Vacuum extraction of the fetus

Extraction of the fetus by the head with the help of a special vacuum apparatus is called vacuum extraction. The operation of vacuum extraction of the fetus is the delivery method.

As is known, the most frequent cause of perinatal morbidity and mortality is fetal oxygen deficiency during childbirth and birth trauma. According to extensive statistics, oxygen starvation of the fetus and craniocerebral trauma account for 50-70% of all deaths of children under one year.

The danger of developing craniocerebral trauma with intrapartum hypoxia of the fetus is especially increased in cases of the need for the production of obstetric delivery operations, since layered "instrumental" asphyxiation occurs on the "pre-instrumental" one.

Vacuum extraction of the fetus is one of the most common birth-giving operations in Ukraine. The vacuum extractor is used on average in 1,3-3,6% in relation to all sorts in obstetric institutions of the country. However, despite the extensive use of the vacuum extractor in continental Europe and the Scandinavian countries, it should be noted that in most countries that speak English, it remains an unpopular operation. In the US, there is a very restrained attitude toward the operation of vacuum extraction of the fetus compared to obstetric forceps. This advantage was further strengthened in favor of obstetric forceps after reports of severe fetal injury due to the vacuum extraction of the fetus appeared in the literature.

American midwives rarely use the vacuum extraction of the fetus. This, apparently, is due to a number of reasons. First, the national preference for obstetric forceps in the United States depends on the settings taught in midwifery. Secondly, some midwives, including domestic ones, overestimated the significance of this operation and it began to be used according to extended indications, which was not always justified and in some cases led to unfavorable results that were revealed in the integrated study of newborns and in the analysis of distant results. Therefore, the positive feedback of many midwives who first used this operation was replaced by a more restrained assessment of it and even to a certain extent the negative attitude of some specialists to it in connection with the increase in the number of children with central nervous system damage after surgical delivery by this method.

However, up to now there is no unified assessment of the use of this operation, the immediate and remote consequences of the physical and neuropsychological development of a newborn child have not been studied in detail. This is all the more important because in some obstetric situations (if urgent delivery is necessary, when the time for the operation of the caesarean section is missed or there are contraindications for it, and the head is not available for imposing obstetric forceps due to its high location) vacuum extraction of the fetus is the only possible operation for the birth of a living child. Some authors in monographs devoted to craniotomy in modern obstetrics believe that the latter can be considered shown if there is an immediate threat to the life of the mother in the presence of contraindications to caesarean section or other surgical interventions (the imposition of obstetric forceps, the classical turn, etc.).

Therefore, the obstetrician must in the particular situation choose the most careful method of delivery for both the mother and the fetus.

In recent years, for the treatment of fetal intrapartum hypoxia, especially in cases of abnormal utero-placental or feto-placental circulation, when methods of treating fetal hypoxia through exposure to the fetus through the maternal organism are often ineffective, the method of craniocerebral fetal hypothermia, which directly affects the fetus with the aim of increasing the resistance of the brain to oxygen starvation and preventing the pathological consequences of oxygen deficiency. However, in the available literature there are no works devoted to craniocerebral fetal hypothermia in operative obstetrics. To this end, the "Vacuum-hypotherm-extractor" apparatus was developed and developed, as well as the technique of vacuum hypothermic-extraction of the fetus. The device allows simultaneous production of craniocerebral hypothermia of the fetus and obstetric operations, in particular, vacuum extraction of the fetus.

The use of simultaneous hypothermia of the fetus during vacuum extraction can reduce the intensity of oxidative and enzymatic processes, slow the development of acidosis, minimize the so-called "biochemical" trauma associated with it, reduce the blood flow and volume flow, improve microcirculation and prevent the development of posthypoxic brain edema. Staying the fetus under the protection of hypothermia makes it possible to extend the time interval for the production of vacuum extraction of the fetus, to perform less forced traction compared to the usual vacuum extraction of the fetus. The new technique of surgery allows the most careful delivery of the delivery, minimizing the possibility of both biochemical and mechanical craniocerebral trauma of the fetus. Noting the expediency of using the developed vacuum hypothermic extractor in obstetric practice, Academician MS Malinovskii wrote that "simultaneous craniocerebral hypothermia is very important for increasing the resistance of the brain tissue to oxygen deficiency and preventing the occurrence of trauma during vacuum extraction."

When determining the site of the operation of vacuum extraction of the fetus in modern obstetrics, the number of pathological conditions in pregnant and parturient women has not decreased, and the frequency of surgical methods of delivery has not decreased. Only the specific weight of individual pathological conditions has changed, which to some extent can complicate the course of pregnancy and childbirth. In addition, a significant increase in indications for the use of a vacuum extractor in individual maternity facilities (up to 6-10% in relation to all genera) did not reduce perinatal mortality and pathology therein. The possibility of using a vacuum extractor, which is used in maternity hospitals of Ukraine in 15-35 cases per 1000 births, was soberly evaluated.

Vacuum extraction of the fetus does not replace obstetric forceps, it is an independent operation, the application of which has its own testimony, conditions and consequences. This operation is theoretically justified and, if carried out correctly, does not increase the trauma of the fetus in comparison with other delivery operations that extract the fetus through the birth canal. At the same time, it should be noted that at present there is no preferential tendency to the operation of forceps application in comparison with the vacuum extraction operation of the fetus.

Indications for vacuum extraction of the fetus

On the part of the mother - complications of pregnancy, childbirth or somatic pathology, which require the reduction of the second period of labor:

• weakness of labor during the second stage of labor;
• infectious-septic diseases with a violation of the general condition of women, high body temperature.

On the part of the fetus: progressive acute hypoxia (distress) of the fetus in the second stage of labor with the inability to perform cesarean section.

Conditions for performing vacuum extraction of the fetus

1. A living fruit.
2. Full opening of the cervix.
3. Absence of a fetal bladder.
4. Correspondence between the size of the fetal head and the pelvis of the mother.
5. The fetal head should be located in the cavity of the small pelvis or in the plane of the exit of the small pelvis in the occipital prelocation.

To perform the operation of vacuum extraction of the fetus, active participation of the parturient woman is necessary, since during the operation the attempts are not turned off. The presence of diseases in the mother, requiring disabling attempts, is a contraindication to this method of fetal extraction. The operation is performed under local anesthesia (pudendal anesthesia). If labor is conducted under epidural anesthesia, then vacuum extraction is performed under this type of anesthesia.

[1], [2], [3]

Models of vacuum extractors

The vacuum extractor consists of a cup, a flexible hose and a special device providing negative pressure under the cup, not exceeding 0.7-0.8 kg / cm ². The cups of the vacuum extractor can be metal (vacuum extractor Matstrem), more modern models have plastic rigid (polyethylene) or extensible (silicone) cups of disposable use. In the Malstrem cup, the vacuum tube and the chain are in the center. Created modified cups (GC Bird): "front" - a chain in the center, and the tube for creating a vacuum is eccentric; "Back" - chain in the center, and the tube on the side. These cups are selected depending on the position of the head. At present, one-time silicone cups are predominantly used.

Technique of operation of vacuum extraction of the fetus

The following points are singled out in the operation:

• the introduction of a vacuum extractor cup;
• creating a vacuum with a special device;
• traction for the fetal head;
• removal of calyx.

The introduction of a cup of vacuum extractor into the vagina is not difficult. With the left hand, the genital slit is moved apart, and the right one, while supporting the cup in a vertically lateral position, is inserted into the vagina and brought to the head.

The inserted cup "sticks" to the head, after which it should be properly positioned, moving over the head. The calyx should be located closer to the wire (leading) point on the head of the fetus, but not on the fontanel. If the calyx is located at I -2 cm anterior to the small fontanel, the head is bent during traction, which contributes to the fulfillment of the flexion moment of the birth biomechanism in the occipital presentation. If the calyx is attached closer to the large fontanel, the traction will unbend the head. A significant dislocation of the cup away from the arrow-like seam during traction contributes to the asynclical insertion of the head.

After placing the cup under it, a special device creates a negative pressure. It should be ensured that the soft tissues of the birth canal of a woman (cervix, vagina) do not fall under the calyx.

To successfully perform the operation of vacuum extraction of the fetus, it is very important to choose the direction of traction. To ensure the head advance according to the biomechanism of delivery, when the wire head point moves along the wire axis of the pelvis. Tractions should be perpendicular to the plane of the calyx. Otherwise, it is possible to tilt and tear off the calyx from the fetal head.

The direction of traction corresponds to the above rules for obstetric forceps. When the head is positioned in the plane of the entrance to the small gas, the traction should be directed downwards (in this position of the head, a caesarean section operation is more rational); in case of displacement of the head into the cavity of the small pelvis, the direction of the traction changes to horizontal (toward oneself); during the eruption of the head, when the suboccipitary fossa is suitable for sex symphysis, tractions are directed upwards. The number of tractions when applying a vacuum extractor should not exceed four.

Tractions are carried out in synchronism with attempts. In case of a slide from the head, it can not be shifted more than twice, as this is a great trauma to the fetus. Sometimes, after an unsuccessful attempt to vacuum-extract the fetus, conditions for performing the operation of imposing obstetric forceps appear.

When a vacuum extractor is applied, an episiotomy is indicated. After completely removing the fetal head, the vacuum extractor cup is removed, reducing the negative pressure underneath.

Contraindications to vacuum extraction of the fetus

• Inconsistency in the size of the fetal head and pelvis of the mother, in particular: hydrocephalus; anatomically or clinically narrow pelvis.
• Stillbirth.
• 3 Facial or frontal insertion of the fetal head.
• High direct head stand.
• Pelvic presentation of the fetus.
• Incomplete opening of the cervix.
• Premature fetus (up to 30 weeks).
• Obstetric or extragenital pathology, in which the exclusion of the second stage of labor is necessary.

[4],

Complications of vacuum extraction of the fetus

Complications of vacuum extraction for the mother may be ruptures of the vagina, perineum, large and small labia, the region of the clitoris. The complications for the fetus include: damage to the soft tissues of the head, cephalohematoma, hemorrhage. When using soft vacuum extractor cups, the incidence of soft tissue damage is less frequent.

[5]