Upload
pramod-sarwa
View
925
Download
1
Embed Size (px)
Citation preview
Dr pramod sarwaDr jayanth kumar
History of fetal surgery1965-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
What is fetal surgeryIt is application of established surgical
techniques to the unborn baby -During gestation - At the time of delivery
Fetal surgery -prerequisitesLesion 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
fetal surgerycontraindicated
Chromosomal and genetic disordersOther associated life threatening abnormalities
Timing Usually performed between 24-29 weeks
gestation
Requires combined expertise ofObstetricianAnaesthesiologistNeonatologistPediatric surgeon
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
Types of fetal surgeryOpen surgeryFETENDO-Fetal endoscopic surgery or
fetoscopy or minimally access fetal surgery (MAFS)
FIGS-Fetal image guided surgeryEXIT-Ex-utero intrapartum treatment
procedure
Open surgeryMost definitive and most invasivePerformed – middle of pregnancyMother anaesthetised by GAUterus opened similar to LSCSIntraoperative sonography – locate the placentaIncision taken close to the area of interestFetal part is exteriorizedSurgical repair of fetus done
Indication for open fetal surgeryDefect 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
FETENDO-fetal endoscopic surgery or MAFSFetoscopic access to the fetusDuring or after the 18th week of pregnancy Useful for treating placental problemsTechnically difficultMaintains fetal positionUnder LA with infiltration of both skin and
peritoneum+/-sedationUnder epidural, spinal or CSE anaesthesiaHigh risk for urgent C-section: CSE preferredSedation required for maternal anxiolysis
FetendoAdvantagesLess invasiveAvoids maternal hysterotomyLess risk of amniotic fluid leakLess blood lossLess preterm labour and uterine ruptureDisadvantagesUterus irrigated with NS – absorbed to peritoneum
through fallopian tubes – pulmonary oedema as mother also receives tocolytics. This can be treated with diuretics
Defect TreatmentE.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
FIGS - fetal image guided surgeryCombination of endoscopic and sonographic
methodUltrasound image guided procedureDone under RA or LA
AdvantagesLeast invasiveLeast risk of amniotic fluid leak of preterm labour
Both diagnostic and therapeutic usesDiagnostic 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
Ex-utero intrapartum treatment (EXIT) procedure OOPS-operation on placental supportIntervention occurring at the time of deliveryUsed in cases where baby’s airway requires
surgical interventionProvide 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
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 clampedBaby delivered
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
Considerations during EXIT procedureUterus needs to stay relaxed to permit
placental perfusionUterus needs to contract at end to limit
bleedingNeeds hemostatic hysterotomyMay permit upto 2 hours of ongoing placental
perfusion
Challenges before the field of fetal surgeryEthical dilemmaMaternal riskFetal riskMaternal anaesthesiaFetal anaesthesiaPost surgical tocolysis
Anaesthesia -basic considerations
Pre operative evaluation and preparationRelief of anxietyAvoidance of fetal asphyxiaAdequate analgesiaUterine relaxationPrevention of preterm labourMaternal safetyAvoidance of teratogenic agentsFetal anaesthesia and monitoring
Fetal assessmentDetailed USG to rule out other malformationsFetal echocardiographyFetal MRI3D and 4D examinationDetail examination of affected organ systemAmniocentesisLocalisation of placenta and umbilical cordVolume of amniotic fluid
Pre-operative preparationConsent for caesarean deliveryMaternal blood cross matchedAvailability of O-negative, CMV-negative,
irradiated, cross matched blood against the maternal antibodies
Adequate aspiration prophylaxisIndomethacin rectal suppository for
postoperative tocolysisEpidural catheter-postoperative pain controlOperating room temp
Avoidance of fetal asphyxiaAvoidance of maternal hypoxiaAvoidance of maternal hypercapneaQuick treatment of maternal hypotension
Fluid bolusesVasopressorsDecreasing anaesthetic concentration
Adequate analgesiaLocal anaesthesia-0.5 ml 1% lidocaine-
infiltration of both skin and peritoneum
Field block
CSE
Prevention and treatment of preterm labourTocolytic agent
indomethacin (rectal)magnesium sulfateterbutaline (subcutaneous) nitroglycerine
Halogenated agents-halothane, isoflurane, sevoflurane
Vascular stasis during hysterotomy-special stapling device
Postoperative pain control-epidural catheter
Maternal sedation and local anaesthesiaIndicated in percutaneous needle aspirations
or catheter insertionsDrug of choice-BZD(diazepam, midazolam),
narcotics(fentanyl, remifentanil) for maternal anxiety
Disadvantages:increased hypoxiaunprotected airway; aspiration riskpresence of foetal movements
Close monitoring for 3-4 hrs required
Regional anaesthesiaIndicated in MAFS(Minimal access fetal surgery)Lumbar epidural, spinal or CSE anaesthesiaAdvantages:
excellent analgesia and good muscle relaxationavoids GAkeeps mother awake and alert
minimal effects on fetal hemodynamics, uteroplacental blood flow and uterine activity
Disadvantages:Hypotensionlack of fetal anaesthesia, difficulty manipulating
uterus and cord while the fetus may be moving
General anaesthesiaAspiration prophylaxis-sodium citrate, ranitidine,
metoclopramidePrevention of supine hypotensive syndrome-left
lateral tiltShort acting amnestic-thiopentoneShort acting muscle relaxant-succinylcholine for RSIMaintenance - 100% O2 with low levels of
inhalational(isoflurane) or 50% O2 and 50% N2O with low inhalational + vecuronium + fentanyl
Maternal and fetal monitoring
Uterus opened similar to LSCSFetal part is exteriorizedSpecial stapling deviceSurgical repair of fetus doneWarmed 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
General anaesthesia• Advantages:
• Profound uterine relaxation• Allowing uterine manipulation with an
immobile anaesthetised fetus
• Disadvantages: • Fetal cardiac depression• Decreased uteroplacental blood flow
Maternal monitoringPulse oximeterECGHR BP monitoringCapnographyTemperature
Fetal monitoring Blood gas, pH, pO2Blood glucoseElectrolytesFetal Hb from cord bloodElectronic measurements of foetal
heart rate, blood pressure and umbilical blood flow
Foetal heart rate cardiotachometer-FHR, temperature
Foetal ECGFoetal echocardiography
Fetal anaesthetic considerationsFetal organ systems are immatureFetal cardiac output is sensitive to HR
changesFetus has high vagal tone and thus response
to stress with precipitous bradycardiaFetal 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
Fetal painNot possible to assess fetal pain directlyAssessed 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
Advantages of fetal surgeryIn utero environment supports rapid post-
operative healingRapid healing, fostered by fetal growth factorInfections are combated by passage of
maternal immune factorsUmbilical circulation meets nutritional and
respiratory needs without outside assistanceMedical agents given directly to fetus have
greater efficacy at reduced doses
Postsurgical tocolysisHigh risk of preterm labourPre-operative: rectal indomethacinMgSO4 is tocolytic of choice and maintained
for 2-3 days-3 gm/hr infusionAdequate maternal analgesia as maternal pain
can cause preterm labour and fetal distressEpidural analgesia (PCEA) for 24-48 hrs is
recommended to prevent uterine contractility
New researchesRemifentanil 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 conditionsMore potent tocolytics to control preterm labourImproved techniques of fetoscopic visualisation