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Proper cup placement: technique called key to vacuum delivery success.

YOSEMITE, CALIF. -- Hematomas from vacuum delivery most often are caused by improper placement of the cup and by applying the cup and pulling before the fetus is in the proper station, Dr. Thomas Moore said at a meeting on obstetrics and gynecology sponsored by Symposia Medicus.

Vacuum-assisted deliveries have a low risk of complications such as cephalohematoma when the cup is placed in the midline of the fetus's head with the center of the cup 3 cm in front of the posterior fontanel, and when the cup is applied only when the fetus is in a low station with the fetal caput visible, said Dr. Moore, director of reproductive medicine at the University of California, San Diego.

When the cup is placed elsewhere, or the fetus is too high up in the birth canal, problems arise.

"If you pull in the wrong direction, you can break the blood vessels not only in the scalp and underneath the scalp, but actually in the brain." Dr. Moore said.

The vacuum cup can produce not only a subdural hematoma, but also the more worrisome subgaleal hematoma, which can lead to shock and even death. In 1998 the Food and Drug Administration issued a public health advisory on vacuum delivery devices, noting that it had received reports of 12 deaths and 9 serious injuries over the preceding 4 years, an average of 5 events per year.

In contrast, there were only 4 deaths and 5 serious injuries in the 11 years before that 4-year period, for an average of 1 event per year.

Since that advisory was issued, many of the specifics regarding vacuum delivery risks have been nailed down, largely though the work of Dr. Aldo Vacca of the University of Queensland. Brisbane, Australia. Dr. Moore said.

According to Dr. Vacca's research, vacuum-delivery is a low-risk procedure and may be used in the following instances, provided the fetal caput is visible and the station is low:

* Descent has become arrested in the second stage of labor.

* The fetus has a nonreassuring heart rate of a short duration.

* There is satisfactory progress when the woman is pushing well, but she has become exhausted.

* Selective shortening of the second stage of labor is desired.

Vacuum delivery is more risky in the following cases:

* The scalp is not visible.

* The fetal heart rate is worrisome, and the use of the vacuum constitutes a rescue operation.

* Labor has become protracted; epidural anesthesia has arrested the labor; and/or the mother is exhausted, her contractions are weak, and the vacuum is going to be used to compensate for the reduced expulsive effort.

* There is significant fetal head molding.

* The presentation is occipitoposterior or occipital transverse.

* The fetus is large.

When at least three of these risk factors are present, vacuum use should be considered contraindicated, Dr. Moore said at the meeting.

Moreover, the head should descend with every pull, and if significant descent has not been achieved in three or four contractions, the procedure should be stopped.

The physician should not regard cup detachment as a safety feature, he added. Two pop-offs probably mean the procedure should be stopped. Most vacuum cups and devices now include detailed instructions for how to apply the proper amount of traction.

There are no data to indicate that vacuum delivery cannot be used with premature infants. Dr. Moore said. Two studies have looked at the outcomes of large series of vacuum use in neonates weighing less than 2,500 g.

One reported an incidence of periventricular-intraventricular hemorrhage of 21% in the vacuum deliveries, compared with 16% in controls (J. Perinatol. 17[1]:37-41, 1997).

The second reported no difference between groups in neonatal morbidity (J. Reprod. Med. 40[2]:127-30, 1995).

BY TIMOTHY F. KIRN

Sacramento Bureau
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Title Annotation:Obstetrics
Author:Kirn, Timothy F.
Publication:OB GYN News
Date:Sep 15, 2004
Words:625
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