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Asphyxia



Definition

In clinical practice, the term "neonatal asphyxia" refers to a clinical syndrome that manifests itself in the first minutes of life with difficulty or complete lack of breathing in the child. In addition to respiratory failure, most children born in a state of asphyxia note inhibition of unconditioned neuro-reflex activity and acute cardiovascular failure.

CODE ICD-R21.0 Severe asphyxia at birth.

P21.1 Mild to moderate birth asphyxia

P21.9 Unspecified birth asphyxiation

ETHIOLOGY AND PATHOGENESIS

The cause of asphyxiation is acute or chronic fetal hypoxia, developing both antenatally and during childbirth. Acute or chronic disorders of the mother’s respiratory, cardiovascular and hematopoietic systems, isolated violations of the uteroplacental circulation, or a combination of several pathological changes in the body of a pregnant woman lead to a restriction of oxygen through the placenta to the fetus. In response to this, compensatory reactions develop in the fetal organism: with a decrease in pa02, an increase in heart rate and an increase in cardiac output occur, which helps to accelerate blood circulation and maintain a sufficient level of metabolism in the brain and heart. At the same time, blood flow through the vessels of the kidneys, intestines and skin decreases, which is referred to as “centralization of blood circulation”.

If the fetus experiences only short-term attacks of hypoxia, due to compensatory reactions of the cardiovascular system, significant changes in cellular metabolism do not occur. In cases of a persistent oxygen deficiency in cells, anaerobic glycolysis is included, a large number of under-oxidized products, including lactic acid, are released into the blood from tissues. The accumulation of excessive amounts of organic acids in the blood is compensated to a certain extent by the blood buffer systems consisting of red blood cell hemoglobin and weak plasma bases.

A prolonged intake of unoxidized products into the blood metabolism leads to a decrease in the concentration of anions in the plasma and the development of base decites. In this case, a pathological decrease in the pH of crozes occurs. Decompensated acidosis exacerbates intracellular metabolism disorders. These changes adversely affect the functional state of the physiological systems of the fetus, reduce their compensatory potential in the process of childbirth.

Prenatal factors predisposing to the development of asphyxia:

• late gestosis;

• diabetes;

• Rhesus sensitization;

• infectious disease in the mother;

• bleeding in the II or III trimester of pregnancy;

• miscarriage and prolongation of pregnancy;

• multiple pregnancy;

• IUGR of the fetus;

• Maternal use of drugs, alcohol and certain drugs during pregnancy.

Intranatal risk factors:

• placenta previa or detachment of a normally located placenta,

• pathological presentation of the fetus;

• prolapse of the umbilical cord loops during childbirth, entwining the umbilical cord;

• use of general anesthesia and cesarean section;

• abnormalities of labor (discoordination, prolonged or quick birth);

• fetal heart rhythm disturbances during childbirth;

• the presence of meconium in the amniotic fluid;

• infectious disease, etc.

CLINIC PICTURE

The clinical manifestations of metabolic disorders due to perinatal hypoxia are the absence or weakness of the contractions of the respiratory muscles immediately after birth, a decrease in the frequency and strength of heart contractions, cyanosis or pallor of the skin, and a decrease in neuro-reflex excitability and muscle tone. There is a direct correlation between the severity of clinical manifestations and changes in biochemical blood constants associated with hypoxemia. In this regard, the severity of asphyxia can be determined both on the basis of an objective assessment of the state of the respiratory, cardiovascular system and central nervous system, and on the basis of a laboratory assessment of blood CBS, concentrations of malate, lactate and other metabolites that enter the blood from cells as a result of anaerobic glycolysis .

Clinical assessment of the severity of asphyxia

Assessment of the severity of the condition of the child at birth is carried out using the criteria proposed in 1952 by V. Apgar (Table 24-1). According to this scheme, a score of 7 points or more after 1 min after birth indicates the absence of asphyxiation, 4-6 points - a sign of moderate asphyxia, 1-3 points - severe asphyxiation. Evaluation 5 minutes after birth currently has not so much diagnostic as prognostic value, as it reflects the effectiveness (or inefficiency) of resuscitation measures.

In domestic practice, a classification is also used that provides for the allocation of mild, moderate and severe asphyxiation, depending on the Apgar score in the 1st minute. In European countries, in case of minor

asphyxia and rapid improvement of the child's condition use the definition of "low score on the Apgar scale", and the diagnosis of "asphyxia" is not put up. Such a diagnosis is used only when assessing on the Apgar scale at the 5th minute below 5 points in combination with signs of hypoxic damage to other organs. The diagnosis of hypoxic-ischemic encephalopathy is made based on the presence of a characteristic neurological picture (see the corresponding section).

Table 24-1. Criteria for evaluating a newborn according to V. Apgar

Sign About points 1 point 2 points
Heart rate Are absent Less than 100 rpm More than 100 / min
Breath Is absent Weak scream (hypoventilation) Strong scream (adequate breathing)
Muscle tone Low (sluggish child) Moderately reduced (weak movements) High (active movements)
Reflexes Not determined Grimace Shout or active movements.
Color of the skin Blue or white Pronounced acrocyanosis All pink
Primary and resuscitation care in the delivery room

When they predict the birth of a child in a state of asphyxiation, a resuscitation team consisting of two people trained in all methods of resuscitation of newborns should be present in the delivery room. To solve the question of the advisability of initiating therapeutic measures, the presence of signs of live birth is checked, which include spontaneous breathing, palpitations, umbilical cord pulsations and voluntary movements. In the absence of all four signs of live birth, the child is considered stillborn and not reanimated. If a child notes at least one of the signs of live birth, begin primary resuscitation.

90-95% of full-term newborns do not need primary resuscitation and medical care in the delivery room is limited to the primary toilet of the newborn. 5-6% of newborns in connection with the development of primary apnea or an insufficiently effective first breath need sanitation of the upper respiratory tract and additional oxygen through a facial mask. 0.5-2% of newborns need tracheal intubation, closed heart massage and drug therapy in the delivery room.
The need for primary resuscitation of premature babies is higher, the lower the gestational age and body weight at birth. Depending on obstetric tactics in childbirth, 30-60% of children with very low birth weight (less than 1500 g) and 50-80% of children with extremely low body weight (less than 1000 g) need primary resuscitation .

The sequence of resuscitation in the delivery room

Initial measures for primary care for a high-risk newborn in the delivery room are as follows:

• at the birth of the head, the contents of the oral cavity and nasal passages are aspirated through a layer of meconium water (before the shoulders are born);

• in case of a threat to the fetal life and conditions detected prenatally, in the first seconds after birth, clamp the umbilical cord and cross it without waiting for the pulsation to stop;

• place the child under a source of radiant heat;

• give the child a supine position with a roller under his shoulders with his head slightly tilted back and the head end lowered by 15 degrees;

• aspirate the contents of the oral cavity and nasal passages;

• wipe the baby dry with a warm cloth and remove the wet cloth from the table, cover the baby with a dry cloth.

The duration of the initial activities should not exceed 1 minute.

In cases of absence or difficulty in independent breathing in the first minute of life in children born through a layer of meconium amniotic fluid, in addition to the above measures, direct laryngoscopy is performed and, with confirmation of aspiration of meconium, tracheal debridement was performed with the help of the endotracheal tube (see the relevant sections).

Further actions of the resuscitation team depend on the severity of the three main signs that characterize the state of the vital functions of the newborn child: skin color, heart rate and the presence of independent breathing. If, against the background of the primary measures, the child has a pale skin color or diffuse cyanosis, he has a bradycardia or does not take a first breath, cardiopulmonary resuscitation should be started before the end of the first minute of life, i.e. prior to the first Apgar assessment.

In the absence of inhalation or irregular shallow breathing, conducting IVL with the help of an Ambu bag and a face mask through which an air-oxygen mixture is supplied (oxygen concentration 60-100%). The effectiveness of forced ventilation of the lungs is indicated by a heart rate above 100 / min, the appearance of adequate spontaneous breathing and rapid pinking of the skin If, for 30-60 seconds, auxiliary ventilation of the lungs through the face mask is ineffective and heart rate continues to decline, tracheal intubation and mechanical ventilation through the endotracheal tube are indicated. A decrease in heart rate of less than 60 / min requires the beginning of a closed heart massage on the background of mechanical ventilation.

The subsequent actions of the resuscitation team depend on the child’s reaction to the resuscitation measures. At a heart rate above 80 / min, indirect heart massage is stopped, mechanical ventilation is continued until adequate independent breathing is restored. While maintaining a heart rate below 80 / min, indirect heart massage is continued on the background of mechanical ventilation and drug therapy is started.

TREATMENT

The first stage of drug therapy is the introduction of an aqueous solution of adrenaline. Indication for the introduction of adrenaline is a decrease in heart rate below 80 / min after 30 s of indirect cardiac massage on the background of mechanical ventilation. Adrenaline is administered intravenously or endotracheally at a dose of 0.1-0.3 ml / kg (at a solution concentration of 1:10 000). It is expected that after 30 s from the time of administration, heart rate should reach 100 / min. If after a specified period the heart rate is restored (exceeds 80 / min), other medications are not administered, indirect heart massage is stopped, and mechanical ventilation is continued until adequate independent breathing is restored. If after 30 s the heart rate remains below 80 / min, indirect heart massage and mechanical ventilation are continued, against the background of which one of the following measures is performed:

• repeat administration of adrenaline (if necessary, this can be done every 5 minutes);

• when signs of acute blood loss or hypovolemia are detected, physiological saline is injected into the umbilical cord vein to replenish the bcc at a dose of 10 ml / kg for 5-10 minutes;

• while maintaining decompensated metabolic acidosis against mechanical ventilation, sodium bicarbonate is administered at a dose of 2 meq / kg (4 ml / kg of a 4% solution) for 2 minutes.

The reason for the cessation of resuscitation in the delivery room is the appearance during the first 20 minutes of life of adequate independent breathing, the normalization of heart rate and the pink color of the skin. In cases when, after normalization of heart rate, spontaneous breathing is not restored, the child is transferred to a mechanical ventilation. If within 20 minutes after birth, against the background of adequate resuscitation, the child does not recover heart activity, resuscitation is stopped.

Baby management after completion of primary resuscitation measures

Immediately after the end of the resuscitation complex, children born in a state of asphyxia are transferred from the maternity hospital to the ICU to an individual observation post. During transportation, it is very important to ensure an adequate temperature regime and continue respiratory therapy. By the time the child is transferred from the maternity hospital to an intensive care unit or to an ICU, an incubator or radiant heat source, respiratory therapy equipment, pulse oximeter or multifunctional monitor should be prepared for work. Immediately after entering PITN, they continuously monitor the state of the vital functions of the child’s body and continue treatment.

If the child did not have indications for umbilical vein catheterization in the delivery room, catheterization of one of the peripheral veins through which the infusion therapy is carried out is performed within 20-30 minutes from the moment of receipt (after warming, stabilization of blood pressure and heart rate). For children born in asphyxia, the prevention of postnatal hypoxia, maintaining a normal temperature, stable blood pressure and normoglycemia is very important. Further etiopathogenetic therapy is carried out in accordance with the principles set forth in the relevant sections of the manual.

In the case of unstable indicators of central hemodynamics (low mean blood pressure, severe tachycardia or bradycardia, a positive symptom of a pale spot), emergency umbilical vein catheterization is performed and anti-shock therapy is performed.

FORECAST

The prognosis of the life and health of children born in a state of asphyxiation depends on the severity of the condition at birth, gestational age and the quality of medical care provided to the child at the stage of the maternity hospital. Of great prognostic value is the dynamics of the state of the child in the first minutes of life. In cases of rapid restoration of the vital functions of the child’s body against the background of primary primary resuscitation measures, the prognosis is favorable. A low Apgar score (less than 4 points) 5 minutes after birth indicates an unfavorable near and distant prognosis. Mortality in the early neonatal period, as well as the risk of future cerebral palsy and mental deficiency in children who had a low score 5 times after birth is 10 times higher than in other newborns. The most unfavorable prognosis for the life and health of children born in asphyxia in the event of shock.

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Asphyxia

  1. Asphyxia of the newborn
    The severity of asphyxia is estimated in points on the Apgar scale at the end of 1 and 5 minutes: moderate asphyxia - 6-4 points, severe - 3-1. Apgar scale Symptoms 0 1 2 Heart rate None Less than 100 in Over 100 in contractions 1 minute 1 minute Breathing None Weak cry, Strong cry, hypoventilation sufficient breathing Muscle tone
  2. Asphyxia
    Asphyxia of newborns is a syndrome characterized by lack of breathing, irregular or ineffective respiratory movements at birth, in a child with cardiac activity. Distinguish fetal asphyxiation, which is divided into antenatal and intrapartum, and newborn asphyxiation. Asphyxia of the newborn is divided into primary, when the newborn after ligation
  3. Asphyxia
    Physical blockage Asphyxia is an extreme difficulty in breathing, or asphyxiation, as a result of which a person may die. With asphyxiation in the body there is a lack of oxygen and an excess of carbon dioxide. Emotional blocking Asphyxia can occur in cases where a person hides for too long a fear that paralyzes him. Perhaps he has managed this fear for some time.
  4. Asphyxia of the newborn
    Scope of examination 1. Asphyxia of newborns at the prehospital stage is possible when taking birth at home or in the saloon of an ambulance. 2. The severity of asphyxia is estimated in points on the Apgar scale by the end of 1 and 5 minutes: mild asphyxia corresponds to 6-5 points, moderate severity - 4-3, severe - 2. Medical care 1. With mild asphyxia, it is necessary to restore free patency
  5. Mechanical asphyxia
    Hypoxia - oxygen starvation of organs and tissues, until the complete cessation of oxygen supply to the body. Asphyxia is the state of the body when, along with a lack of oxygen, carbon dioxide accumulates in it. Mechanical asphyxia arises from the action of an external mechanical factor. According to the pace of development, hypoxia is divided into: acute, developing and leading to
  6. ASPHIX OF THE NEWBORN
    Definition Asphyxia of a newborn is a decrease in arterial pO, and an increase in arterial pCO ^ as a result of inadequate placental or pulmonary gas exchange. Etiology Dietary insufficiency of the newborn. Heart failure of a newborn. Typical cases Asphyxia of the newborn is often associated with fetal asphyxia or fetal distress, which may be
  7. Intrauterine Hypoxia. ASPHIXIA AND RESUSCITATION OF BABIES
    Asphyxia of a newborn is the lack of effective gas exchange in the lungs immediately after birth in a child with at least one sign of live birth. Signs of life: spontaneous breathing, palpitations, umbilical cord pulsation, voluntary muscular movement. Asphyxia of newborns is the cause of death of about a million children in the world every year and about the same number of children
  8. Hypoxia and Asphyxia
    By definition, P.S. Gurevich (1989), intrauterine asphyxia is acute fetal hypoxia (anoxia) resulting from a sudden violation of the uteroplacental or placental-fetal circulation in a previously healthy fetus. However, the term “asphyxia” is recognized as very conditional, because does not quite accurately reflect the essence of pathology. In this regard, the WHO scientific team has proposed replacing
  9. Primary and resuscitation care for newborn asphyxiation
    Fetal hypoxia and asphyxia of the newborn (perinatal asphyxia) are pathological conditions that develop as a result of acute or chronic oxygen deficiency and metabolic acidosis, which are manifested by disorders of the activity of vital systems (central nervous system, circulation, respiration). Perinatal asphyxia is one of the main causes of perinatal mortality, amounting to
  10. Strangulation Asphyxia
    Strangulation asphyxia is one of the varieties of acute violation of airway patency that occurs with direct compression of the trachea, blood vessels and nerve trunks of the neck. It is characterized by rapidly onset of gas exchange disorders such as hypoxemia and hypercapnia, short-term spasm of the cerebral vessels, and then their persistent expansion with deep disturbances of cerebral circulation,
  11. Strangulation Asphyxia
    Strangulation asphyxia is one of the varieties of acute violation of airway patency that occurs with direct compression of the trachea, blood vessels and nerve trunks of the neck. It is characterized by rapidly onset of gas exchange disorders such as hypoxemia and hypercapnia, short-term spasm of the cerebral vessels, and then their persistent expansion with deep disturbances of cerebral circulation,
  12. APPENDIX №3 Tasks for predicting asphyxia on the Apgar scale
    TASK №1 The child was born with a weight of 3.200. When evaluated on the Apgar scale, the heartbeat is 120 in 1 minute, the skin is pink, muscle tone is reduced, the number of breaths is 40 in 1 minute, grimaces appear on the soles of the soles. Определить степень асфиксии. ЗАДАЧА №2 Ребенок родился с весом 2 кг с резкими единичными дыхательными движениями. Число ЧСС 100 в 1 минуту. Кожа розовая, конечности цианотичные. Мышечный тонус
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    Непроходимость верхних дыхательных путей может быть обусловлена их обтурацией (инородное тело, опухоль, отек, гематома), а также сдавлением извне — странгуляцией. При полной обтурации гортани или трахеи, а также при странгуляции смерть наступает через несколько минут. Для механической асфиксии характерно сочетание гипоксии с гиперкапнией. Возникает кратковременный спазм, а затем парез мозговых
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