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Sabtu, 17 Oktober 2009

Post-partum Haemorrhage (PPH)

Post-partum Haemorrhage (PPH)

This is excessive bleeding following delivery and is described as primary and secondary.

The WHO definitions:
  • Primary post-partum haemorrhage is loss of blood estimated to be >500ml, from the genital tract, within 24 hours of delivery (commonest obstetric haemorrhage).
  • Secondary PPH is defined as abnormal bleeding from the genital tract, from 24 hours after delivery until 6 weeks post-partum.
Primary PPH

Aetiology

The commonest cause of PPH is uterine atony.
Other common causes are:

Atony and retained placenta are 80% of all cases, lacerations comprise the bulk of the other 20%.
Cervical lacerations, uterine rupture, broad ligament haematoma and extra genital bleeding also need to be excluded.

Epidemiology

Most studies quote an incidence of around 5%,1 but a figure of 12% of vaginal deliveries was recorded in one Australian tertiary referral hospital.2

Risk factors

  • Factors relating to the pregnancy:
  • Factors relating to delivery:
    • Emergency Caesarean section (9x risk)3
    • Elective CS (4x risk) - especially if >3 repeat procedures4
    • Retained placenta (5x risk)
    • Mediolateral episiotomy (5x risk)
    • Operative vaginal delivery (2x risk)
    • Labour of >12 hours (2x risk)
    • >4kg baby (2x risk)
    • Maternal pyrexia in labour (2x risk)
  • Pre-existing maternal haemorrhagic conditions:

Presentation

  • Symptoms: Continuous bleeding, which fails to stop after delivery of placenta - third stage
  • Signs: Loss of >1000ml may be accompanied by clinically apparent shock i.e. tachycardia, hypotension

Investigations

  • Thorough examination of the lower genital tract. This may require theatre/anaesthesia.
  • FBC, Clotting screen, Cross match
  • Hourly urine output
  • Continuous pulse/BP or CVP monitoring
  • ECG, pulse oximetry

Associated diseases

HELLP (Haemolysis, Elevated Liver enzymes and Low platelets)

Management

Non-drug

Ideally one of the emergency drills to be practised by the team on labour ward, along with shoulder dystocia.

  • Calling and alerting expert assistance. If the perceived blood loss is 500-1000ml and there are no signs of clinical shock, basic measures, (cross match 2 units, FBC, Clotting screen, IV access and monitoring clinical observations ) should suffice.
  • However loss of greater than 1000mls or any signs of shock should lead to full alert of the clinical team: experienced midwife, obstetric registrar, (alert consultant), anaesthetic registrar (alert consultant), alert haematologist, alert transfusion service, call porters for transport of specimens and blood products.

Drugs

  • Oxygen should be given by mask at 8 litres per minute.
  • Transfuse cross matched blood (6 units initially) a.s.a.p.
  • Until then infuse crystalloid or colloid as required.
  • If 3.5 litres given and no blood available, give O NEG, or uncross matched blood of own blood group.
  • Use a warming device and a pressure cuff.
  • Do not use a blood filter.
  • Do not use dextrans.
  • Give up to 1 litre of FFP and 10 units of cryoprecipitate if clinically indicated.

A new haemostatic agent- recombinant Factor VII a - has had some clinical success, but its efficacy and safety is untested in clinical trials as yet.5,6

Surgical

  • Secure IV access with 2 x14 gauge cannulae
  • Stop the bleeding
  • Exclude other causes than atony
  • Ensure bladder empty and bi-manually compress the uterus ±rub up a contraction. A Sengstaken-Blakemore tube has been used to compress the uterus. One series of 17 cases showed a 71% success rate in stopping the haemorrhage.7
  • Give IV syntocinon 10 units or IV ergometrine 500 mcg
  • Commence syntocinon infusion 30 units in 500ml
  • IM Carboprost 500mcg
  • Resort to surgery early. At laparotomy inject carboprost directly into the myometrium.
  • Bilateral ligation of the uterine arteries or bilateral ligation of the internal iliac (hypogastric) arteries.
  • An alternative to ligation is embolisation with gelatine sponge.8 Amenorrhoea has been reported following this, secondary to necrosis of the uterine wall and obliteration of the cavity.9
  • Uterine Bracing suture, (the B-Lynch suture) to anterior and posterior uterine walls has been shown to be effective and safe,10 with reports of successful pregnancy following its use.11,12
  • Hysterectomy should be considered early, especially in cases of placenta accreta or uterine rupture.

Complications

Prognosis

The Confidential Enquiry into Maternal Deaths for 2000-2002 reported 17 deaths related to obstetric haemorrhage in that triennium.13 This gives a rate of 8.5 per million.

Prevention

The Active Management of the Third stage of Labour; prophylactic oxytocics should be routinely used in the third stage of labour as they decrease the risk of PPH by 60%.14 For most women syntometrine ( ergometrine 0.5mg with 5i.u oxytocin) is the drug of choice. Oxytocin alone (10i.u) is preferred by some clinicians in women with hypertension.

Secondary PPH

This commonly presents in primary care as prolonged or excessive bleeding once the woman has returned home after delivery.

Aetiology

The two commonest causes are:

  • Infection- endometritis. Occurs in 1-3% after spontaneous vaginal delivery. It is the most common cause of postnatal morbidity between day 2 and day 10.
  • Retained products of conception (RPOC)

Endometritis risk factors

Caesarean section, prolonged rupture of membranes, severe meconium staining in liquor,15 long labour with multiple examinations, manual removal of placenta,16 mothers age at extremes of reproductive span, low socio-economic status, maternal anaemia, prolonged surgery, internal fetal monitoring and general anaesthetic.

Assessment

History: As above, also extended labour, difficult 3rd stage, ragged placenta, primary PPH.
Examination: Systemic illness, fever, rigors, tachycardia, tissue visible within loss. Suprapubic area may be tender, with elevated fundus that feels boggy in RPOC.

Investigation

  • FBC
  • Blood cultures are positive in 10-30%
  • Check MSU
  • High vaginal swab, also gonorrhoea/chlamydia
  • Ultrasound; may be used if RPOC suspected, although there may be difficulty distinguishing between clot and products. RPOC are unlikely if a normal endometrial stripe is seen.

Management

  • Speculum examination will allow visualisation of cervix and lower genital tract to exclude lacerations. If clot is visible within the cervical os, it may be removed with tissue forceps (though few GP regularly carry these), allowing the cervix to close.
  • If infection suspected, combinations of broad spectrum e.g. amoxicillin, gentamicin and metronidazole, can be given.17 Patient may need to be referred if too unwell to tolerate oral medication; IV clindamycin and gentamicin tds until afebrile for greater than 24 hours.18 Oral follow up treatment is not required. Use doxycyline if chlamydia is suspected.
  • If retained products of conception are suspected elective curettage with antibiotic cover may be required.
  • Patient may require iron supplementation if Hb has fallen. Warn of the risk of constipation.

Prognosis

90% of cases treated with antibiotics improve within 48-72 hours. If this is not the case, the patient should be re-evaluated.