Maternal Anesthesia for FetalSurgery

Hans P. Sviggum, MDa,b,*, Bhavani Shankar Kodali, MDb

KEYWORDS

� Fetal surgery � Obstetric anesthesia � Fetal anesthesia � EXIT procedure

KEY POINTS

� Fetal surgery is increasingly becoming a beneficial intervention for many fetal anomaliesdiagnosed in utero.

� Physiologic and anatomic changes related to pregnancy may require adaptations of sur-gical and anesthetic techniques.

� Open fetal procedures and ex utero intrapartum therapy (EXIT) procedures typically areperformed under general anesthesia, whereas minimally invasive procedures are routinelyperformed under neuraxial or local anesthesia.

� Maternal complications associated with fetal surgery include difficulties in airway man-agement, hemorrhage, infection, preterm labor, premature membrane separation, throm-boembolism, and pulmonary edema.

� Anesthesiologists must consider the anesthetic requirements of the fetus, includingimmobility and analgesia.

� A multidisciplinary approach with input and communication between nursing, obstetrics,pediatrics, surgery, maternal-fetal medicine, and anesthesiology optimizes coordinatedcare of both mother and fetus.

INTRODUCTION

Fetal surgery (Box 1) has evolved into a mainstream mode of therapy, giving manyfetuses with significant anomalies an increased chance of survival.1 Improvementsin diagnostic and therapeutic technology, along with advances in understanding fetalpathophysiology and the natural history of many of these conditions, have opened the

Funding Sources: None.Conflict of Interest: None.a Department of Anesthesiology, Mayo Clinic College of Medicine, 200 First Street Southwest,Rochester, MN 55905, USA; b Department of Anesthesiology, Brigham and Women’s Hospital,75 Francis Street, CWN-L1, Boston, MA 02115, USA* Corresponding author. Department of Anesthesiology, Mayo Clinic College of Medicine, 200First Street SW, Rochester, MN 55905.E-mail address: sviggum.hans@mayo.edu

Clin Perinatol 40 (2013) 413–427http://dx.doi.org/10.1016/j.clp.2013.05.012 perinatology.theclinics.com0095-5108/13/$ – see front matter � 2013 Elsevier Inc. All rights reserved.

Box 1

Fetal surgery overview

Techniques

1. Open fetal surgery

2. Minimally invasive fetal surgery

3. EXIT procedure: distinct fetal surgical technique, which includes a fetal procedure at thetime of cesarean delivery

Goals

1. Correct or improve a fetal anomaly

2. Minimize the risks posed to the mother

Sviggum & Kodali414

door for prenatal surgical interventions to prevent irreversible organ damage or fetaldemise.It is estimated that approximately 1000 fetal surgeries were performed in 2012 in the

United Sates, and this number likely will rise substantially in the near future.2 Currently,only certain fetal anomalies are amenable to in utero intervention during pregnancywhereas other conditions are better managed at or after delivery. Fetal surgery is areasonable option if several specific conditions are met (Box 2).Providing anesthesia for fetal surgery presents a unique challenge, because more

than one patient needs to be considered. The parturient has been referred to as an“innocent bystander,” who is exposed to surgical and postpartum risk but receivesno health benefits.3 The mother should always be protected from undue risks.4,5

MATERNAL ANESTHETIC ASPECTS OF FETAL SURGERY

An understanding of maternal physiologic and anatomic changes during pregnancyhelps anesthesiologists safely care for the mother. Although these changes are usuallywell tolerated, even subtle disturbances can have an impact on management. Thereare several changes that occur during pregnancy that can influence anesthetic man-agement (Table 1).

Inhalational anesthetics have a long history of successful outcomes in pregnancy.Local and regional anesthetic techniques are often used, however, in pregnant pa-tients for the following reasons6:

Box 2

Conditions that must be met for fetal surgery to be a reasonable option

� Informed consent obtained from parent(s)

� Correct diagnosis of a significant isolated fetal anomaly

� Accurate assessment of fetal anomaly, both in severity and prognosis

� Maternal risks of surgery and anesthesia acceptably low

� Reason to believe that neonatal outcome would be improved more by in utero interventionthan by postnatal surgery

� Multidisciplinary team in agreement regarding the treatment plan

� Patients with access to high-level medical, bioethical, and psychosocial care

Table 1Important systemic changes of pregnancy

System Changes Notes

Cardiovascular Cardiac output increases 30%–50%Systemic vascular resistance

decreases 30%

Due to increases in both heart rateand stroke volume

Respiratory Minute ventilation increases40%–50%

Oxygen consumption increases20%–40%

Function residual capacity isreduced 20%

Normal PaCO2 is 28–32 mm Hg

Mostly due to increased tidalvolume

Leads to rapid progression tohypoxia on apnea

Alveolar-arterial gradient is lower

Gastrointestinal Upward rotation of stomachProgesterone effectIncreased incidence of reflux

Relaxation of lower esophagealsphincter tone

Increased risk of aspiration

Hematologic Plasma volume increases more thanred blood cell volume increases

Most clotting factors increaseProtein and albumin levels decrease

Physiologic anemia (hematocrit33%–36%)

Consider thromboprophylaxisIncreased risk for edema

Renal Renal blood flow and glomerularfiltration rate increase

Normal serum creatinine values arelower (0.5–0.8)

Nervous Minimal alveolar concentrationdecreases 30%–40%

More extensive block after neuraxialanesthesia

Reduce doses for spinal and epiduralanesthesia

Anatomic Weight gain, soft tissue edema,increased vascularity of mucousmembranes

Enlarging gravid uterus,polyhydraminos

Each contributes to difficult airwaymanagement

Leads to aortocaval compression

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� Improved pain control� Reduced need for airway management� Reduced fetal drug exposure� Increased maternal safety� Patient preference

Fetal surgery is most often performed in the latter part of the second trimester orearly in the third trimester of pregnancy, with the exception of EXIT procedures thatare performed at the time of cesarean delivery. Patients undergoing fetal surgerysafely undergo general, neuraxial, or local anesthesia, depending on the type of pro-cedure. Although care should be adapted to individual patients, there are a few gen-eralities that apply to nearly all patients undergoing fetal surgery (Box 3).Prevention of preterm labor is an essential part of fetal surgery.7 Tocolytic agents

are used before, during, and after surgery, depending on the risk for preterm labor.Although well tolerated by most patients, they can contribute to maternal complica-tions, including the development of pulmonary edema.8 Other essential componentsof fetal surgery include blood pressure management (Box 4) and airway management(Box 5).Women with pregnancy-induced disease states (eg, preeclampsia) or other signifi-

cant comorbidities are usually not considered candidates for fetal interventions.

Box 3

Considerations for all patients undergoing fetal surgery

� Aspiration prophylaxis with multiple agents

� Left lateral decubitus positioning to prevent aortocaval compression

� Restrictive use of intravenous (IV) fluids to limit pulmonary edema

� Maintenance of end-tidal CO2 in normal range for pregnancy (30–34 mm Hg)

� Aggressive blood pressure treatment to maintain uteroplacental perfusion

� Developing a plan for adequate postoperative pain control

� Necessary equipment and personnel available should delivery become imminent

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Although there are no clear guidelines for the exclusion of candidates for fetal surgery,any coexisting disease that places the mother at a greater surgical or anesthetic riskmay be reason to withdraw her from consideration for the procedure. Anesthesiolo-gists must participate in multidisciplinary presurgical assessment efforts to determinewhether maternal risk is acceptably low for the potential fetal benefit.

FETAL ANESTHETIC ASPECTS OF FETAL SURGERY

Maternal anesthesia can have both direct (Box 6) and indirect effects on the fetus. In-trauterine asphyxia is the most important fetal risk, and anything that disrupts maternaloxygenation, ventilation, perfusion, or acid-base status is a potential threat to thefetus. Although transient mild decreases in maternal oxygenation or blood pressureare usually well tolerated by the fetus, maintenance of normal maternal hemodynamicparameters is critical to maintaining adequate uteroplacental blood flow. In addition,maternal hypercapnia can lead to fetal acidosis whereas hyperventilation candecrease maternal cardiac output, create uteroplacental vasoconstriction, and cause

Box 4

Blood pressure management

Rationale: maintaining normal or baselinematernal blood pressure during fetal surgery is vitalfor ensuring adequate uteroplacental perfusion.

Agents: historically, ephedrine has been the vasopressor of choice during pregnancy. Recentexperience has shown, however, both phenylephrine and ephedrine are safe and effective atmaintaining maternal blood pressure.9,10

Clinical pearls: the decision to use phenylephrine, ephedrine, or both in combination should beindividualized and guided by the maternal heart rate, suspected cause of hypotension, andfetal heart rate tracing. Regardless of the agent used, therapy should be administered as soonas the blood pressure begins to decrease rather than after the occurrence of clinicallysignificant hypotension.

Adjuncts: noninvasive cardiac output monitoring may be useful in guiding blood pressuremanagement and optimizing treatment.

Data from Cooper DW, Carpenter M,Mowbray P, et al. Fetal andmaternal effects of phenyleph-rine and ephedrine during spinal anesthesia for cesarean delivery. Anesthesiology2002;97:1582–90; and Lee A, Ngan KeeWD, Gin T. A quantitative systematic review of random-ized controlled trials of ephedrine versus phenylephrine for the management of hypotensionduring spinal anesthesia for cesarean delivery. Anesth Analg 2002;94:920–6.

Box 5

Airway management

Pregnant patients have a higher incidence of difficult airway management than nonpregnantpatients, with the rates of difficult and failed intubation approaching 3.3% and 0.4% of cases,respectively.11

A recent study confirmed that the expected incidence of failed tracheal intubation isapproximately 8 times higher in pregnant patients (1:224) than in the general population.12

Pregnant patients are also at higher risk for gastric aspiration.13 In addition, they have areduced functional residual capacity and an increased metabolic rate that can result in a rapidprogression to hypoxia on induction of general anesthesia.14

Recent advances in video laryngoscopy have increased intubation success,15 and this likelyholds true in the pregnant population as well.16

Maternal Anesthesia for Fetal Surgery 417

a leftward shift of the oxyhemoglobin dissociation curve—all of which can compro-mise fetal oxygenation.The question of whether a fetus experiences pain continues to be a challenge.20

Fetuses undergoing procedures at mid to late gestation may have the requisite neuraldevelopment and the hormonal and hemodynamic stress responses to noxious stimulito indicate they are capable of experiencing pain.29–31 Despite ongoing debateregarding fetal experiences of pain, fetal anesthesia and analgesia are warranted forfetal surgical procedures because they serve additional purposes unrelated to painreduction,29 including

Box 6

Anesthetic effects on the fetus

Volatile anesthetics

These have direct depressant effects on fetal cardiovascular system. Low concentrations (1–1.5minimal alveolar concentration) have minimal fetal effects in animal models.17 Higherconcentrations may result in fetal acidosis,18 although prolonged or deep maternal inhalationanesthesia has not been shown to cause fetal hypoxia or acidosis clinically.19

Intravenous agents

Induction agents and opioids can decrease fetal heart rate variability but do not lead to fetalmorbidity as long as maternal hemodynamic parameters remain stable.20

Teratogenicity

There is no evidence of teratogenicity of anesthetic agents used at clinical concentrations anddoses in pregnant women undergoing surgery.21 Several early retrospective studies linked first-trimester diazepam use with an increased incidence of cleft palate; however, the currentconsensus is that benzodiazepines are safe for clinical use.22,23

Neurodevelopmental consequences

Some animal studies show that an exposure of an immature brain to anesthetic agents cancause neurodegeneration, decreased spatial recognition, impaired memory, and subsequentlearning problems.24,25 This evidence is weak, however, and mixed within human studies.26

These adverse neurodevelopmental consequences may be attenuated or blocked by providingadequate fetal analgesia and anesthesia.27

A recent review suggests changes in clinical practice should not be based on animal studies andthat a change in current practice is currently unwarranted.28

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� Inhibiting fetal movement� Achieving uterine relaxation� Preventing hormonal stress responses associated with poor fetal outcomes� Possibly preventing adverse effects on long-term neurodevelopment andbehavior responses to pain

The current consensus is to provide fetal analgesia and anesthesia during all poten-tially painful fetal interventions.32

Fetal anesthesia and analgesia can be achieved by placental transfer of agentsgiven to the mother or by direct fetal administration intramuscularly or through umbil-ical vessels. Intra-amniotic administration of agents can potentially be effective,33

although this is not routinely used in practice. Fetal anesthesia helps prevent fetalmovements and has also been shown to blunt fetal stress responses to noxiousstimuli.34 Medications that may be used for fetal anesthesia, immobility, or resuscita-tion include

� Fentanyl (10–50 mg/kg)� Vecuronium (0.1–0.3 mg/kg) or pancuronium (0.1–0.3 mg/kg)� Atropine (0.02 mg/kg)� Epinephrine (1 mg/kg)

These medications should be ready for the surgeon to administer in single-dosesyringes to avoid accidental overdosing.19 If the clinical situation dictates, O-negative,cytomegalovirus-negative, leukocyte-depleted blood should be available in 5 mL/kgto 10 mL/kg aliquots in case fetal transfusion becomes necessary.

Open Fetal Surgery

Open surgery involves a hysterotomy. An epidural is placed for postoperative paincontrol but is not dosed before surgery to avoid any contribution to intraoperative hy-potension. Preoperative intrathecal opioids can be used as an alternative to epiduralanalgesia. After a rapid sequence induction and intubation, volatile anesthetics areused for anesthetic maintenance because they produce dose-dependent uterinerelaxation desired for optimal surgical exposure and placental gas exchange.20,35 Iso-flurane is less potent than desflurane or sevoflurane in producing uterine relaxation,36

although all 3 agents have been used successfully. Early institution of high concentra-tions of volatile agents for long periods of time before hysterotomy may cause hypo-tension and has also resulted in the development of intraoperative fetal bradycardia,especially with the use of desflurane.37 It may be prudent to use supplemental IV anes-thesia initially and only increase the volatile anesthetic concentrations to 2 to 3 minimalalveolar concentration to achieve the desired uterine tone just before hysterotomy. Anarterial line is usually placed after induction for close monitoring of blood pressure.Central venous access is rarely needed.The surgeon assesses uterine tone for adequate relaxation before hysterotomy. IV

nitroglycerin boluses (50–100 mg IV) or infusion (0.5–1 mg/kg/min IV) can be usedfor uterine relaxation when placental transfer of volatile agent is not sufficient to obtainoptimal uterine tone. In cases when neuraxial anesthesia is used, IV nitroglycerin canbe used as the sole agent for intraoperative uterine relaxation.38,39 This technique maybe associated with greater maternal morbidity, including hypotension, reflex tachy-cardia, methemoglobinemia, tachyphylaxis, headache, and pulmonary edema.40,41

After ensuring placental positioning, the uterine incision is made with a stapling deviceto prevent excessive bleeding and seal the membranes to the endometrium. Amnioin-fusion with warm lactated Ringer solution is used to keep the fetus warm, maintain

Maternal Anesthesia for Fetal Surgery 419

uterine volume, and prevent umbilical cord compression.40 Vasopressors arecommonly needed to maintain adequate maternal blood pressure (maintaining utero-placental perfusion), particularly with the use of high concentrations of volatile anes-thetics. IV fluids should be limited to reduce risk of postoperative pulmonary edema.5

Fetal well-being can be assessed intraoperatively with fetal pulse oximetry, intermit-tent or continuous fetal echocardiography, fetal scalp electrodes, and umbilical bloodsampling.35 Although placental transfer of inhalational agents may provide adequatefetal anesthesia and immobility, fentanyl and a muscle relaxant are commonly admin-istered directly to the fetus (intramuscularly) (discussed previously). After uterineclosure, the volatile agent can be greatly reduced or discontinued to limit its effecton uterine tone. Anesthesia can be maintained with IV agents (eg, propofol) and/ornitrous oxide. The epidural catheter is activated after ensuring hemostasis and hemo-dynamic stability, facilitating a timely, comfortable emergence. Coughing or strainingduring emergence should be avoided to prevent disruption of the uterine closure.Adequate postoperative pain control is associated with lower maternal concentra-

tions of oxytocin,42 reducing the risks of uterine contractions and preterm labor. Ifneeded, systemic opioids can supplement a functioning epidural catheter. Preopera-tive rectal indomethacin (50 mg) and postprocedure magnesium sulfate (4–6 g IVloading dose, followed by 1–2 g/h IV infusion) are administered for tocolysis.43 If uter-ine contractions persist, additional tocolysis with indomethacin, nifedipine, or terbuta-line may be used.7 Magnesium potentiates the effects of nondepolarizing musclerelaxants, and diligent monitoring of neuromuscular function is required (Box 7).Emergence from anesthesia is a critical time period. A review of maternal deaths at

cesarean delivery under general anesthesia revealed that no maternal deathsoccurred during induction or maintenance of anesthesia; all the deaths occurred dur-ing extubation and emergence from anesthesia.45 Extubation should only occur whena patient is fully awake and responsive and when muscle relaxation has been reversedto minimize the chance of gastric aspiration or loss of airway tone.Mothers undergoing open fetal surgery are typically not allowed to labor in current

or future pregnancies due to increased risk of uterine rupture after vertical uterine in-cisions, rates of which are comparable to those after classic cesarean section.46 Otherpotential maternal risks of open fetal surgery include5

� Pulmonary edema� Hemorrhage� Premature rupture of membranes

Box 7

Neuromuscular blockade

Neuromuscular blocking drugs do not readily cross the placental barrier. They do not produceuterine relaxation.

Despite increased hepatic clearance, pregnant patients are more sensitive to nondepolarizingneuromuscular blocking drugs.

The duration of succinylcholine-induced block may be reduced due to an increased volume ofdistribution (despite reduced plasma cholinesterase), although clinical dosing for intubation isthe same as in nonpregnant patients.

Despite both being quaternary compounds, neostigmine may cross the placenta more readilythan glycopyrrolate due to its low molecular weight. If there is concern about neostigmine-induced fetal bradycardia during reversal of neuromuscular blockade, atropine can be usedinstead of glycopyrrolate because it freely crosses the placenta.44

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� Chorion-amnion membrane separation� Preterm labor� Preterm delivery (and subsequent complications of prematurity)� Fetal demise� Chorioamnionitis� Placental abruption� Increased need for maternal transfusion at the time of delivery

Most mothers tolerate surgery well, however, and ICU admissions are generally notnecessary.

Minimally Invasive Fetal Surgery

To reduce maternal and fetal morbidity, surgical approaches without large incisions ora hysterotomy have been developed, which reduce the stresses inflicted on motherand fetus compared with open surgery.1 These minimally invasive endoscopic, percu-taneous, and image-guided procedures on the fetus, placenta, or membranes haveevolved from largely diagnostic procedures into therapeutic modalities that haveproved successful for treating many fetal conditions, including

� Twin-twin transfusion syndrome: laser ablation of vessels47

� Obstructive uropathy: shunt insertion and valve ablation48

� Aortic or pulmonary stenosis: valvuloplasty (Fig. 1)49

� Cyanotic heart disease: atrial septostomy50

� Congenital diaphragmatic hernia: tracheal balloon occlusion51

� Spina bifida: fetoscopic closure of the malformation52

� Twin reversed arterial perfusion: radiofrequency ablation53

Maternal anesthetic management for minimally invasive surgery has both similaritiesand differences compared with open fetal surgery and EXIT procedures (Box 8,Table 2).When using local or regional anesthesia, the fetus does not receive any anesthesia,

analgesia, or immobility.55 Many minimally invasive procedures (eg, selective laser

Fig. 1. Ultrasound-guided needle placement into fetal left ventricle. A balloon catheter wassubsequently placed through the needle across the aortic valve for performance of aorticvalvuloplasty.

Box 8

Anesthesia for minimally invasive surgery

General, neuraxial, and local anesthetic techniques have been used successfully for minimallyinvasive surgeries.54

If general anesthesia is used, less volatile anesthetic is needed compared with open surgerybecause uterine relaxation is not necessary.

Profound uterine relaxation can make maintaining correct fetal position difficult.

Maternal hemodynamic stability may be achieved more easily with neuraxial anesthesia forfetoscopic fetal surgery.

Neuraxial anesthesia is chosen over local anesthesia based on the following factors20:

1. Anatomic location of surgery

2. Length and complexity of procedure

3. Desire for postoperative analgesia

4. Probability of progressing to cesarean delivery

Maternal Anesthesia for Fetal Surgery 421

photocoagulation of communicating vessels) do not require fetal immobilization oranesthesia, whereas others do to prevent fetal movement, responses to noxious stim-uli, and pain (eg, aortic valvuloplasty). Supplemental maternal sedation and analgesiawith IV opioids, benzodiazepines, and/or low-dose propofol can provide varying

Table 2Comparing management of different types of fetal surgery

Open Surgery Minimally Invasive EXIT

Gestational age Late 2nd/early 3rdtrimester

Late 2nd/early 3rdtrimester

Time of delivery

Maternal anesthesia General, epiduralfor postoperativeanalgesia

Local or neuraxialanesthesiaa � IVsedation

General, � epiduralfor postoperativeanalgesia

Desired uterine tone Complete relaxation Minimal relaxation Complete relaxation

Fetal anesthesia Transplacentalinhalation agents,direct (IM orumbilical cord)opioids andmuscle relaxants

Direct (IM orumbilical cord)opioids andmuscle relaxantsor transplacentalopioidsb

Transplacentalinhalation agents,direct (IM orumbilical cord)opioids andmuscle relaxants

Preterm labor risk Increased Minimal Not applicable

Invasive bloodpressuremonitoring

Yes No Yes

Amnioinfusion Yes No Yes

Future laborallowed

No Yes Yes

Abbreviation: IM, intramuscular.a Local anesthesia is usedmostly for surgery on the placenta or membranes. Neuraxial anesthesia

is used for more complex fetoscopic procedures.b Remifentanil is most reliable.

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degrees of fetal immobility and anesthesia via placental transfer. Specifically, remifen-tanil has been shown to provide adequate maternal sedation and fetal immobiliza-tion.56 Direct intramuscular or umbilical vein administration of a nondepolarizingmuscle relaxant results in onset of fetal paralysis in approximately 2 minutes, lastingfor 1 to 2 hours.57 Similarly, direct opioid administration to the fetus supplementsany medications given to the mother. Atropine is often coadministered to prevent fetalbradycardia. At the authors’ institution, ultrasound-guided intramuscular fentanyl andvecuronium are given for fetal immobility and anesthesia for all fetoscopic proceduresperformed under maternal regional anesthesia.Unlike with open fetal surgery, patients undergoing minimally invasive surgery are

usually allowed to labor in their current and future pregnancies. Compared withopen fetal surgery, there is a reduced risk of preterm labor and delivery due to lessuterine manipulation and trauma. Risks of chorion-amnion membrane separation, pre-term rupture of membranes, infection, and bleeding remain as well as morbidity asso-ciated with improper endoscope or needle placements.7

Ex utero Intrapartum Treatment Procedures

The EXIT procedure is a modification of cesarean delivery. Although placental supportis maintained, the baby is partially (head and upper torso) or, less often, completelydelivered. Procedures needed for the infant’s survival are performed before clampingthe umbilical cord and completing the delivery (Figs. 2 and 3). The EXIT procedure isprimarily performed in cases of potential airway compromise to allow for continuingplacental perfusion and oxygenation until a definitive airway has been established.Most procedures last a matter of minutes (eg, tracheal intubation), but procedureslasting more than 2 hours have been successfully performed.58 Although pregnancyshould be extended close to term to decrease the complications of prematurity, theEXIT procedure is ideally performed before onset of labor or development of fetalcompromise.Most EXIT procedures are performed with the mother under general anesthesia,

using high concentrations of volatile anesthetics at the time of hysterotomy for uterinerelaxation.40 Uterine relaxation is important not only to facilitate delivery of fetal headbut also to prevent placental separation and to preserve uteroplacental flow during theprocedure. An arterial line for close blood pressure monitoring and judicious use ofvasoactive medications to maintain normotension and adequate uteroplacental bloodflow are imperative, similar to open fetal surgery.

Fig. 2. EXIT procedure showing intubation of a fetus with a large cervical teratoma.

Fig. 3. EXIT procedure with intubation and neck incision for extracorporeal membraneoxygenation initiation in a fetus with severe congenital heart disease.

Maternal Anesthesia for Fetal Surgery 423

An epidural catheter may be placed preoperatively for postoperative analgesia.Rapid sequence induction and intubation are used to secure the airway, as describedpreviously for open fetal surgery. Amnioinfusion with warm lactated Ringer solution isprovided to keep the fetus warm, maintain uterine volume, and prevent umbilical cordcompression.40 Fetal analgesia and anesthesia can be directly administered as previ-ously described, either before (under ultrasound guidance) or after (under direct vision)hysterotomy. When neuraxial anesthesia is performed, IV nitroglycerin is used for pro-found and transient uterine relaxation (described previously).38,39

Ideally, a second anesthesiologist dedicated to the baby ensures that there isnecessary equipment (eg, pulse oximeter) and medications for the fetus. A secondadjacent operating room should be available if additional surgery should be neededon the baby after delivery. Increased uterine blood flow during pregnancy, reduceduterine tone from volatile anesthetics and tocolytics, and possible need for verticaluterine incision all increase the risk of hemorrhage, particular during lengthy proce-dures.59,60 Blood products for both mother and baby should be available foradministration.After complete delivery of the baby, uterine tone should be prioritized to prevent

excessive bleeding from uterine atony and the placental bed. Reducing or eliminatingvolatile anesthesia in favor of IV agents with or without nitrous oxide and administeringoxytocin can accomplish this. Additional uterotonic agents should be available in caseuterine atony persists.40 After ensuring hemodynamic stability, the epidural cathetermay be loaded with a bolus of local anesthetic and opioid to ensure patient comfortat the time of emergence. With adequate preparation and vigilance, maternal out-comes after EXIT procedures are comparable to those after cesarean delivery.58,61

Postoperative Management

Postoperative maternal management of patients undergoing fetal surgery includes

� Close monitoring of fetal heart rate and uterine activity during the immediatepostoperative period after minimally invasive surgery and for the first 24 to48 hours after open fetal surgery

� Adequate analgesia using a multimodal regimen with acetaminophen, opioids(oral, parenteral, or neuraxial), neuraxial and local anesthetics, nonpharmaco-logic modalities, or a combination of these

Sviggum & Kodali424

� Consideration of venous thromboprophylaxis, especially in those patients withlimited mobility

� Postoperative tocolytic administration as part of a regimen designed to preventpreterm labor

SUMMARY

Maternal fetal surgery is a multidisciplinary effort that requires vigilant communicationbetween teams of physicians and nurses. Maternal anesthetic care can be demandingbecause of the physiologic and anatomic changes associated with pregnancy. Main-tenance of adequate blood pressure, prevention of hypoxia and acidosis, andproviding adequate analgesia are the cornerstones of creating a safe environmentfor the fetus. In addition to providing maternal anesthesia, it is recommended to pro-vide adequate fetal anesthesia and analgesia during potentially painful proceduresduring in utero life.Not all infants benefit from early intervention and fetal surgery. More work is needed

to determine whether baseline characteristics can predict which fetuses are more orless likely to benefit from prenatal surgery and in developing less traumatic ap-proaches to fetal interventions.62 Further studies are also needed to determine theoptimal anesthetic technique that ensures maternal and fetal cardiovascular stability,optimal uteroplacental perfusion, necessary uterine relaxation, adequate fetal anes-thesia and immobility, minimal fetal myocardial depression, and adequate blockadeof the fetal stress response.

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