Vacuum hypotherm-extraction of the fetus

The risk of injury to the fetus during surgical delivery through the natural birth canal is constant, but this danger rises sharply against the background of hypoxia (asphyxia) of the fetus. In addition, the obstetric operations themselves cause reflex changes in the fetal cardiac activity, expressed in varying degrees and resembling those in asphyxiation. Data from the literature and obstetric practice show that surgical interventions in childbirth are often combined with fetal asphyxia. In many cases, operations are used for threatening or asphyxiated intrauterine fetus, as well as in such conditions of the mother (late toxicosis, bleeding, etc.), which in themselves endanger the fetus asphyxia.

For a long time, many obstetricians believed that the main cause of birth trauma with consequences in the form of asphyxia, cerebral hemorrhage, or neurologic symptoms in neonates was considered to be a mechanical trauma that occurs during obstetric operations.

Now there are more and more reports that the main cause of the defeat of the fetal CNS is the intrauterine asphyxia arising due to various reasons, which can lead to severe circulatory disorders, up to the appearance of cerebral hemorrhages and tearing of the cerebellar nerve.

In recent years, for the treatment of fetal asphyxia, the developed method of craniocerebral fetal hypothermia during labor has been successfully used.

In modern biology and medicine, in order to increase the resistance of the brain tissue (which, as is known, first of all suffers with hypoxia of the organism) to oxygen deficiency, preventing the development of hypoxia and eliminating its pathological consequences, a lowering of the temperature of the brain - "hypothermia" and reversibly convert the body to a reduced level of life. Numerous studies have shown that under conditions of a moderate decrease in brain temperature, oxygen consumption by its tissues is reduced by 40-75%.

In the process of human cooling, oxygen consumption by the body decreases by 5% with a drop in temperature per degree. Under the influence of hypothermia, the connection of oxygen with hemoglobin increases, the solubility of carbon dioxide in the blood increases.

Cranio-cerebral hypothermia, in comparison with the general, allows to reduce the danger of complications from the respiratory and cardiovascular systems with the same or even deeper cooling of the brain, because a significant gradient is reached between the temperature of the brain and the body. More experiments Parkins et al. (1954) showed that against the background of hypothermia of the brain (32 °), the animals painlessly tolerate a 30-minute cardiac shutdown from the circulation. Similar results were also obtained by Allen et al. (1955). According to the data of Duane-Hao-Shen (1960), when the head was cooled (30 °) in experimental animals, stopping the inflow to the brain through the cervical arteries for 40-60 min did not lead to irreversible changes. At a brain temperature of 30.1-27.1 ° C (respectively, in the rectum 33-34 ° C), blood filling decreased by 40-50%, with deep hypothermia it decreased by 65-70%.

Studies indicate a decrease in the rate of blood flow through the cerebral vessels with craniocerebral hypothermia. In the process of it, slow potentials appear on the electroencephalogram, the bioelectrical activity of the brain is suppressed. According to the author, with moderate hypothermia, that is, a decrease in the temperature of the brain to 28 ° C, the intensity of blood flow in the main vessels was reduced by half. The amount of blood entering the brain decreased the sooner the faster its temperature decreased. The most important result of the action of cranio -cerebral hypothermia is its ability to significantly extend the time of use of oxygen reserves and maintain functional activity in conditions of its insufficiency.The conditions created by craniocerebral hypothermia second, it should be regarded as gentle, switching operation of the vital functions of the body to a new, more economical level.

Conducting craniocerebral hypothermia in hypoxic conditions in a clinic has several objectives:

• decrease in the need of the body and, in particular, the brain in oxygen;
• prevention or elimination of cerebral edema due to the restoration of blood flow and microcirculation in the cerebral vessels;
• restoration of the equilibrium between the formation and removal of H ⁺ ions.

Hypothermia, causing a decrease in oxygen consumption by the brain tissue, does not reduce its ability to absorb oxygen. The positive quality of craniocerebral hypothermia should be considered the possibility of rapid, effective supercooling for a relatively short time.

The basis for the development and introduction into clinical practice of the method of craniocerebral hypothermia of the fetus and the newborn under hypoxic conditions was the observation of a large number of authors who proved harmless to cooling the fetus during hypothermia of the mother's body through which the temperature of the fetus decreased. Hypothermia in pregnant women was performed with indications for surgery due to severe diseases of the cardiovascular system and the brain. The safety of the maternal cooling of the mother for the fetus was demonstrated even in experimental studies, which showed that cessation of blood circulation in the mother and a temperature drop below 0 ° are compatible with normal fetal development, except for the stage of pregnancy when the hemocorial placenta is formed. Animals that underwent cooling during fetal development subsequently had normal offspring. In experiments on dogs, it was shown that a decrease in uterine circulation with general hypothermia does not worsen the condition of the fetus. The authors conclude that hypothermia increases fetal resistance to hypoxia, because the metabolic activity and oxygen consumption decrease sharply due to a decrease in temperature.

Newborn animals are much more resistant to cooling. This was shown in the experiments of Fairfield (1948), which reduced the body temperature of newborn rats to + 2.5 ", while in some observations they had no heart contractions for an hour and no oxygen consumption, animals survived. According to Davey et (1965), Kamrin, Mashald (1965), Herhe et al (1967), with intracranial operations in pregnant women under general hypothermia, pregnancy and childbirth proceeded without complications, and after operations, no adverse effects on the fetus and its subsequent development: Hess, Davis (1964) conducted Continuous recording of the maternal and fetal electrocardiograms during operation in a pregnant woman under general hypothermia Observation continued for 16 hours - from the onset of hypothermia to normal temperature recovery As the temperature decreased, blood pressure decreased and the mother's pulse slowed down, and the fetal heart rate decreased. The initial parameters gradually returned to the initial level. Immediate delivery occurred 1 month after the operation. The child at birth was assessed on the Apgar scale by 7 points. Barter et al. (1958) described 10 cases of hypothermia using caesarean section for eclampsia, with a favorable outcome for the mother and fetus. Herhe, Davey (1967), in a 4-year-old child whose mother had undergone an intracranial operation under general hypothermia at 36 weeks of gestation, did not find any abnormalities in the psychomotor development of the child with a special psychological examination. Application of the craniocerebral fetal hypothermia method during labor, undertaken in obstetrics for the first time KV Chachava, P. Ya. Kintraia et al. (1971) made it possible to conduct fetal cryotherapy with its hypoxia, when other methods of influencing the fetus to improve its functional state proved to be ineffective. According to P. Ya. Kintraia et al. (1971), the use of this method in complicated births reduced perinatal mortality by 24.3%. AA Lominadze (1972) concluded that when the craniocerebral hypothermia of the fetus is carried out in childbirth, the functional state of its cardiovascular system is improved, normalization of the resistance and tone of the cerebral vessels occurs, intracranial pressure decreases, and cerebral circulation improves. Clinical neurological and electrophysiological (ECG, EEG, REG) examination of children who underwent intrauterine asphyxia in the presence of craniocerebral hypothermia confirmed that the use of this method prevents the development of irreversible changes in the fetal brain, contributing to accelerating the recovery processes in the neonatal CNS. In the neonatal period, the body temperature gradually increased after hypothermia (for 48 hours). This can be regarded positively, since the normalization of metabolic processes in the tissues of the central nervous system after asphyxia occurs relatively slowly. The lower temperature of the brain, therefore, reduces the need for oxygen in tissues, not only during asphyxiation, but also in the subsequent period of recovery of impaired functions.

With the birth of fetal asphyxia in the birth and the need for surgical delivery through the natural birth canal, modern obstetrics employs the imposition of obstetric forceps or vacuum extraction of the fetus. Instrumental fetal extraction is an extreme obstetrical measure. As KV Chachava (1969) wrote, an obstetrician is taken for tools when the health, life of the mother and fetus are under threat. If it is a question of indications for an operation due to the threatening condition of the fetus, then this is primarily asphyxia, a circulatory disorder. The forceps and vacuum extractor are designed in such a way as to securely fix the head for subsequent traction. And this fixation does not pass without a trace on the newborn and in itself can cause asphyxia and disorders of cerebral circulation.

With surgical delivery, compared with spontaneous labor, the frequency of perinatal morbidity and mortality naturally increases. Thus, according to Friedbeig (1977), the results of an analysis of 14,000 births showed that babies with a low Apgar score (21.5%) are more likely to be born with a cesarean delivery in term of full term delivery. The operation of cesarean section not only negatively affects the adaptation of the child to extrauterine existence in the first minutes of life, but also throughout the early neonatal period. Thus, the rate of perinatal mortality in women delivered by cesarean section was 3.8%, with independent childbirth - 0.06%.

Especially dangerous for the fetus are obstetric surgeries, performed for delivery through the natural birth canal. From the methods of operative delivery through the natural birth canal to date, one of the most frequently used is the method of vacuum extraction of the fetus. It should be noted that in a number of cases, in order to obtain a living child, vacuum extraction is the only possible delivery operation. According to Altaian et al. (1975), the frequency of perinatal mortality with the use of obstetric forceps was 2.18%, and with vacuum extraction - 0.95%. The incidence of severe traumatism in the mother is 16.4% when using obstetric forceps and 1.9% when using a vacuum extractor. According to the data of MA Mchedlishvili (1969), the largest mortality was found in the group of children extracted through obstetric forceps (7.4%), then in the group of cesarean sections extracted during surgery (6.3%) and the lowest in vacuum -extractor (4.4%). An identical regularity was also revealed in the work of VN Aristova (1957, 1962). According to GS Muchieva OG Frolova (1979), the rate of perinatal mortality in women whose labor resulted in the delivery of forceps was 87.8%, and in the vacuum extraction of the fetus 61%. " According to Plauche (1979), when using a vacuum extractor, subaponeurotic hematomas occur in 14.3% of cases, abrasions and skull injuries in 12.6%, cephalogematomes in 6.6%, intracranial hemorrhages in 0.35% of observations . In assessing the incidence of early and late neurologic disorders in children, only a small difference was noted between births using a vacuum extractor and spontaneous labor. It is concluded that with a technically correct vacuum extractor shown in each individual case, it is effective and less traumatic than other delivery methods.

Vacuum extractor has proven to be an effective tool for observing indications and with less adverse consequences compared to obstetric forceps. Children were examined according to the Brazelton's Neonatal Behavior Scale and standard nephrological examinations on the 1 st and 5 th day after birth. The children extracted by the vacuum extractor reacted less to the external stimuli for the behavior tests on the first day and gave less optimal reactions for the neurological examination than in the control. These differences between the groups disappeared on the 5th day. It was revealed that the lowest perinatal mortality (1.5%) and incidence (1.6-2.1%) of children was noted in cases when in the absence of intrauterine fetal asphyxia the indications for the application of forceps were heart diseases in the mother or weakness of labor . When forceps were applied for late toxicosis of pregnant women, or threatening intrauterine asphyxia, or when combined with these indications, the perinatal mortality and morbidity of children increased 3-4 times. The latter increased with increasing duration of intrauterine asphyxia. Perinatal mortality also increased as the duration of labor and the anhydrous period increased, but this relationship was not established for the incidence of children in subsequent development.

In the opinion of KV Chachava (1962), who first applied vacuum extraction in the CIS countries, with clinico-neurological and electrophysiological examination of children extracted with the help of obstetric forceps and vacuum extractors, obstetric forceps represent a more serious interference and together with neurological complications often cause significant changes in the electrical activity of the brain, and when using a vacuum extractor that significantly reduces the possibility of brain trauma, an electroencephalogram in pain Most cases are characterized by a normal picture. Surveying newborns extracted with obstetric forceps and a vacuum extractor, scientists concluded that their clinical and neurological status, electrophysiological indices (ECG, EEG) indicate a greater damaging effect of obstetric forceps compared to a vacuum extractor. In the study of the acid-base state of blood of the mother and fetus during vacuum extraction, the presence of maternal and fetal acidosis was revealed in independent and operative births, and vacuum extraction does not adversely affect the parameters of the acid-base state of blood in the mother and fetus. A number of researchers noted an increase in the number of newborns with hemorrhages in the retina in the fetal vacuum-extraction operation compared with spontaneous births. Thus, according to studies, hemorrhages in the retina of the eye were found in 31% of newborns after spontaneous delivery and in 48.9% after vacuum extraction. It is believed that the appearance of hemorrhages in the retina of the eye is associated not so much with the operation of vacuum extraction itself as with the obstetric situation that required this intervention. Vacuum extraction of the fetus is currently the most common among the delivery operations.

It should be noted that many authors, comparing the long-term effects of the operation of applying forceps and vacuum extraction, do not take into account the position of the head in the small pelvis, therefore in a number of works a comparison of the operation of vacuum extraction of the fetus is performed with the head pressed to the entrance to the small pelvis as compared to the cavity or obstetric forceps. When comparing the same operations with the same indications and conditions, many researchers come to the conclusion that the operation of vacuum extraction of the fetus is a more gentle operation for children than the imposition of obstetric forceps, and most of the unfavorable outcomes in its application are explained by a violation of the rules of the operation ( rapid formation of vacuum, continuous traction, their deviation from the wire axis of the pelvis and separation of the calyx of the apparatus).

To assess the most subtle deviations in the psyche of children of preschool and school age, they are subjected to psychological examination. To this end, use a variety of tests to identify the level of mental development of the child, the type of personal experience, the imagination of the child. The relationship between the coefficient of mental development and methods of delivery was absent. There was no dependence between the coefficient of mental development and the frequency of development during pregnancy of late toxicosis, prolonged labor, evaluation of the child's state according to the Apgar scale. The level of the psychic was the same (56% of the children began to speak an average of 18.4 months of life) and physical development (65% of children began to walk at 12.8 months of age) of children.

In conclusion, it should be noted that vacuum extraction and the operation of superimposing obstetric forceps are not mutually substituting operations, as some modern authors point out, and each of them has its own conditions, indications and contraindications.

As you know, there are no safe operations for the fetus and the mother of delivery. If the fetus is not exposed to the damaging effect of hypoxia, short-term delivery of vacuum extraction or forceps will not cause damage to the fetus under favorable conditions for delivery (normal pelvis and head size, head position in the pelvic cavity). In the case of fetal asphyxiation, the possibility of damage in any method of surgical intervention increases, the degree of which is directly related to both the duration and severity of asphyxia, and the duration of the operation. Modern methods of operative delivery through the natural birth canal, in spite of the great achievements in practical obstetrics, are still sufficiently imperfect. Therefore, it is important to invent and introduce new obstetrical instruments into obstetric practice, which allow the most careful, atraumatic fetal extraction.

Analysis of literature data and own research show that craniocerebral fetal hypothermia in childbirth is a new, effective method of combating hypoxia, which allows to protect the fetal CNS from intracranial birth trauma, the risk of which is especially increased with instrumental delivery. In addition, most authors come to the conclusion that when fetal hypoxia, in combination with other indications for surgical delivery, which are known to often combine, vacuum extraction is more sparing and in some cases the only possible operation.

Due to the fact that in the domestic literature there are no works of a monographic nature concerning the application of the fetal hypothermia method in the delivery of obstetric operations and there is no data on the comparative evaluation of cesarean section operation, obstetric forceps and vacuum hypothermic extractor in perinatal fetal protection, -hypotherm-extractor, as well as the technique of operation, indications and contraindications to this operation.