Neonatal asphyxia is a continuation of intrauterine hypoxia and acidosis in the fetus. In the absence of spontaneous respiration for 20 min after birth, irreversible hypoxic damage will occur to the heart, kidneys, brain and other vital organs, which is an important cause of neonatal death or the occurrence of impaired infants.
Key Points of Diagnosis
(A) Medical history
1. Complications during labor: such as fetal distress, excessive or weak contractions, stalled labor, birth trauma with non-appropriate techniques (huge fetus, breech delivery, etc.), pelvic abnormalities, excessive use of analgesic anesthetics, etc.
2. Inadequate blood perfusion to the uteroplacenta: such as overdue pregnancy, hypertension, chronic nephritis, hypertension, placental insufficiency, low amniotic fluid, antepartum hemorrhage, excessive expansion of the uterus (multiple births, excessive amniotic fluid), inappropriate application of contractions and maternal hyperthermia, etc.
3.Abnormal umbilical cord: pre-disclosed, prolapsed, wrapped around the neck, knotted, twisted, thinning, too short, etc.
4.Congenital anomalies of the newborn: such as congenital heart disease, diaphragmatic hernia, pulmonary hypoplasia, nasal tumor, cervical lymphatic hydrocele obstructing the airway, pneumothorax, etc.
(B) Clinical manifestations
Apgar score is used to determine the degree of neonatal asphyxia, which is usually assessed by non-midwives and preferably equipped with a time alarm. If possible, PH and gas measurement of umbilical artery blood should be performed.
1, the degree of asphyxia is based on the score within 1 min after birth, the score directly reflects the degree of hypoxia and acidosis. The score 0~3 is pale asphyxia (severe asphyxia), 4~7 is cyanotic asphyxia (mild asphyxia), 8~10 is normal.
2. The second assessment was performed at 5 min after birth, and this score has a positive effect on estimating prognosis and guiding clinical management. If the score is low at 5 min, a longer score (20 min after birth) is appropriate.
3, low scores can be considered clinically as the following possibilities: a, recent complications of asphyxia such as ischemic-hypoxic encephalopathy, intracranial hemorrhage, pulmonary aspiration (amniotic fluid, meconium or blood). b, malformation problems. c, severe uncorrected acidosis.
(iii) Ancillary tests
1, Blood gas examination may show respiratory and metabolic acidosis, the latter has a serious prognosis and is proportional to intracranial hemorrhage, brain damage.
2, blood glucose, blood calcium, blood sodium are willing to reduce, and blood potassium is elevated.
3, acute bedside thoracic and abdominal upright radiographs are helpful for timely diagnosis of pneumothorax and diaphragmatic hernia.
The Treatment
(A) Measures for asphyxia resuscitation
The neonatologist must be present at the time of delivery to prepare for resuscitation of neonatal asphyxia, including low negative pressure (80~100mmHg) suction, warming appliances (hot water bag, lamp, far-infrared open warmer, underwear, diapers, etc.), oxygen, tracheal intubation equipment and various types of catheters, “T” tube balloons, drugs, etc. In the process of resuscitation, three keys are essential: attraction, warmth and oxygen supply.
1.Removal of mucus
(1) When the fetal head is delivered, before the shoulder is delivered, turn it to the side and remove the mucus from the fetal mouth, nose, pharynx and subpharynx, and if fetal feces is seen, suction should be used to attract.
(2) After delivery, the baby should be placed in a lying position or with the head 15 degrees lower, and then suck the pharyngeal secretions with a suction tube or a suction device, and the operation of sucking mucus should be completed within 1 min. The choice of suction tube to thin wall is not easy to fold deflated, the distal side wall has openings and scale is preferred.
(3) Disinfection swab roll out the sticky thick amniotic fluid and meconium.
(4) Tracheoscopy can pick up the epiglottis, see the vocal cords and then insert the catheter, suction while pumping is more effective. Mouth-to-mouth aspiration can be used without conditions.
(5) Avoid stimulating its cry before clearing the respiratory secretions and cause deep breathing, resulting in aspiration pneumonia, pulmonary atelectasis, and meconium aspiration syndrome.
2.Oxygen
(1) Use open mask to give oxygen to light cases (note that the edge below the funnel should be close to the nostril), and use closed mask with nasal catheter to give oxygen to heavy cases, with oxygen concentration of 40%~50%.
(2) Indications for oxygen administration by tracheal intubation with pressure: a. No spontaneous respiration even after removal of mucus. b. Slowed heart rate. c. Paler skin color. d. Lower muscle tone. e. When diaphragmatic hernia is suspected.
Methods.
Intra-organic catheter is inserted and oxygen is administered under pressure, with the distal end of the catheter reaching only the midclavicular point on the line of the clavicle, pressure of 2,45~3,43kiPa, oxygen flow rate of 5L/Vmin, and respiratory rate of 30~40 breaths/min.
Precautions.
a. It is necessary to listen to both sides of the lungs for symmetry of breath sounds and observe whether the abdomen is bulging. b. If low breath sounds are heard on the left side, pull the catheter slightly outward. c. A bulging abdomen indicates misinsertion into the digestive tract and should be reinserted immediately. d. If the pressure is >6, 86 kPa, it can lead to the risk of pneumothorax in full-term newborns, and a bulging abdomen is also seen in those who have pneumothorax. Caution and care must be taken when adding pressure, and the pressure should be strictly controlled.
Extubation: It is not advisable to extubate prematurely. The tube should be removed only when the newborn’s skin turns red, spontaneous respiration is established and the nausea reflex is not tolerated, and the tube must be removed while suctioning.
3.Keep warm
In the whole process of resuscitation, the newborn must be given a warm environment, so that its abdominal skin temperature is maintained at about 36,5 degrees, warming work directly affects the success and failure of resuscitation, improper warming will occur acidosis, hypoglycemia, pulmonary hypertension, fetal circulation reproduction, increased cardiac burden leading to heart failure, sclerosis, induced respiratory distress syndrome and nuclear jaundice risk.
4.Correction of acidosis
The total amount of 5% sodium bicarbonate should not exceed 10~13ml/kg a day, but it should not be used until good ventilation is established. For those with persistently high blood potassium, 5% glucose solution can be used as a sedative drip, with 1u insulin for every 3g of glucose.
5.Restore circulation
(1) Severely asphyxiated children with a heart rate below 80 beats/min after tracheal intubation and pressurized oxygen administration should undergo extracardiac massage. Method: The operator uses both thumbs to put his chest at the junction of the middle and lower 1/3 of the sternal body, the remaining four fingers around the chest to hold behind, press with the second thumb, 100~120 times/min, every 4 presses to pressurize oxygen once, press down the depth of the depression 1,5~50px, when the pressure is effective, you can gouge and femoral artery pulsation.
(2) If there is no pulsation, 1:10,000 epinephrine 0,1ml/kg can be injected intratracheally (usually diluted 10 times with 1:10,000 epinephrine), the effect is to make the drug quickly reach the alveoli and increase the myocardial contraction by vascular diffusion.