Prematurity PDF

**Prematurity** **Introduction** Any newborn whose life or quality of existence is threatened is considered to be in a high-risk category and requires close supervision by professionals in a special neonatal intensive care unit (NICU). Preterm newborns constitute a majority of these patients. Pret...

**Prematurity** **Introduction** Any newborn whose life or quality of existence is threatened is considered to be in a high-risk category and requires close supervision by professionals in a special neonatal intensive care unit (NICU). Preterm newborns constitute a majority of these patients. Preterm birth is responsible for more deaths during the first year of life than any other single factor. Preterm infants also have a higher percentage of birth defects. Prematurity and low birth weight are often concomitant, and both factors are associated with increased neonatal morbidity and mortality. The less an infant weigh at birth, the greater the risks to life during delivery and immediately thereafter. **Objectives** 1. Define Preterm 2. List the classification of Newborn 3. Identify the etiology of prematurity 4. State the health risk for the preterm 5. Discuss the assessment of the premature newborn 6. Describe the effects of prematurity on body systems 7. Discuss the nursing management of the preterm 8. Outline the complication of Prematurity **Definition** The term premature has been replaced by the more descriptive adjective preterm. **"Preterm": (Premature)** infant means any infant of less than 37 completed weeks' gestation. **Classification of Newborn** In the past, a newborn was classified solely by birth weight. The emphasis is now on gestational age and level of maturation. Gestational age refers to the actual time, from conception to birth, that the fetus remains in the uterus. For the preterm infant this is less than 37 weeks. 1. **An Early Term Infant** This is a neonate born between 37 weeks and 38 weeks, 6 days. 2. **A Full-term Infant** This is one born between 39 and 40 weeks, 6 days 3. **The Late Term Infant** This is one born between 41 weeks and 41 weeks, 6 days. 4. **The Postterm Infant** This is one born beyond 42 weeks 5. **Extremely Premature** This is a neonate born less than 28 weeks' gestation 6. **Very premature** This is a neonate born less than 32 weeks' gestation 7. **Moderately Premature** This a neonate born less than 34 weeks' gestation 8. **Late Preterm** This is a neonate born between 34- and 37-weeks' gestation **Etiology of Prematurity** There are many risk factors for a premature birth. Sometimes the cause of a premature birth is never really known. Known risk factors for a premature delivery include: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. **Health Risk for Premature Newborns** 1. **Respiratory system dysfunction**---due to surfactant deficiency leading to distress 2. **Glycemic instability**---due to increased energy demands needed for temperature regulation and increased respiratory effort, which cause the blood glucose to remain low for prolonged periods of time 3. **Poor Thermoregulation-** due to the immature heat-regulating center of the brain 4. **Jaundice**---due to feeding difficulties and inability of liver to conjugate bilirubin 5. **Inadequate oral intake**---due to a decreased ability to suck and swallow 6. **Susceptibility to infection**---due to immaturity of the immune system 7. **Neurologic immaturity**---due to reduced cortical development, which occurs during the 34th and 40th week of gestation **Assessment of the Preterm Newborn** Determining an infant\'s gestational age is essential, as it provides key insights for interpreting physical examination findings and planning developmentally appropriate care. Accurate maternal menstrual history or the measurement of fetal size using ultrasound imaging prior to 20 weeks' gestation are the preferred methods of assessing gestational age. However, where these data are not available, or may be inaccurate, assessment of gestational age of the newborn can be made by physical examination. The assessment of preterm infants is a critical responsibility of the bedside nurse. Employing a systematic approach to the physical assessment of high-risk infants enables neonatal nurses to accurately evaluate the infant's condition and estimate gestational age efficiently. Ongoing assessments also help detect subtle changes, allowing caregivers to anticipate and address potential complications promptly, thereby safeguarding the infant\'s health and well-being. It relies on two sets of characteristics: physical and neurological. One standardized method used to estimate gestational age within 1 to 2 weeks is the Ballard scoring system, which is based on the infant's external characteristics and neurological development. The Ballard score, the estimated gestational age based on the mother's last normal menstrual period, and ultrasound evaluations all are methods used to evaluate the gestational age of the newborn infant. **Examination Techniques** The examination techniques used with premature infants include: 1. Inspection 2. Auscultation 3. Palpation 4. Transillumination When examining an infant, timing is important. The infant should be warm and positioned comfortably. Changes in condition should be evaluated against baseline values. The examination should be clustered with other caregiving activities to provide adequate rest intervals between care and before feedings. **Physical Features of the Newborn** - The head and abdomen are disproportionately large - Heart murmurs may be present related to patent Ductus arteriosus. - Anemia is common, especially among very low birth weight babies - Hypotension may occur among extremely low birth weight infants. - Apnea, cessation of breathing for at least 10-15 seconds, and bradycardia, heart rate less than 100 beats per minute, are commonly observed - Birth weight of less than 5.5 lb **The major anatomical parts used in determining gestational age are:** - **Lanugo:** present between 20- and 28-weeks. At 28 weeks gestation, lanugo begins to disappear on the face and the front of the trunk. - **The skin:** is translucent, transparent, and red. Subcutaneous fat is decreased. Skin is thin and arteries and veins are visible. It is fragile and looks smooth and shiny. - **Creases:** on the anterior part of the feet are not present until 28-30 weeks. As gestation increases, plantar creases increase and spread toward the heel of the foot. For example, a preterm infant at 33 weeks has only an anterior crease. - **Fingernails and toenails** may only be partially formed and short. - **The cheeselike vernix caseosa** is abundant - **Eyelids:** are fused in very preterm neonates. The eyelids are often fused until 25 weeks' gestation. Eyelids open between 26- and 30-weeks' gestation. - **Ears:** The pinna of the ear is thin, soft, flat, and folded. Ear cartilage develops progressively in the ear from the centre to the periphery. Preterm infant at 28 weeks has little ear cartilage. Until 32 weeks' gestation there is so little cartilage present that the ear retains the shape that has been applied to it. - **Breast tissue:** In the very preterm newborn, the nipple is barely visible and the areola non-existent. These develop during gestation and by 34 weeks' gestation a breast nodule becomes palpable. For example, a preterm infant at 28 weeks has no breast tissue. - **Genitalia:** The genitalia are small. Extremely preterm infant males will have undescended testicles which are found in the inguinal canal. The testes descend into the scrotum at about 29 weeks' gestation but may not be deep within the scrotum until term. Coincident with testicular descent is the development of increased rugosity of the scrotum. In girls the labia majora may be open. The labia minora and clitoris are prominent early in gestation. Only by term have the labia majora developed to cover the labia minora and clitoris. **Neurological Features** - **Cry:** The cry is weak. - **Muscle Tone:** As gestation progresses, there is an increase in muscle tone, particularly flexor tone. There is a concomitant increase in muscle strength. Very preterm infants have less muscle tone. - **Reflexes:** may be diminished or absent. Immature suck, swallow, and breathing patterns are observed in very premature infants. These neonates may not be able to take adequate oral feedings. - **Posture:** The very preterm newborn adopts a deflexed posture of the limbs. By term there is marked limb flexion at rest. Tremors and jittery movement may be noted. - Several reflexes develop during the third trimester: the pupil responds to light from 29 weeks' gestation, there is a blink response to a tap on the glabella from 32 weeks' and flexion of the arms or neck when pulled by the wrists from supine from 34 weeks'. - The premature baby does not lie in a fetal position until 35 weeks. **Effects of Prematurity on Body Systems** Since the preterm newborn did not remain in utero long enough, every body system may be immature, affecting the newborn's transition from intrauterine to extrauterine. The age and weight of the premature newborn influence the severity of the complications. Without full development, organ systems are not capable of functioning at the level needed to maintain extrauterine homeostasis. **Respiratory System** **Immature Respiratory System:** The respiratory system is one of the last body systems to mature. Therefore, the preterm newborn is at great risk for respiratory complications. A few of the problems that affect the preterm newborn's breathing ability and adjustment to extrauterine life include: 1. Surfactant deficiency, leading to the development of respiratory distress syndrome 2. Unstable chest wall, leading to atelectasis 3. Immature respiratory control centers, leading to apnea 4. Smaller respiratory passages, leading to an increased risk for obstruction 5. Inability to clear fluid from passages, leading to transient tachypnea **Cardiovascular System** **Changing from fetal to newborn circulation pattern.** The preterm newborn has great difficulty making the transition from intrauterine to extrauterine life Higher oxygen levels in the circulation once air breathing begins spur this transition. If the oxygen levels remain low secondary to perinatal asphyxia, the fetal pattern of circulation may persist, causing blood flow to bypass the lungs. **Increased incidence of congenital anomalies** Another problem affecting the cardiovascular system is the increased incidence of congenital anomalies associated with continued fetal circulation: 1. patent ductus arteriosus 2. an open foramen ovale. **Impaired regulation of blood pressure in preterm newborns** This may cause fluctuations throughout the circulatory system. One special note is cerebral blood flow, which may predispose the fragile blood vessels in the brain to rupture, causing intracranial hemorrhage. **Gastrointestinal System** 1. Preterm newborns usually lack the neuromuscular coordination required to maintain the suck, swallow, and breathing regimen necessary for sufficient calorie and fluid intake to support growth. 2. Perinatal hypoxia causes shunting of blood from the gut to more important organs such as the heart and brain. Subsequently, ischemia and damage to the intestinal wall can occur. This combination of shunting, ischemia, damage to the intestinal wall, and poor sucking ability places the preterm infant at risk for malnutrition and weight loss. 3. Preterm newborns have a small stomach capacity, weak abdominal muscles, compromised metabolic function, limited ability to digest proteins and absorb nutrients, and weak or absent suck and gag reflexes. All of these limitations place the preterm newborn at risk for nutritional deficiency and subsequent growth and development delays. The preterm infant's ability to coordinate sucking, swallowing, and breathing is challenged. As a result, preterm infants often require enteral or intravenous feeding. Enteral tube feeding will help to conserve energy even in an infant who is able to suck. Currently, minimal enteral feeding is used to prepare the preterm newborn's gut to overcome the many feeding difficulties associated with gastrointestinal immaturity. It involves the introduction of small amounts, usually 0.5 to 1 mL/kg/hr, of enteral feeding to induce surges in gut hormones that enhance maturation of the intestine. This minute amount of breast milk or formula given via gavage feeding prepares the gut to absorb future introduction of nutrients. It builds mucosal bulk, stimulates development of enzymes, enhances pancreatic function, stimulates maturation of gastrointestinal hormones, reduces gastrointestinal distention and malabsorption, and enhances transition to oral feedings. **Renal System** The renal system of the preterm newborn is immature, reducing the baby's ability to concentrate urine and slowing the glomerular filtration rate. As a result, the risk for fluid retention, with subsequent fluid and electrolyte disturbances, increases. Preterm newborns have limited ability to clear drugs from their systems, thereby increasing the risk of drug toxicity. Close monitoring of the preterm newborn's acid-base and electrolyte balance is critical to identify metabolic inconsistencies. Prescribed medications require strict evaluation to prevent overwhelming the preterm baby's immature renal system **Immune System** The preterm newborn's immune system is very immature, increasing his or her susceptibility to infections. 1. A deficiency of IgG may occur because transplacental transfer does not occur until after 34 weeks' gestation. This protection is lacking if the baby was born before this time. 2. Preterm newborns have an impaired ability to manufacture antibodies to fight infection if they were exposed to pathogens during the birth process. 3. The preterm newborn's thin skin and fragile blood vessels provide a limited protective barrier, adding to the increased risk for infection. Thus, anticipating and preventing infections is the goal; preventing infections has a better outcome than treating them. **Central Nervous System** The preterm newborn is susceptible to injury and insult to the CNS, increasing the potential for long-term disability into adulthood. Like all newborns, preterm newborns have difficulty with temperature regulation and maintaining stability due to: 1. Inadequate amounts of insulating subcutaneous fat 2. Lack of muscle tone and flexion to conserve heat 3. Inadequate brown fat to generate heat 4. Limited muscle mass activity reducing the Possibility of producing their own heat 5. Inability to shiver to generate heat 6. An immature temperature-regulating center in the brain Preventing cold stress, which would increase the newborn\'s metabolic and oxygen needs, is crucial. The goal is to create a neutral thermal environment in which oxygen consumption is minimal, but body temperature is maintained. The preterm newborn is especially susceptible to hypoglycemia due to: 1. immature glucose control mechanisms 2. decreased glucose stores 3. a reduced availability of alternative fuels such as ketone bodies. **Nursing Management** **Promoting Oxygenation** 1. Monitor respiratory effort (rate, character, effort) to identify changes every hour 2. Anticipate need for bag and mask setup and wall suction to allow for prompt intervention should respiratory status continue to worsen. 3. Maintain slight head elevation to prevent upper airway obstruction. 4. Observe skin color to evaluate tissue perfusion every hour (any changes to duskiness, blueness, or pallor) 5. Monitor oxygen saturation level via pulse oximetry to provide objective indication of perfusion status every hour 6. Observe for cues (grunting, shallow respirations, tachypnea, apnea, tachycardia, central cyanosis, hypotonia, increased effort) to identify need for additional oxygen. 7. Auscultate Lung sounds to differentiate breath sounds in upper and lower fields 8. Cluster nursing activities to reduce oxygen consumption. 9. Maintain a neutral thermal environment to reduce oxygen consumption. 10. Provide supplemental oxygen via nasal canula or head box as indicated and ordered to ensure adequate tissue oxygenation 11. Repositioning the newborn every 2 hours helps to reduce the risk for pneumonia and atelectasis. 12. Provide suctioning when necessary to prevent airway obstruction, hypoxia, and asphyxiation. 13. Offer gentle stimulation during apneic spells Maintaining Thermal Regulation 1. Monitor the axillary temperature every hour 2. Monitor vital signs, including heart rate and respiratory rate, every hour to identify deviations. 3. Check radiant heat source or isolette to ensure maintenance of appropriate temperature of the environment to prevent hypo or hyperthermia 4. Avoid bathing and exposing newborn to prevent cold stress 5. Warm all blankets and equipment that come in contact with newborn; place warmed cap on the newborn's head and keep it on to minimize heat loss. 6. Check the environment for sources of heat loss or gain through evaporation, conduction, convection, or radiation to minimize risk, of heat loss. 7. Observe for clinical signs of cold stress, such as respiratory distress, central cyanosis, hypoglycemia, lethargy, weak cry, abdominal distention, apnea, bradycardia, and acidosis. 8. Monitor blood glucose level twice daily 9. Swaddle in flexion with arms and hands placed toward the infant's midline. 10. Create a nest with blankets to enhance containment. 11. Avoid swaddling or nesting that is overly restrictive to neonatal movement **Promoting Nutrition and Fluid Balancing** 1. Initiate early oral feedings or gavage feedings to maintain blood glucose levels. 2. Monitor blood glucose levels as ordered to determine status and establish a baseline for interventions 3. Decrease energy requirements, including clustering care activities and providing rest periods, to conserve glucose and glycogen stores. 4. Monitor for tolerance of oral feedings, including intake and output, to determine effectiveness. 5. Maintain temperature using warmed blankets, radiant warmer, or warmed isolette to prevent heat loss and possible cold stress and reduce energy demands 6. Observe behavior for signs of low blood glucose to allow early identification 7. Observe skin for pallor and sweating to identify signs of hypoglycemia. 8. Monitor neurologic status for tremors, seizures, jitteriness, and lethargy to identify further drops in blood glucose levels. 9. Monitor temperature to prevent cold stress resulting in decreased blood glucose levels. 10. Weigh neonate daily and plot on a growth chart 11. Encourage and support breast-feeding by facilitating maternal breast pumping. 12. Encourage nuzzling at the breast in conjunction with kangaroo care if the newborn is stable. 13. Continually monitor for enteral feeding intolerance: a. measure abdominal girth b. auscultate bowel sounds c. measure gastric residuals before the next tube feeding (Note the amount, color, and consistency of the contents.) **Preventing Infection** 1. Monitor for changes in vital signs such as temperature instability, tachycardia, or tachypnea. 2. Monitor oxygen saturation levels and initiate oxygen therapy as ordered if oxygen saturation levels fall below acceptable parameters. 3. Monitor laboratory test results for changes. 4. Observe feeding tolerance, typically an early sign of infection. 5. Avoid using tape on the newborn's skin to prevent tearing. 6. Remove all jewelry on your hands prior to washing hands; wash hands upon entering the nursery and in between caring for newborns. 7. Adhere to standard precautions; use clean gloves to handle dirty diapers and dispose of them properly. 8. Use sterile gloves when assisting with any invasive procedure; attempt to minimize the use of invasive procedures. 9. Avoid coming to work when ill and screen all visitors for contagious infections. **Preserving Skin Integrity** 1. Inspect skin frequently but at least every shift for changes in color, turgor, texture, vascularity, and signs of irritation or infection. Pay special attention to areas in which equipment is attached or inserted. 2. Reposition the preterm newborn every 2 to 4 hours and PRN as necessary. 3. Pad pressure prone areas by using sheep skin blankets, waterbeds, pillows, or egg crate mattresses to help prevent additional skin breakdown to these areas. 4. Monitor intake and output and avoid dehydration and over hydration. 5. Apply creams and ointments and medication as prescribed for relief of itching, infections, and to prevent breakdown. Complications of Prematurity The preterm newborn's physiologic immaturity causes many difficulties involving virtually all body systems, the most critical of which is respiratory. Pediatricians and nursery staff should be alerted to the impending birth of a preterm infant so that equipment for resuscitation and emergency care is ready. **Respiratory Distress Syndrome (RDS)** This is also known as **hyaline membrane disease**. It occurs because the lungs are too immature to function properly. Normally, the lungs remain partially expanded after each breath because of a substance called surfactant, a biochemical compound that reduces surface tension inside the air sacs. The premature infant's lungs are deficient in surfactants and thus collapse after each breath, greatly reducing the infant's vital supply of oxygen. This damages the lung cells, and these damaged cells combine with other substances present in the lungs to form a fibrous substance called hyaline membrane. This membrane lines the alveoli and blocks gas exchange in the alveoli. **Intraventricular Haemorrhage (IVH)** This is an intracranial hemorrhage frequently associated with prematurity. The more premature the infant, the more likely it is the infant will have an IVH. The bleeding usually occurs within the first three days of life. The most frequent site of origin is the subependymal germinal matrix. This area of the brain is rich in capillary blood vessels. As the infant grows, the number of blood vessels decreases until about 36 weeks' gestation. The premature infant is unable to regulate blood flow in this area. Thus, changes in blood flow related to asphyxia, trauma, hypercarbia, or rapid fluid infusion may place a strain on the delicate underdeveloped vessels, causing them to rupture and bleed. **Retinopathy of Prematurity (ROP)** This refers to a complication commonly associated with the preterm newborn. It results from the growth of abnormal immature retinal blood vessels. Preterm birth may be a factor contributing to this growth. In addition, the use of high concentrations of oxygen has been identified as a major cause. The immature blood vessels constrict when high levels of oxygen are given, depriving the retinal tissue of adequate nutrition. In addition, in some newborn\'s capillaries increase, leading to scarring and eventually retinal detachment. These events lead to varying degrees of blindness. **Necrotizing Enterocolitis (NEC)** This is an acute inflammatory disease of the intestine. Although it may occur in full-term neonates, it most often occurs in small preterm newborns. The cause is not clearly defined. Precipitating factors are hypoxia, causing poor tissue perfusion to the bowel; bacterial invasion of the bowel; and feedings of formula, which provide material on which bacterial enzymes can work. Clinical manifestations include: 1. distention of the abdomen 2. return of more than 2 mL of undigested formula when the gastric contents are aspirated before a feeding 3. occult blood in the stool 4. The newborn feeds poorly and may experience vomiting and periods of apnea. This disorder usually occurs within the first 10 days of life. Diagnosis is confirmed by abdominal radiographs. The infant with necrotizing enterocolitis is gravely ill and must be cared for in the NICU. **Cold Stress** All newborns are subject to heat loss, and maintaining thermoregulation is crucial. For the preterm newborn, thermoregulation is a major problem. The preterm newborn has a large body surface area when compared to the body weight, allowing for greater heat loss through evaporation, radiation, conduction, and convection. In addition, the preterm newborn has little subcutaneous fat to act as insulation. This in conjunction with the preterm newborn's immature muscular development interfering with the newborn's ability to keep his body flexed and to actively move about to generate heat. Moreover, the preterm newborn cannot shiver or sweat, mechanisms useful for generating and dissipating heat, respectively. Immaturity of the central nervous system and the lack of integrated reflex control of peripheral blood vessels (to cause vasodilation or vasoconstriction) also affect the preterm newborn's ability to maintain body temperature. **Jaundice** The immature liver cannot manage all the bilirubin produced by hemolysis (destruction of red blood cells with the release of hemoglobin), making the infant prone to jaundice and high blood bilirubin levels (hyperbilirubinemia) that may result in brain damage. The preterm infant is at increased risk of hyperbilirubinemia due to: 1. decreased reabsorption of bilirubin from the GI tract because of poor GI motility 2. inability to feed 3. feeding intolerance 4. delayed stooling 5. Also functional immaturity of the blood--brain barrier results in an increased likelihood of free bilirubin crossing from the blood into the brain increasing the risk of kernicterus. **Patent Ductus Arteriosus (PDA)** This results from the failure of the ductus arteriosus to close or from its reopening after closure. This failure to close is often the result of the increased pulmonary tension of the premature infant's lungs. When the ductus arteriosus remains open after birth, a left-to-right shunt through the ductus may occur. This shunting may lead to pulmonary edema. The more premature an infant is, the more likely it is the infant will have a PDA. **Gastroesophageal reflux (GER)** This is defined as the return of gastric contents into the esophagus. The premature infant is at great risk for GER secondary to: 1. immature muscle tone 2. poor sphincter control 3. delay in gastric emptying 4. increased intra-abdominal pressure. Common signs of GER are vomiting, small wet burps, poor weight gain, apnea, bradycardia, esophagitis, and recurrent aspiration. Collaborative management is essential in GER. **Conclusion** Understanding and addressing the complexities of prematurity is vital to ensuring optimal outcomes for preterm infants. By applying a systematic approach to assessment and care, healthcare providers can identify and respond to the unique challenges faced by this vulnerable population. Continued vigilance, evidence-based practices, and interdisciplinary collaboration empower caregivers to anticipate complications and provide developmentally appropriate interventions, fostering growth, stability, and long-term well-being for preterm infants and their families.