Asphyxia of a newborn is a condition of pathology of a newborn, which is caused by violations of the respiratory apparatus with the resulting lack of oxygen.
The content of the article:
Causes of asphyxia
Symptoms of asphyxia
Treatment and assistance for asphyxia
Consequences of asphyxia
Asphyxia of newborns
Primary asphyxia that occurred at the birth of a child and secondary asphyxia that occurs during the first hours and days of life of newborns are revealed.
Causes of asphyxia
The causes of primary asphyxia of the newborn are acute and chronic oxygen deficiency in the womb. It includes:
fetal hypoxia;
intracranial injuries;
immunological incompatibilities of fetal and maternal blood;
various intrauterine infections;
the presence of complete or partial inability to function of the respiratory tract of the fetus or newborn due to their overflow with amniotic fluid (aspiration asphyxia), as well as mucus;
the presence of fetal malformations.
Asphyxia of newborns occurs due to extragenital diseases of a pregnant woman:
cardiovascular pathologies in the decompensation stage;
diseases of the respiratory system and lungs in severe forms;
anemia;
diabetes mellitus of various types;
thyrotoxicosis;
all kinds of infectious diseases.
The causes of asphyxia of newborns are also very often called late toxicosis of a pregnant woman, pregnancy in the stage of overgrowth, premature detachment of the placenta, pathology of the placenta, fetal membrane and umbilical cord. In the presence of complications in childbirth, such as early discharge of amniotic fluid, anomalies of labor activity of a pregnant woman, incorrect positions of the fetal head, inconsistencies in the size of the pelvic part of the woman in labor and the fetal head, the possibility of asphyxia of newborns is not excluded. With a violation of cerebral circulation in a newborn, pneumopathy and other diseases, secondary asphyxia occurs.
The newborn’s body, despite the cause of asphyxia, will undergo a restructuring of all metabolic processes from oxygen deficiency. Hemodynamics and microcirculation are part of the restructuring in the fetal body. The longer and more intense the hypoxia, the more pronounced and brighter the picture of changes. Metabolic and respiratory-metabolic acidosis develops, which is accompanied by manifestations of hypoglycemia, azotemia and hyperkalemia, then this process is replaced by potassium deficiency. Cellular hyperhydration begins as a result of electrolyte imbalance and metabolic acidosis. The volume of circulating red blood cells in the event of acute hypoxia provokes an increase in the volume of circulating blood.
Hypovolemia accompanies asphyxia of the newborn, which develops during the chronic course of fetal hypoxia. The ability of erythrocytes and platelets to aggregate increases, blood gradually thickens, its viscosity increases. The brain, heart, kidneys, adrenal glands and liver of a newborn after a microcirculatory disorder suffer edema, hemorrhage and ischemia, tissue hypoxia of the newborn develops. Central and peripheral hemodynamics are accompanied by a decrease in shock and minute heart volumes, a sharp drop in blood pressure. The urinary function of the kidneys is impaired due to disorders of metabolism, hemodynamics and microcirculation.
Symptoms of asphyxia
The main symptom of asphyxia of a newborn is a violation of respiratory function, which leads to changes in cardiac activity, disorders of neuromuscular conduction and reflex activity of organs. The Apgar scale is an indicator of the severity of asphyxia of newborns. The International Classification of Diseases of the 9th revision provides for 2 stages of asphyxia of the newborn — the stage of asphyxia of moderate severity and severe (the first minute after birth reveals 7-4 and 3-0 points on the Apgar scale). Clinical practice distinguishes three degrees of severity of asphyxia of a newborn:
light (7-6 points on the Apgar scale);
asphyxia of moderate severity (5-4 points, respectively);
severe (the Apgar scale has 3-1 points);
Clinical death is detected with an overall score of 0 points. A slight degree of severity is manifested in the first breath in the first minute of life: weakened breathing, acrocyanosis and cyanosis of the nasolabial triangle, a slight decrease in muscle tone. The average degree of severity shows the presence of the first breath in the first minute after birth: weakened breathing (both regular and irregular), the presence of a weak cry of the newborn, bradycardia, tachycardia, decreased muscle tone and reflexes, the skin of the newborn is bluish (mainly the area of the face, hands and feet), pulsating umbilical cord. The severe degree of asphyxia of the newborn is manifested in irregular individual breaths, or in their absence, the silence of the child (possibly the presence of moans), a slow heartbeat, which may be accompanied by a single irregular contraction of the heart, muscle hypotension and atony. In this case, reflexes are not observed, that is, they are absent. Spasm of peripheral vessels causes pallor of the skin, there is no pulse in the umbilical cord, the development of adrenal insufficiency occurs in most cases.
In newborns who have suffered asphyxia in the first hours and days of life, the development of posthypoxic syndrome is noted, its main lesion is the central nervous system. Disorders of cerebral circulation of 1-2 degrees are detected in 1 child out of 3 who suffered asphyxia at the time of birth. Severe asphyxia suffered by children, as a rule, gives rise to the development of disorders of cerebrospinal fluid dynamics and cerebral circulation of 2-3 degrees. The formation of hemodynamics and microcirculation is disrupted due to oxygen deficiency and disorders of the functions of the external respiratory apparatus. As a result, fetal communications are preserved — the arterial (botall) duct is open, spasm of the pulmonary capillaries leads to an increase in pressure in the area of the small circle of blood circulation, the right region of the heart is overloaded, the oval opening remains unclosed. Atelectases and hyaline membranes are detected in the lung area.
Cardiac activity also notes the following disorders: deaf tones, extrasystolic pattern, detection of arterial hypotension. Hypoxia and reduced immune protection cause microbial colonization of the intestine, that is, the occurrence and development of dysbiosis.
The first 5-7 days of a child’s life show the persistence of metabolic disorders, which manifest themselves in the accumulation of acidic metabolic products, urea, hypoglycemia, electrolyte imbalance, potassium deficiency in the child’s body. On the 2-3 day of the child’s life, edematous syndrome develops due to impaired kidney function and with a sharp decrease in diuresis.
In the first minutes of a newborn’s life, when determining the degree of respiratory function disorders, as well as changes in heart rate, muscle tone, reflex function, skin color, the diagnosis of asphyxia and its severity is determined. The acid-base state shows the severity of asphyxia suffered by the child.
A healthy newborn has:
The PH of the blood taken from the umbilical cord is 7.22-7, 36;
VE — (base deficiency) — 9-12 mmol/l;
Mild asphyxia and its indicators:
Blood PH — 7.19-7.11;
VE — 13-18 mmol/l;
Severe asphyxia and its indicators:
Blood PH- less than 7.1;
VE — 19 mmol/l and more;
Hypoxic and traumatic lesions of the central nervous system are detected during a thorough neurological examination and ultrasound examination of the brain. A hypoxic lesion of the central nervous system begins, focal neurological symptoms cannot be detected, and a syndrome of increased neuro-reflex excitability develops. In a severe case, a syndrome of central nervous system depression is possible. In newborns who have a predominance of the traumatic component (extensive subdural, subarachnoid and intraventricular hemorrhage, etc.), hypoxemic vascular shock occurs in the first moments of life, accompanied by spasm of peripheral vessels, the skin is pale, hyperexcitability is also noted, often focal neurological disorders and convulsive syndromes occur, which manifest themselves in the first moments after birth.
Treatment and assistance for asphyxia
Newborns in an asphyxic state, do not do without the help of resuscitation. The effectiveness of resuscitation care lies in the timely start of treatment. Resuscitation measures and assistance to newborns with asphyxia are beginning to be carried out in the parturition hall. The control of the main parameters of human life activity must be observed: respiratory capabilities and their frequency, blood pressure, hematocrit and acid-base conditions.
Immediately after the birth of the child, the doctor, using a soft catheter and an electric pump, carefully removes all excess from the upper respiratory tract (tees are used, creating intermittent rarefaction of air), the umbilical cord is cut off immediately. The child is placed under heat sources on the intensive care table. The nasal passages, oropharynx, and stomach contents are aspirated again here. With the diagnosis of mild asphyxia, the child is placed in the knee-elbow position, he is prescribed inhalation of 60% oxygen-air mixture, cocarboxylase (8 mg / kg) and 10-15 ml of 10% glucose solution are injected into the umbilical vein. With moderate asphyxia, the newborn is shown artificial ventilation of the lungs with a mask to normalize respiratory capabilities. As the restored regular breathing occurs and the skin turns pink (duration 2-3 minutes), oxygen therapy continues through inhalation measures. Any method of oxygen therapy provides moistened and warmed oxygen. Cocarboxylase is injected into the umbilical vein at the same dose that is prescribed for mild asphyxia.
With severe asphyxia, after the umbilical cord is cut off and the contents of the upper respiratory tract of the newborn are removed, tracheal intubation measures are started with the control of direct laryngoscopy and artificial ventilation of the lungs until regular breathing is fully restored (resuscitation measures stop after 15-20 minutes of the child’s life without a single breath and in the presence of a heartbeat).
After the recovery of breathing, the child is transferred to the ward in the neonatal unit (intensive care).
Caring for such a newborn is of particular importance. Rest is provided immediately, the head is placed on a hill. With the diagnosis of mild asphyxia, the child is placed in an oxygen tent. There are children with diagnoses of moderate and severe asphyxia in kuvez. Often, repeated removal of mucus residues from the oropharynx and from the stomach is carried out. The child’s temperature, diuresis, and bowel function are monitored. After 12-18 hours, the child is prescribed the first feeding with expressed breast milk (diagnosis of mild to moderate asphyxia). With severe asphyxia of newborns, feeding occurs after a day with the help of a probe.
Consequences of asphyxia
In the first year of life of a child who has suffered asphyxia of a newborn, the following consequences are observed:
hypo- and hyperexcitability syndrome;
hypertensive-hydrocephalic, convulsive, diencephalic disorders.
