tocolysis for tpl

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Tocolysis for Threatened Preterm Labour WACSClinProc2.7/09J an-10

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LGH Policy 2.27/09WACS

Title: Tocolysis for Threatened Preterm LabourReplaces: Tocolysis for Threatened Preterm Labour

WACSClinProc2.7/06WACSDescription: Administration of tocolytic agents to delay birth

Target Audience: Midwifery and Medical Staff, Queen Victoria Maternity UnitKey Words: Threatened preterm labour, tocolysis, nifedipine, salbutamol

Policy Supported: P2010/0498-001 Preterm LabourP2010/0507-001 Preterm Prelabour Rupture of Membranes

Purpose:

The aim of tocolysis is to delay preterm birth to allow time for the administration ofcorticosteroids and/or in-utero transfer to a tertiary perinatal centre. Preterm birth is amajor cause of perinatal morbidity and mortality. Tocolytic agents are effective in reducingthe likelihood of birth within 48 hours, but do not reduce the overall risk of preterm birth.

Indications for TocolysisConsideration should be given for the administration of tocolytics to all womenexperiencing preterm labour when there is a need to delay birth: to permit in-utero transfer to a tertiary perinatal centre to gain up to 48 hours to allow for the administration of corticosteroids to enhance

pulmonary maturity.

Tocolytic AgentsUnless contra-indicated, the first line tocolytic to be used should be nifedipine. Nifedipineis a calcium channel blocker that inhibits both prostaglandin and oxytocin inducedcontractions. It has similar tocolytic activity to Salbutamol but a lower incidence ofmaternal side effects.

Salbutamol may be used a second line tocolytic agent in the absence of contraindications.It must not be used in addition to Nifedipine as the two drugs have potentially synergisticactions.

Contraindications and Side Effects o f TocolyticsPrior to the administration of tocolytics the mother should be informed of the need fortocolytics as well as the benefits and possible maternal and fetal side effects of the agentto be used.

NifedipineMaternal Contraindications

Hypotension (systolic BP less than 90mmHg) Previous adverse reaction to calcium channel blockers Cardiac disease (congestive cardiac failure, aortic stenosis)

Hepatic dysfunction Pre-eclampsia
http://pssbpr-trim02/PandP/showdoc.aspx?recnum=P2010/0507-001http://pssbpr-trim02/PandP/showdoc.aspx?recnum=P2010/0507-001


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Fetal contraindications

Suspected intrauterine infection Labour in the presence of placenta praevia Placenta abruptio/undiagnosed significant vaginal bleeding Severe fetal growth restriction Lethal fetal abnormalities Fetal death in utero

Common Side EffectsPalpitations, peripheral oedema, hypotension, dizziness, flushing, headache, nausea,vomiting

Rare Side EffectsAbnormal liver function tests, congestive cardiac failure, transient hyperglycaemia,tachycardia, chest pain, ischaemia (retinal, cerebral) tinnitus, pruritus

Administration

Initial dose 20mg Nifedipine crushed to aid digestion. If uterine contractions persist after 30 minutes administer another 20mg Nifedipine

crushed. This can be repeated at 30 minutes intervals for a further two doses (total 80mg) Maximum dose in 24 hours is 160 mg. If contractions cease commence maintenance dose of 20 to 40mg six hourly with a

maximum dose of 160 mg in 24 hours.

Maternal and Fetal Observations

Maternal blood pressure, temperature, pulse and respiratory rate hourly initially. Once stabilised, observations should be recorded fourth hourly. Report systolic BP less than 100mmHg, temperature greater than 37.5C or pulse

greater than 100. Report any of the side effects listed above. If initial cardiotocograph is reactive, record fetal heart rate hourly with Doppler during

the acute stabilisation phase then at least 6 hourly during for the first 48 hours.

SalbutamolMaternal Contraindications

Cardiac disease Hyperthyroidism Uncontrolled diabetes mellitus

Fetal contraindications

Placenta abruptio or significant uterine bleeding of unknown cause Fetal death or major fetal abnormality Chorioamnionitis

Maternal Side Effects

Beta-sympathomimetics are not utero-specific and have significant cardiovascularand other side effects (chest pain, cardiac arrhythmias, palpitations, tachycardia,hypotension, tremor, dizziness, headache, dyspnoea, nausea and vomiting).

Several maternal deaths have been reported, which have been associated with either

pre-existing cardiac disease or pulmonary oedema after excessive use ofintravenous fluids.


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Administration

Remove 10ml normal saline from 100ml bag and discard. Add 10mg (10ml) Salbutamol to remaining 90ml of normal saline. Using an infusion pump commence infusion at 12ml per hour. Increase rate by 6ml per hour every 30 minutes until there is a suitable response,

either cessation of contractions or a reduction in the frequency and strength ofcontractions.

Do not exceed 36ml/hr.

Maternal and Fetal Observations

Maternal blood pressure, pulse and respiratory rate following each increase in theinfusion rate during the acute stabilisation phase.

Observations may then be recorded less frequently, but at least four hourly duringtreatment.

If initial cardiotocograph is reactive, record fetal heart rate with Doppler after eachincrease in the infusion rate during the acute stabilisation, then at least 6 hourly forfirst 48 hours.

If maternal pulse greater than 140 bpm or sustained fetal tachycardia (greater than180bpm) reduce infusion rate until pulse or fetal heart rate return below these levels. Cease the infusion if the woman complains of chest pain, dyspnoea or vomiting.

Attachments

Attachment 1 Nifedipine Administration Protocol

Attachment 2 Salbutamol Infusion Protocol

Attachment 3 References

Performance Indicators: Evaluation of compliance with guideline to be achieved throughmedical record audit annually by clinical Quality improvementMidwife WACS

Review Date: Annually verified for currency or as changes occur, andreviewed every 3 years.

Stakeholders: Midwives and medical staff WACS

Developed by: Dr A Dennis Co-Director (Medical) Sue McBeath Co-Director

(Nursing & Midwifery) Womens & Childrens Services

Dr A Dennis Sue McBeathCo-Director (Medical) Co-Director (Nursing & Midwifery)Womens & Childrens Services Womens & Childrens Services

Date: _________________________


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APPENDIX 1

Nifedipine Administration Protocol

Note: Nifedipine is classified as a risk category c drug in pregnancy. Itcarries the potential for fetal hypoxia associated with maternal hypotension.The blood pressure lowering effect o f Nifedipine may be potentiated by otherantihypertensive drugs.

PRESENTATION 20mg tablets

ADMINISTRATION Nifedipine tablets should be crushed to aid absorption inpregnancy. Dose may vary with clinical situation & should betitrated against tocolytic effect. Nifedipine is highly lightsensitive. Broken tablets should not be used.

INITIAL DOSE 20 mg Nifedipine (crushed) orally statMAXIMUM DOSE 160mg in 24 hoursIf uterinecontractionspersist after 30minutes:

A further 20mg Nifedipine (crushed) orally may begiven at 30 minute intervals for two further doses.

If contractionscease

A maintenance dose of 20 to 40mg Nifedipine 6 hourlymay be given, depending on uterine activity and otherclinical circumstances, to a maximum of 160mg in 24hours.

Decision about cessation of treatment will be on anindividual basis and need to take into account location,steroid cover and gestational age.

MATERNAL andFETALOBSERVATIONSAND

MONITORING

Maternal blood pressure, temperature, pulse andrespiratory rate hourly during the acute stabilisationphase. Observations may then be recorded lessfrequently but at least 4 hourly during treatment.

Report systolic BP less than 100mmHg, temperaturegreater than 37.5 C or pulse greater than 100.

Report side effects listed above. If initial cardiotocograph is reactive, record fetal heart

rate hourly with doppler during the acute stabilisationphase, then at least 6 hourly for the first 48 hours.

OverdosageSymptoms(observed incases of severenifedipine

intoxication)

Disturbed consciousness to the point of coma A drop in blood pressure Tachycardic/bradycardic heart rhythm disturbances Hyperglycaemia

Hypoxia Cardiogenic shock with pulmonary oedema


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APPENDIX 2

Salbutamol Infusion Regime

Note: To prevent hypotension due to aorto-caval compression, the womanshould lie on her side during the infusions.

PRESENTATION Ventolin Obstetric 5mg ampoules (1mg per ml)ADMINISTRATION Salbutamol should be given by infusion pump to control dose

and fluid volume.Caution is required when changing to salbutamol form a

vasodilator such as nifedipine, which has a half-life of 6to 12 hours. In these circumstances, frequent maternaland fetal observations are required.

DOSE Draw up 10ml (10mg) of obstetric salbutamol in a 10ml syringe

Withdraw 10ml from a 100ml bag of normal saline andreplace with the 10ml salbutamol. The resultingsolution will contain 100 micrograms per ml

Start the infusion at 12ml per hour Increase the rate by 6 ml every 30 minutes until there

is a suitable response, either cessation of contractionsor a reduction in the frequency and strength ofcontractions

Do not exceed 36ml/hrIf maternal pulsegreater than 140bpm or sustainedfetal tachycardia(greater than 180bpm)

Slow infusion rate until pulse or fetal heart rate returnbelow these levels

Side effects Tremor, anxiety, nausea and palpitations are likely and

the woman should be warned CEASE INFUSION if chest pain, dyspnoea or vomiting

occursIf contractionscease

Maintain infusion rate for the next 4 hours and thenreduce by 6ml/hr every 4 hours until 12ml/hr.

Decisions about cessation of treatment are to be madeon an individual basis.

MATERNAL andFETALOBSERVATIONANDMONITORING

Maternal blood pressure, pulse and respiratory ratefollowing each increase in infusion rate following eachincrease in the infusion rate during the acutestabilisation phase. Observations may then berecorded less frequently, but at least 4 hourly duringtreatment;

If initial cardiotocograph is reactive, record fetal heartrate with Doppler after each increase in the infusionrate during the acute stabilisation phase, then at least6 hourly for the first 48 hours.


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APPENDIX 3Choice of Tocolytic agents

Beta-sympathomimetics - SalbutamolThese are the most widely used tocolytic and have been extensively studied inrandomised controlled trials. Salbutamol has been the most widely used beta-sympathomimetic in Australia and was recommended by the NHMRC in it 1996 report. Itmust be given intravenously; it has several maternal contraindications and significant

maternal side effects.

Calcium antagonists nifedipineNifedipine is an equally effective tocolytic, as shown by a recent Cochrane Review. It isadministered orally and has fewer maternal side effects. However, nifedipine is notapproved for use in pregnancy and is classified as a risk Category C drug by theAustralian Evaluation Committee.

Oxytocin antagonists atosibanAtosiban appears to be as effective as beta-mimetics. It has fewer side effects but ismuch more expensive than other options in preterm labour. However, it is not approved

for used in Australia.

Prostaglandin antagonists - indomethacinIndomethacin has been compared in small trials with beta-mimetics. These havesuggested equal efficacy in delaying preterm birth but there are concerns about adverseaffects on the fetal circulation.

Other agents glyceryl trinitrateGlyceryl trinitrate patches have been evaluated in a small number of women and there isinsufficient evidence to support use in routine clinical practice.

Magnesium SulphateMagnesium sulphate is used for tocolysis in the USA. Magnesium sulphate was found tobe ineffective at delaying birth or preventing preterm birth, and its use is associated withan increased mortality for the infant.


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APPENDIX 4REFERENCES

Crowther CA, Hiller J E, Doyle LW. Magnesium sulphate for preventing preterm birth inthreatened preterm labour (Cochrane Review). The Cochrane Database of SystematicReviews 2002, Issue 4. Art. No.: CD001060. DOI:10.1002/14651858.CD001060.

Ingemarsson I. Lamont R. An update on the controversies of tocolytic therapy for the

prevention of preterm birth. Acta Obstetricia et Gyncologica Scandinavica 2003: 82:1-9.

Lamont R and the International Preterm Labour Council. Evidence-based labour wardguidelines for the diagnosis, management and treatment of spontaneous preterm labour.

J ournal of Obstetrics and Gynaecology 2003: 5:460-478.

New South Wales Department of Health Policy Directive 2005 Tocolytic agents Protocolsfor administration for threatened preterm labour. Online:http://www.health.nsw.gov.au/policies/PD/2005/PD2005_249.html

Royal College of Obstetricians and Gynaecologists Clinical Guideline No.1(B) 2002

Tocolytic drugs for women in preterm labour. Online:http://www.rcog.org.uk/womens-health/clinical-guidance/tocolytic-drugs-women-preterm-labour-green-top-1b

Attachments

Attachment 1

Performance Indicators: Evaluation of compliance with guideline to be achieved throughmedical record audit

Review Date: Annually verified for currency or as changes occur, andreviewed every 3 years

Stakeholders: Midwives and medical staff WACS

Developed by: Dr A Dennis Co-Director (Medical) Sue McBeath Co-Director(Nursing & Midwifery) Womens & Childrens Services

Dr A Dennis Sue McBeathCo-Director (Medical) Co-Director (Nursing & Midwifery)Womens & Childrens Services Womens & Childrens Services

Date: December 2009
http://www.health.nsw.gov.au/policies/PD/2005/PD2005_249.htmlhttp://www.health.nsw.gov.au/policies/PD/2005/PD2005_249.htmlhttp://www.rcog.org.uk/womens-health/clinical-guidance/tocolytic-drugs-women-preterm-labour-green-top-1bhttp://www.rcog.org.uk/womens-health/clinical-guidance/tocolytic-drugs-women-preterm-labour-green-top-1bhttp://www.rcog.org.uk/womens-health/clinical-guidance/tocolytic-drugs-women-preterm-labour-green-top-1bhttp://www.rcog.org.uk/womens-health/clinical-guidance/tocolytic-drugs-women-preterm-labour-green-top-1bhttp://www.rcog.org.uk/womens-health/clinical-guidance/tocolytic-drugs-women-preterm-labour-green-top-1bhttp://www.rcog.org.uk/womens-health/clinical-guidance/tocolytic-drugs-women-preterm-labour-green-top-1bhttp://www.health.nsw.gov.au/policies/PD/2005/PD2005_249.html

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