The purpose of the study is to quantify biomarkers of neural damage in neonates exposed to varying levels of volatile anesthetic in utero.

This study will enroll 130 pregnant patients undergoing C-section or fetal surgery with EXIT (Ex Utero Intrapartum Treatment) procedures under epidural or general anesthesia with low (0.75 MAC) or high (2.5 MAC) concentrations of desflurane. Patients will be recruited from both the Hospital of the University of Pennsylvania (100 C Section) and Children's Hospital of Philadelphia (30 EXIT procedure).

The standard of care protocol for patients undergoing anesthesia for these cases will be followed throughout the surgery. These include monitoring and management of blood pressure, heart rate and rhythm, ventilation, oxygenation, temperature, and fluid status. Management of these parameters will be at the discretion of the clinical team. The choice of the anesthetic technique will also be at the discretion of the clinical team. Typical anesthetic management includes the following:

C-section under epidural anesthesia: induction and maintenance with 1.5% lidocaine, sodium bicarbonate and 1:200,000 epinephrine

C-section under general anesthesia: induction with propofol 2 mg/kg and succinylcholine 2 mg/kg intravenously; maintenance with desflurane 4.5-5%

EXIT procedure under general anesthesia: induction with propofol 2 mg/kg and succinylcholine 2 mg/kg intravenously; maintenance with desflurane 15-18%

1. After the baby is delivered, and the umbilicus is cut, two ml of blood will be taken from the umbilical vein and artery on the placenta side. A portion of the blood will be used for the blood gas and the remainder will be used for the S100B study assay.
2. 5 ml of blood will be taken from the mother via the existing intravenous catheter.
3. 5 ml of amniotic fluid will be obtained at hysterotomy and will be used for the S100B study assay.

All subjects will receive standard of care post operative clinical care and monitoring.

Inclusion Criteria:

1. Women delivering a child via cesarean section or EXIT procedure
2. Informed consent

Exclusion Criteria:

1. Known fetal neurologic defect

2. Known maternal neurologic abnormality

3. Sensitivity or allergy to medications used in the study

   1. C-section under epidural anesthesia: induction and maintenance with 1.5% lidocaine, sodium bicarbonate and 1:200,000 epinephrine
   2. C-section under general anesthesia: induction with propofol 2 mg/kg and succinylcholine 2 mg/kg intravenously; maintenance with desflurane 4.5-5%
   3. EXIT procedure under general anesthesia: induction with propofol 2 mg/kg and succinylcholine 2 mg/kg intravenously; maintenance with desflurane 15-18%

pregnant women