Randomized trial of percutaneous central venous lines versus peripheral intravenous lines.

OBJECTIVE: To compare the occurrence of systemic infection or death in preterm infants with elective percutaneous central line (PCVL) placement versus peripheral intravenous catheter (PIV) placement. STUDY DESIGN: A total of 96 infants < or =1250 g or < or =30 weeks gestation were randomized by 4 days of age to elective placement of a PCVL or continued use of PIV catheters. The primary outcome of systemic infection (defined as a positive blood or cerebrospinal fluid (CSF) culture treated for at least 5 days) or death was monitored until the infants did not require intravenous (iv) support for 7 consecutive days. RESULTS: Systemic infection or death occurred in 17/46 (39%) infants in the PCVL group and 14/50 (28%) in the PIV group (relative risk (RR)=1.32 with 95% confidence interval (CI) 0.70, 2.53; risk difference (RD)=0.09 with 95% CI -0.10, 0.28). The PCVL group had significantly fewer skin punctures for iv access. CONCLUSION: There was no significant difference in systemic infection or death (expressed either as a combined outcome or as separate component outcomes) between the groups. The number of skin punctures was significantly reduced in the PCVL group.

Monitoring fetal development with magnetocardiography.

Fetal heart rate variability (fHRV) is useful for noninvasive assessment of the status of the autonomic nervous system of the developing fetus. In this pilot study we acquired fetal magnetocardiograms (fMCG) in a magnetically shielded environment. Each recording was of 5-minute duration and was subsequently repeated in a high-frequency noise environment to examine the feasibility of conducting future recordings in clinical environments that lack facilities for magnetic shielding. The fMCG (n=17) were recorded at 9 spatial locations above the pregnant abdomen at 26 to 35 weeks gestational age (GA) by a second-order SQUID gradiometer. The signal-to-noise was adequate for reliable QRS detection even in the noisy environment, especially for GA >/= 30. The total spectral power of the RR-series, as well as band powers at low (0.05 to 0.25 Hz) and high (0.25 to 1.00 Hz) frequencies independently exhibited an increasing trend with GA. There was no evidence of bias in spectral power due to lack of shielding. These results provide experimental evidence supporting further studies in magnetically unshielded environments and may have an important implication for future clinical use of fMCG in the assessment of fHRV.

Evaluation of the performance of a QRS detector for extracting the heart interbeat RR time series from fetal magnetocardiography.

Fetal magnetocardiography is a useful technique for non-invasive diagnostics of the electrophysiological activity of the fetal heart. The purpose of this study was to acquire fetal magnetocardiograms (FMCG) in a magnetically shielded environment as well as in a high-frequency noise environment, implement a QRS detection algorithm, and evaluate its performance. The FMCG were recorded over a period of 5 minutes at several sensor locations above the pregnant abdomen by second-order SQUID gradiometers. Quantitative analysis of FMCG with normal pregnancies and gestational ages 26-35 weeks showed improved QRS detection performance with signal pre-processing and parameter tuning.

Heart rate variability of preterm neonates quantified by energy entropy.

Identifying variables predictive of neurobehavioural sequelae is a key objective in the study of high-risk neonates. Examination of heart rate variability (HRV) characteristics may be a finer discriminator of the neonate's response to physiologic stressors than the mean heart rate. The energy entropy of the heart beat tachogram, computed in four different domains, was used to quantify the HRV in 13 preterm neonates. The entropies of energies were computed from 1024 interbeat time intervals obtained once per week from 26 to 35 weeks postconceptional age (PCA). The energy entropy computed in three of the domains, like the standard deviation of intervals, distinguished between the 10 neonates that were measured at 35 weeks PCA with 100% specificity and 67% sensitivity, but did not distinguish between healthy and unhealthy neonates at earlier ages. The findings suggest that energy entropy may be a discerning measure of physiologic stress in the preterm infant, although future research is needed to refine the test and determine statistical significance.

Diagnostic techniques in cardiac disorders: Part II.

Advances in technology over the past 15 years have given birth to a new field of multidisciplinary cardiovascular care and research, that of perinatal cardiology. Today's neonatal nurse must become familiar with the battery of tools that may be enlisted to assist in the assessment, diagnosis, intervention, and evaluation of cardiac disorders and therapeutic maneuvers in the neonate. In the first part of this two-part article, the standard initial examination of the history and physical, the chest x-ray, and the electrocardiogram were reviewed. This second part discusses the role of both invasive and noninvasive "high-tech" diagnostic techniques commonly used in today's management of neonatal cardiac disease.

Diagnostic techniques in cardiac disorders: Part I.

Advances in technology over the past 15 years have given birth to a new field of multidisciplinary cardiovascular care and research, that of perinatal cardiology. Today's neonatal nurse must become familiar with the battery of tools that may be enlisted to assist in the assessment, diagnosis, intervention, and evaluation of cardiac disorders and therapeutic maneuvers in the neonate. In this first part of a two-part article, the history and physical examination, the chest x-ray, and the electrocardiogram are reviewed. The second part will discuss the role of both invasive and noninvasive "high-tech" diagnostic techniques in the management of cardiac disorders.

Bronchopulmonary dysplasia: its effects upon the heart and lungs.

Bronchopulmonary dysplasia (BPD) is one of the most significant sequelae of prematurity, affecting the pulmonary and cardiovascular structures especially. From the first weeks of life, there exists a close anatomical and functional relationship between these two systems. Changes in intrathoracic pressure or pulmonary vascular resistance greatly impact both the left and right sides of the heart. In turn, increasing afterload and decreasing preload affect blood flow through the lung, as well as the state of oxygenation and ventilation. BPD affects the function, growth, and development of the heart and lung, due to the hypoxia, acidosis, hyperoxia, and fibrosis associated with the fibroproliferative repair process. Significance of clinical findings and the role of the bedside caregiver are also discussed.

The ethical use of fetal tissue for transplantation and research.

The exercise of organ and tissue transplantation is a common occurrence in our society. Expectations of future advances in this arena are raising many ethical, moral and public-policy questions. The scientific data base supporting the usefulness of fetal tissue to repair or reverse disease is modest, and uses are speculative. Should fetal tissue transplantation research proceed and, if so, under what conditions? This paper examines the issues related to the use and procurement of fetal tissue for research and transplantation.

PIP: In October 1983, an Australian committee report on medical research involving human fetal tissue was adopted, and the transplantation of human fetal tissue into already-born patients was discussed. The propagation of fetal cells in tissue culture was carried out, but only after the death of the fetus and with the prior consent of the pregnant woman. In 1984, the French National Ethics Committee discussed the use of tissues from embryos and dead fetuses for therapeutic, scientific, and diagnostic purposes. The Council of Europe's Parliamentary Assembly adopted a recommendation in 1986 which also formulated rules for therapeutic use of tissue from dead externalized human fetuses. In the United States, research in the early 1970s investigated transplanting human tissue to alleviate Parkinson's disease and diabetes. In the wake of the debate on abortion, Congress established the National Commission for the Protection of Human Subjects of Biomedical and Behavioral research, which investigated research involving the living fetus. The Department of Health put a moratorium on therapeutic transplants of tissue from aborted fetuses. Various issues were studied; the concepts of morality vs. immorality in Catholic medical ethics, the definition of fetus and person, fetal viability, and various definitions of fetal death (cessation of heart beat, interruption of blood circulation). The use of human fetal tissue and transplantation is governed by the Uniform Anatomical Gift Act of 1988 allowing donation provided parental consensus is reached. The ethical dilemma is whether tissues from 1.6 million abortions in the US should be discarded or used in clinical research or therapy. Justification, authorization of use, sufficiency of maternal consent, and donors benefiting from the use of fetal tissue are also examined. There is not enough information about the usefulness of human fetal tissue in contributing to high-technology medicine, yet the ethical objections are insufficient to continue a moratorium.

Interpretations of nonstress tests by obstetric nurses.

Five 20-minute nonstress-test strips were mailed to 1,000 members of NAACOG--the organization for obstetric, gynecologic, and neonatal nurses. The individuals were selected systematically from NAACOG's 10 districts. For the 412 (41%) respondents, at least 84% of the answers concurred on each of the five strips. The majority opinion was taken to be the correct answer. Concurrence with the majority was independent of clinical experience, clinical training, and the extent of present nonstress-test responsibilities. The same five strips were interpreted by obstetricians in a previously reported survey. On a two-point, reactive-nonreactive scale, the sample of obstetric nurses' degree of agreement differed significantly from the sample of physicians' degree of agreement (92 versus 98%) on only one strip.