anesthetic consideration of fetal surgery

1. Dr pramod sarwa
Dr jayanth kumar

2. History of fetal surgery
 1965-first intrauterine transfusion…. A.W.Liley
 1974-fetoscopy …. Hobbin
 1981-fetoscopic transfusion…… Rodeck
 1982-first open fetal surgery for obstructive uropathy
by Dr. Michael Harrison (father of open fetal surgery),
University of California, San Francisco

3. What is fetal surgery
 It is application of established surgical techniques to
the unborn baby
-During gestation
- At the time of delivery

4. Fetal surgery -prerequisites
 Lesion
diagnosed accurately
severity is assessed correctly
defined natural history
 Associated anomalies are excluded
 Maternal risk is acceptably low
 Neonatal outcome would be better than with surgery
performed after delivery

5. fetal surgery
 contraindicated
 Chromosomal and genetic disorders
 Other associated life threatening abnormalities
 Timing
Usually performed between 24-29 weeks gestation
 Requires combined expertise of
 Obstetrician
 Anaesthesiologist
 Neonatologist
 Pediatric surgeon

6. Indications
 obstructive uropathy
 Congenital diaphragmatic hernia
 Cardiac anomalies-
complete heart block, AS, PS
 Neural tube defects
 Thoracic space occupying lesions
 Giant neck masses
 Tracheal atresia-stenosis
 Congenital adenomatoid
malformation (CCAM)
1. Anatomic lesions that interfere
with development:
2. Anomalies associated with
twins
• TTS-
twin-twin transfusion syndrome
• TRAP-
twin reverse arterial perfusion
3. Anomalies of placenta, cord or
membranes
• Amniotic band
• Chorioangioma

7. Types of fetal surgery
 Open surgery
 FETENDO-Fetal endoscopic surgery or fetoscopy or
minimally access fetal surgery (MAFS)
 FIGS-Fetal image guided surgery
 EXIT-Ex-utero intrapartum treatment procedure

8. Open surgery
 Most definitive and most invasive
 Performed – middle of pregnancy
 Mother anaesthetised by GA
 Uterus opened similar to LSCS
 Intraoperative sonography – locate the placenta
 Incision taken close to the area of interest
 Fetal part is exteriorized
 Surgical repair of fetus done

9. Indication for open fetal surgery
Defect Treatment
CCAM (Congenital cystic adenomatoid
malformation of lung)
Lobectomy
SCT (Sacro-coccygeal teratoma) Resection
MMC (Meningomyelocele) Repair
CDH Temporary tracheal occlusion
Obstructive hydronephrosis Vesicostomy, ureterostomy

10. FETENDO-fetal endoscopic surgery or MAFS
 Fetoscopic access to the fetus
 During or after the 18th week of pregnancy
 Useful for treating placental problems
 Technically difficult
 Maintains fetal position
 Under LA with infiltration of both skin and
peritoneum+/-sedation
 Under epidural, spinal or CSE anaesthesia
 High risk for urgent C-section: CSE preferred
 Sedation required for maternal anxiolysis

11. Fetendo
Advantages
 Less invasive
 Avoids maternal hysterotomy
 Less risk of amniotic fluid leak
 Less blood loss
 Less preterm labour and uterine rupture
Disadvantages
 Uterus irrigated with NS – absorbed to peritoneum
through fallopian tubes – pulmonary oedema as mother
also receives tocolytics. This can be treated with diuretics

12. Defect Treatment
E.g. CDH( Congenital diaphragmatic
hernia)
Balloon occlusion of trachea
TTTS (Twin-twin transfusion
syndrome)
Laser coagulation of vessels
Acardiac twins in TRAP sequence (twin
reverse arterial perfusion)
Cord ligation
ABS-Amniotic band syndrome Division of amniotic bands
BOO-Bladder outlet obstruction Vesicoamniotic shunt

15. FIGS - fetal image guided surgery
 Combination of endoscopic and sonographic method
 Ultrasound image guided procedure
 Done under RA or LA
Advantages
 Least invasive
 Least risk
of amniotic fluid leak
of preterm labour

16.  Both diagnostic and therapeutic uses
Diagnostic Therapeutic
-Chorion villus
sampling
-Amniocentesis
-Cordocentesis
-Fetal skin biopsy
-RFA of
anomalous twins
-Cord cauterization
in twins
-Vesical/pleural
shunts/catheter
-Balloon dilatation
of aortic stenosis

17. Ex-utero intrapartum treatment (EXIT)
procedure
OOPS-operation on placental support
 Intervention occurring at the time of delivery
 Used in cases where baby’s airway requires surgical
intervention
 Provide the baby with patent airway that can provide
oxygen to the lungs after separation of placenta
 Starts as a routine LSCS but under GA with maximum
volatile agent(>2 MAC)
 Head of the baby is delivered, but placenta is in situ
 Baby gets oxygen from placenta via umbilical cord

18.  Surgeon removes the
occlusive device
 Bronchoscopy of fetal airway
 Endotracheal intubation
done
 If unsuccessful, then
tracheostomy tube below the
level of airway blockage is
placed
 Oxygen delivery to lungs
confirmed
 Umbilical cord is clamped
 Baby delivered

19. Defect Treatment
CHAOS –
Congenital high airway obstruction
syndrome
Tracheostomy
CDH
(Congenital diaphragmatic hernia)
Removal of tracheal balloon
Giant cervical neck masses Resection
CCAM (Congenital cystic adenomatoid
malformation)
Resection

20. Considerations during EXIT
procedure
 Uterus needs to stay relaxed to permit placental
perfusion
 Uterus needs to contract at end to limit bleeding
 Needs hemostatic hysterotomy
 May permit upto 2 hours of ongoing placental
perfusion

21. Challenges before the field of fetal
surgery
 Ethical dilemma
 Maternal risk
 Fetal risk
 Maternal anaesthesia
 Fetal anaesthesia
 Post surgical tocolysis

22. Anaesthesia -basic considerations
 Pre operative evaluation and preparation
 Relief of anxiety
 Avoidance of fetal asphyxia
 Adequate analgesia
 Uterine relaxation
 Prevention of preterm labour
 Maternal safety
 Avoidance of teratogenic agents
 Fetal anaesthesia and monitoring

23. Fetal assessment
 Detailed USG to rule out other malformations
 Fetal echocardiography
 Fetal MRI
 3D and 4D examination
 Detail examination of affected organ system
 Amniocentesis
 Localisation of placenta and umbilical cord
 Volume of amniotic fluid

24. Pre-operative preparation
 Consent for caesarean delivery
 Maternal blood cross matched
 Availability of O-negative, CMV-negative, irradiated,
cross matched blood against the maternal antibodies
 Adequate aspiration prophylaxis
 Indomethacin rectal suppository for postoperative
tocolysis
 Epidural catheter-postoperative pain control
 Operating room temp

25. Avoidance of fetal asphyxia
 Avoidance of maternal hypoxia
 Avoidance of maternal hypercapnea
 Quick treatment of maternal hypotension
 Fluid boluses
 Vasopressors
 Decreasing anaesthetic concentration

26. Adequate analgesia
 Local anaesthesia-0.5 ml 1% lidocaine-infiltration of
both skin and peritoneum
 Field block
 CSE

27. Prevention and treatment of preterm labour
 Tocolytic agent
 indomethacin (rectal)
 magnesium sulfate
 terbutaline (subcutaneous)
 nitroglycerine
 Halogenated agents-halothane, isoflurane,
sevoflurane
 Vascular stasis during hysterotomy-special stapling
device
 Postoperative pain control-epidural catheter

28. Maternal sedation and local
anaesthesia
 Indicated in percutaneous needle aspirations or
catheter insertions
 Drug of choice-BZD(diazepam, midazolam),
narcotics(fentanyl, remifentanil) for maternal anxiety
 Disadvantages:
 increased hypoxia
 unprotected airway; aspiration risk
 presence of foetal movements
 Close monitoring for 3-4 hrs required

29. Regional anaesthesia
 Indicated in MAFS(Minimal access fetal surgery)
 Lumbar epidural, spinal or CSE anaesthesia
 Advantages:
 excellent analgesia and good muscle relaxation
 avoids GA
 keeps mother awake and alert
 minimal effects on fetal hemodynamics, uteroplacental
blood flow and uterine activity
 Disadvantages:
 Hypotension
 lack of fetal anaesthesia, difficulty manipulating uterus and
cord while the fetus may be moving

30. General anaesthesia
 Aspiration prophylaxis-sodium citrate, ranitidine,
metoclopramide
 Prevention of supine hypotensive syndrome-left lateral tilt
 Short acting amnestic-thiopentone
 Short acting muscle relaxant-succinylcholine for RSI
 Maintenance - 100% O2 with low levels of
inhalational(isoflurane) or 50% O2 and 50% N2O with low
inhalational + vecuronium + fentanyl
 Maternal and fetal monitoring

31.  Uterus opened similar to LSCS
 Fetal part is exteriorized
 Special stapling device
 Surgical repair of fetus done
 Warmed Ringer Lactate along with
antibiotics infused to replace amniotic fluid
 At the time of closure, i.v. MgSO4 6 gm over
20 minutes
 During extubation, coughing or straining
avoided to maintain integrity of uterine
closure

32. General anaesthesia
• Advantages:
• Profound uterine relaxation
• Allowing uterine manipulation with an immobile
anaesthetised fetus
• Disadvantages:
• Fetal cardiac depression
• Decreased uteroplacental blood flow

33. Maternal monitoring
 Pulse oximeter
 ECG
 HR
 BP monitoring
 Capnography
 Temperature

34. Fetal monitoring
 Blood gas, pH, pO2
 Blood glucose
 Electrolytes
 Fetal Hb from cord blood
 Electronic measurements of foetal
heart rate, blood pressure and
umbilical blood flow
 Foetal heart rate cardiotachometer-
FHR, temperature
 Foetal ECG
 Foetal echocardiography

35. Fetal anaesthetic considerations
 Fetal organ systems are immature
 Fetal cardiac output is sensitive to HR changes
 Fetus has high vagal tone and thus response to stress
with precipitous bradycardia
 Fetal circulatory blood volume is low, hence little
intra-operative bleeding can cause hypovolemia, so
trigger for transfusion is low
 During prolonged surgery, fetus need to be transfused
O-negative blood

36. Fetal pain
 Not possible to assess fetal pain directly
 Assessed indirectly by ability of fetus to mount a stress
response to noxious stimulus-increased fetal cortisol,
beta-endorphins and central sparing hemodynamic
changes
 Fetal administration of narcotic inhibits cortisol and
beta-endorphin release but does not inhibit central
sparing hemodynamic changes
 Fetal stress to pain starts in 8 weeks gestation age and
may cause preterm labour

37. Advantages of fetal surgery
 In utero environment supports rapid post-operative
healing
 Rapid healing, fostered by fetal growth factor
 Infections are combated by passage of maternal
immune factors
 Umbilical circulation meets nutritional and
respiratory needs without outside assistance
 Medical agents given directly to fetus have greater
efficacy at reduced doses

38. Postsurgical tocolysis
 High risk of preterm labour
 Pre-operative: rectal indomethacin
 MgSO4 is tocolytic of choice and maintained for 2-3
days-3 gm/hr infusion
 Adequate maternal analgesia as maternal pain can
cause preterm labour and fetal distress
 Epidural analgesia (PCEA) for 24-48 hrs is
recommended to prevent uterine contractility

39. New researches
 Remifentanil produces improved fetal immobilization with good
maternal sedation and only minimal effects on maternal
respiration (Anesth Analg, 2005)
 Continuous fentanyl infusion with midazolam provides
acceptable maternal analgesia and sedation during
fetoscopy(Masui, 2008)
 In fetoscopic interventions under GA, cardiopulmonary
functions remain stable. However, a moderate increase in
extravascular lung water(EVLW) and pulmonary vascular
permeability indicates an increased risk for maternal pulmonary
oedema(Br J Anaesth, 2013)
Future possibilities
 Stem cells or DNA to treat sickle cell anaemia or other genetic
conditions
 More potent tocolytics to control preterm labour
 Improved techniques of fetoscopic visualisation