I. Indications
- Severe variable FHR decelerations
- Pts randomized to amnioinfusion vs. usual care had greater resolution of variable decels and, in nulliparous pts, was ass'd with decreased incidence of c/s (Am. J. Obs. Gyn 153:301, 1985; cited in AFP rvw)
- Thick meconium
- Might help either by diluting the mec, preventing variables that might lead to fetal gasping, or both
- Meta-analyses have reported decreased incidence of meconium aspiration syndrome and neonatal ventilation
- Some controversy exists as to its utility
II. Risks
- Generally safe; few case reports, e.g. of uterine scar disruption, elevated intrauterine pressure leading to fetal bradycardia, amniotic fluid embolism (though all reports ass'd w/other risk factors for that),
- Contraindications
- Amnionitis
- Polyhydramnios
- Uterine hypertonicity
- Multiple gestation
- Known fetal anomaly
- Known uterine anomaly
- Severe fetal distress
- Nonvertex presentation
- Fetal scalp pH < 7.20
- Placenta previa
- Abruptio placentae
III. Protocol
- FHR monitoring with fetal scalp electrode is recc'd
- Warming of infusion is not necessary
- Place intrauterine pressure catheter (IUPC) and document resting tone (should be < 15mm Hg)
- Practice varies
- One protocol for variables is for 250ml bolus over 20-30min then 10-20ml/min up to total infusion of 600ml or resolution of decelerations, then additional 250ml, then stop unless decels resume. Recc'd max total of 1 liter
- For thick mec, infuse 250-500ml over 30min then constant infusion at 60-180ml/h
- Use NS If intrauterine pressure is consistently elevated (> 30mm Hg or > 15mm Hg above baseline resting tone, d/c in fusion and recheck at 5min intervals
(Source: AFP 57:504, 1998)