premature baby
Introduction
Introduction to premature babies The shorter the gestational age, the smaller the baby's weight and the shorter the length. A live birth born at 37 weeks before gestational age is called a premature infant or a premature infant. The birth weight is mostly below 2,500g, and the head circumference is below 33cm. A small number of premature infants who have a weight of more than 2,500 g, whose organ function and adaptability are worse than those of full-term children, should still be given special care for premature infants. Birth weight loss due to factors such as insufficient placental function to the gestational age below the 10th percentile or lower than the mean by two standard deviations is called small for gestational age (small sample, mature child, small- For-dateinfant, undersizedinfant, dysmaturity). Also known as low birth weight infants (lowbirthweightinfant), birth weight less than 1,500g are called very low birth weight infants (very lowbirthweightinfant), including premature infants and less than gestational age. basic knowledge The proportion of illness: 15% Susceptible people: premature infants Mode of infection: non-infectious Complications: sepsis pneumonia neonatal respiratory distress syndrome scleredema metabolic acidosis premature infant anemia
Cause
Causes of premature babies
Causes:
Placenta previa (30%):
The normal attachment of the placenta is at the posterior, anterior or side wall of the uterine body. If the placenta is attached to the lower uterus or over the cervix, the position is lower than the exposed part of the fetus, called the placenta previa. Placenta previa is one of the main causes of late pregnancy and premature delivery, and is a serious complication during pregnancy. More common in maternal, especially multi-partum women.
Pregnancy-induced hypertension (30%):
Pregnancy-induced hypertension, known as pregnancy toxicosis, pre-eclampsia, etc., is a unique condition for pregnant women, most of which occurs in 20 weeks of gestation and two weeks after delivery, accounting for about 5% of all pregnant women. Some of them are accompanied by proteinuria or edema, which is called pregnancy-induced hypertension syndrome. In severe cases, headaches, blurred vision, and upper abdominal pain may occur. It is one of the causes of premature birth.
Multiple pregnancy (25%):
There are two or more fetuses in a single pregnancy, called a multiple pregnancy. Multiple pregnancy has many complications during pregnancy and childbirth, and it is a high-risk pregnancy because of premature birth, perinatal mortality, and high neonatal mortality. In order to improve the pregnancy outcome, in addition to early diagnosis, we should strengthen pregnancy care and pay attention to delivery during childbirth.
Prevention
Premature infant prevention
1. The cause of premature birth is mainly maternal factors. Therefore, the mother should be actively prevented from preventing complications. The method of preventing premature birth is intravenous injection of 9.5% ethanol, which can prevent the release of oxytocin (oxytocin) and prevent contraction. The application of salbutamol can be used. Inhibition of uterine smooth muscle contraction, for the inevitable premature delivery, glucocorticoids can be given 48 hours before birth to accelerate fetal maturity and contribute to the pulmonary circulation after birth.
2. For low birth weight infants, physical development, neurodevelopment, mental development, and regular follow-up of sequelae should be performed after the neonatal period. The influence of social and environmental factors on the early development and cognitive function of premature infants is increasingly apparent. Important, especially the parental care ability, education level, occupation and socio-economic status are directly related to the quality of life of premature infants. Health care workers, families and society should work together to care about their health and improve the cognitive ability of premature infants. And behavioral ability to improve their quality of life to the greatest extent.
Complication
Premature infant complications Complications sepsis pneumonia neonatal respiratory distress syndrome scleredema metabolic acidosis premature infant anemia
Due to the above physiological and anatomical features, the organs of premature infants are immature, have poor adaptability to the external environment, and are prone to various complications. The incidence of diseases in various systems is high, and the mortality rate is high. For example, intracranial hemorrhage and cold injury syndrome are prone to occur. Sepsis, pneumonia, necrotizing enterocolitis, hypoxic ischemic encephalopathy, acidosis, hyperbilirubinemia, bilirubin encephalopathy, hemorrhagic disease, anemia, rickets, etc., prone to heart, liver, kidney, brain, Damage and exhaustion of organ function and so on.
1, neonatal respiratory distress syndrome
Due to insufficient synthesis of pulmonary surfactant, the disease is mainly found in premature infants and cesarean section, especially in less than 33 weeks, the incidence rate is about 50% in the 26 to 28 weeks of pregnancy, and 20% in the 30 to 31 weeks. 30%.
2, frequent apnea
About 70% of very low birth weight infants can have apnea, and the apnea can be as many as 40 times a day. The apnea can be primary or secondary to hypothermia, fever, hypoxia, acidosis, and hypoglycemia. , low blood calcium, hyperbilirubinemia, etc., apnea usually disappears after 34 to 36 weeks of gestational age.
3. Chronic lung injury
Premature infants are immature due to airway and alveolar development, and are easily injured by barotrauma and oxygen poisoning or open arterial catheterization, causing bronchopulmonary dysplasia syndrome and chronic pulmonary insufficiency in premature infants. This disease is more common in ELBWI, with an incidence of up to 40. % ~ 50%, of which bronchopulmonary dysplasia is more common.
4. Bronchopulmonary dysplasia
Its characteristics are:
(1) Intermittent positive pressure ventilation for more than 3 days within 1 week after birth.
(2) Chronic respiratory distress (hypnea, lung snoring, etc.) lasts for more than 28 days.
(3) In order to maintain PaO2>6.67 kPa, oxygen supply is required for more than 28 days.
(4) The chest radiograph has abnormal performance.
5, brain damage
About 7% of premature infants develop intraventricular hemorrhage or periventricular white matter softening. The incidence of body weight <1500g can be as high as 50%, and the symptoms are more common in the first few days after birth.
6, scleredema
Premature infants have poor body temperature regulation, relatively large body surface area, thin skin, abundant blood vessels, easy to dissipate heat, and a small amount of brown fat, which is easy to cause hypothermia and hard skin swelling.
7, infection
Due to the immature cellular and humoral immune function, insufficient antibody from the mother, immature skin barrier function, frequent device operation, etc., premature infants are prone to infectious pneumonia, sepsis and necrotizing enterocolitis.
8, low blood sugar
Postnatal blood glucose <2.2mmol / L for hypoglycemia, premature infants due to maintaining body temperature, breathing, muscle activity and other metabolism need to rely on carbohydrates to supply heat, and liver glycogen storage is small, if not timely feeding, it is easy to occur Hypoglycemia, clinical manifestations of bruising, apnea, lethargy, convulsions, screaming, muscle weakness and abnormal rotation of the eye, the incidence of hypoglycemia in preterm infants within 72 hours of birth is 1.5% to 5.5%.
9, hyperbilirubinemia
Korean premature babies are prone to hyperbilirubinemia and bilirubin encephalopathy, associated with hypoproteinemia, hypoxia, acidosis, hypoglycemia, infection, and bilirubin intestinal-hepatic circulation, mainly due to the lack of glucitol in the liver. Acyltransferase failed to convert free bilirubin to conjugated bilirubin.
10. Late metabolic acidosis
It is a common nutritional metabolism problem in premature infants, especially low birth weight infants. This is related to the quality and quantity of protein in the diet and the imperfect development of renal function. It is usually found in non-formulated milk-fed, often 2 weeks after birth, protein supply. When it reaches 5g/(kg·d), although it is treated with sodium bicarbonate, acidosis often lasts for 7 to 14 days.
11, premature infants with anemia premature infants to 1 to 2 months, often have anemia, but because the blood vessels are exposed to the surface of the skin, anemia is not easy to see with the naked eye, the cause of anemia in premature infants is:
(1) Insufficient iron storage: After 1 month of birth, the amount of serum iron drops sharply. At 3 months, the amount of serum iron can be reduced to one-third of that at birth. At this time, ferrous sulfate 2 mg/(kg·d) or 10% ferric ammonium citrate solution, supplemented with vitamin E 10mg / d, vitamin C 25mg / d, the effect is good.
(2) Need to increase: premature babies develop too fast, need to increase blood volume, but the hematopoietic function is poor, failing to catch up with the speed of weight gain, so sometimes although iron is given early, it is inevitable that anemia, when there is anemia, and Hemoglobin <120g / L, or although there is no anemia symptoms, but hemoglobin <70 ~ 80g / L, should be transfused.
12. Retinopathy of prematurity
Mainly for inhaling high concentration of oxygen within 10 to 14 days after birth, so that PaO2>13.3kPa, the retinal blood vessels will expand, bend, exude and hemorrhage, and finally form scars, scar tissue contraction, push the lens forward, anterior chamber change Shallow, corneal opacity, visual impairment, severe cases of ciliary body and retinal detachment, this disease often complicated by myopia, strabismus or glaucoma, the disease is more common in VLBWI, especially ELBWI.
13, rickets
Premature infants have low serum calcium, but can return to normal levels on the 7th day. Generally, there is no symptoms of low calcium, no calcium supplementation, but ultra-low birth weight children are prone to rickets. The reasons are:
(1) Calcium, phosphorus and vitamin D are stored less.
(2) The function of absorbing fat and fat-soluble vitamins is poor.
(3) Due to the rapid growth, the general supply of calcium and phosphorus often cannot meet the needs, especially the deficiency of phosphorus.
(4) It is easy to have infection and digestive tract disorder, so it is difficult to absorb minerals and fat.
Symptom
Symptoms of premature babies Common symptoms Inability to breathe, metabolic acidosis, dehydration, hypotension, suffocation, sputum, feeding difficulties, nuclear jaundice
1. The earlier the premature baby is born, the thinner the skin, the more water content of the tissue, the depressed indentation, the red color, the less subcutaneous fat, the less muscle, the short nails, and the longer the hair of the trunk, the more the head hair Less and shorter, the head is larger, the cardia is wide, the ear shell is soft and the skull is attached, the thorax is soft, the areola is spotted, the edge is not protruding, and the breast is small or can not be touched. The abdomen is swollen and the scrotum is poorly developed. The testes of male premature infants are often in the outer groin and gradually fall into the scrotum during development. The more premature women get, the more separate and prominent the labia minora. Less wrinkles in the hands and feet.
2, body temperature regulation is difficult and unstable to use its heat production is limited, less muscle, low tension, can not change the posture to reduce the area of heat loss. On the other hand, due to the immature development of the sweat gland, the sweating function is incomplete, and the body temperature is also prone to occur.
3, weak resistance to all kinds of infections are extremely weak, even a slight infection can lead to serious consequences such as sepsis.
4, premature infants breathe fast and shallow, and often have irregular intermittent breathing or apnea. The crying is very small, often cyan.
5, premature infants with weak milk and swallowing ability, cardia sphincter relaxation, easy to cause cough, vomiting, diarrhea and bloating.
6, when trauma, hypoxia, infection, blood coagulation machine is affected, often bleeding and heavier. The blood vessels in the brain are particularly vulnerable to bleeding. Sometimes there is an unexplained pulmonary hemorrhage.
7, 1 premature infants have poor binding and excretion of bilirubin, and their physiological jaundice is longer than that of full-term children, and heavier. 2 Because the liver of premature infants is immature, liver dysfunction, prothrombin V factor, factor VII, factor X, etc. are lower than full-term children, so the coagulation mechanism is not perfect, easy to bleed. 3 The storage of iron and vitamins A and D is reduced, and it is easy to get the nutritional deficiency. 4 The function of turning liver glycogen into blood sugar is reduced, so that when hunger, blood sugar is liable to be too low and shock occurs. 5 The function of synthetic protein is not good, and edema can be formed due to low plasma protein.
8, due to glomerular, renal tubular immature, glomerular filtration rate is low, urea, chlorine, potassium, phosphorus clearance rate is also low, proteinuria is more common. Premature infants lose weight after birth and are prone to acid-base balance disorders due to infection, vomiting, diarrhea, and changes in ambient temperature.
9. The center is immature, the crying is weak, the activity is low, the muscle tension is low, the nerve reflex is not obvious, and the reflexes such as cough, sucking, and swallowing are all poor.
10. The weight gain of premature infants is larger than that of full-term children. At 1 year old, the weight of full-term infants is roughly equal to 3 times of that of newborns. The weight of 1501~2000g premature infants at 1 year old can reach 5 times and half of that of newborns. 1001 ~ 1500g can reach 7 times.
11. The amount of IgG in the premature infant through the mother placenta is small, the self-cell immunity and the synthesis of antibodies IgA, D, E, G, and M are insufficient, the level of complement is low, and the serum lacks opsonin, so the resistance to infection is weak, which is easy to cause septicemia.
Examine
Premature infant examination
In the case of concurrent infection, infectious blood, white blood cell count and neutrophil increase, blood loss, anemia, hemoglobin concentration and red blood cell count decreased, when abnormal conditions, attention should be paid to the presence or absence of hypoxemia and hyperphosphatemia Should pay attention to check blood electrolytes and blood pH, pay attention to the presence or absence of intrauterine infection, pay attention to the detection of antigen and antibody, and assist in clinical diagnosis.
According to the history and clinical features, select the necessary auxiliary examinations, such as chest radiographs, understand the lungs, CT examinations, and other intracranial lesions.
Diagnosis
Diagnosis and differential diagnosis of premature infants
Premature babies have a clear diagnosis and generally do not need to be differentiated from other diseases. The following are diagnostic criteria:
1, the body weight is mostly below 2500g, the body length is less than 47cm, the crying is light, the neck muscles are weak, the muscles of the limbs are low, the skin is red and tender, the baby hair is more, the ear shell is soft, the areola is unclear, the foot line is less, the baby testicles come. Falling or not falling, the baby's labia majora can not cover the labia minora.
2, the respiratory center is relatively more immature, irregular breathing; apnea often occurs. Apnea refers to a breathing stoppage of 15 to 20 seconds, or less than 15 seconds, but with a slow heart rate (<100 beats/min) and purpura. Premature infants have immature lung development and few surfactants, which are prone to hyaline membrane disease. Premature babies with a history of intrauterine distress are prone to aspiration pneumonia.
3, swallowing reflexes are weak, easy to suck milk and milk inhalation. The gastric cardia sphincter is loose, the volume is small, and the breast is easy to overflow. Premature infants should be breastfed, but protein should be added in time. Premature infants are prone to necrotizing enteritis, it should be noted that the osmotic pressure of milk should not exceed 460mmol / L.
