Reducing the medicolegal risk of vacuum extraction

Fewer neonatal respiratory problems with vaginal delivery

Compared with cesarean section, vaginal delivery is thought to diminish the risk of intrapartum aspiration and respiratory problems in the newborn. It also may facilitate the transition from fetal to neonatal circulation and reduce the need for immediate resuscitation at birth.

Neonatal risks include soft-tissue injury and potential hemorrhage

Infants delivered by vacuum extraction have a significantly higher rate of intracranial hemorrhage, brachial plexus injuries, convulsions, central nervous system depression, and the need for mechanical ventilation, compared with spontaneously delivered infants (TABLE 3).^12,13

Although vacuum extraction is associated with a wide range of soft tissue injuries, they are often less serious than the fetal scalp injuries associated with obstetric forceps. Cup marks, bruising, and minor lacerations of the scalp and caput succedaneum are common fetal injuries, although the majority resolve without apparent sequelae.¹⁴

Subgaleal hemorrhage is the most serious neonatal complication of vacuum extraction, occurring in 1% to 3.8% of vacuum extractions (FIGURE).¹⁵ It coexists with neonatal coagulopathy in 19% to 29% of newborns¹⁶ and increases the risk of progression to hemorrhagic shock and death. Subgaleal hemorrhage has a mortality rate ranging from 2.7% to 22.8%.^15-17

Cephalhematoma is another complication associated with vacuum extraction. It involves an accumulation of blood beneath the periosteum of a cranial bone (usually the parietal bone), and it almost always resolves spontaneously. The incidence of cephalhematoma varies. It is significantly more common in deliveries involving vacuum extraction (9.8%) than in forceps deliveries (4.1%).¹⁸ Its incidence increases with the length of time the vacuum cup is applied and with paramedian application.¹⁸

Intracranial hemorrhage occurs in 1 of 860 vacuum extractions, 1 of 664 forceps deliveries, 1 of 954 cesarean deliveries, and 1 of 1,900 spontaneous deliveries.¹² Subdural hemorrhage is the most common form of intracranial hemorrhage and is almost invariably the result of birth trauma. However, asymptomatic subdural hematoma occurs in up to 6.1% of uncomplicated vaginal deliveries.¹⁹

Other, less common types of intracranial hemorrhage, such as subarachnoid, intraventricular, and intraparenchymal hemorrhage, have a more complex etiology, which includes birth asphyxia, hemorrhagic diathesis, infection, and vascular abnormalities.²⁰

Retinal hemorrhage also may occur after vacuum extraction, with an incidence of 49% to 77.8%, compared with 30.3% after forceps delivery, 30.4% after normal vaginal delivery, and 8.3% after cesarean delivery.²¹ It generally resolves spontaneously without any permanent damage.²²

TABLE 3

Vacuum extraction can injure the fetus

Shoulder dystocia and brachial plexus palsy

Vacuum extraction also is associated with shoulder dystocia and brachial plexus palsy, although the primary risk factor for these complications is thought to be increased fetal size.^23-25 The incidence of shoulder dystocia with vacuum extraction is 3.5%, compared with 1.5% for forceps delivery.²⁵

The risk of brachial plexus palsy also increases with vacuum extraction, especially as the duration of the procedure increases.²⁵

Less common complications associated with vacuum extraction are skull fractures, fetal hemorrhage from bleeding at the site of scalp electrodes, sepsis originating from infected scalp trauma, and corneal injury.

No long-term impairment

Long-term outcome studies of children delivered by vacuum extraction show no differences in physical or cognitive functioning or intelligence scores, compared with other modes of delivery.²⁶

3. Technique: Create conditions that ensure success

Certain prerequisites to vacuum extraction can assure successful application and strict adherence to protocol. These prerequisites include having an appropriate indication, thorough informed consent, proper maternal positioning, adequate anesthesia, and knowledge of fetal position and station (TABLE 4).¹ These objectives can be accomplished in the following steps:

1. After an informed consent discussion, assess maternal positioning and repeat the pelvic exam. Also ascertain the adequacy of anesthesia. Insert a bladder catheter.
2. Perform a “ghost” trial of vacuum extraction to visualize the procedure before the actual attempt.
3. Test the function of the vacuum.
4. Lubricate the vacuum cup with surgical soap or gel, insert it into the vagina, and maneuver it onto the fetal head. Place the vacuum extractor over the sagittal suture about 6 cm distal to the anterior fontanel and 2 cm proximal to the posterior fontanel. (The illustration on page 74 demonstrates positioning.) Apply a small degree of vacuum (approximately 20 mm Hg). Double-check application.
5. Gradually apply full vacuum (550–600 mm Hg, depending on cup size), allowing the scalp to mold to the extractor cup.
6. Apply 2-handed traction in concert with uterine contractions and supplemented by maternal pushing. Assuming there is no loss of vacuum (“pop-off” of the cup), the initial traction effort should produce a gain in station. If a “pop-off” occurs, a single additional attempt at delivery may be warranted.
7. As the head crowns, perform episiotomy as needed and slowly deliver the fetal head. Remove the vacuum cup.
8. After delivery of the placenta, inspect the vagina, cervix, and perineum closely.
9. Dictate a full operative note and annotate the delivery in the chart. See the section on documentation, below.