The thymus gland.

This article reviews the embryology, physiology, and pathophysiology of the thymus. The anatomy of this lymphoid organ, the significance of the presence or absence of the thymus radiographically, and the role of the thymus in immunity are also reviewed. Finally, the pathologic presentation of thymic hypoplasia (DiGeorge syndrome) is discussed. Despite advances in modern science, little was known about the thymus, one of the body's key organs in the immune system, until 1961, when Dr. Jacques Miller performed thymectomies in mice. Then it became evident that the thymus played a key role in the body's defense against infection. Since that time, researchers have continued to examine the role of the thymus from fetal life through adulthood.

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.

Neonatal cancer: a clinical perspective.

The diagnosis of a neonatal malignancy, while rare, requires complex knowledgeable care from members of the health care team. The neonatal intensive care nurse plays an important role on that team. The types of malignancies found in neonates differ from those in older children, as do the neonate's responses to treatment. A review of the presentation, diagnosis, and management of the more common types of neonatal malignancies provides the context for consideration of the nurse's role in providing specialized care to neonates with cancer.

Interpretation of neonatal blood gases, Part II: Disorders of acid-base balance.

Timely and accurate interpretation of blood gases is of paramount importance in providing comprehensive neonatal care. Disorders of acid-base balance may evolve quickly in respiratory problems or develop over time with metabolic imbalances. In many cases, the interpretation of acid-base disorders may be complicated by the mixed metabolic and respiratory origins of the disorder. An overview of the underlying physiology of acid-base balance and oxygen transport helps the nurse understand the causes and subsequent treatments of the various disorders. Such an overview was presented in part I of this series (Vol. 16, No. 5). This article presents a discussion of the four basic types of acid-base disorders. A systematic plan for blood gas evaluation is presented, along with several case studies illustrating the principles of blood gas analysis.

Interpretation of neonatal blood gases, Part I: Physiology and acid-base homeostasis.

Accurate interpretation of blood gases is paramount in clinical management in the NICU. This interpretation should be based on a sound understanding of acid-base physiology. Acid-base homeostasis depends on a series of complex chemical reactions controlled by the kidneys and the lungs. The maintenance of a blood pH within the narrow range required for normal cellular reactions requires a balance between acid production and excretion. Somewhat separate but equally important to blood gas interpretation is an understanding of oxygen transport. Included in this is the relationship between oxygen and hemoglobin. This article, the first in a two-part series, discusses the physiology of acid-base balance and oxygen transportation. The second article provides an approach for systematic interpretation of blood gases.

Neonatal personnel in Canada.

Although the need for trained personnel to care for neonates with complex needs is recognized, there has been no systematic analysis of present or future personnel requirements. The Canadian Paediatric Society's Neonatal-Perinatal Medicine Section sponsored a symposium on neonatal personnel, inviting four Canadian experts to address issues related to future needs. Areas addressed included neonatal nurse practitioners providing increased patient care in some parts of the country as resident involvement in neonatal intensive care decreases, the extended roles of other health care personnel and increased direct patient care by neonatologists. There is no approved method to determine personnel needs, but paediatric department heads have indicated that the number of neonatologists needed is substantially greater than available funding allows. Considering economic factors and the need to educate perinatal care providers, it is important to assess present and future needs to ensure that quality care can be provided.

Bacterial and fungal infections in the neonate.

Despite tremendous advances in technology, sepsis remains a major threat in neonatal intensive care. The incidence of neonatal infection ranges from 7.3 to 16 per 1,000 live births. Nurses play an important role in the recognition and treatment of the septic infant. An understanding of the classification, epidemiology, and signs and symptoms of bacterial and fungal sepsis will better position the nurse to identify the infant at risk for sepsis and to initiate supportive care.

The clinical nurse specialist and the research process.

With the growing emphasis on clinically based research as the foundation for nursing practice, the clinical nurse specialist (CNS) is in an ideal position to identify problems within the clinical arena and use research methods to support and advance practice. In the case of the Transition of the Preterm Infant to an Open Crib project sponsored by the Association of Women's Health, Obstetric, and Neonatal Nurses (AWHONN), CNSs served as site coordinators at most of the 10 implementation sites. The educational background of the CNS, combined with a grounding in clinical experience, was ideal for this role. This article discusses the role of the CNS in the implementation of a research utilization project using two case studies as examples.