Difficult Airway of Fetus: Making a Safe Ex Utero Intrapartum Treatment.

Large neck masses involving the airway can lead to hypoxia or the demise of the newborn in case the airway is not secured in time. A planned ex utero intrapartum treatment (EXIT) enables to access the airway by various means under optimal conditions. Advancements in imaging and well-orchestrated teamwork enable to improve the survival by EXIT procedure. Copyright:

INTRODUCTION

Perinatal management of large neck masses is always challenging because of difficulty in accessing the distorted airway and if unidentified has a mortality of 80%–100%.[1] The advancements in prenatal diagnosis of these masses have helped in developing various strategies, one of which being the ex utero intrapartum treatment (EXIT), which has improved the survival in these patients. We report a case of EXIT procedure performed in 36 weeks of gestation with a fetus having large cervical lymphatic malformation.

CASE REPORT

A 29-year-old female, G3P2 L1A1, at 31-week pregnancy, presented with an antenatal scan showing polyhydramnios and a fetus having a large cervical mass. Fetal magnetic resonance imaging (MRI) [Figure 1] was suggestive of a large multiseptated neck mass of size 10 cm × 9 cm × 5 cm involving the lower face and the anterior neck and extending into the mediastinum. The mass was displacing and compressing the trachea on the opposite side.

Figure 1

Fetal magnetic resonance imaging (T2-weighted sagittal image) with a large cervical mass causing tracheal compression (marked with arrow)

The findings were discussed with a multidisciplinary team comprising an obstetrician, a neonatologist, a pediatric surgeon, an anesthesiologist, a radiologist, a pulmonologist, and ear-nose-throat specialists. The mode of delivery, timing of delivery, and associated risks were discussed. Because of distorted airway anatomy, conventional cesarean seemed to be the least favorable option and all team members decided to plan delivery by EXIT procedure. Weekly meetings involving nursing staff and technicians were conducted to discuss all necessary strategies to access the airway. The parents were counseled and informed consent was taken. The necessary sets of airway equipment including endotracheal tubes (ET), neonatal rigid bronchoscope, and tracheostomy were procured. It was decided to plan the procedure at completion of 36 weeks.

A cesarean section was performed under complete monitoring using the EXIT procedure. The challenge for anesthetists was to avoid hypotension due to deep general anesthesia and the risk of bleeding. Rapid sequence induction with fentanyl, propofol, and succinylcholine was performed, and maintenance was done with sevoflurane and vecuronium.

A wide low-transverse laparotomy and a low anterior segment hysterotomy incision was given, exposing the layers sequentially. As the uterine stapler was not available, reefing sutures were used to control the bleeding. After entering the uterine cavity, amnioinfusion was started with a warm lactated ringer solution. To prevent spontaneous breathing, fetal anaesthesia was given with vecuronium and fentanyl over the right arm of the partially delivered fetus, with a pulse oximeter in place. The fetus was intubated with difficulty in two attempts with ET no. 2.5 mm using direct laryngoscopy within 14 min [Figure 2]. After the intubation, the cord was clamped and cut. The newborn was transported to the nursery on a ventilator. The total duration of the EXIT procedure was 91 min. Maternal blood loss was estimated to be 600 mL, and she was extubated at the end of the procedure.

Figure 2

Hysterotomy and ex utero intrapartum treatment procedure for securing the airway

After stabilization, the baby underwent MRI, which was suggestive of a large lymphatic malformation with predominantly microcystic components (80%–85%) involving the neck and upper mediastinum. The extubation was attempted but failed. Flexible bronchoscopy was done which revealed the lymphatic malformation involving the oropharyngeal mucosa. Given the predominantly microcystic component and failed attempts to extubate, the decision was taken for excision of the mass. The partial excision of the mass around the trachea was done with the purpose to relieve the obstruction around the trachea. Even after the surgery, the child could not be extubated and subsequently required tracheostomy probably because of the oro-pharyngeal involvement. The histopathology confirmed it to be lymphatic malformation. At present, the child is on tracheostomy with the plan to start sclerotherapy.

DISCUSSION

After being first described by Norris in 1989, with the advancements in ultrasound techniques, EXIT procedure has been refined and is used for large cervical masses with anticipated airway obstruction. Unlike routine cesarean, EXIT is a high-risk procedure to the mother as it carries a high risk of bleeding because of general anesthesia and the use of uterine relaxants. The commonly used criteria for EXIT delivery are deviation/compression/obstruction of the airway and involvement of the floor of the mouth.[2]

The principle of the procedure is to create a controlled environment so that the airway of the fetus can be secured using direct laryngoscopy, bronchoscopy, or tracheostomy with intact feto–placental circulation. To prevent the placental detachment, complete uterine relaxation and maintenance of uterine volume are mandatory.

Most of the large published series of EXIT procedure[234567] for neck masses report a success rate of 94%–100% with a no or very low fetal mortality (<3% in one series). There have been no maternal deaths reported. The access to the airway was successfully achieved in 48%–92%, with direct laryngoscopy/bronchoscopy and tracheostomy required in 7%–53% of cases. The duration of placental support required will depend on the type of intervention performed on the fetus. The placental bypass duration in these series has varied from a minimum of 2 min to a maximum of 150 min. If maternal hemodynamics is stable, the uteroplacental circulation can be maintained for >90 min, although in the case of cervical teratoma reported by Hirose et al.,[5] resection of mass and tracheostomy was performed in 150 min. It is important to define every step/alternative step and designate the time for each step to minimize the duration of access to the airway before the cessation of feto–placental circulation. Ideally, the procedure should be planned near or at term, although associated polyhydramnios always increases the risk of premature delivery. The team has to be prepared in advance in the case of unavoidable circumstances to schedule the procedure even in early gestation.

Various strategies which can help in reducing the maternal complications are adequate management of polyhydramnios to avoid premature delivery, placental mapping by ultrasound to avoid any inadvertent bleeding, use of uterine staplers to avoid bleeding and reduce the intraoperative time, and good coordination between surgeon and anesthetist.[7]

CONCLUSION

EXIT procedure should be considered whenever there is a potential risk of fetal airway obstruction so that airway access can be achieved under controlled settings without any risks to the mother and fetus. A detailed informed consent regarding the failure of the procedure, fetal demise, and associated maternal risks should be taken. A well-planned strategy by experienced multidisciplinary planning is mandatory for the optimal outcome of the EXIT procedure.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.