressure in all women to below

150/100, with urgent treatment to achieve this in

women with severe

hypertension.

If women have a blood pressure over 140mmHg

systolic or 90mmHg

diastolic on 2 occasions in

labour or immediately

after birth they should be

considered for transfer to a

Consultant unit.

Staff should be aware that

agitation and restlessness may

be a sign of an underlying problem in

women with hypertension.

Whilst intubation may be required for airway control,

maternal stabilisation and blood pressure control is vital

prior to intubation in

order to minimise

maternal risk.

Neuroimaging should be performed

urgently in any woman with

hypertension or pre-eclampsia who has focal neurology or who has not

recovered from a seizure.


•A significant cause of maternal and fetal morbidity and mortality Hypertensive disorders in

pregnancy

•Chronic hypertension, gestational hypertension and pre-eclampsia Wide spectrum

• Is essential to reduce complications and may need invasive monitoring and intravenous medications Controlling blood pressure

• Include cerebral ischaemia, intracerebral haemorrhage, hepatic dysfunction and fetal death (pulmonary oedema much reduced) Lethal complications

• Is the intravenous vasodilator used for prevention of severe complications and for treating eclampsia Magnesium sulfate

• Is best done by a multiprofessional team Management

Documents

Hypertensive disorders of pregnancyHypertensive disorders of pregnancy Dr Mark Porter FRCA Fluids in severe pre-eclampsia Monitor, control and limit Listen to the chest regularly Limit