Anesthesia for Fetal Surgery: A Survey of Fetal Therapy Centers in the North American Fetal Therapy Network

Research background: identifying types of fetal surgery and anesthesia staffing among fetal therapy centers

Fetal surgery has rapidly evolved over the years. Numerous fetal therapy centers (FTC) around the world perform a wide range of fetal interventions to save the fetus, prevent permanent organ damage or allow for a successful transition to extrauterine life. The major types of fetal interventions include:

• Minimally invasive procedures
• Ex-utero intrapartum treatment (EXIT)
• Open fetal surgery

There has also been an evolution in the anesthetic management of fetal interventions, which varies depending on the approach and complexity of each procedure. Researchers conducted an online survey to identify the number and type of fetal interventions, anesthesia staffing models and techniques used at FTCs affiliated with the North American Fetal Therapy Network (NAFTNet).

Anesthesiologists and maternal fetal medicine specialists at the Colorado Fetal Care Center at Children’s Hospital Colorado were among the study authors, who hypothesized anesthesia staffing models and anesthetic techniques would greatly vary from center to center.

Research methods: a survey of anesthesiology directors at FTCs

A 45-question survey was sent to the anesthesiology director at every NAFTNet FTC about fetal interventions performed in 2018. The questions included:

• Location of FTC
• Types performed
• Average number
• Anesthesia staffing models
• Availability of labor and delivery services
• Anesthetic technique
• Fetal monitoring
• Post-operative management of patients

At the time of the survey, 40 FTCs were registered with NAFTNet, and four were excluded because they were not actively performing fetal interventions. Of the 36 remaining FTCs, 33 completed the survey, for a 92% response rate.

Location of FTC

• 15 within an adult university/academic hospital
• 4 within an adult community/private hospital
• 11 within a children’s hospital
• 3 within both an adult and children’s hospital

Subspecialty background of anesthesiology director

• 16 employed fellowship-trained obstetric anesthesiologists
• 7 employed fellowship-trained pediatric anesthesiologists
• 2 employed obstetric & pediatric anesthesia fellowship-trained anesthesiologists
• 5 employed anesthesiologists without fellowship training
• 3 employed no anesthesiology director

Types of procedures

All FTCs surveyed offer labor and delivery services and perform minimally invasive fetal interventions.

Annual number of minimally invasive procedures:

• 14 FTCs performed < 25
• 11 FTCs performed 26 to 75
• 8 FTCs performed 75 to 150

Of the FTCs surveyed, 30 perform EXIT procedures:

• All used general endotracheal anesthesia (GETA)
• 3 first attempted with neuraxial anesthesia and converted to GETA if the case required additional uterine relaxation with a volatile anesthetic
• Annual number of EXIT procedures:
  • 18 FTCs performed 1 to 2
  • 10 FTCs performed 3 to 5
  • 2 FTCs performed 6 to 10

Of the FTCs surveyed, 20 perform open mid-gestation fetal surgeries:

• All reported performing open myelomeningocele repairs
• All reported using GETA
• Annual number of open mid-gestation fetal surgeries:
• • 2 FTCs performed 1 to 2
  • 7 FTCs performed 3 to 5
  • 3 FTCs performed 6 to 10
  • 6 FTCs performed 11 to 20
  • 2 FTCs performed > 20 cases

FTCs that perform open fetal surgeries vs. those that do not

FTCs that perform open fetal surgeries are more likely to be directed by a pediatric surgeon and perform more than 25 minimally invasive procedures

Discussion: most common fetal surgery was minimally invasive

This is the first known formal survey of FTCs in the NAFTNet consortium to evaluate anesthesia staffing models and anesthetic techniques for fetal interventions.

Minimally invasive fetal interventions were the most commonly performed:

• All FTCs performed ultrasound-guided fetal interventions
• Almost all FTCs performed fetoscopic interventions
• The majority of FTCs performed ≤ 75 minimally invasive fetal interventions annually
• Almost half of the FTCs performed ≤ 25 minimally invasive fetal interventions annually

EXIT cases are rare:

• The majority of FTCs performed EXIT procedures
• > 90% of FTCs performed <5 EXIT procedures annually
• Almost half of FTCs used multiple subspecialty trained anesthesiologists
• 79% of FTCs used both obstetric and pediatric anesthesiologists

Open mid-gestation fetal surgeries likely benefit from multidisciplinary anesthesiology approach:

• 61% of FTCs performed open mid-gestation fetal surgeries
• 90% of FTC performed <10 annually
• 55% of FTCs used multiple anesthesiology subspecialists
• 82% of FTCs used both obstetric and pediatric anesthesiologists

When comparing FTCs that perform open fetal surgeries with those that do not, only two significant differences were found: FTCs performing open fetal surgeries are more likely to be directed by a pediatric surgeon, and these FTCs perform more minimally invasive fetal interventions.

Conclusions: there is a varied approach to fetal surgery amongst the centers

There is considerable variability in the anesthesia staffing, caseload and anesthetic techniques used across FTCs in NAFTNet. Most FTCs used maternal sedation for minimally invasive procedures and general anesthesia for EXIT and open fetal surgeries.

This survey is the first step toward developing standards and improving maternal and fetal anesthetic care in these complex cases.