Asphyxia ( hypoxia) fruit
Obstetrics And Gynecology / / August 12, 2017
intrauterine asphyxia - acute hypoxia (anoxia) fetus resulting from a sudden violation of utero-placental-platsentarnoto or fetal blood flow in previously healthy fetus.In relation to the fetus while it is in the uterus, the term "asphyxia" (gasp) sufficiently conditions as pulmonary respiration it lacks.Correct to speak of hypoxia.However, the term "fetal asphyxia" is widely used in clinical, mortem and statistical literature.
Determining the true frequency of intrauterine asphyxia meets with difficulties, since, until recently, this term describes all the variety of the fruit asfiksicheskih states.Gives a figure of 40-80%.However, in view of the above, we can assume its share in perinatal death more modest - about 15-20%.
Acute violation of utero-placental and fetal-placental blood flow in most cases is the result of complications of childbirth.Thus, intrauterine asphyxia usually occurs intrapartum premature at full or large detachment of normally situated placenta and placental infar
Violation of the blood supply to the fetus occurs when the umbilical cord is damaged: loss, pressed against the head at birth in breech presentation, excessive tension on a short umbilical cord, tightened the real nodes.As anecdotal cause of intrauterine asphyxia described aneurysm umbilical artery.
Since implantation (after 18 days of intrauterine development) exchange of germ substances through the placenta.As the exchange rate of embryo development (including oxygen demand) increases.In the first half of pregnancy, this growth is mainly due to the increase in weight of the placenta and the area of its contact with the bloodstream of pregnant women.After 5th month of placental mass increases slightly and exchange rate increases mainly by increasing the permeability of the placental barrier.
oxygen partial pressure in the blood below the fetal than adult blood and during delivery is 60-80% of the adult levels.However, this disadvantage is offset by a large oxygen storage capacity of fetal blood (due to the increased content of red blood cells and hemoglobin) and the characteristics of its tissue metabolism.An important role is played by the intensification of the fetal circulation at strengthening the work of its cardiovascular system, the rhythmic movements of the chest and skeletal muscle contractions (stirring).The rhythmic movement of the chest fetal cells can not fully identified with the respiratory movements, as the unfolding of the alveoli is not happening, although a certain amount of amniotic fluid in the alveoli comes constantly.They are removed from the lungs through the lymphatic system, and during childbirth - when compressing the chest of fetal cells in the mother's birth canal.
should be borne in mind that the fruit, especially premature, suffers a lack of oxygen is better than a child or an adult.This is due to the immaturity and therefore more resistant brain, particularly the cerebral cortex, to oxygen deficiency and a higher possibility of anaerobic glycolysis because of the glycogen reserves in the organs.Only in relatively rare cases (6% of all births), fetal oxygen supply is inadequate and hypoxia occurs.In the primary pathogenetic mechanisms of fetal asphyxia is anoxic hypoxia, as it is linked to inadequate oxygen supply to the fetus.Later, in connection with the accession of developing circulatory disorders circulatory hypoxia.In the blood, other than the lack of oxygen generated decompensated metabolic and respiratory acidosis (through C02 and other metabolic products), alkaline reserve decreases from fabrics washed potassium.In the tissues of growing intensity of glycolytic processes and therefore glycogen content decreases.Emission has a value in the blood and tissues of suffering from anoxia, particularly from skeletal muscle of various enzymes, in particular - kreatininfoofokinazy.
most important links of pathogenesis of intrauterine asphyxia is damage to the vascular system and brain.First, there is a significant rise in blood pressure and slowing of fetal heart.Later, the vascular tone falls, develops general venous congestion, sharply increases vascular permeability.Significant changes occur in the blood coagulation and anticoagulation systems, fibrinolytic activity predominates in severe cases.Hemorrhagic diathesis result is damage to the vascular wall and the coagulation system, until the development of disseminated intravascular coagulation syndrome, which can lead to hemorrhage into the cerebral ventricles, under the liver capsule, the adrenal glands, lungs, and other organs.Brain damage initially expressed in irritation of the respiratory center, the appearance of the respiratory movements of the chest and diaphragm.There is aspiration of amniotic fluid and the birth canal content.Irritation of the centers of the vagus nerve leads to increased bowel motility, paralysis of the anus and the allocation of meconium.