Debbie Fraser Askin

The neonatal liver, Part 1: embryology, anatomy, and physiology.

The liver is the largest organ in the body and is critical to a number of metabolic, regulatory, and detoxification processes. These include the production of bile, metabolic processing of nutrients, synthesis and regulation of plasma proteins and glucose, and biotransformation of drugs and toxins.

Cocaine: effects of in utero exposure on the fetus and neonate.

In North America, an increasing number of babies are prenatally exposed to cocaine, yet the implications of cocaine use during pregnancy are not fully understood. The effects of cocaine are exerted primarily by its influence on aminergic receptors in the central and peripheral nervous systems. Developmental, physiological, and behavioral problems in infants and children are likely outcomes of maternal cocaine abuse, but these findings are confounded by concomitant use of other drugs such as marijuana and cocaine and by factors such as time, dosage, and route of cocaine intake. Different screening options exist for cocaine and its metabolites, including sampling of neonatal urine, hair and meconium need to be considered, as do the sensitivity and the ethical implications of such testing. Clinical management of cocaine-exposed infants requires attention to several issues, including: central nervous system irritation, cardiac anomalies, apnea, and feeding difficulties, as well as infant safety and follow-up postdischarge. Early detection and intervention remain the primary objectives of caring for cocaine-exposed infants.

Noninvasive ventilation in the neonate.

One of the most common and concerning complications seen in low-birth-weight infants is chronic lung disease. A variety of factors have been implicated in the etiology of chronic lung disease including lung inflammation and injury. Noninvasive ventilation (NIV), a term applied to a variety of devices capable of supporting neonatal ventilation without the use of an endotracheal tube, is receiving increasing attention as means to reduce damage often incurred with mechanical ventilation. This article will review the history of continuous positive pressure ventilation and will provide an overview of some of the other types of NIV being used in neonates. The literature supporting the use of NIV is reviewed, and nursing care of the infant receiving NIV is examined.

Fetal-to-neonatal transition--what is normal and what is not?

These articles review the physiologic adaptations occurring during the transition from fetal to neonatal life and examine common red flags which may alert care providers to an infant experiencing delayed transition or an underlying disease process, congenital abnormality, or birth injury.

Sacrococcygeal teratoma in the newborn: a case study of prenatal management and clinical intervention.

Sacrococcygeal teratomas (SCTs) are the most common germinal cell neoplasms of the fetus and neonate. They originate during embryonic development when the primitive streak fails to differentiate among mesodermal, ectodermal, and endodermal tissues in the embryonic disc. This article discusses the fetal pathophysiology of SCTs and the impact of the condition on the newborn. Fetal SCTs can have life-threatening physiologic effects— such as premature labor, dystocia, and high-output cardiac failure—if not managed appropriately. Clinical manifestations, prenatal diagnosis, therapeutic approaches and treatment options for the fetus and newborn, and current research related to SCTs are addressed to aid practitioners caring for a fetus or infant diagnosed with an SCT.

Retinopathy of Prematurity

This article briefly reviews the history of ROP followed by a discussion of the pathogenesis of this complex disorder. We describe the International Classification System for ROP and identify risk factors and screening recommendations. Finally, we discuss some of the measures that have been used in an attempt to both prevent and treat ROP.

The neonatal liver part II: Assessment and diagnosis of liver dysfunction.

The liver, the largest organ in the body, performs many essential functions, including the storage and filtration of blood, production of bile, regulation of plasma proteins and glucose, and biotransformation of drugs and toxins. Many neonates display signs of hepatic dysfunction such as hyperbilirubinemia, hepatomegaly, or elevated liver enzymes. Primary liver disease in neonates is rare; much of the liver dysfunction seen in the neonatal period is secondary to systemic illness such as sepsis or hypoxic injury. It is important for the clinician to have the skills and knowledge necessary to distinguish intrinsic liver disease from liver dysfunction resulting from extrahepatic causes. Early intervention to address the cause of dysfunction is critical to successful management of liver disease. This article reviews the assessment of liver function in neonates and examines the techniques used to diagnose liver dysfunction.

Gastroschisis: etiology, diagnosis, delivery options, and care.

Gastroschisis, one of the more common congenital abdominal wall defects, results in herniation of fetal abdominal viscera into the amniotic cavity. This article discusses theories about gastroschisis etiology, in utero diagnostic tools, delivery options, and postdelivery care. Included are detailed considerations regarding immediate interventions after delivery to support the infant’s thermal and fluid management needs and to protect the exposed bowel. Surgical options and postoperative care issues and complications are reviewed, as are respiratory distress and vena cava compression from increased abdominal pressure, nutritional support, and interventions related to the prevention of infection. Giving birth to an infant with gastroschisis is an upsetting experience for parents. Evidence suggests, however, that with today’s advances in neonatal care and nutrition and with meticulous attention, the survival rate for infants born with gastroschisis can be excellent.

Pathogenesis and Prevention of Chronic Lung Disease in the Neonate

Often used interchangeably, chronic lung disease (CLD) or bronchopulmonary dysplasia (BPD) develops primarily in extremely low birth weight infants weighing <1000 g who receive prolonged oxygen therapy and or positive pressure ventilation. CLD, which occurs in as many as 30 percent of infants born weighing <1000 g, contributes significantly to the morbidity and mortality seen in very low birth weight infants. Despite extensive research aimed at identifying risk factors and devising preventative therapies, many questions about the etiology and pathogenesis of BPD remain. This article reviews the embryologic development of the lung and the pathogenesis of CLD or BPD. The authors discuss some of the measures that have been used in an attempt to both prevent and treat BPD.

The neonatal liver: Part III: Pathophysiology of liver dysfunction.

The liver, the largest organ in the body, is critical to a number of key metabolic functions. It also plays an important role in removing the waste products of metabolism (particularly ammonia) and in detoxifying drugs and other substances such as endogenous hormones and steroid compounds. In addition, the liver plays a major role in the production of clotting factors, plasma proteins, bile salts, and bilirubin. Many neonates display signs of hepatic dysfunction such as hyperbilirubinemia, hepatomegaly, or elevated liver enzymes. These often occur secondary to systemic illness, such as sepsis or hypoxic injury, or following the use of drugs or parenteral nutrition to treat other problems. Although rare, primary liver disease does occur in neonates and must be recognized promptly, with treatment initiated in a timely manner to prevent unnecessary sequelae. This article, the third in a series on the liver, examines causes of liver dysfunction in neonates, beginning with an overview of jaundice and hepatomegaly and moving to a discussion of specific diseases.