Vacuum-Assisted Delivery

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Chapter 254 Vacuum-Assisted Delivery

DESCRIPTION

Vacuum-assisted delivery is a method of assisting or expediting vaginal vertex delivery through the application of a vacuum assist device. (Discussion here is limited to vacuum-assisted deliveries with the fetus presenting within 45 degrees of directly occiput anterior.)

INDICATIONS

Fetal: nonreassuring fetal status, acute fetal distress. Maternal: fatigue, prolonged second stage of labor (nulliparous women: lack of continuing progress for 3 hours with regional anesthesia or 2 hours without regional anesthesia; multiparous women: lack of continuing progress for 2 hours with regional anesthesia or 1 hour without regional anesthesia), certain types of pulmonary, cardiac, or neurologic disease.

CONTRAINDICATIONS

Incompletely dilated cervix, significant fetal malpresentation, unengaged fetal head, intact fetal membranes, inability to assess fetal position or obtain maternal cooperation, distorted or contracted maternal pelvic anatomy, gestational age less than 34 weeks, fetal demineralization or clotting disorder, prior scalp sampling, or multiple attempts at fetal scalp electrode placement (relative).

REQUIRED EQUIPMENT

• Standard equipment for spontaneous vaginal delivery including sterile gowns and gloves

• Fetal heart rate monitor

• Vacuum delivery device (cephalic cup and vacuum hand pump); vacuum cups may be soft (pliable) or rigid and the shape may be domed (bell) or M-shaped (Soft cups are generally associated with less fetal trauma but a higher incidence of “pop offs.”)

TECHNIQUE

Adequate maternal anesthesia or analgesia should be ensured in all but the most extreme circumstances. Whenever possible, the maternal bladder should be emptied (by catheter). The exact position of the fetal head must be ascertained by palpation of the sagittal suture and fontanels. All other preparations for vaginal delivery should be in place before the vacuum device is applied.

Optimal placement of the vacuum cup is over the flexion point of the fetal head. Normally, the flexion point is in the midline, over the sagittal suture, approximately 6 cm from the anterior fontanel and 3 cm from the posterior fontanel. When the center of the vacuum cup is placed over this point, the edges of the cup should be roughly 3 cm from the anterior fontanel and just above the edge of the posterior fontanel.

To place the vacuum cup, the labia are separated and the bell-shaped cup is compressed and inserted it into the vagina while the device is angled toward the posterior vagina. (If an M-shaped or rigid cup is used, the device is flexed at the base of the shaft and inserted sideways into the vagina while being angled backward.)

The cup is placed in contact with the fetal head, with the center of the cup placed over the flexion point. The entire circumference of the cup must then be inspected (visually or by touch) to ensure that no maternal tissues intercede between the cup and the fetal head. The cup should be clear of both fontanels.

After correct placement of the cup is established, vacuum pressure should be increased to 100 to 150 mm Hg to maintain the cup’s position. The edges of the cup should again be swept to ensure placement and that no maternal tissues are entrapped. Just prior to traction, the vacuum should be increased to between 450 and 600 mm Hg. The maximal suction should not exceed 600 mm Hg.

Traction must be coordinated with maternal expulsive efforts. Traction on the vacuum device begins in a horizontal or slightly downward (axis of the maternal pelvic canal) manner. Rocking movements or torque should not be applied to the device; only steady traction in the line of the birth canal should be used. Traction is applied gradually as the contraction builds and is maintained for the duration of the contraction, coordinated with maternal expulsive efforts. During traction, the stem of the device must be kept perpendicular to the plane of the cup to maintain the seal with the fetal head to reduce the risk of detachment from the scalp. Traction should be gradually discontinued as the contraction ends or the mother stops pushing. Between contractions, suction pressure can be fully maintained or reduced to less than 200 mm Hg. (Fetal morbidity is similar either way.) To mimic the normal birth process, traction in the horizontal plane continues until the descending fetal head distends the vulva. (An episiotomy, if required, may be performed at this point.)

As the fetal head further distends the vulva, the axis of traction is gradually rotated upward, following the normal extension process of the head as it rotates under the symphysis. Once the brow is palpable through the perineum, the suction may be released and the vacuum cup removed, allowing the fetal head to be delivered by pressure on the perineum (modified Ritgen maneuver). More often, the cup may be left in place until the fetal chin has cleared the perineum. The remainder of the delivery proceeds as with a spontaneous delivery.

COMPLICATIONS

It is difficult (if not impossible) to separate the effects of vacuum-aided vaginal delivery from those of spontaneous vaginal delivery. Randomized trials and meta-analysis studies have failed to show conclusive differences. Both forceps delivery and vacuum extraction have been associated with the development of maternal hematomas and possibly linked to pelvic floor injury. However, other factors associated with pelvic floor injury include normal spontaneous vaginal delivery, episiotomy, prolonged second stage of labor, and increased fetal size. Similarly, studies have failed to identify neonatal or fetal injuries or developmental abnormalities that can be directly linked to vacuum-assisted delivery. Fetal scalp lacerations, cephalohematoma (14% to 16%), subgaleal (subaponeurotic) hematoma (26 to 45 per 1000), intracranial hemorrhage, hyperbilirubinemia, and retinal hemorrhage are all possible. The higher rates of neonatal jaundice associated with vacuum delivery may be related to the higher rate of cephalohematoma. Overall, the incidence of serious complications with vacuum extraction is approximately 5%.

CPT CODE(S)

59400 Routine obstetric care including antepartum care, vaginal delivery (with or without episiotomy, and/or forceps) and postpartum care

59610 Routine obstetric care including antepartum care, vaginal delivery (with or without episiotomy, and/or forceps) and postpartum care, after previous cesarean delivery

59409 Vaginal delivery only (with or without episiotomy and/or forceps);

59410 Vaginal delivery only (with or without episiotomy and/or forceps); including postpartum care

59612 Vaginal delivery only, after previous cesarean delivery (with or without episiotomy and/or forceps);

59614 Vaginal delivery only, after previous cesarean delivery (with or without episiotomy and/or forceps); including postpartum care

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American College of Obstetricians and Gynecologists. Vaginal birth after previous cesarean delivery. ACOG Practice Bulletin 54. Obstet Gynecol. 2004;104:203.

Cunningham FG, Gant NF, Leveno KJ, et al, editors Williams Obstetrics 21st ed. 2001 McGraw-Hill New York 503

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