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Making an EXIT (Ex-utero Intrapartum Treatment)

MUSC Children's Health
November 18, 2022
Matthew Finneran, M.D., Latha Hebbar, M.D., and William Carroll, M.D.
Dr. Matthew Finneran, Dr. Latha Hebbar, and Dr. William Carroll.

Obstetricians, ENT (ear, nose, and throat) surgeons and anesthesiologists, among other specialists, painstakingly prepare for, practice and perform one of the most complex fetal medicine surgeries to enable safe delivery of babies with a severe airway blockage.

By Gary Logan

Matthew Finneran, M.D., notes that in medical school he decided on a residency and career in general obstetrics and gynecology because it would allow him to experience the full scope of practice, including both surgery and primary care. Then he took a rotation in high-risk obstetrics that widened his vision to the challenges of managing two patients simultaneously, the mom and baby. Among the most complex conditions he would face, the high-risk obstetrician at the Medical University of South Carolina (MUSC) found, are conditions that compress fetal airways and pose a high risk of brain damage or death upon delivery.

Other causes include an underdeveloped lower jaw, tumors and a blockage of the trachea or larynx called Congenital High Airway Obstruction Syndrome (CHAOS).

"The airway can be malformed or obstructed, which makes it really difficult for the pediatric and neonatal team to take care of that baby before suffering brain damage from lack of oxygen," says Finneran. "Sometimes there are large lung masses needing immediate surgery for the baby."

That surgery is the EXIT procedure, or Ex-utero intrapartum treatment, which is as complicated as it sounds. In the simplest terms, Finneran says, the baby is partially delivered through a delicate incision in the uterus and remains attached to the umbilical cord and on placental support to allow time for surgeons to secure the baby's airway and fully repair the underlying condition another day. Once a baby is delivered and takes its first breath, the lungs kick in to do their job and the placenta, no longer required as a source of oxygen, detaches.

"An EXIT procedure extends mom's support of the baby for the critical period needed to provide some treatment so that baby can breathe again," says Finneran. "It provides pulmonary cardio bypass through the placenta."

In other words, the EXIT procedure is a potential on-ramp to a safe delivery for these vulnerable babies. But it doesn't happen without communication, coordination, planning and practice by the team members involved, including physicians in fetal medicine, neonatology and otolaryngology, or ear-nose-throat (ENT), and nurses. Detailed preparations begin following ultrasound detection of an airway obstruction or another anomaly indicating the need for the surgery. Considering the fetal indications and the gestational age required for delivery, an EXIT delivery is typically planned for between 33 and 39 weeks of gestation.

"We need to recommend delivery in this time frame—who is available and where and when can we coordinate the procedure and what supplies do we need?" says Finneran. "Much of the complexity of the procedure is in the coordination and communication between all the teams. There is no such thing as an emergent EXIT—it has to be planned for."

Obstetric anesthesiologist Latha Hebbar, M.D., adds, "In deciding how we're going to carry out the procedure we create a road map of where each one of us is situated in the operating room. Before the surgery, we do a rehearsal."

In the OR, first steps in making an EXIT include a small incision into the uterus. As bleeding from uterine muscle is the major concern here, surgeons choose the location of the incision carefully, ideally away from the placenta, and use a hemostatic stapler to reduce that risk. They then deliver only the head, neck and one arm—a partial delivery Hebbar calls "a C-section with a twist." At the same time the uterus, stimulated by the partial delivery, is now at risk of contracting and bleeding.

"When you deliver part of the baby, the uterus wants you to deliver the baby the rest of the way," says Hebbar.

Anesthesiologists counter that risk by filling the uterine cavity with saline via a transfuser and canula and administering medications to relax both the baby and the uterus and delay contractions.

"The uterus needs to be as floppy as ever," says Hebbar. "You have to trick the uterus into thinking it is still full and that the baby is still there."

These actions are designed to give the ENT team time to obtain the compromised airway and place a breathing tube down the throat. In some cases, if regular intubation doesn't provide access to the obstruction, bronchoscopy or, as a last resort, tracheostomy through the neck may be required. However, these are more technical procedures that take time to administer while the clock is ticking and increasing the risk of oxygen deprivation to the baby.

"ENTs may spend about 15 minutes attempting to get an airway in a patient that we deliver, and 15 minutes without breathing is a major problem," says Hebbar.

ENT surgeon William Carroll, M.D., agrees the procedure is a race against time and among the most challenging and stressful anatomical surgeries he performs. Why?

"You're working in unusual quarters up against the mother with the baby partially out," says Carroll. "The anatomy is usually going to be very challenging and then there's amniotic fluid everywhere making it more difficult to see."

As Carroll continues to work on securing an airway, Hebbar and the anesthesia team, which often includes a pediatric anesthesiologist, continue to monitor the mother and baby, keeping a sharp eye on the effects of medications designed to relax the baby that may adversely affect the mother.

"Anytime you administer medications to relax the smooth muscles of the uterus, you are also relaxing the smooth muscles of the mother's blood vessels, which can drop her blood pressure," says Hebbar. "That's the challenge—keeping the mother's blood pressure up while using the mother's placenta to perfuse the baby."

"Literally, you hold your breath until the ENT secures the airway," says Hebbar.

Then, once the airway is obtained, there comes the challenge of "transitioning from uterine relaxation to uterine contraction in a jiffy," says Hebbar. "We use short-acting medications to relax the uterus, so once it is turned off, the relaxant effects are reversed."

After the baby is delivered, medications are administered to increase uterine tone. A soft and weak uterus, which may occur when uterine muscles don't contract enough to clamp placental blood vessels after childbirth, can lead to life-threatening blood loss. Mothers are made well aware of such risks and what lies ahead for them and the baby early on.

"We have very long and detailed conversations about what this looks like and how we're doing the procedure in a way they really understand," says Finneran.

The need for the procedure remains relatively rare, note team members, but add that they are always prepared to prepare for the next case. The establishment of the Advanced Fetal Care Center at MUSC Shawn Jenkins Children's Hospital, they say, has enhanced communication between maternal fetal-medicine health and pediatrics in such complex cases requiring an EXIT procedure.

"We understand the uniqueness of having maternal-fetal medicine in a children's hospital and the value of being able to do simultaneous patient consultation with the pediatric team," says Finneran.

The rewards of the arduous planning and performing an EXIT in all its complexity?

"The patients know that everything possible was done to achieve the best outcome for their baby," says Finneran. "You go into this being as hopeful as possible but also knowing the baby has a severe condition, which is why we do an EXIT, to give the baby a chance."