The aim of management is to rapidly restore circulating volume and prevent tissue hypoxia. Initial resuscitation will be the same whatever the cause of the haemorrhage. Subsequent obstetric management will depend on whether the baby is delivered and/or viable. In many cases, the patient will require an anaesthetic for exploration of the uterus and surgical haemostasis. During on-going severe haemorrhage, senior anaesthetic and obstetric help should be sought if available. A blood transfusion will usually be required once the blood need to be alerted. The operating obstetrician should be confident that she/he can perform a caesarean hysterectomy.
Role of the Anaesthetist
The anaesthetist can initiate and lead the resuscitation and stabilization, including the estimation of blood loss and appropriate ordering of blood and blood products. The anaesthetist has responsibility to administer an appropriate anaesthetic technique to allow surgical exploration, administer drugs to control haemorrhage and help appropriate postoperative critical care.
Initial Resuscitation and Stabilization
Any resuscitation should follow the obstetric ABC principle as follows:
- Tilt-if still pregnant
- 100% Oxygen
- ABC with rapid initial assessment and corrections as found
- Diagnosis and Definitive treatment.
Prior to delivery supine aorto-caval compression must be avoided by placing the patient in either the left latter position or providing 15 degree left lateral tilt with a wedge under the right hip. If the patient is supine, the gravid uterus will compress the vena cava and prevent adequate Venus return to the heart. This will reduce cardiac output by up to 30%, worsening hypotension due to blood loose and prevent effective resuscitation. If neither manoeuvre is possible, the uterus must be manually displaced to the left.
Administer 15 litters/minutes oxygen or as much as is available, via a tight-fitting face mask with a resurveys bag if possible. These will achieve optimal oxygen saturation of the blood remaining in the circulation and help to prevent tissue hypoxia. In addition, the nitrogen in the functional residual capacity of the lungs will be washed out and replaced by the oxygen - this provided a valuable resurveyed for continue oxygen and pulmonary blood should respiratory compromise occur.
A severely shocked patient may lose consciousness due to hypotension and require tracheal intubation to protect the airway from gastric acid aspiration and to maintain adequate oxygenation/ventilation.
This may become inadequate and the patient may require ventilation as consciousness is lost and as severe tissue hypoxia and metabolic acidosis supervene.
Rapid assessment of the estimated blood volume lost should be done at the same time as 2 x wide bore (14G) IV canulae are inserted, basic monitoring applied if available i.e. pulse oximeter, non invasive blood pressure, EEG, but do not delay fluid resuscitation indicators of hypovolaemia.
When blood loss is estimated to be less than 30% of the blood volume (up to 2000 ml), IV crystalloid or colloid fluid resuscitation or colloid fluid resuscitation may be adequate. However, when blood loss has reached 50% of blood volume, the mother will almost certainly require a blood transfusion.
Once the diagnosis of major haemorrhage has been made, take 20ml blood for FBC, coagulation screen and cross match blood if possible.
Common pitfall: Normal blood pressure does not exclude major blood loss in the pregnant patient.
The physiologically increased plasma volume and red cell mass in pregnancy means total blood volume is increased up to 40%. Therefore, up to 40% blood volume can be lost (1500-2000ml) before any degree of hypotension is apparent. This is because blood is shunted away from the feto-placental unit (750 ml/minute) to maintain flow to vital organs such as the brain, heart, and kidneys.
Early signs of impending maternal collapse with a normal blood pressure include:
- Tachycardia > 100 bpm
- Fetal distress
- Skin pallor with increased capillary refill time (>2 seconds, or the time it takes to say capillary refill)
- Decreased/absent urine output <30 ml/hr, this is often not apparent in the acute situation.
Sign of life-threatening hypovolaemia i.e > 50% blood volume loss include:
- Mental clouding progressing to unconsciousness
Ensure that all blood sampling is correctly labelled and inform blood bank of the degree of urgency. It is often useful to delegate a team member to this task, and also to assign someone to record all events, with timings.
Infuse 2 l of crystalloid (Hartmanns/Normal saline) rapidly and set up a blood warming device and pressure infuser. if available. The patient may need to be transferred to theatre at the same time, and the obstetrician should establish the underlying cause of bleeding and decide on the surgical management plan.
Assess the Response to Initial Volume Replacement
- 15-30% blood loss (750 - 1500ml) will respond to crystalloids alone: tachycardia will improve and remain improved
- 30-40% blood loss (1500 - 2000 ml) will have a transitory response to crystalloids and will require colloid infusion while waiting for cross matched or group specific blood.
- >50% blood loss (>2500 ml) is life-threatening and requires blood transfusion as soon as possible.
The mother will require regular heart rate and blood pressure monitoring. During active bleeding, this should be at 5-minute intervals. If bleeding is extreme, direct arterial monitoring and/or CVP monitoring can provide additional measurements to aid the management of fluid replacement. These additional techniques should only be used if readily available and there is experience with there is experience with their use because insertion can be difficult and cause significance harm. Urine output is a simple and useful guide to successful fluid management. After major blood loss, it may take several hours for normal urine output to be restored (>30 ml/hr) even with adequate fluid management. An in-dewelling urinary catheter will help monitoring. Oxygen saturation gives beat to beat assessment of adequate oxygenation and should be used if possible. It is also a useful aid in the diagnosis of pulmonary oedema, which is common after major blood loss and rapid fluid replacement.