The ex utero intrapartum treatment (EXIT) procedure is used to maintain utero-placental flow and fetal gas exchange allowing the management of a potentially obstructed fetal airway. The EXIT procedure was first proposed for the management of congenital diaphragmatic hernia but is now also being used when the fetal airway is compromised by cervical masses or congenital obstructions . Adequate uterine relaxation during the anaesthetic is obtained by high concentrations of inhalational agents, if necessary supplemented by nitroglycerin or tocolytics . We report a case of EXIT for a giant fetal cervical mass.
A 36-year-old gravida 2, para 1, was admitted in week 38 due to the presence of a giant fetal cervical mass. At 32 weeks of gestation, a right anterolateral fetal cervical mass of 8-cm diameter had been diagnosed by ultrasonography. Magnetic resonance imaging was performed which suggested a mass compatible with a cystic lymphangioma associated with airway deviation. A multidisciplinary team was assembled for management using the EXIT procedure.
The patient received midazolam 2 mg, omeprazole 40 mg and metoclopramide 10 mg intravenously (i.v.) as premedication. In addition to standard monitoring, maternal direct blood pressure was also established. After left uterine displacement and 100% oxygen administration for 5 min, general anaesthesia was induced by a rapid-sequence technique with thiopental 450 mg and succinylcholine 75 mg followed by endotracheal intubation. Anaesthesia was maintained with 50% nitrous oxide and 2-3% isoflurane in oxygen, fentanyl (2 μg kg−1) and vecuronium (0.1 mg kg−1). Ephedrine 5 mg boluses were administered i.v. to maintain maternal mean arterial pressure at >65 mmHg.
Head delivery occurred 26 min after induction. A uterine infusion with lactate Ringer's solution was begun to preserve uterine volume and prevent placental separation. While the feto-placental circulation was preserved, orotracheal intubation of the fetus was attempted by direct laryngoscopy and also by rigid broncoscopy but was unsuccessful. Tracheostomy was impossible due to the enormous cervical mass and gross distortion of the anatomy. A paediatric surgery team then performed partial resection of the cervical mass. The left arm of the fetus was then delivered, a sterile pulse oximetry probe placed and continuous electrocardiogram recorded. Atropine 0.05 mg and fentanyl 30 μg were administered intramuscularly to the fetus. After further surgical resection of the cervical mass, orotracheal intubation was achieved and confirmed by rigid bronchoscopy.
Fetal haemodynamics remained stable throughout the procedure with pulse oximetry values between 82% and 87% and heart rate 130-160 beats min−1. No extra tocolytics or nitroglycerin was necessary to reinforce uterine relaxation.
Sixty-eight minutes elapsed from maternal anaesthesia induction to umbilical cord clamping. At the time of clamping, umbilical artery pH was 7.26. The umbilical vessels were cannulated and the newborn was transferred to an adjacent operating room to complete surgical resection under general anaesthesia.
After delivery and cord clamping, isoflurane was discontinued and oxytocin 5 U was given i.v. followed by a continuous infusion (20 U of oxytocin per litre) and anaesthesia maintained using nitrous oxide 70% and oxygen 30%. Uterine tone improved and maternal bleeding was minimal. Neuromuscular blockade was reversed by neostigmine 2.5 mg and atropine 1 mg. The patient's preoperative haematocrit had decreased by 3%. She was discharged on the fourth day. The newborn was admitted to the intensive care unit and underwent further surgery to remove sublingual cysts on the thirteenth day.
Large fetal neck masses can cause a life-threatening situation after birth due to airway obstruction leading to asphyxia and secondary brain damage . In this case, the airway deviation by the cervical mass observed on the scan predicted intubation difficulty and therefore the EXIT procedure was planned for week 38. Management by a multidisciplinary team was of paramount importance to optimize fetal outcome.
General anaesthesia is the best technique for the EXIT procedure because it allows the use of high concentrations of inhalational agents important not only for the maintenance of uterine relaxation but also for fetal anaesthesia. Uterine relaxation is crucial to prevent placental separation, to maintain placental perfusion and fetal oxygenation while securing the fetal airway. The uterine atony caused by high concentrations of halogenated agents markedly increases the risk of maternal haemorrhage. A hysterotomy stapling device and the administration of oxytocin after clamping the umbilical cord minimizes bleeding. High doses of halogenated agents also induce maternal hypotension and consequently, fetal distress. Ephedrine is recommended for the prevention and treatment of maternal hypotension.
Excellent uterine relaxation was achieved with 2-3% isoflurane, the use of additional tocolytics being unnecessary. No uterine stapling device was necessary and haemodynamic stability was maintained with i.v. fluids and small doses of ephedrine. Blood loss was insignificant. The uterine infusion of warmed lactate Ringer's solution maintains uterine temperature and normal amniotic fluid volume and prevents umbilical cord compression.
During the EXIT procedure, fetal anaesthesia is essentially provided by administering inhalational agents to the mother and, if needed, supplemented with opiates and muscle relaxants. Fetal oxygenation depends on the uterine and umbilical blood flow, as well as on the maternal arterial oxygen content. Hundred percent oxygen during hysterotomy has been used in previous EXIT case reports although in this case, 50% oxygen was used and no fetal hypoxia was detected during the fetal surgery .
Uteroplacental support was maintained for 46 min. During this period, orotracheal intubation was attempted and partial recession of the mass was performed. The fetal pH after birth was 7.26, which suggests that uteroplacental gas exchange was acceptable. In a review of 52 EXIT cases, the average time of placental support was 45 ± 25 min with a maximum of 150 min .
In conclusion, the EXIT procedure allowed safe delivery of a fetus with cervical anomalies that would have interfered with ventilation.
Departamento de Anestesiologia e Cuidados Intensivos, Serviço de Anestesiologia, Hospital S.João e Faculdade de Medicina do Porto, Porto, Portugal
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