By definition, the diagnosis of shoulder dystocia requires a time delay (60 seconds or more) between the delivery of the baby’s head and shoulders. (1) The American College of Obstetricians and Gynecologists (ACOG) defines shoulder dystocia as a condition requiring special maneuvers to deliver the shoulders. Traditionally, brachial plexus palsies injuries have been attributed to the impaction of the shoulder behind the symphysis, and to excessive force applied to the fetal head in an attempt to release the shoulder. Whether or not they are the result of a “difficult” delivery, brachial palsies are a major source of obstetrical litigation. (2) Nearly 30 percent of infants with brachial plexus palsy have no identifiable risk factors. (1, 2) As a result, prediction and prevention of shoulder dystocia remains difficult. Macrosomia, one of the major risk factors for shoulder dystocia, remains hard to predict with either Leopold maneuvers or ultrasound examination. ACOG guidelines recommend cesarean section delivery for fetuses having an estimated weight greater than 5,000 grams in non-diabetic mothers, and over 4,500 grams for mothers with diabetes. Despite an increase in cesarean section deliveries, the incidence of brachial plexus injury has not decreased. (1,2)

Case Report

A 16-year-old primigravida with poorly controlled type I diabetes was diagnosed with shoulder dystocia. Initial management included the McRoberts maneuver combined with simultaneously applied suprapubic pressure. Both took approximately one minute and failed. Then rotational maneuvers were applied, then Wood’s corkscrew, followed by attempts to deliver a posterior arm. They took around four minutes and also were unsuccessful. At this point, the fetal head turned blue and became very edematous. Maternal soft tissues were very swollen as well, effectively ruling out Zavanelli maneuver. At this point, the decision was made to intubate the fetus once the head and upper portion of the neck had been delivered. After the first attempt of orotracheal intubation failed, a transoral intubation was performed successfully using rigid bronchoscope. Improvement of fetal head and face color was noted within 60 seconds. The additional time allowed the team to resume their efforts and finally resolve the condition successfully. The newborn was finally born weighing 4,250 grams, with Apgar scores of three at one minute and eight at five minutes. The newborn was diagnosed with mild brachial palsy and was discharged home on day nine. Symptoms of brachial palsy resolved by six months of age. Symphysiotomy incision healed well and three months later, the patient was discharged from the orthopedic ambulatory service.

Discussion

Over 90 percent of shoulder dystocia cases can be resolved within minutes by the sequential use of the McRoberts maneuver and suprapubic pressure, rotational maneuvers, and finally the delivery of the posterior arm. The greatest effect was seen with delivery of the posterior arm, which decreased anterior nerve stretch by 71 percent and showed an 80 percent decrease in delivery force. (2) However, severe shoulder dystocia may become a perilous complication for the fetus causing severe asphyxia. Hope et al. (3) reviewed autopsy results on 56 cases of fatal shoulder dystocia. Maternal obesity and large babies were overrepresented in labors complicated by fatal shoulder dystocia. Fetal distress was recorded in 26 percent of cases. Animal studies would suggest that a healthy fetus could withstand at least 5-10 minutes of hypoxia and still respond to resuscitation. Mechanisms of fetal demise in severe cases of shoulder dystocia may be different than those in cerebral hypoxia due to umbilical cord prolapse or placental abruption. (3) In cases of shoulder dystocia, compression of the neck causes cerebral venous obstruction, further aggravated by excessive vagal stimulation and fetal bradycardia. From the clinical standpoint, when all the efforts to resolve shoulder dystocia appear fruitless, the Zavanelli maneuver remains the last hope. The Zavanelli maneuver consists of cephalic replacement with subsequent delivery by cesarean section. (5) However, the Zavanelli maneuver is not always possible and, in the best scenario, requires additional time. In our case, significant maternal soft tissues and fetal neck edema ruled out the Zavanelli maneuver. At this point, the decision was made to perform fetal head intubation to allow more time for the resolution of shoulder dystocia while maintaining fetal oxygenation. Intubation of the fetus before severing the umbilical cord had previously been reported and named (i.e., EXIT procedure). (6-8) The EXIT procedure offers the advantage of ensuring uteroplacental gas exchange while on placental support. (6, 7) Skarsgard et al. (8) first described the EXIT procedure for management of fetuses with in utero airway obstructions.

Now, the EXIT procedure is used for a variety of indications, including teratomas, laryngeal atresia, among others. (9-12) The EXIT procedure is based on a multidisciplinary approach, with the goal of maintaining airway patency in extrauterine life. It uses the nasotracheal intubation, laryngeal mask, or tracheostomy, while uteroplacental circulation is maintained. In this way, asphyxia due to tumor compressive effect can be avoided, while treating the obstruction. The EXIT surgery provides a 45-60 minute working time, to ensure control of the neonatal airway, while the fetus has uteroplacental perfusion. This technique involves many risks. An adequate uteroplacental perfusion must be maintained, with a good uterine relaxation, and a recommended mean arterial pressure above 65 mmHg with CVP around 10 cmH20. (14) The EXIT procedure secures excellent fetal blood perfusion, but it is frequently accompanied by poor uterine relaxation, the appearance of arterial desaturation, bradycardia, placental abruption, or umbilical cord compression. (16, 17)

Previously, our experience with in utero excess to fetal oropharynx (13, 14) led us to consider intubation of the fetal head as a temporary measure to maintain fetal oxygenation, which allows more time to resolve shoulder dystocia. Details of measurement of severe shoulder dystocia is beyond the scope of the report. Our goal was to present head intubation as a step to allow extra time for further measures while sustaining fetal oxygenation.

References

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