Introduction
The ex utero intrapartum treatment (EXIT) technique was developed to provide cardiopulmonary support safely and efficiently during delivery while keeping the placenta functioning. The indications for using the EXIT approach are expanding and currently include various procedures such as establishing an airway, performing a resection, using extracorporeal membrane oxygenation (ECMO), and separating conjoined twins. EXIT surgery is conducted by a well-trained multidisciplinary team, employing a careful and gentle approach to accessing the uterine cavity. It significantly enhances the perinatal outcome. This technique ensures the safety of both the mother and the fetus.
What Is the EXIT Procedure?
The EXIT procedure is a unique delivery performed when it is expected that a baby will face an urgent and critical issue upon being separated from the mother during delivery. The EXIT technique involves partially delivering the fetus through a surgical incision in the uterus while maintaining relaxation and support from the placenta. This allows for the controlled establishment of neonatal cardiopulmonary stability. During the EXIT procedure, different interventions can be performed on the fetus, such as intubation, tracheostomy, mass excision, removal of a temporary tracheal occlusive device, and ECMO cannulation. The key aspect of an EXIT procedure is the collaboration of a multidisciplinary team with expertise in fetal intervention throughout the prenatal, intraoperative, and postpartum periods.
What Are the Goals of the EXIT Procedure?
During the EXIT procedure, the objectives include:
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Attaining a condition of uterine hypotonia to sustain the uteroplacental circulation through the utilization of profound general anesthesia.
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Safeguarding the uterine volume to avert placental abruption.
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Reaching a profound level of maternal anesthesia while ensuring the maintenance of normal maternal blood pressure.
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Accomplishing a surgical level of fetal anesthesia without inducing cardiac depression.
What Are the Types of EXIT Procedures?
Exit-To-Airway
The primary indication for the EXIT procedure is a fetus with a compromised airway due to a neck mass (such as cervical teratoma or lymphangioma), trachea or laryngeal atresia (leading to congenital high airway obstruction syndrome), or severe micrognathia. The EXIT procedure provides an opportunity to secure the fetal airway through techniques like laryngoscopy, bronchoscopy, endotracheal intubation, or tracheostomy. By performing the EXIT-to-Airway, an airway emergency can be transformed into a well-managed, premeditated procedure.
Exit-To-Extra-Corporeal Membrane Oxygenation (ECMO)
The EXIT-to-ECMO strategy is a helpful approach for severe pulmonary or cardiac malformations. It is used when separating from the uteroplacental circulation would immediately destabilize the newborn. In these cases, the strategy involves securing the airway and inserting venous and arterial cannulas for ECMO while still on placental support. This method ensures that there is no period of hypoxia or acidosis during neonatal resuscitation.
Exit-To-Resection
When dealing with large, high-risk chest tumors, including congenital pulmonary airway malformations (CPAM) of the lung or mediastinal teratomas that impede the intrathoracic trachea, the EXIT-to-Resection approach might be appropriate. When using the EXIT strategy, the goal is to allow the mass to be removed while preserving placental support. This will help with postnatal ventilation and guarantee an appropriate venous return to the heart in the event that pulmonary hypoplasia necessitates extracorporeal membrane oxygenation (ECMO).
What to Expect When Undergoing an EXIT Procedure?
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The mother is always given general anesthesia to induce sleep during the surgery. To prevent bleeding, a special uterine stapling device is utilized to open the uterus. While still connected to the placenta, the baby is partially delivered through the incision. The anesthesia helps keep the uterus relaxed, allowing the placenta to continue functioning.
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This procedure ensures that the exchange of gasses between the uterus and placenta is maintained, enabling the baby to receive oxygen and nutrients from the mother while the surgical team establishes an airway for the baby to breathe and obtain oxygen after delivery.
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There are potential risks associated with the EXIT procedure, such as uterine bleeding. However, these risks are minimized through close coordination between the surgeon and anesthesiologist. The clinical team works together to reduce the concentration of inhalation anesthetic and administer oxytocin to contract the uterus before cutting the umbilical cord.
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By combining this technique with the use of the uterine stapling device, the average amount of blood loss during the surgery remains within the accepted range for a traditional C-section.
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The successful outcome of an EXIT delivery relies on the seamless coordination of an experienced team, which includes pediatric surgeons, fetal and maternal anesthesiologists, maternal-fetal medicine specialists, neonatologists, and obstetrical, neonatal, and operating room nurses. This collaborative effort ensures excellent outcomes for both the mother and baby.
What Is Required to Carry Out an EXIT Procedure Successfully?
The first step involves identifying infants who require assistance with their airways during delivery. This is achieved by using high-resolution two dimensional and three dimensional ultrasound examinations that focus on the head and neck region. Additionally, ultrafast magnetic resonance imaging provides critical supplementary information. Once the prenatal diagnostic testing is complete, a team of skilled specialists who will be present during delivery will engage in discussions regarding the necessary management strategy.
The successful outcome of both the mother and the fetus depends on the collaborative planning of the expert team. The presence of obstetric and pediatric anesthesiology, neonatology, and appropriate pediatric surgical specialties during delivery, alongside the fetal therapy team, ensures a safe transition for the newborn into the world outside the uterus.
Conclusion
The EXIT procedure is a valuable method to secure the fetal airway before the delivery is fully completed and the umbilical cord is clamped. This procedure is particularly important in cases where there may be obstructions in the fetal oropharyngeal and cervical areas, as these can pose a serious threat to the baby's life upon birth. Allowing a trained multidisciplinary team to have controlled access to the fetal airway ensures that proper airway management can be carried out while still maintaining the circulation between the mother and the baby.
