Intrauterine Resuscitation

Foetal distress is progressive foetal asphyxia that if not corrected or circumvented, will result in decompensation and permanent CNS damage or death. Intrauterine resuscitation:

Describes techniques used to correct common and reversible causes of foetal hypoxia prior to harm occurring
Non-correctable (e.g. anencephaly) or rare (e.g. ruptured vasa praevia) causes are not captured.
Relies on detection of foetal distress by electronic foetal monitoring

Causes

Contractions
Contractions in uncomplicated labour result in short and long-term reduction in oxygenation; and this effect is markedly ↑ with excessively frequent contractions.
Aorto-caval compression
Cord compression
Epidural
Rarely associated with severe hypotension.
- Around 50% of FHR decelerations after regional analgesia can be attributed to ↑ in uterine activity
Maternal hypoxia
- Opioids
- Nitrous oxide
- Post-contraction
  Hypoventilatory period occurring due to low PaCO₂ after a contraction.
Placental abruption
Foetal haemorrhage
- Vasa praevia

Management

Optimise foetal DO₂ by ↑ uterine perfusion pressure:

↑ Systemic driving pressure
↓ Intrauterine pressure
↑ Maternal oxygen saturation
Removing any cord impingement

Steps:

Listed in an ↑ degree of escalation.

Place in full left (or right) lateral position
Removes aorto-caval compression.
Reduce/cease oxytocin infusion
Reduces intrauterine pressure, reducing foetal compression and improving uteroplacental blood flow.
Give fluid bolus
500ml-1L CSL.
- Associated with improvement in foetal oxygenation even with adequate maternal driving pressure
- Caution in women with pre-eclampsia or receiving tocolytics
Give vasopressor
Particularly if foetal distress is epidural or spinal associated.
- Phenylephrine 50-100μg
- Ephedrine
Give tocolytics
- 250μg terbutaline SC
- GTN 60-180μg IV
  Likely faster onset and offset than SC terbutaline.
- GTN 800μg SL
Delivery
If foetal distress is not corrected by fixing reversible factors.

Second-line Strategies

Administer 15L/min O₂
- Placental transfer of oxygen is driven by tension (mmHg) rather than content (ml/100ml), and so this may be effective even in a normoxic mother
- Evidence supporting this practice is inconsistent, and potential harms have limited this practice
Alternate maternal position
May alleviate cord compression depending on relationship between pelvis, foetus, and cord. Consider:
- These positions
  - Full left lateral
  - Full right lateral
  - All fours
- Will probably be unhelpful if oligohydramnios or nuchal cord is present
Amnioinfusion
Transfusion of normal saline into the uterine cavity where foetal distres is due to cord compression secondary to oligohydramnios.
Elevation of the foetal vertex
Transvaginal elevation of the foetal head out of the birth canal for foetal distress due to cord prolapse.

References

Garite TJ, Simpson KR. Intrauterine resuscitation during labor. Clin Obstet Gynecol. 2011 Mar;54(1):28-39.
Thurlow, J.A., and S.M. Kinsella. Intrauterine Resuscitation: Active Management of Fetal Distress. International Journal of Obstetric Anesthesia 11, no. 2 (April 2002): 105–16. https://doi.org/10.1054/ijoa.2001.0933.