9: Emergencies in late pregnancy (from 20 weeks)

CHAPTER 9
Emergencies in late pregnancy (from 20 weeks)


This chapter addresses the recognition and management of emergencies in the later stages of pregnancy, including the first and second stages of labour – up to and including delivery of the baby.


9.1 Hypertension in pregnancy


Hypertension from all causes is the commonest medical problem in pregnancy and affects between 10% and 15% of all pregnancies. Hypertensive conditions include PIH, pre‐existing hypertension (e.g. ‘essential’ hypertension), pre‐eclampsia and eclampsia. The two conditions of HELLP syndrome and AFLP are felt to be part of the spectrum of disease that includes pre‐eclampsia and eclampsia.


Pre‐existing hypertension


Definition


Women may enter pregnancy with pre‐existing hypertension. If hypertension is detected before 20 weeks, this is likely to reflect pre‐existing hypertension. Hypertension in a young person may only be detected for the first time in early pregnancy. At some point, this will require formal investigation to exclude an underlying cause (e.g. renal or cardiac disease, or Cushing’s syndrome). However, most will not have a defined cause and fall under the category of mild ‘essential’ hypertension. These women are at increased risk of developing superimposed pre‐eclampsia and fetal growth restriction. The risk is almost 50% if there is severe hypertension in early pregnancy (diastolic BP >110 mmHg, systolic BP >160 mmHg). Again, such patients require close monitoring in order to detect complications, and in particular the development of pre‐eclampsia or growth restriction.


Pregnancy‐induced hypertension


Definition


Pregnancy‐induced hypertension is a significant rise in blood pressure occurring after 20 weeks in the absence of proteinuria or other features of pre‐eclampsia. Women with uncomplicated PIH require close monitoring in the antenatal period to pick up those who are going to develop pre‐eclampsia. If hypertension is uncomplicated by pre‐eclampsia, the maternal and fetal outcomes are good.


Pre‐eclampsia


Definition


Pre‐eclampsia is hypertension associated with proteinuria developing after 20 weeks’ gestation. It can occur as early as 20 weeks but more commonly occurs in the third trimester. It is more common in first pregnancies where one in ten women will develop pre‐eclampsia. Severe pre‐eclampsia is pre‐eclampsia with severe hypertension (>160/110 mmHg) and/or with symptoms and/or haematological impairment. The incidence of severe pre‐eclampsia is approximately 1% of all pregnancies.


The underlying pathophysiology is not fully understood. However, it is known that the placenta plays an important role, such that the normal physiological changes that occur in the vessels of the uterus do not occur. This leads to poor perfusion of the placenta, resulting in a fetus which is growth restricted.


In the 2013–15 report, pre‐eclampsia accounted for 3 of the 88 maternal deaths related to direct pregnancy causes (MBRRACE‐UK, 2017). In previous reports, the care of 70% of women who died was deemed to be substandard, and these deaths may have been avoided with better care (CMACE, 2011).


Risk factors for pre‐eclampsia and eclampsia



  • Primigravidity or first child with a new partner
  • Previous severe pre‐eclampsia
  • Essential hypertension
  • Diabetes
  • Obesity
  • Twins or higher multiples
  • Renal disease
  • Advanced maternal age (over 40 years)
  • Young maternal age (less than 16 years)
  • Pre‐existing cardiovascular disease
  • Cushing’s disease


Diagnosis


Women with mild to moderate pre‐eclampsia are asymptomatic and the disease is usually diagnosed at routine antenatal visits. This is often managed on an outpatient basis initially, with regular review on the obstetric day unit. However, it may require admission to hospital and early delivery if the disease progresses.


When measuring BP, the woman should be semi‐recumbent and an appropriately sized cuff should be used. In women with a larger arm, using a normal‐sized cuff may result in falsely high BP readings. It is important to record both systolic and diastolic pressures. The latter should be assessed using Korotkoff V (that is, sound disappearance). Korotkoff IV (that is, ‘muffling’) should only be used if heart sounds do not disappear as pressure readings fall to zero (see Chapter 5).


Severe pre‐eclampsia may present in a patient with known mild pre‐eclampsia or may present with little prior warning. The BP is significantly raised (<160/110 mmHg) with proteinuria and/or more of the following symptoms and signs:



  • Headache – severe and frontal
  • Visual disturbances (such as blurring or flashing)
  • Papilloedema
  • Epigastric pain (due to stretching of the liver capsule) – often mistaken for heartburn
  • Right‐sided upper abdominal pain – due to stretching of the liver capsule
  • Muscle twitching or tremor
  • Other symptoms – nausea, vomiting, confusion
  • Rapidly progressive oedema

Severe pre‐eclampsia is a ‘multi‐organ’ disease – although hypertension is a cardinal feature, other complications include:



  • Intracranial haemorrhage
  • Stroke
  • Renal failure
  • Liver failure
  • Abnormal blood clotting such as disseminated intravascular coagulation (DIC)
  • Placental abruption and associated massive haemorrhage

One of the ‘top ten recommendations’ in the CEMACH report highlighted the importance of aggressive treatment of high systolic BP (160 mmHg or more) in order to reduce the chance of maternal intracerebral bleeding and stroke (CEMACH, 2007b). Therefore, these obstetric patients require immediate admission to an appropriate obstetric unit.


Pre‐hospital management


Pre‐hospital healthcare practitioners will not usually be involved with management of gestational hypertension or mild pre‐eclampsia. However, it is important that any pregnant woman should have their BP checked during assessment, even if they do not have suspicious symptoms. A new finding of a BP of 140/90 or higher requires review by a midwife or discussion with the local obstetric unit to decide if admission is necessary.


The following recommendations relate to the management of women with severe pre‐eclampsia:



  1. Perform an obstetric primary survey following an ABCDEFG approach; address life‐threatening findings in priority order.
  2. Consider the patient’s position according to gestational stage and presenting condition.
  3. Give oxygen if SpO2 (on air) falls below 94%; aim for a target saturation of 94–98%.
  4. Assess for any ‘time‐critical’ features requiring immediate transfer:

    • Headache – severe and frontal
    • Visual disturbances
    • Epigastric pain
    • Right‐sided upper abdominal pain
    • Muscle twitching or tremor
    • Confusion

  5. Secure venous access en route to the hospital in case IV medication is required (see Eclampsia section).
  6. DO NOT give routine IV fluids as these patients are at risk of developing acute pulmonary oedema, even with small boluses of crystalloid. If fluids are attached to the cannula, the flow rate should be no more than 80 ml/h (use normal saline or Hartmann’s, but not dextrose in water).
  7. Measure blood pressure continually (the aim is for a BP of 150/80–100 mmHg).
  8. Provide the receiving hospital with a pre‐alert message.
  9. Assess and document all other vital signs: respiratory rate, oxygen saturation, pulse rate (including quality), conscious level, temperature and blood glucose level.
  10. Take a detailed obstetric history (if patient’s condition allows); request hand‐held notes where possible as a review of these will highlight any changes in BP over the preceding weeks.


Eclampsia


Definition


Eclampsia is defined as tonic‐clonic, generalised ‘grand mal’ seizures, usually in association with signs or symptoms of pre‐eclampsia. It is one of the most dangerous complications of pregnancy, with a mortality rate of 2% in the UK. It occurs in 2.7:10 000 deliveries, usually beyond 24 weeks (Knight, 2007). Many patients will have had pre‐existing pre‐eclampsia (of mild, moderate or severe degree), but cases of eclampsia can present acutely with no prior warning. One‐third of cases present for the first time post‐delivery (usually in the first 48 hours).


Although eclampsia is often preceded by severe pre‐eclampsia, in many cases the blood pressure will only be mildly elevated at presentation.


The hypoxia caused during a grand mal seizure may lead to significant fetal compromise and even death. There is a risk of placental abruption and massive haemorrhage. Occasionally, there may be cortical blindness after an eclamptic fit. Fitting is usually self‐limiting, but may be prolonged and repeated.


Other complications associated with eclampsia include renal failure, hepatic failure and DIC.


Diagnosis


The diagnosis is made through the presence or history of a tonic‐clonic fit after 20 weeks of pregnancy.


Pre‐hospital management



  1. Perform an obstetric primary survey following an ABCDEFG approach; address life‐threatening findings in priority order.
  2. Consider the patient’s position according to gestational stage and presenting condition.
  3. Give oxygen if SpO2 (on air) falls below 94%; aim for a target saturation of 94–98%.
  4. If the mother has continuous or recurrent fits at scene, secure IV or IO access. Otherwise postpone obtaining access until en route to the hospital.
  5. This is a time‐critical situation and transport to the hospital should be arranged at the earliest opportunity.
  6. Provide the receiving hospital with a pre‐alert message.
  7. If magnesium sulphate is unavailable and the patient is in status epilepticus, consider Diazemuls® 10–20 mg IV or IO, or rectal diazepam 10–20 mg, titrated against effect.
  8. The definitive treatment of eclampsia, either to treat ongoing or recurrent fits, or to prevent further fits occurring, is magnesium sulphate 4 g loading dose IV or IO over 10 minutes (this would then be followed by an infusion of 1 g/h for 24 hours in hospital).
  9. Assess and document vital signs: respiratory rate, oxygen saturation, pulse rate (including quality), CRT or blood pressure, conscious level, temperature and blood glucose level.
  10. Take a detailed obstetric history (if patient’s condition allows); request/review hand‐held notes where possible.

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Apr 10, 2020 | Posted by in OBSTETRICS | Comments Off on 9: Emergencies in late pregnancy (from 20 weeks)

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