OBSTETRIC ANAESTHESIA
Obstetric haemorrhage Learning objectives
Rosanne Ching After reading this article, you should be able to:
C define postpartum haemorrhage
Thomas Mount
C classify the aetiology of postpartum haemorrhage
Kirsty MacLennan
C list two ways to reduce risk of amniotic fluid embolism when
using intraoperative cell salvage
Abstract
Obstetric haemorrhage remains a significant cause of maternal
morbidity and mortality. It is the leading obstetric cause for admission Definitions
to intensive care units. Knowledge of risk factors and early recognition
of haemorrhage enables rapid activation of a coordinated multidisci- Antepartum haemorrhage (APH) occurs prior to delivery in the
plinary team response. Clear unit protocols for the management of period of 24 weeks’ gestation to full term of pregnancy. It is much
massive haemorrhage that are reinforced by team drills help to in- less common than postpartum haemorrhage. The common cau-
crease awareness in the multidisciplinary team, improve performance ses include placenta praevia, placental abruption, trauma and
and thus can improve patient outcome. Pharmacological agents and uterine rupture.
surgical manoeuvres are reviewed in the article, as are blood conser- Postpartum haemorrhage is defined as primary if blood loss
vation techniques. from the genital tract occurs within 24 hours of delivery or sec-
ondary if blood loss occurs over 24 hours following delivery up
Keywords Cell salvage; interventional radiology; obstetric haemor-
to 6 weeks post-delivery. Primary postpartum haemorrhage
rhage; resuscitation; uterotonic drugs
(PPH) is the most common form of major obstetric haemorrhage.
Royal College of Anaesthetists CPD Skills Framework: Obstetrics The Royal College of Obstetricians and Gynaecologists define
PPH as minor (with 500e1000 ml blood loss) or major (with over
1000 ml blood loss). Major PPH can be further classified into
moderate (with between 1000 ml and 2000 ml blood loss) or
severe (with over 2000 ml blood loss).4
Other definitions include the need for a transfusion of greater
Background
than four units of packed red cells or a haemoglobin fall of
Obstetric haemorrhage is a significant cause of maternal greater than 4 g/dl. Definitions based upon physiological changes
morbidity and mortality. The Mothers and Babies: Reducing Risk can be unreliable due to the physiological changes associated
through Audits and Confidential Enquiries across the UK with pregnancy.
(MBRRACE-UK) report published in November 2018, placed
obstetric haemorrhage as the second most common direct cause Postpartum haemorrhage
of death and seventh as the overall leading cause of maternal
deaths for the period 2014e2016.1 The mortality rate was 0.78 The aetiology of PPH can be classified as per the ‘Four Ts’:
per 100,000 maternities, which was not significantly different to tone e abnormalities of uterine contraction
the previous triennial period (2013e2015).2 The lack of signifi- thrombin e abnormalities of coagulation
cant decrease in mortality therefore stresses the need to improve trauma e genital tract injury
the care of women with haemorrhage. tissue e retained products of conception, abnormally
Paucity of observations following delivery and lack of recog- invasive placenta.
nition of haemorrhage were implicated in many of the cases, Risk factors are summarized in Table 1.4 The occurrence of
more evidently when women were being cared for from outside secondary postpartum haemorrhage is associated with retained
the theatre, such as recovery or postnatal ward. Human factor products of conception or puerperal sepsis.
was identified as a persistent problem, with the lack of leadership
and failure to escalate appropriately featuring in many deaths.1 Management (Figure 1)
Obstetric haemorrhage causes significant morbidity and is the
most common cause of obstetric-related intensive care Team preparation
admissions.3 Early involvement of appropriate senior staff (including the
anaesthetic team and relevant clinicians) is fundamental to the
management of PPH, especially those who are at risk of
abnormal placentation.4 There is some evidence that intensive
Rosanne Ching MBChB is a Trainee in Anaesthesia in the North West educational programmes, comprehensive obstetric haemorrhage
Deanery, UK. Conflicts of interest: none declared.
treatment protocols and post-event team review may individually
Thomas Mount MBChB BSc (Hons) FRCA is a Senior Anaesthetic Trainee or in combination lead to reductions in the incidence of severe
in the North West Deanery, UK. Conflicts of interest: none declared. PPH and thus morbidity.5 The enquiry into maternal morbidity
Kirsty MacLennan MB ChB MRCP FRCA is a Consultant Obstetric from haemorrhage identified improvements in care for almost
Anaesthetist at St Mary’s Hospital, Manchester, UK. Conflicts of 90% of women; in 74% this would have made a difference to
interest: none declared. their outcome.1
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OBSTETRIC ANAESTHESIA
recognizing evolving physiological trends over time. These
Risk factors and the associated levels of risk for observation systems allow signs such as tachypnoea, poor urine
postpartum haemorrhage (PPH) output, temperature, change in pallor, pathological cardiotocog-
Risk factor The four Ts OR (95% CI) raphy due to placental hypoperfusion to be monitored and
detected, along with the basic observations of tachycardia and
Multiple pregnancy Tone 3.30 (1.00e10.60) hypotension.
4.70 (2.40e9.10) Pathways such as massive haemorrhage protocols allow the
Previous PPH Tone 3.60 (1.20e10.20) obstetric multidisciplinary team to obtain blood products quickly
Pre-eclampsia Thrombin 5.00 (3.00e8.50) to enable rapid empirical treatment of major blood loss when
2.20 (1.30e3.70) necessary.
Fetal macrosomia Tone 2.11 (1.62e2.76) Resuscitation should be informed by laboratory results where
2.40 (1.90e2.90) possible, and there is an increased awareness of the importance
Failure to progress Tone 3.40 (2.40e4.70) of correcting hypofibrinogenaemia in obstetric haemorrhage.6
in second stage 1.90 (1.20e2.90) More appropriate administration of red cells, blood compo-
Prolonged third Tone 7.60 (4.20e13.50) nents and coagulation factors may be guided by point-of-care
stage of labour 2.61 (1.83e3.72) testing of haemoglobin values, e.g. Haemocue, and thromboe-
Retained placenta Tissue 7.83 (3.78e16.22) lastography (TEG) or thromboelastometry (ROTEM). Evidence
3.50 (2.10e5.80) has stated that the use of such tests have an increased sensitivity
6.00 (3.50e10.40) in identifying deficits in the coagulation cascade when compared
Placenta accreta Tissue 3.30 (1.70e6.40) to laboratory-based tests and an increase in accurate assessment
Episiotomy Trauma 4.70 (2.60e8.40) of the deficit phase of coagulation cascade.7
2.18 (1.68e2.76) Maintenance of normothermia is also important as both sepsis
1.70 (1.20e2.50) and hypothermia increase the oxygen demand of the women and
Perineal laceration Trauma 1.40 (1.04e1.87) may lead to disseminated intravascular coagulation. Calcium
2.40 (2.00e2.80) must also be replaced to support the coagulation system.
1.70 (1.10e2.50)
General anaesthesia Tone 2.90 (1.90e4.50) Pharmacological management
Alongside the initial resuscitation of the patient, the first-line
Adapted from Green-top Guideline No. 52 published by the Royal College of
treatment for obstetric haemorrhage is pharmacological inter-
Obstetricians and Gynaecologists, December 2016.4
CI, confidence interval; OR, odds ratio. vention to encourage uterine contraction (Table 2).
Table 1 Haemostatic agents
Additional agents can be used to promote haemostasis when
treating life-threatening haemorrhage.
A combination of prediction and prevention, early recognition
and rapid coordinated action in treating PPH will aid in pre- Tranexamic acid is a synthetic derivative of the amino acid
empting worst-case scenarios. Excellent communication lysine. It is an anti-fibrinolytic agent that competitively inhibits
amongst the multidisciplinary obstetric team is paramount. the activation of plasminogen to plasmin, which causes fibrin
degradation. Tranexamic acid reduced death due to bleeding in
Recognizing the haemorrhage women according to the WOMAN Trial Collaborators.8 The risk
As placental blood flow at term can exceed 750 ml/minute, ob- of serious adverse events is minimal. The use of tranexamic acid
stetric haemorrhage can be rapid and catastrophic. Failure to should be considered in addition to oxytocin, at caesarean sec-
recognize the severity of the situation was identified in 26% of tion to reduce blood loss in women who are at increased risk of
deaths in the MBRRACE-UK report.1 This was more evident PPH.4
when the patient was being cared for out of theatre.
The initial recognition of obstetric haemorrhage is often Fresh frozen plasma (FFP) is a blood product that contains all
challenging. The haemorrhage may be concealed or in the case of coagulation factors. If there is ongoing bleeding without immi-
an overt haemorrhage, estimation of total loss is notoriously nent haemostatic results, FFP should be infused at a dose of 12
inaccurate. Amniotic fluid, loss of blood into sheets and pads, e15 ml/kg after 4 units of red blood cells transfusion. If pro-
blood loss occurring out of hospital and operator underestima- thrombin time/activated partial thromboplastin time is more
tion of blood loss are all causes of inaccuracies. than 1.5 times normal and haemorrhage is continuing, volumes
The ability of the pregnant patient to compensate for hae- of FFP in excess of 15 ml/kg are likely to be needed to correct
morrhage with an increase in heart rate, stroke volume and coagulopathy.
vascular tone mean that haemorrhage may go unrecognized until
physiological extremes have been reached. In some cases, more Fibrinogen is a glycoprotein that is converted to fibrin and
than 40% total blood loss can occur before the physiological subsequently a blood clot. During ongoing PPH, a plasma
signs of haemorrhage become recognizable. fibrinogen level of greater than 2 g/litre should be maintained
The use of standardized observation systems such as modified with the use of cryoprecipitate which contains fibrinogen, von
early obstetric warning scores (MEOWS) can be vital in Willebrand factor, factor VIII, factor XIII and fibronectin.
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OBSTETRIC ANAESTHESIA
Figure 1
The routine use of recombinant factor VIIa (rFVIIa) is not Surgical intervention
currently licensed for use in obstetrics. Although there are some
Surgical manoeuvres and pharmacological agents are used side
positive results in case studies, the use of rFVIIa is limited to
by side in the treatment of persistent haemorrhage.
patients with refractory haemorrhage; where embolization is
Retained products of conception should be removed and any
unavailable; or hysterectomy is the only alternative. The initial
genital tract trauma should be identified and repaired.
dose administered is 90 mg/kg, and it is specified that prior to
If uterine atony is the cause of the haemorrhage, uterine compres-
administration the patient must have a fibrinogen level of greater
sion should be initiated. Emptying the bladder is also advocated.4
1 g/dl, adequate platelets, normal calcium levels, correction
External uterine tamponade by means of bi-manual uterine
of acidosis and be normothermic. The main side effects are
compression should be initiated. If this manoeuvre is successful,
the occurrence of a thromboembolic event or absence of
a B-Lynch suture can be sited.
response.
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OBSTETRIC ANAESTHESIA
Pharmacological management
Drug name Action Dose and frequency Side effects Contraindications
Oxytocin A naturally occurring Bolus dose 5 IU slow IV Reflex tachycardia Caution in hypovolaemic
polypeptide (bolus can be repeated if Hypotension and cardiac patients due to
Acts on oxytocin-specific needed) Short acting so vasodilatation and
receptors in uterine often administered as 10 hypotension
myometrium promoting IU/hour infusion over 4
uterine smooth muscle hours
contraction
Ergometrine Acts on a-adrenergic, 250e500 mcg IV or IM Tachycardia Avoid in patients with pre-
dopaminergic and serotonin Hypertension eclampsia and
5-HT2 receptors Vomiting cardiovascular disease
Uterine smooth muscle Nausea
contraction not clearly
associated with a specific
receptor
Carboprost Prostaglandin F2a analogue 250 mcg IM. Dose can be Bronchospasm Avoid in asthmatics and pre-
Profound smooth muscle repeated every Intrapulmonary existing respiratory and
contractor 15 minutes (maximum of shunting cardiac disease (not for IV
eight doses) Hypoxia administration)
Vomiting
Diarrhoea
Shivering
Pyrexia
Misoprostol Prostaglandin E1 analogue 800e1000 mcg rectally/ Shivering Allergy to misoprostol or
vaginally/sublingually Pyrexia other prostaglandins
Diarrhoea
IM, intramuscular; IV, intravenous; mcg, micrograms.
Table 2
Internal uterine tamponade can be achieved using a Bakri or Blood conservation techniques
Rusch balloon. The balloon is placed inside the uterus and is Early replacement of blood products should be considered.
inflated with 500e1000 ml of sterile water. The balloon should However, transfusion of blood and blood components are not
be used alongside an oxytocin infusion to further promote uter- without complications.9 There are the associated risks of blood
ine contraction. transfusion-related immunosuppression, microchimerism,
alloimmunization and the potential of an increase in blood-borne
Uterine artery ligation cancers in recipients.10
Ligation of the bilateral uterine or internal iliac arteries may help Transfusion-related acute lung injury (TRALI) is another real
to reduce haemorrhage. Ligation of the arteries can be technically risk and the most common cause of death following transfusion,
difficult, and the presence of collateral vessels may reduce accounting for 51% compared with 27% caused by non-ABO and
effectiveness. Early senior involvement is essential. Interven- ABO-related haemolytic transfusion reactions.9
tional radiology can be utilized to facilitate cannulation of the Risks aside, the availability of blood is also reducing as more
internal iliac arteries. This allows catheterization of the uterine donor restrictions are enforced.
arteries, which enables uterine artery balloon occlusion or se- For all of these reasons blood conservation techniques should
lective uterine artery embolization. This specialist interventional be embraced commencing with the recognition of antepartum
radiology procedure can be used in either elective cases (placenta anaemia and treatment aimed at replenishing iron stores.
praevia or accreta) or in the emergency setting. Due to its
specialist nature this service may not be available in all hospitals, Cell salvage
particularly out of hours. Intraoperative cell salvage (IOCS) has been endorsed by several
authoritative bodies including CEMACE, the Obstetric Anaes-
Hysterectomy thetists’ Association and the National Institute for Health and
In drastic cases where uterine bleeding cannot be controlled by Care Excellence (NICE) guidelines. It is considered as a clinically
any of the above measures, emergency hysterectomy may be effective and cost-effective means of providing autologous red
needed. cells.4 The NICE guideline11 addressing intraoperative blood cell
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OBSTETRIC ANAESTHESIA
salvage in obstetrics also acknowledges that it may also be useful In an elective setting where major blood loss is anticipated,
when there are difficulties with cross-matching. However, there the decision between general and regional anaesthesia is decided
was no statistically significance in the overall reduction observed by the anaesthetist, the patient and the anticipated degree of
in donor blood transfusion associated with the routine use of cell blood loss.
salvage during cesarean section in the SALVO study, a random-
ized controlled trial of IOCS during caesarean section in 3028 Postoperative management
women.12 Patients who suffer an obstetric haemorrhage will require
The theoretical safety concerns include infusion of fetal cells ongoing monitoring and close observation. This patient group
(which could potentially cause haemolytic disease in future preg- will need level two or three care postoperatively to continue
nancies) and the potential risk of amniotic fluid embolism (AFE).10 resuscitation and administration of supportive medication and
The guidance noted that the theoretical safety concerns transfusions and to monitor for ongoing bleeding. A
include infusion of fetal cells (which could potentially cause
haemolytic disease in future pregnancies) and the potential risk
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