Any woman with severe proteinuric hypertension where the decision has been made to deliver and where one of the following criteria is met (Either A, B or C):

A) Hypertension ( = 140/90 mm Hg) with proteinuria ( = 0.3 g / day or = 2+ on urinalysis) and at least one of the following:

a) Headache, visual disturbance, epigastric pain
b) Clonus ( = 3 beats)
c) Platelet count < 100 x 109, ALT > 50 IU / litre

B) Severe hypertension (systolic = 170 mm Hg or diastolic = 110 mm Hg) with proteinuria ( = 0.3 g / day or = 2+ on urinalysis)

C) Eclampsia

If these criteria are met, the patient is managed according to the following guidelines irrespective of mode of delivery or method of analgesia.

Whenever a patient is commenced on the protocol, ensure:

1. Consultant on call is aware
2. Anaesthetist on call for Delivery Suite is aware.

 

This protocol was drawn up by the Special Interest Group in Maternal / Fetal Medicine Northern Deanery. Queries about the guidelines or problems that arise from their use should be directed to: Professor S. Robson, Royal Victoria Infirmary, Newcastle NE1 4LP Tel: 0191 2825831 Email: s.c.robson@ncl.ac.uk Last updated September 2002 Review date September 2005

Magnesium Levels

Experience from the Collaborative Eclampsia Trial indicates that MgSO4 administered according to the above regimen can be used safely without the need to monitor Mg levels. Mg is excreted by the kidneys and toxicity is more likely if there is oliguria (urine output < 100 ml / 4 hrs) or urea > 10 mmol / L. Measurement of Mg levels may facilitate care however where there are signs of toxicity.

Toxicity

Signs of toxicity are extremely uncommon and correlate with magnesium levels.

	Mg level (mmol/L)
Therapeutic Range	2-4
loss of tendon reflexes, weakness, nausea, feeling of warmth, flushing, somnolence, double vision, slurred speech	5
muscle paralysis, respiratory arrest	6-7.5
cardiac arrest	> 12

Patellar reflex and oxygen saturation MUST be recorded on the PET chart. If the midwife is to carry out clinical monitoring, the SHO should ensure these are performed and recorded adequately.

 

Further Management

 

Loss of patellar reflex	Stop maintenance infusion If possible, check Mg level Withold further Mg until patellar reflexes return or Mg levels known †
Oxygen saturation persistently < 92%	Commence O2, check patellar reflexes, inform anaesthetist If patellar reflexes present, exclude other causes (eg) opiates, pulmonary oedema If patellar reflexes absent, see above.
Cardiorespiratory arrest	Stop maintenance infusion Institute CPR Administer 10 ml Calcium gluconate IV Intubate immediately and manage with assisted ventilation until resumption of spontaneous respirations If possible, check Mg levels
Seizure on Magnesium	Treat seizure with a further bolus of Mg 2 g over 5 minutes If possible check Mg levels prior to this †† If further seizures despite this, consider: Diazemuls 10 mg IV bolus then infusion Thiopentone infusion on ITU

† Once tendon reflexes return, if Mg level < 4 mmol / L restart maintenance dose at 0.5 g / hr and recheck levels in 3 hours.

†† If Mg level < 2.0 mmol / L restart maintenance dose at 2 g / hr.

 

Anaesthetic Guidelines

 

LABOUR

Epidural is the preferred method of analgesia Contraindications; Platelet count < 80x 109 /l Elevated APTT or TT, Maternal refusal Fluid Pre-load; 500 ml Hartmann's (over 15 min) prior to block Thereafter continue on Hartmann's (1 litre/12h) unless oliguric

CRITERIA FOR CONSIDERING TRANSFER TO ITU

1. Recurrent seizures 2. MAP > 125 mm Hg despite IV hydralazine & Labetalol 3. Persistent oliguria with normal / high CVP 4. Pulmonary oedema with oliguria 5. Compromised myocardial function

 

Antihypertensive Therapy Guidelines

 

*	MAP is calculated as DBP + (SBP- DBP/3)
*	Above a MAP of 140 mm Hg a previously normotensive woman will lose cerebral autoregulation and is at progressively increasing risk of cerebral haemorrhage - MAPs > 140 mm Hg constitute an obstetric emergency
*	There is no evidence that hydralazine is superior to Labetalol - the choice of drug should therefore be based on familiarity (Cochrane Library 2002)
*	Both drugs can precipitate fetal distress and therefore continuous fetal heart rate monitoring is mandatory. Expanding the circulation with colloid prevents fetal distress
*	Automated oscillometric devices may underestimate blood pressure in some women with pre-eclampsia: measurements must be validated against standard mercury sphymomanometry

 

 

 

 

 

 

 

 

 

 

MAINTENANCE THERAPY

Subsequent episodes of hypertension can be managed with intermittent IV bolus therapy
(hydralazine 5 mg or Labetalol 40 mg) but if these are required more than once / hour consider an infusion:

HYDRALAZINE

• 40 mg in 40 ml N/Saline: start at 10 ml/h and double every 30 min until satisfactory response, reach 40 ml/h, tachycardia (>120 / min) or side effects (headache, flushing, dizziness) in which case change to Labetalol

LABETALOL

• 200 mg in 50 ml N/Saline: start at 40 mg/h and double every 30 min until satisfactory response or reach 160 mg/h.
  

 

 

Fluid Guidelines

MIDWIFERY CARE OF WOMEN ON PET GUIDELINE

 

Only women with severe PET/eclampsia will be managed according to the guideline.
All women will remain on labour ward for a minimum of 24 hours after delivery.
Please ensure that when the patient is transferred to the PN ward the ward staff are made aware of the need for strict fluid balance for at least 48 hours.

Aspects of Care

1	PET charts: These should be filled in HOURLY ie at 8am, 9am etc. Record the hourly fluid intake (IV & oral), urine output & fluid balance, BP, CVP, oxygen saturation & reflexes (whilst on magnesium). Remember to fill in important events ie antihypertensive treatment, epidural insertion, top ups, delivery and mark delivery BLOOD LOSS.
2	BP measurements: Automatic sphygmomanometers may underestimate BP. It is necessary to validate automated measurements against standard mercury sphymomanometry at the beginning of monitoring and intermittently (e.g. every 2 hours) thereafter. BP measurements should be made every 15 minutes and recorded on the PET chart. Inform the SHO if there are two consecutive readings with MAP >125 mm Hg or one reading >140 mm Hg.
3	Fluid intake: The standard IV fluid regime is 85 ml/hour. This includes the 20 ml of magnesium each hour (ie women on Mg will be on 65 ml Hartmann's/hour). Once oral fluids are established the hourly oral intake needs to be subtracted from the IV input (if a women is drinking 50 ml/hour she needs approx. 35 ml/hr IV).
4	Urine output: This is measured hourly using the calibrated meters. Inform the SHO if the output is <100 ml over a FOUR hour period.
5	CVP: This is recorded hourly. The anaesthetist is responsible for the insertion and subsequent care of the CVP line. If you have any concerns regarding measurement then inform the anaesthetist. If the CVP is >12 cm inform the SHO.
6	Magnesium sulphate: The drug is given by IV infusion. The first signs of toxicity are loss of tendon reflexes & respiratory depression. Therefore throughout the infusion hourly recordings must be made of; a) Patellar reflex; The method of testing the patellar &/or biceps reflex will be explained by the SHO. If you fail to detect a reflex or are unhappy about the method of testing you must let the SHO know immediately; it is their responsibility to teach you! b) Oxygen saturation; Inform SHO if persistently < 90%
7	Cord gases: Every attempt must be made to get arterial & venous samples and complete results should be recorded in the delivery notes.