Eric W. Reynolds

Brain-Type Natriuretic Peptide in the Diagnosis and Management of Persistent Pulmonary Hypertension of the Newborn

Objective. The diagnosis of persistent pulmonary hypertension (PPHN) can often be difficult to make, especially in a clinical setting in which pediatric echocardiography is not readily available. A noninvasive test that could differentiate PPHN from other cardiorespiratory disease would be very useful in the early management of the disease, because it would allow rapid identification of those infants at greatest risk of requiring the services of a level 3 nursery. Brain-type natriuretic peptide (BNP) is an endogenous peptide hormone secreted by the cardiac ventricles in response to increased wall stress and related ventricular filling pressures. The purpose of this study was to determine if BNP levels are elevated in newborns with PPHN and therefore may be used as a marker for differentiating PPHN from other forms of respiratory disease during the early newborn period. Method. We used a prospective cohort design with 3 groups. One group was diagnosed with PPHN by clinical and echocardiographic criteria (PPHN group: n = 15). The second group had been diagnosed with respiratory disease; however, PPHN had been ruled out by having no evidence of elevated pulmonary pressure by echocardiography (RD group: n = 17). The third group had no respiratory disease and was breathing room air (RA group: n = 15). BNP levels were measured with a point-of-care fluorescence immunoassay at various time intervals between birth and 150 hours of life. Results. There were no differences between groups for birth weight, gestational age, gender, race, Apgar scores at 1 minute, or age at time of initial blood sampling. Initial BNP levels (pg/mL) were elevated in the PPHN group relative to both the RA and RD groups (median [25%, 75%]: PPHN group = 1610 [1128, 1745]; RD group = 132 [76, 327]; RA group = 248 [127, 395]). There was no difference in the initial BNP level between the RA and RD groups. BNP levels remained elevated in the PPHN group over both groups for the first 4 days of life. BNP levels correlated with the gradient of the tricuspid regurgitation jet and with the ratio of tricuspid regurgitation jet gradient to mean blood pressure. BNP levels were not affected by administration of dopamine or dobutamine. BNP weakly correlated with the oxygenation index but not with the alveolar-arterial oxygenation gradient. Conclusions. Our findings indicate that BNP levels are elevated in infants with PPHN but not in infants with other forms of respiratory distress not associated with PPHN. Elevated BNP levels in term or near-term infants with respiratory distress should increase the suspicion of PPHN. Serial determination may also be helpful in monitoring the clinical course of such infants.

Neonatal Abstinence Syndrome and Cerebral Infarction Following Maternal Codeine Use During Pregnancy

Neonatal withdrawal from maternal drugs and medications is common in some NICUs. Codeine-containing cough preparations given to pregnant mothers have been identified as a cause of neonatal abstinence syndrome. However, many women do not consider prescription cough syrups when asked about drug use. Maternal medication or illicit drug use has been identified as a cause of perinatal arterial stroke. Since codeine is an opiate with similar pharmacodynamic effects to morphine, it is reasonable to investigate if maternal codeine use has effects on the fetus that are similar to other opiates. The authors present 2 cases of newborn infants with perinatal arterial stroke that may have been associated with in utero exposure to codeine. Physicians should ask about maternal medication use, including codeine-containing cough preparations, when evaluating newborn infants with evidence of cerebral infarction.

Nonphysician Clinicians in the Neonatal Intensive Care Unit: Meeting the Needs of Our Smallest Patients

Regional variations in the distribution of neonatal physicians and dependence on housestaff with restricted work hours have created workforce shortages in many NICUs. Although neonatal nurse practitioners assist in the delivery of high-quality care, availability of these providers may be inadequate in certain regions. Physician assistants represent a historically underutilized resource to resolve neonatologys workforce issues. We have developed a postgraduate training program for physician assistants in neonatology that we hope will improve local and regional workforce shortages. In this article we discuss the history of neonatal nurse practitioners and physician assistants in newborn care and outline the program that we developed. We further discuss some of the barriers we had to overcome in developing this program. Our program can serve as a model for other neonatology programs to adequately prepare physician assistants for a career in the NICU.

Adrenal hemorrhage in a newborn.

Sometimes in the course of care in a neonatal intensive care unit, there may be a rush to intervene in cases where limited intervention is actually the correct course. One such example is that of neonatal adrenal hemorrhage. We present the case of a male term neonate with shock, metabolic acidosis, distended abdomen, and falling hematocrit. His prenatal and delivery histories were uneventful except for a nuchal cord. Apgar scores were 9 and 9. Because of his dramatic presentation, certain members of the medical team suggested immediate surgical intervention. However, a calm and careful evaluation revealed the true diagnosis and course of action. Ultrasound of the abdomen showed a mass between the liver and kidney, but the origin was difficult to identify. A computed tomography scan supported the diagnosis of right adrenal hemorrhage. His serum cortisol level was normal. The patient was managed conservatively and discharged home after a 1-week stay in the hospital. Subsequent abdominal ultrasound showed resolving adrenal hemorrhage with minimal calcification. A review of the pertinent literature is presented. Physicians should remember adrenal hemorrhage when evaluating a newborn infant with shock, acidosis, abdominal distention, and falling hematocrit and that conservative management is usually indicated.

Pharmacology of drugs of abuse

The pharmacology of most addictive substances is being studied extensively, not just for their acute effects but also the mechanisms that lead to drug seeking and addiction. The understanding of how these drugs alter their effects at the molecular level with continuing use gives promise toward investigation of novel substances that may be used for treatment. Genetic predisposition and gender differences are also some of the areas where more research is needed. Women who are addicted are likely to continue drug use during pregnancy, which can have an impact on the next generation. Prevention measures at the population level are as important. Programs need to address risks, social issues, and environmental factors that promote drug use and addiction.

Superior mesenteric artery syndrome: an uncommon cause of feeding intolerance in infancy.

The patient was a preterm infant boy, born at 23 6/7 weeks, with a birth weight of 635 g and Apgar scores of 1 and 5 at 1 and 5 minutes, respectively. He was a product of assisted reproductive technology and a twin gestation. His mother was 32 years old, gravida 1, para 2, with unremarkable maternal laboratory results. His neonatal course was complicated by respiratory distress syndrome, hyperbilirubinemia, grade I intraventricular hemorrhage, patent ductus arteriosus that required surgical ligation, gastrointestinal reflux and feeding intolerance, apnea and bradycardia, necrotizing enterocolitis, retinopathy of prematurity, nephrocalcinosis, hypertension, and bronchopulmonary dysplasia, which eventually led to pulmonary hypertension and cor pulmonale. His feeding progressed slowly at first, reaching fullvolume tube feeds on day of life (DOL) 14. On DOL 26, continuous feeds were instituted because of a diagnosis of gastroesophageal reflux unresponsive to conservative management and first-line medical therapy. He was given nothing by mouth on DOL 41 because of an episode of necrotizing enterocolitis, which responded to gut rest and medical management. Trophic feeds were again started on DOL 49. By DOL 62 he was back to full-volume tube

Autonomic Nervous System Function Following Prenatal Opiate Exposure

In utero exposure to opiates may affect autonomic functioning of the fetus and newborn. We investigated heart rate variability (HRV) as a measure of autonomic stability in prenatal opiate-exposed neonates (n = 14) and in control term infants (n = 10). Electrocardiographic data during both non-nutritive and nutritive sucking were evaluated for RR intervals, heart rate (HR), standard deviation of the consecutive RR intervals (SDRR), standard deviation of the differences of consecutive RR intervals (SDDRR), and the power spectral densities in low and high frequency bands. In controls, mean HR increased significantly, 143–161 per min (p = 0.002), with a trend toward a decrease in RR intervals from non-nutritive to nutritive sucking; these measures did not change significantly among exposed infants. Compared to controls, exposed infants demonstrated significantly greater HRV or greater mean SDRR and SDDRR during non-nutritive period (p < 0.01), greater mean SDDRR during nutritive sucking (p = 0.02), and higher powers in the low and high frequency bands during nutritive feedings. Our findings suggest that prenatal opiate exposure may be associated with changes in autonomic nervous system (ANS) functioning involving both sympathetic and parasympathetic branches. Future studies are needed to examine the effects of prenatal opiate exposure on ANS function.

Swallow-Breath Interaction and Phase of Respiration with Swallow during Nonnutritive Suck among Low-risk Preterm Infants

This study describes swallow-breath interaction and phase of respiration with swallow during nonnutritive suck (NNS) in low-risk preterm infants. Suckle and swallow, thoracic motion, and airflow were measured in 16 infants during NNS. Logistic regression models were used to describe swallow-breath interaction and phase of respiration with swallow. One hundred seventy-six swallows occurred in 35 NNS periods. Swallow-breath interaction occurred as: central apnea (CA), obstructive apnea (OA), or attenuated respiration (AR). AR was associated with increased weeks post-first nipple feeding. OA occurred less often in males and with increased weeks post-first nipple feeding. In looking at the phase of respiration, more swallows occurred at beginning expiration with increased gestational age, increased weeks post-first nipple feed, and increased weeks before first nipple feed. More swallows occurred at midexpiration with more swallows per study, increased birth weight (BWT), and weeks before first nipple feed. Fewer swallows occurred at end expiration with increased weeks before first nipple feed. Fewer swallows occurred at midinspiration with increased swallows per study. Fewer swallows occurred at apnea with increasing BWT, more occurred with increased swallows per study. In low-risk preterm infants, swallow-breath interaction progresses from CA and OA to AR. The phase of respiration with swallow shows a maturation progression.

Nesiritide for the Treatment of Pulmonary Hypertension and Cor Pulmonale in an Infant

Nesiritide is a synthetic form of B-type natriuretic peptide. It is approved for the treatment of acute exacerbations of congestive heart failure in hospitalized adult patients. It is currently under investigation for use in other settings and other patient populations. This article describes administration of nesiritide to an infant patient with severe pulmonary hypertension and cor pulmonale. No adverse reactions occurred during administration of the drug. Specifically, there was no hypertension, vomiting, arrhythmia, or changes in renal function. No changes in renal function occurred in the months subsequent to treatment. This case report illustrates that nesiritide can be safely administered to critically ill infants with pulmonary hypertension and cor pulmonale. Our patient experienced a decrease in pulmonary pressure and improved clinical condition during and after the infusion. However, further study is required to fully evaluate the safety and efficacy of nesiritide for these patients.

Asymmetric Mandibular Dysplasia Due to In Utero Compression

Mandibular asymmetry can be congenital, developmental, or acquired. In the newborn period, nonsyndromic mandibular asymmetry usually is benign and requires no inter vention. Syndromic or structural defects can occur that may require physical therapy or surgical treatment. Below is a case report of an infant recently delivered at our facility who had unilateral mandibular dysplasia due to extrinsic compression of the jaw by the infant’s shoulder and a brief review of the literature.