Clinical Review

Reducing the medicolegal risk of vacuum extraction

OBG Manag. 2007 June;19(6):74-87

References

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7. Bofill JA, Rust OA, Schorr SJ, et al. A randomized prospective trial of the obstetric forceps versus the M-cup vacuum extractor. Am J Obstet Gynecol 1996;175:1325-1330.

8. Salamalekis E, Loghis C, Pyrgiotis E, et al. Soft cup vacuum extractor versus forceps delivery. J Obstet Gynecol. 1995;15:245-246.

9. Zetterstrom JP, Lopez A, Anzen B, et al. Anal incontinence after vaginal delivery: a prospective study in primiparous women. Br J Obstet Gynaecol. 1999;106:324-330.

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18. Bofill JA, Rust OA, Devidas M, et al. Neonatal cephalohematoma from vacuum extraction. J Reprod Med. 1997;42:565-569.

19. Doumouchtsis SK, Arulkumaran S. Head injuries after instrumental vaginal deliveries. Curr Opin Obstet Gynecol. 2006;18:129-134.

20. Govaert P. Cranial Hemorrhage in the Term Newborn Infant. London: Mac Keith Press; 1993.

21. Hughes LA, May K, Talbot JF, Parsons MA. Incidence, distribution, and duration of birth-related retinal hemorrhages: a prospective study. J AAPOS. 2006;10:102-106.

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24. Mollberg M, Hagerg H, Bager B, et al. Risk factors for obstetric brachial plexus palsy among neonates delivered by vacuum extraction. Obstet Gynecol. 2005;106:913-918.

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Vacuum extraction may fail for a number of reasons (TABLE 5).

TABLE 4

Perform these predelivery checks before applying traction

Is anesthesia adequate? Is maternal positioning correct?
Is the bladder empty?
Is the fetus in the proper attitude (flexion)?
Is fetal status reassuring?
Is the vacuum properly applied? The handle of the soft-cup extractor is parallel to the sagittal suture No maternal tissue is beneath the cup margin The middle of the cup is positioned over the point of cranial flexion (point F). This point lies in the midline above the sagittal suture. Cup margins should be about 3 cm distal to the posterior edge of the anterior fontanel
Has the patient been instructed on when and how long to push?
Are the proposed maneuvers appropriate?

TABLE 5

Why might vacuum extraction fail?

INSTRUMENT-RELATED
Pump failure
Vacuum leak
TECHNIQUE-RELATED
Failure to encourage maternal valsalva with traction efforts
Inappropriate intensity of traction
Incorrect axis of traction
Maternal tissue trapped beneath vacuum cup
Poor cup position
OBSTETRIC CONDITIONS
Congenital anomaly anencephaly ventriculomegaly
Fetal macrosomia
Incomplete cervical dilation
Position and attitude problems deflexion occiput posterior position asynclitism
Unappreciated cephalopelvic disproportion
SOURCE: Modified from Plauche et al³²

Most important variable: Cup placement

The single most critical step in vacuum extraction is placement of the cup. It should be applied at the point of maximum fetal cranial flexion, which is proximal to the leading edge of the posterior fontanel.

Once full vacuum is achieved, encourage the mother to push with the next contraction, and apply steady traction in concert with her efforts.

The initial application of traction should be directed to maintain proper flexion of the fetal head, and should bring about descent of the fetal head. If there is no descent with the first application of traction, and correct technique and cup placement have been applied, abandon operative vaginal delivery (TABLE 6).

Do not make a further attempt to deliver the child using forceps, as the risk of intracranial hemorrhage appears to be highest in infants delivered using a combination of vacuum extraction and forceps.

TABLE 6

Repeat traction efforts reap a diminishing return

NUMBER OF TRACTION EFFORTS	SUCCESS RATE
NUMBER OF TRACTION EFFORTS	VACUUM EXTRACTION (N=433)	FORCEPS (N=555)
1 or 2	68.4%	38.4%
3 or 4	24.9%	48.6%
5 or more	6.7%	12.9%
Adapted from Sjostedt³³

4. Documentation: The chart is the most important witness

The value of complete and contemporaneous notation cannot be overstated. The patient’s chart is the permanent repository of the record of delivery. It is without doubt the most important witness to the event and should be treated as such. Include a dictated operative note as well as notation in the chart itself. Notes should be legible and properly dated, with the time of day indicated.

When operative vaginal delivery is performed, record the following:

indication for the procedure
course of labor
anesthesia
personnel present
instruments used
position and station of the fetal head
force and duration of traction
complications, including how they were recognized and managed
immediate condition of the newborn and all steps taken in resuscitation.

Assisted delivery has walked a long and winding road

Operative vaginal delivery is no newcomer to obstetrics. Hindu writings from about 1000 BC, and Hippocrates’ own musings from the fifth century BC, describe instruments and techniques to combat arrested labor and salvage the lives of both mother and child.²⁷ Crude forceps were described by the Muslim physician Albucasis in the 11th century.²⁷

Before the advent of safe cesarean section, many maternal lives were no doubt saved by these instruments and techniques. Unfortunately, destruction of the fetus and maternal death were frequent outcomes of operative vaginal delivery by forceps before the 20th century.²⁸

As for vacuum extraction in particular, the idea of attaching a device to the fetal head to aid in delivery is credited to Arnett, a 19th century surgeon and inventor, who envisioned the “pneumatic tractor.”²⁹

In 1957, Malmstrom reintroduced the vacuum as an aid in delivery, designing a rigid cup that was connected by rubber tubing to a vacuum source.³⁰ This allowed the separation of the pump mechanism from the cup and made for easier application.

Most recently, Kobayashi developed the soft-cup design, a low-cost flexible plastic alternative that allows for a disposable instrument.³¹

Minimizing medicolegal risk

The best way to prevent an accusation of medical malpractice is to develop strong clinical and interpersonal skills. These simple, intuitive suggestions may help:

Understand the role of operative vaginal delivery in current practice.
Develop a simple and interactive discussion model for use in labor and delivery with the patient and her family.
Consider a woman’s preferences for delivery.
Know the indications and contraindications for vacuum extraction.
Use the checks and safeguards listed under 3. Technique: Create conditions that ensure success.
Perform vacuum extraction in the cesarean section room. Stop the procedure at once if any problem arises, and proceed to cesarean delivery.
Make all chart notations completely legible, and add dictated notes.