Obstetric trauma

Question 1

What pregnancy related issues does trauma increase the risk of?

Answer 1

Pre-term labour
Placental abruption
- Uterine tenderness and vaginal bleeding
Uterine rupture
- Peri-arrest, EFAST
Feto-maternal haemorrhage with rhesus isoimmunisation
Pregnancy loss/FDIU

Question 2

What changes affect the airway and breathing?

Answer 2

Difficult intubation
- Large breasts
- mucosal oedema
- LO sphincter relaxation + higher gastric pressures increase risk of aspiration

Difficult ventilation
- Increased abdominal pressures
- Diaphragm 4cm higher
- increase TV/RR but reduced FRC, ERV and residual volume by 20%
- Faster desaturation

Chest drain
- Higher diaphragm means put ICC in 3-4th ICS

Question 3

What changes affect the circulation?

Answer 3

• Relative hypervolaemia
• Relative anaemia
• Baseline higher Hr (10-15) but lower BP (<10 -15, SVR reduced by 20%), can lead to over resuscitation
• IVC compression with supine <BP
• Uterine blood flow 500-600ml/min with massive haemorrhoage from rupture or penetration
• Foetoplacental autotransfusion may mask hypovolaemia
• Transfuse to normotension not perimessive hypotension
• Hypercoagulable state places woman at higher risk for DIC
• 90% of women have an ESM and the second heart sound splits

Question 4

What is the indication for resuscitative hysterotomy aka peri-mortem c-section?

Answer 4

• Maternal cardiorespiratory arrest
• No ROSC within 4 minutes
• > 24 weeks gestation (foetal viability + when it causes CVS compromise)

Question 5

What are the factors associated with foetal death during trauma?

Answer 5

• Maternal shock is associated with 80% foetal mortality
• The best approach to foetal survival is to ensure maternal survival
• The commonest cause of traumatic foetal death is death of the mother

Question 6

What are the indications and contraindications to Anti-D?

Answer 6

Indications
- Following sensitizing events eg trauma, ectopic pregnancy
- Following Rh +ve blood administration to Rh-ve woman

Contraindications
- Known sensitivity
- Rh +ve

Question 7

What is the Kleihauer-Betke test used for?

Answer 7

Indication
- Rh-ve women at risk of massive foeto-maternal haemorrhage (ie major trauma) for which 625IU will not be enough

• helps determine the degree of foeto-maternal haemorrhage
• once determined give 100IU for every 1ml of Rh positive cells circulating
• No necessarily required <16 weeks as foetal blood <30mls

Question 8

What is the dosing of Anti-D?

Answer 8

<12 weeks- Unclear if needs to be given, however if given then dose is 250IU for single pregnancy and 625IU for multipregnancy

> 12weeks- 625IU, then repeat doses at 28 and 34 weeks and final dose postpartum

Question 9

What are the features of placental abruption in trauma?

Answer 9

• 10-15% maternal mortality and 40-50% foetal mortality
• Inelastic placenta shears away from the elastic uterus
• Ultrasound is poorly sensitive and can miss mild to moderate abruption (assess for subchorionic haematoma)
• Diagnosis is based on clinic signs + non-reassuring CTG

Clinical
- Abdominal pain
- Vaginal bleeding
- uterine tenderness or rigidity
- Tetanic contractions
OR
- may be asymptomatic

Question 10

What are the pregnancy specific injuries that can occur with trauma?

Answer 10

Question 11

What are the limitations of ultrasound in pregnant trauma?

Answer 11

• Poor sensitivity for detecting placental abruption
• Poor sensitivity for detecting uterine rupture (unless full rupture)
• Can not monitor foetal distress
• Distracts from maternal resus

Question 12

What are the main additional tests done in trauma for pregnant patients?

Answer 12

• CTG monitoring for at least 4-6hrs
• Kleihauer-Betke test
• Vaginal swab for Foetal Fibronectin or Ferning test suggesting ROM