Premature Infant

an infant born before the expiration of the complete term of pregnancy; such an infant weighs between 1,000 and 2,500 g and is 37 to 46 cm long. After birth, the premature infant remains in the fetal position, with his spine bent and his arms and legs pressed to his trunk. The head is large in comparison with the trunk, and the fontanelles and cranial sutures are open. The neck is thin and long. The limbs are long and have short nails that do not always reach the edges of the nail bed. The skin is wrinkled and folded, and the trunk is profusely covered with lanugo. In extremely premature infants, the lanugo covers the face. The umbilical ring is located in the lower part of the abdomen. The subcutaneous fat and the muscles are poorly developed. Respiration is rapid, superficial, feeble, and irregular; sometimes there is temporary cessation of breathing. The pulse is weak and averages 120 to 140 beats per minute; during crying or feeding the frequency increases significantly. The sucking and, in some infants, the swallowing reflexes are weakly expressed or completely absent. In girls the genital cleft is open; in boys the scrotum may be empty, and the testes may be located in the inguinal canals or in the abdominal cavity. Underdevelopment of the central nervous system produces inadequate thermoregulation, respiratory insufficiency, and twitching of the facial musculature. Initial weight loss fluctuates between 130 and 200 g; weight is often restored between the 12th and 20th day of life. Anemia often develops at the end of the second month.

Premature infants characteristically gain weight rapidly during the first year of life. By 2 1/2 to three months of age the infants double their weight at birth, and by four to six months of age, they have tripled it. By the time the infants are one year old, their weight is four to six times greater than at birth, and their height has increased 24 to 29 cm. When the child is three years old, its weight and height approach those of three-year-olds who were full-term births. (Heavier premature infants reach normal body measurements at age 1 1/2.) The nervous and mental development in premature infants is characterized by retardation in motor, speech, and other abilities by 1 1/2 to two months in comparison with full-term infants.

Because the body of a premature infant is marked by the rapid exhaustion of physiological processes, a strict regimen requiring regulation of temperature, light, sound, and other stimuli, as well as adherence to rules of asepsis and antisepsis, should be observed in the first two months of life. Premature infants weighing less than 1,500–1,700 g require special hospital care. To ensure adaptation to the new environment, the infant is kept in a closed incubator for the first two to four weeks and sometimes even longer; if an incubator is not available, the infant is kept warm with hot-water bags.

Because of the small volume of his stomach, the infant is fed ten to 12 times a day during the first days of life; the number of feedings later decreases to seven daily. The caloric value of food in the first days after birth is from 30 to 60 calories (cal) per kg of newborn weight (1 cal = 4.19 joules), by the seventh or eighth day 70–80 cal per kg, and by the tenth to 14th day 100–120 cal per kg. At one month of age the infant must receive 135–40 cal per kg of weight (about 200 g of milk per kg of weight).

Infants weighing less than 1,200–1,300 g should be fed through a catheter during the first 1 1/2 to two weeks of life even if the sucking reflex is present. This is because the infant would expend too much energy sucking. A polyethylene catheter may be left in the stomach for three or four days; sometimes a pipette is used for feeding the premature infant. If the infant is not in an incubator, oxygen is given before and after feeding. When the infant reaches a weight of approximately 1,700 g, it may be breast-fed.

Multiple vitamins are strongly recommended. Vitamin D is prescribed at the end of the first month (in the third week of life). Natural fruit and vegetable juices are introduced when the infant is two months old—beginning with two or three drops and increasing the dosage to 15–20 g at three months of age and to 50–60 g at six months of age.

REFERENCES

Spravochnik pediatra. Moscow, 1966.
Nedonoshennye deti. Sofia, 1971.

E. CH. NOVIKOVA

premature infant

infant

[in´fant] a human child from birth (see infant" >newborn infant) to the end of the first year of life. Emotional and physical needs at this time include love and security, a sense of trust, warmth and comfort, feeding, and sucking pleasure.Growth and Development. Development is a continuous process, and each child progresses at his own rate. There is a developmental sequence, which means that the changes leading to maturity are specific and orderly. The various types of growth and development and the accompanying changes in appearance and behavior are interrelated; that is, physical, emotional, social, and spiritual developments affect one another in the progress toward maturity.
Development of muscular control proceeds from the head downward (cephalocaudal development). The infant controls the head first and gradually acquires the ability to control the neck, then the arms, and finally the legs and feet. Movements are general and random at first, beginning with use of the larger muscles and progressing to specific smaller muscles, such as those needed to handle small objects. Factors that influence growth and development are hereditary traits, sex, environment, nationality and race, and physical makeup. See also growth.large-for-gestational-age infant a preterm, term, or postterm infant who is above the 90th percentile for gestational age in head circumference, body weight, or length.low-birth-weight infant one that weighs less than 2500 grams at birth. This standard is routinely used for infants in developed countries, but infants born in other countries typically weigh less at birth. In India the criterion for normal birth weight is 2150 grams and in Malaysia it is 2000 grams.newborn infant a human infant from the time of birth through the 28th day of life. At birth, the gestational age as well as birth weight is assessed and the newborn classified accordingly; for example, large for gestational age, preterm (premature), or low birth weight. Called also neonate and newborn.premature infant (preterm infant) one born before a gestational age of 37 completed weeks (259 days). The duration of gestation is measured from the first day of the last menstrual period and is expressed in completed days or weeks.postmature infant (postterm infant) one born any time after the beginning of the forty-second week (288 days) of gestation.small-for-gestational-age infant a preterm, term, or postterm infant who is below the 10th percentile for gestational age in head circumference, body weight, or length.term infant one born at a gestational age of 37 to 42 completed weeks (259 to 293 completed days).very-low-birth-weight infant one that weighs less than 1000 grams at birth.Patient Care. Low-birth-weight and very-low-birth-weight infants require special care and support, preferably in a neonatal intensive care unit (NICU), until sufficient weight is gained and the infants have matured and are able to thrive without elaborate support systems.
At the time of delivery, whether cesarean or vaginal, a skilled neonatal team should be present to provide immediate care. After resuscitation measures under a radiant warmer are completed and the newborn is stabilized, transfer to the NICU is done without interruption of warming and oxygen therapies.
Among the problems associated with low birth weight are hypothermia, respiratory distress, hyperbilirubinemia, fluid and electrolyte imbalance, susceptibility to infection, and feeding problems.
Very-low-birth-weight newborns and infants are at significant risk for hypothermia because of their small body mass, large surface area, thin skin, minimal subcutaneous tissues, and posture. Thermoregulation is provided through the use of a standard incubator or a radiant warmer. Radiant warmers have the advantage of accessibility for caregivers and improved visibility of the infant. Their chief disadvantage is increased insensible water loss.
respiratory distress syndrome" >Neonatal respiratory distress syndrome is the major cause of death in newborns. Atelectasis can lead to hypoxemia and elevated serum carbon dioxide levels and all the problems related to inadequate gas exchange. Oxygen therapy must be administered with caution because of the danger of retinopathy.
The treatment of hyperbilirubinemia remains a challenge because of lack of consensus on the level of serum bilirubin concentration at which therapy should begin, the uncertain diagnosis of kernicterus, and the currently limited knowledge of the blood--brain barrier. It is believed that these infants are at critical risk for bilirubin-related brain damage at serum concentrations as low as 6 to 9 mg/dl. Phototherapy is the treatment of choice and may be given prophylactically in some institutions to all infants weighing less than 1000 grams.
The management of fluid and electrolyte administration to maintain proper balance is highly complex. Factors taken into consideration are proportion of body, composition of water, renal function, and insensible water loss. Fluid and electrolyte status must be closely monitored. Overhydration is a hazard because it has been implicated in the development of such serious complications as pulmonary edema, patent ductus arteriosus, and necrotizing enterocolitis in these infants.
Low-birth-weight and very-low-birth-weight infants are particularly susceptible to infection because their immunologic system is deficient. Additionally, equipment and care related to long-term respiratory and nutritional support, together with frequent laboratory testing, increase exposure to infectious agents. Infection control measures must be adhered to faithfully. In some NICUs reverse isolation is required for all infants weighing less than 1000 grams.
Since the skin of these infants is highly permeable and easily traumatized, every effort must be made to preserve its integrity. Routine care to preserve the integrity of the skin, caution in the use of topical ointments and antiseptic preparations, and minimal handling also are essential.
At the beginning, nutritional support in the form of total parenteral nutrition may be necessary until enteral feedings are feasible. Oral feedings usually are initiated by the end of the first week of life. Continuous gastric feedings via infusion pump have the advantage of preventing vomiting and aspiration and abdominal distention associated with intermittent feedings of larger amounts. The enteral feedings given in this manner include breast milk (donor or mother) and special formulas.
Discharge planning and follow-up care are begun upon admission to the NICU. Individual family needs should be assessed and available community resources identified. Parental education and support are provided throughout the time the infant is in the NICU. At the time of discharge parents should be confident of their ability to care for the infant, knowledgeable about sources available to them, and able to utilize those resources to the fullest.