Birth asphyxia is a pathology of the early neonatal period caused by respiratory disorders and the development of hypoxia in a born child. Birth asphyxia is clinically manifested by the absence of independent breathing of the child in the first minute after birth or by the presence of separate, superficial or convulsive irregular respiratory movements with preserved cardiac activity. Newborns with asphyxia need resuscitation measures. The prognosis for birth asphyxia depends on the severity of the pathology, the timeliness and completeness of the provision of therapeutic measures.
P21 Asphyxia during childbirth
Of the total number of newborns, asphyxia is diagnosed in 4-6% of children. The severity of asphyxia is due to the degree of violation of gas exchange: accumulation of carbon dioxide and lack of oxygen in the tissues and blood of the newborn. According to the time of development, birth asphyxia is primary (intrauterine) and secondary (extrauterine), which occurred on the first day after birth. Birth asphyxia is a formidable condition and serves as one of the frequent prerequisites for stillbirth or neonatal mortality.
Birth asphyxia is a syndrome that develops due to a violation of the course of pregnancy, diseases of the mother and fetus. Primary birth asphyxia is usually associated with chronic or acute intrauterine oxygen deficiency caused by:
- intracranial injuries;
- intrauterine infections (rubella, cytomegalovirus, syphilis, toxoplasmosis, chlamydia, herpes, etc.);
- immunological incompatibility of maternal and fetal blood;
- fetal malformations;
- partial or complete obstruction of the newborn’s airways with amniotic fluid or mucus (aspiration asphyxia).
The causes of secondary asphyxia of the newborn, as a rule, are disorders of the cerebral circulation of the child or pneumopathy. Pneumopathies are perinatal non-infectious lung diseases caused by incomplete expansion of the lung tissue; they are manifested by atelectasis, edematous hemorrhagic syndrome, hyaline membrane disease.
The development of birth asphyxia is facilitated by the presence of a pregnant woman:
- extragenital pathology (anemia, heart defects, lung diseases, thyrotoxicosis, diabetes mellitus, infections);
- burdened obstetric anamnesis (late toxicosis, premature placental abruption, gestation, complicated labor);
- bad habits.
Regardless of the etiology of respiratory disorders with birth asphyxia, pathogenetically identical disorders of metabolism, microcirculation and hemodynamics develop in his body. The severity of birth asphyxia is determined by the duration and intensity of hypoxia. With a lack of oxygen, respiratory and metabolic acidosis develops, characterized by azotemia, hypoglycemia, hyperkalemia (then hypokalemia). With an imbalance of electrolytes, cellular hyperhydration increases.
Acute birth asphyxia is characterized by an increase in the volume of circulating blood due to erythrocytes; asphyxia occurring against the background of chronic hypoxia – hypovolemia. This leads to blood thickening, an increase in its viscosity, an increase in platelet and erythrocyte aggregation. With such microcirculatory shifts in a newborn, the brain, kidneys, heart, adrenal glands, liver suffer, in the tissues of which edema, ischemia, hemorrhages, hypoxia develop. As a result, there are violations of central and peripheral hemodynamics, the shock and minute volume of ejection decreases, blood pressure drops.
The defining criteria for newborn asphyxia are respiratory disorders leading to impaired hemodynamics, cardiac activity, muscle tone and reflexes. According to the severity of manifestations in obstetrics and gynecology, there are 3 degrees of birth asphyxia with an assessment in points on a 10-point scale (methodology) Apgar within the first minute after birth:
- 6-7 points – easy;
- 4-5 points – average;
- 1-3 points – heavy.
An Apgar score of 0 points is regarded as clinical death. The criteria for assessing the severity of birth asphyxia are heartbeat, breathing, skin color, the severity of muscle tone and reflex excitability (heel reflex).
With a mild degree of asphyxia, the newborn takes the first breath in the first minute after birth, the child listens to weakened breathing, acrocyanosis, cyanosis of the nasolabial region, reduced muscle tone is detected. Birth asphyxia of moderate severity is characterized by inhalation in the first minute, weakened regular or irregular breathing, weak cry, bradycardia, decreased muscle tone and reflexes, cyanosis of the skin of the face, feet and hands, pulsation of the umbilical cord.
Severe birth asphyxia corresponds to irregular breathing or apnea, lack of screaming, rare heartbeat, areflexia, atony or pronounced hypotension of muscles, pallor of the skin, absence of umbilical cord pulsation, development of adrenal insufficiency. In the first day of life, newborns with asphyxia may develop posthypoxic syndrome, manifested by a lesion of the central nervous system – a violation of cerebral circulation and cerebrospinal fluid dynamics.
Asphyxia is diagnosed in the first minute of a newborn’s life, taking into account the presence, frequency and adequacy of breathing, heartbeat, muscle tone, reflex excitability, skin color. In addition to an external examination and assessment of the severity of the newborn’s condition on the Apgar scale, the diagnosis of asphyxia is confirmed by a study of the acid-base state of the blood.
Methods of neurological examination and ultrasound of the brain (ultrasonography) are aimed at differentiating hypoxic and traumatic damage to the central nervous system (extensive subdural, subarachnoid, intraventricular hemorrhages, etc.). For newborns with hypoxic damage to the central nervous system, the absence of focal symptoms and increased neuro-reflex excitability are characteristic (with severe asphyxia – depression of the central nervous system).
Newborns with asphyxia need emergency resuscitation aid aimed at restoring respiratory function and cardiac activity, correcting disorders of hemodynamics, metabolism, and electrolyte metabolism.
- Asphyxia of mild and moderate severity. Aspiration of the contents from the nasopharynx, oral cavity and stomach is performed; auxiliary ventilation of the lungs by a mask method; introduction of a 20% solution of glucose and cocarboxylase by weight into the umbilical vein. If spontaneous respiration has not been restored after the measures taken during birth asphyxia of moderate severity, tracheal intubation is performed, aspiration of contents from the respiratory tract is performed, and a hardware ventilator is being adjusted. Additionally, a sodium bicarbonate solution is injected intravenously.
- Severe asphyxia. It requires a ventilator, with bradycardia or asystole – indirect heart massage, administration of glucose, steroid hormones, vitamins, vasoconstrictors, calcium gluconate. Resuscitation of premature newborns with asphyxia is somewhat different from the scheme of resuscitation measures in full-term children.
In the future, newborns who have suffered asphyxia require intensive monitoring and therapy: oxygen support, craniocerebral hypothermia, infusion of solutions, vitamins, symptomatic treatment. Newborns with mild asphyxia are placed in an oxygen tent; with moderate and severe – in a couvez. The question of feeding and its methods is solved based on the condition of the newborn. After discharge from the hospital, a child who has suffered asphyxia requires the supervision of a neurologist.
The immediate and long-term prognosis is determined by the severity of asphyxia of the newborn, the completeness and timeliness of the medical aid. To assess the prognosis of primary asphyxia, the newborn’s condition is assessed according to the Apgar scale 5 minutes after birth. With an increased assessment, the prognosis for life is considered as favorable. In the first year of life, children born in asphyxia often have hyper- and hypovexcitability syndromes, hypertensive-hydrocephalic or convulsive perinatal encephalopathy, diencephalic (hypothalamic) disorders. Some children may have a fatal outcome from the effects of asphyxia.
Nowadays, obstetrics and gynecology pay great attention to the implementation of effective measures for the prevention of pathology of newborns, including birth asphyxia. Measures to prevent the development of birth asphyxia include timely therapy of extragenital diseases in a pregnant woman, pregnancy management taking into account existing risk factors, intrauterine monitoring of the placenta and fetus (dopplerography of utero-placental blood flow, obstetric ultrasound).
Prevention should be done by the woman herself, giving up bad habits, observing a rational regime, following the instructions of an obstetrician-gynecologist. Prevention during childbirth requires the provision of competent obstetric aids, prevention of fetal hypoxia during childbirth, and the release of the upper respiratory tract of the child immediately after birth.