EXIT procedure: Uterine atony
The ex utero intrapartum treatment (EXIT procedure) involves partial delivery of the infant and maintenance of uteroplacental circulation long enough to secure the airway and provide potentially lifesaving interventions (bronchoscopy, tracheostomy, cannulation for ECMO) based on the condition of the neonate. It was initially used for patients diagnosed with congenital diaphragmatic hernias in utero, but is now used for neonates with congenital heart disease, teratomas, cystic hygromas, and other pathology.
Unlike Caesarean sections, in which excess uterine relaxation is to be avoided, for the EXIT procedure uterine relaxation should be maximal (facilitates delivery; maintains fetal DO2; provides anesthesia for the fetus). Usually this is accomplished with 2-3 MAC of volatile anesthetic . This may lead to uterine atony and hypotension , the former of which may be reduced via the use of a uterine stapling device and immediately reducing the volatile anesthetic agents and bolusing oxytocin after the cord is clamped (as well as starting an oxytocin infusion, and keeping methergonivine (0.25 mg), carboprost (250 µg), and calcium immediately available and the latter of which may require administration of significant pressors (bearing in mind that low uterine vascular resistance is essential ) . Uterine blood loss can be substantial.
- General anesthesia with 2-3 MAC to facilitate uterine perfusion
- Favor ephedrine over phenylephrine (also to facilitate uterine perfusion)
- After cord clamping, immediately lower volatile levels and bolus oxytocin