S1E7: Unwitnessed Maternal Collapse - Obstetrics
Welcome back to another episode from TheCase.Report!
This month, Orla, Leah and Deirdre sat down to discuss the case of an unwitnessed maternal collapse and the changes in approach to having an expectant mother in your resuscitation room.
Our AITR to oversee our work this week is Dr Andreit Engelbrecht, a fantastic EM Consultant from Connolly Hospital.
Then, we head over to Tallaght Hospital and Dr Aileen McCabe to lead us through the full work-up and examination for obstetrics and gynaecology presentations in our emergency departments.
Finally, we turn to our talented obstetric colleagues in the National Maternity Hospital for some further tips and tricks and a full walk-through of the perinatal caesarean section from Professor Mary Higgins.
Causes of Maternal Collapse
Causes of Maternal Collapse
Vasovagal Syncope
Epilepsy
Intracranial haemorrhage
Anaphylaxis
BEAUCHOPS (Causes of Maternal Cardiac Arrest)
Bleeding/ Disseminated Intravascular Coagulation (DIC)
Embolism: Pulmonary/ coronary/ amniotic fluid embolism
Anaesthetic complications
Uterine atony
Cardiac disease: myocardial ischaemia/ infarction, aortic dissection, cardiomyopathy
Hypertension, preeclampsia, eclampsia
Other: Hs & Ts
Placental abruption/ praevia
Sepsis
Initial Approach?
Collateral history
Insert 2x wide bore IVC
ECG, Cardiac Monitor
Bloods: FBC, U&E, LFTs, VBG, G+CM, Coag
Rhesus status is important
Any significant bleed over 12/52 will require anti-D if Rh -ve
IV fluids
Resuscitate with 500ml Hartmann’s
Antepartum Haemorrhage
Major obstetric haemorrhage was the cause of thirteen maternal deaths between 2012 and 2014. Causes include:
Major antepartum haemorrhage (any bleed after 20/40)
Placental abruption
Placenta praevia
Vasa praevia
Cervical lesions
Always consider domestic abuse as a possible differential in an traumatic APH
Postpartum haemorrhage
Uterine rupture
Ectopic pregnancy
Placental Abruption
Risk Factors:
Abruption in previous pregnancy
4.4% incidence of recurrent abruption (adjusted OR 7.8; 95% CI 6.5-9.2)
Pre-eclampsia
Foetal growth restriction
Polyhydramnios
Advanced maternal age
Multiparity
Low BMI
Pregnancy following assisted reproductive techniques
Implications for the Mother:
Hypovolaemia and hypovolaemic shock
DIC
As the tissue separates, clot formation and the repeated release of thromboplastic material into the circulation increases the risk of DIC
Uterine rupture and multi-organ failure
Blood accumulating in the uterine wall can stimulate the myometrium causing strong, painful contractions
Implications for the Foetus:
Impaired oxygen and nutrient supply
Preterm delivery
Growth restriction
Foetal hypoxia
Foetal death
So- we have a significant APH. What do we do?
Activate the Massive Transfusion Protocol
Resuscitate with O-negative blood
FFP (dose 12-15ml/kg) administered fore very 6 units of red cells
Subsequently, titrate FFP transfusion to maintain PT and APTT ratios <1.5x normal
Administer cryoprecipitate early
Reduce risk of DIC
Maintain fibrinogen levels about 1.5g/L
Contact for emergency obstetrics input.
And our lovely TXA?
As per the RCOG Guidelines for Management of Antepartum Haemorrhage, there is no specific role indicated for TXA. The famous WOMAN trial that was published in the Lancet in 2017 examined the use of TXA in post-partum haemorrhage and there are no other trials available that seek to explore its use before this. It’s also important to note when interpreting the results of the WOMAN trial, that it actually had a negative primary endpoint as there was no statistically significant difference in all cause mortality or hysterectomy rates. It was only in a revised outcome with death secondary to PPH that demonstrated a moderate benefit in the use of TXA.
Our obstetrics colleagues have advised us that this is sufficient evidence to use 1g TXA IV following a peri-mortem Caesarean Section in order to stop any heavy bleeding.
Any Changes to CPR?
Manual Displacement of the Uterus
Displace the uterus laterally to the left by placing a hand below the uterus on the maternal right and displacing upwards and to the left
Reduces aortocaval compression
Keeps the patient in a supine position, allowing for more efficient chest compressions
Assigning someone to manually displace the uterus is more effective than the use of a Cardiff wedge or prop
Compressions 2-3cm Higher
Perform chest compressions approximately 2-3cm higher on the sternum
Studies have consistently shown chest compressions to be less effective in pregnant patients >20/40 gestation
POP the Pads On Properly
If it’s difficult to apply pads due to breast tissue, then apply to the anterior and posterior praecordium.
No need to change the defibrillator settings
No evidence of adverse consequences to the foetus (although obviously difficult to prove)
IV Access above the Diaphragm
Avoid deleterious effects of vena caval compression
Hs & Ts & Drugs- No Change
Interpreting the Data: Physiological Changes in Pregnancy
Heart rate does increase by 15-20 bpm in pregnancy. In general, be wary of attributing maternal tachycardia to anxiety or pain. It could be the only sign of hypovolaemia until very late in haemorrhage.
Cardiac output increases in pregnancy by 30%. There is also a reduction in peripheral vascular resistance which can low blood pressure by 10-15mmHg- especially diastolic BP. It is estimated that blood volume increases overall by 30%.
A hyperdynamic circulatory system such as this, allows for the uterus to receive 10% of cardiac output at term. Healthy pregnant women can tolerate blood loss remarkably well and can lose up to 35% of their circulation before becoming symptomatic.
When interpreting VBGs, remember that pregnant woman trend towards a respiratory alkalosis secondary to hyperventilation in the third trimester. This is due to a combination of lung volume changes and release of progesterone. Usually, it is compensated by renal excretion of bicarbonate.
The most important thing to remember is to use the IMEWS when a woman who is pregnant presents to the emergency department. Our obstetrics and gynaecology colleagues will need this information in order to determine the clinical status of the patient.
To Intubate or Not To Intubate?
Nicely- there’s no black and white answer for this. The general rule of thumb is that early intubation in maternal cardiac arrest is ideal. However, the priority is always good CPR and a progression towards a resuscitative hysterotomy may be more appropriate.
Gastric motility is reduced in pregnancy so there is an increased risk of aspiration and also there may be significant laryngeal oedema making intubation even more challenging. If you’re achieving good oxygen saturations with BVM.
Resuscitative Hysterotomy/ Peri-Mortem CS
Timing?
The traditional thinking is that if there is no response to correctly performed CPR after four minutes of a maternal cardiac arrest in a woman >20/40 gestation (or a gravid uterus above the umbilicus), then a resuscitative hysterotomy should be performed within 5 minutes. However, this isn’t always a possibility in reality. Case studies have demonstrated maternal survival with resuscitative hysterotomy at 15 minutes and neonatal survival at 30 minutes. Of course, as soon as possible is key. Remember that it should take place at the site of the arrest. There is no time to delay for transfer.
What’s the aim of a resuscitative hysterotomy?
Assist maternal resuscitation not necessarily foetal survival
Emptying the uterus reduces the compression on the aorta and IVC, increasing preload
Improves lung volume and compliance
Increased blood supply redirected to maternal circulation from placenta
What’s the evidence like?
Katz et al. (1986)
Focus on infant survival
Source of the target times of 4-5 minutes
69% survival (42/ 61 cases) when C-section undertaken within 5 minutes of cardiac arrest
Maternal hypoxic brain injury only occurred in women who underwent a C-section that started >6 minutes after cardiac arrest
Review in 2005 of 38 cases
Supported 4-5 minute rule
No true validity proven
Systematic review 1980-2010
80 papers with 94 patients
PMCS beneficial in 31.7% of cases and “not harmful” in any identified cases
54.3% (51/94) of mothers survived to hospital discharge
78.4% (40/51) surviving with good to moderately impaired neurological outcome
Maternal outcomes favourable if performed <10 minutes
Neonatal survival only occurred in cases of maternal cardiac arrest in hospital
This Isn’t Easy.
We all need support.
Maternal cardiac arrest scenarios can be particularly emotionally challenging for both the resus team and the family or partner. On arrival in the ED, assign a team member to obtain collateral information if there is a partner or family member available. This can provide valuable information to the team but also offers the family a point-of-contact and builds a relationship with the family.
A formal and thorough team debrief will be required regardless of the outcomes.
