Transcript Magnesium sulphate in Management of PIH

Magnesium sulphate in the
Management of Eclampsia in
Malawi
Dr. Chisale Mhango FRCOG
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Objectives of Use of MgSO4 in the
Eclampsia Management
1. To prevent severe pre-eclampsia
progressing to eclampsia (lifethreatening convulsions).
2. To stop the convulsions of
eclampsia.
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Evidence of Effectiveness of
Magnesium sulphate
1. In a series of 300 consecutive cases, of
eclampsia, Pritchard in Texas USA achieved
100% survival
2. A 1998 review concluded that it is effective in
preventing convulsions in women who have
severe pre-eclampsia and in stopping
convulsions in eclamptic women. (Obstetrics
and Gynaecology, Vol. 92, pp. 883-889).
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Local guidelines on use of
magnesium sulphate
Health Centre
– All pre-eclampsia and eclampsia
patients shall be referred to the
hospital immediately after
admission.
– Give first dose (correct loading
dose) to prevent progression of
severe pre-eclampsia to eclampsia
or stop fits and then refer to
hospital.
– On the way to hospital patient
must be accompanied by an
experienced clinician to stabilise
patient during transit.
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Hospital
– Give MgSO4 to prevent
progression of severe
pre-eclampsia to
eclampsia as per
national guidelines
depending on whether or
not the patient already
has a loading dose at
source.
– Follow national protocol
for the management of
the eclamptic patient 4
Use of Valium
• NB MgSO4 is the drug of choice in all
circumstances – it should always be available
at both health centre and hospital levels
• Give diazepam 10 mg (2 ml) over 2 minutes if
– Convulsions recur after giving MgSO4
– Convulsions occur early in pregnancy
– There is MgSO4 toxicity
– MgSO4 is not available
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Administration of magnesium sulphate
Health Centre
•
Loading dose: 4 grams IV (over 5-15
min) plus 10 grams IM,
– 5 grams IM in each buttock: deep
intramuscular injection with 1ml
2% lignocaine or 2ml 1%
lignocaine
•
Rationale:
– Pre-eclampsia can quickly
develop into eclampsia
– Shaking during transport is a
convulsion stimulus
– There is no risk of overdose after
loading dose even in a woman
with anuria.
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Hospital
• Loading dose: 4grams IV plus
10 grams IM (5 grams IM in
each buttock)
• Maintenance dose: 5 grams IM
every 4 hrs.. in alternate
buttock
NB
a. Check for reflexes before
giving the maintenance dose
b. At least 100ml urine /4 hrs.
c. At least 16 breaths/minute
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Administration of MgSO4
20% MgSO4 Solution
50% MgSO4 Solution
Recommended for IV
injection
• 20% solution means
20g/100ml, i.e..
4g/20ml.
Recommended for IM
injection
• 50% solution means
50g/100ml, i.e.
5g/10ml.
– i.e.. Give 20ml 20%
solution IV over 5-15
minutes
– i.e.. Give 10ml
solution IM
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Administration in Hospitals with High
Dependency Wards
• IV MgSO4 is the initial drug administered to
terminate seizures and lower BP.
• Seizures usually terminate after the loading
dose of magnesium.
• A loading dose of 6 g (15-20 min)
• and a maintenance dose of 2 g per hour as a
continuous IV solution (preferably using a
pump to administer).
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1. Is Magnesium sulphate dangerous?
• After administration, about 40% of plasma magnesium is
protein bound.
• The clinical effect and toxicity of MgSO4 can be linked to its
concentration in plasma.
– The unbound magnesium ion diffuses into the extravascularextracellular space, into bone, and across the placenta and foetal
membranes and into the foetus and amniotic fluid.
• Magnesium is almost exclusively excreted in the urine, with
90% of the dose excreted during the first 24 hours after an
intravenous infusion of MgSO4. Hence the need to monitor
urine output in patients receiving the drug.
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2. Is Magnesium sulphate dangerous?
• MgSO4 toxicity is rare when it is carefully
administered and monitored.
• Studies show that the benefits of MgSO4 may
outweigh the risks to her and to her baby.
The answer to this question is NO!
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Do we need to control MgSO4
concentration in PIH management?
• In pregnant women, apparent volumes of
distribution usually reach constant values
between the third and fourth hours after
administration, and range from 0.250 to 0.442
L/kg.
• A concentration of 1.8 to 3.0 mmol/L has been
suggested for treatment of eclamptic
convulsions.
The answer to this question is NO!
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Why is Eclampsia still a major cause of
maternal deaths in Malawi?
1. Fear of use of MgSO4 by clinicians
1. Unjustified fear of fatal side-effects
2. Lack of training/confidence in use of drug
2. Late initiation of drug
1. Most patients develop eclampsia at home
2. Health centres not using MgSO4
3. Inappropriate use of drug
1. Lack of relating fluid balance to dosage of drug
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Antidote for MgSO4
In the rare situations when the
patient is found to have no reflexes
and not breathing wells after MgSO4
the antidote is:
Calcium gluconate(10%) 10 mls. IV
over 10 minutes, especially if there is
< 16 breaths/minute or no reflexes.
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Can Magnesium be Administered in
Combination with Other Drugs?
• Avoid the use of multiple agents to abate eclamptic
seizures, unless necessary.
• Antihypertensive can be used together with MgSO4
• Only where there is pulmonary oedema can a diuretic
be used – otherwise diuretics are contraindicated in
management of eclampsia
• Steroids may be administered in anticipation of
delivery when gestational age is < 34 weeks.
– Betamethasone (12 mg IM q24h × 2 doses) or
dexamethasone (6 mg IM q12h × 4 doses) is
recommended.
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