Anaesthesia for foetal ex-utero intrapartum therapy (EXIT) surgery

Dear Editor, Ex-utero intrapartum therapy (EXIT) allows the survival of children with congenital high airway obstruction (CHAOS), a condition considered incompatible with life. Herein, we describe the specifics of managing such a case under general anaesthesia. A 28-year-old primigravida presented at 20 weeks gestation with polyhydramnios, gross foetal ascites, bilateral echogenic enlarged lungs, and magnetic resonance imaging-confirmed CHAOS in the foetus. An EXIT procedure was planned jointly by a multidisciplinary team involving foetal medicine, paediatric surgery, and anaesthesia. Resuscitation drugs and O-negative, leukocyte-reduced, irradiated, cytomegalovirus-negative blood for the foetus and group-matched blood for the parturient were kept ready. General anaesthesia with rapid sequence induction was performed with intravenous propofol 1.5 mg/kg, fentanyl 2 µg/kg, and tracheal intubation was performed after administering suxamethonium 1.5 mg/kg intravenously. Invasive arterial and central venous pressure monitoring were performed. Uterine relaxation was maintained with sevoflurane at 2.0–3.0 minimum alveolar concentration (MAC). Normothermia was maintained in the parturient with forced air warmers and warmed intravenous fluids. An intramuscular foetal cocktail comprising fentanyl 20 µg/kg, atropine 20 µg/kg, and vecuronium 0.2 mg/kg was prepared under sterile precautions for foetal immobility and analgesia. Following a transverse hysterotomy on the lower uterine segment, continuous irrigation of warm lactated Ringer’s solution into the uterus maintained the uterine volume while maintaining temperature for the foetus. A live male baby was partially extracted vertex first and brought out of the uterine incision till the level of its nipple [Figure 1]. An attempt to intubate the baby’s trachea was made with laryngoscope with Miller’s blade 00 but was unsuccessful. A tracheostomy was performed in 15 minutes, before clamping the cord, while the baby was maintained on the placental circulation. On ventilating with an Ambu bag connected to oxygen, chest rise was seen and bilateral air entry confirmed on auscultation. Following this, the cord was clamped and the baby delivered. Sevoflurane was reduced to 1.0 MAC after the delivery of the baby. Intravenous oxytocin 3 U bolus followed by an infusion of 20 U over 1 h was administered to restore uterine tone. After confirmation of adequate uterine contraction, the parturient was extubated after the procedure. The baby, weighing 2.38 kg, was shifted to the neonatal intensive care unit for further management.Figure 1: Tracheostomy with foetus in-uteroCHAOS can result from laryngeal atresia, laryngeal web, laryngeal cyst, subglottic stenosis, or tracheal atresia.[1] These lead to accumulation of lung fluid and high intrathoracic pressure, which reduce venous return and result in hydrops.[2] One-third of foetuses do not survive, one-third spontaneously establish airway, while one-third present uncorrected at birth. Our patient presented with a foetus that lacked airway communication between the glottis and the tracheal tree [Figure 2]. General anaesthesia with opioids is the preferred anaesthetic technique as risk of respiratory depression to the baby is not a concern.[3,4] We used sevoflurane at 2–3 MAC, and the uterine incision was made following the assessment of relaxation of uterine tone by manual palpation. The high MAC used for uterine relaxation can cause foetal bradycardia. Supplementing intravenous propofol or remifentanyl can reduce the inhalational agent requirement and facilitate uterine relaxation. If uterine relaxation is inadequate, then intravenous nitroglycerine boluses (50 µg) or an infusion can be used. Blood pressure falls should be corrected with intravenous ephedrine (3 mg), phenylephrine boluses (50 µg) or phenylephrine infusion 10–200 µg/min.[5] The delivery of the foetal head may need assisted instrumentation as the relaxed uterus does not assist the effort of delivery. Hypothermia in the foetus can be prevented by constant infusion of warm crystalloid into the uterine cavity, while cord kinking should be watched for or discontinued. Following the delivery of foetus, good contraction of uterus is needed; inhalational agents should be reduced; and oxytocin, carboprost, and manual massage of the uterus may be required to enable effective uterine contraction. Multidisciplinary management and meticulous monitoring are crucial for favourable outcomes.[6]Figure 2: Computed tomography – lateral view showing the absence of airway continuityDeclaration of patient consent The authors certify that they have obtained all appropriate consent forms. In the form, the parents consented to the images and other clinical information to be reported in the journal. The parents understand that the name and initials will not be published and due efforts will be made to conceal neonate identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.