Neonatal Network
September/October 2005
Vol. 24, No. 5

ABSTRACTS

Medium-Chain Acyl-CoA Dehydrogenase Deficiency: A Case Presentation
Darlene J. Moore, RNC, MN, NNP

When an infant presents with hypoglycemia, acidosis, hepatomegaly, and respiratory arrest, the neonatal team must be alert to the possibility of a metabolic disorder. Among those to be considered is medium-chain acyl-CoA dehydrogenase deficiency, which occurs in 1 in 10, 000-23,000 live births. Recognizing and treating this disorder early could decrease the morbidity and mortality associated with the diagnosis.

The Neonatal Respiratory Pump: A Developmental Challenge with Physiologic Limitations
Jay. S. Greenspan, MD
Thomas L. Miller, PhD
Thomas H. Shaffer, PhD

Newborn lungs are particularly susceptible to pathophysiology. Respiratory distress commonly brings infants to the intensive care nursery. Premature birth compromises the infant’s ability to respond to early lung dysfunction because of the reduced functional reserve available at younger gestational ages. The respiratory pump consists of respiratory musculature and the chest wall. The respiratory pump is the physiologic “machine” that responds to lung pathology. From gestation onward, components of the pump undergo developmental changes that influence its compensatory ability in the neonate. Careful observation of the synchrony of the chest wall and abdomen during spontaneous breathing efforts assists the caretaker in detecting respiratory compromise and impending respiratory failure.Noninvasive monitoring of respiratory patterns is a valuable tool for the neonatal caregiver, who must understand the developmental changes in the respiratory pump and be able to identify an infant’s ineffective responses to lung pathophysiology.

Myelomeningocele, Avocados, and Rubber Tree Plants
Jobeth Pilcher, RN, BSN, MS
Lisa Sogard, RN, BSN

Infants with myelomeningocele and the nurses who care for them have something in common. Both are at higher risk than the general population for developing latex allergies. This article provides a review of the literature regarding latex production, latex allergic responses in children and adults, types of latex allergic reactions, and prevention of latex allergies.

Heparin-Induced Thrombocytopenia in Neonates
Julie Martchenke, RN, MS, PNP
Lynn Boshkov, MD

Heparin-induced thrombocytopenia (HIT), an immune-mediated response to heparin administration, has been recognized in adults for some time, but only recently recognized in neonates and children. HIT Type I is a mild, self-limiting condition. HIT type II is a severe immune reaction to heparin that leads to thrombocytopenia and often thromboembolic complications. The incidence of HIT Type II is 2–5 percent in adults on heparin products and may be as high in neonates and children. The mortality rate from HIT in adults is 7–30 percent and is unknown but potentially high in newborns as well. The cardinal sign of HIT is a drop in platelet count by 50 percent or platelet counts below 70,000–100,000/mm3. This drop usually occurs five to ten days after the first exposure to heparin.Treatment is immediate cessation of all heparin therapy and initiation of alternative anticoagulants, especially the direct thrombin inhibitors lepirudin and argatroban. This article reviews the literature on HIT and presents a case of neonatal HIT following heart surgery.

Newborn Screening Guidelines for the Critically Ill Infant
Katherine B. Balk, MSN, CRNP

The use of mass spectrometry in newborn screening has made possible the early diagnosis of various metabolic diseases. However, because aminoglycosides, blood transfusions, nothing by mouth status, and the presence of heparinized solutions all affect the results of newborn screens, neonates in critical care units who receive such treatments ought to be screened under specific practice guidelines. Many of the devastating sequelae of metabolic diseases are preventable if diagnosed early, making the development of such practice guidelines for use in the NICU especially important. Additionally, no standardized practice guidelines presently exist for determining who, whether birth hospital or primary care provider, is responsible for notifying the parent of a positive result and thus ensuring invaluable follow-up care. Such standardized guidelines for screening practice are needed to prevent devastating neurologic sequelae for children whose condition may otherwise escape unaddressed. Newborn screening guidelines developed at Johns Hopkins Hospital and Memorial Regional Hospital provide a helpful starting point.