Lieselotte Kirchner

Is the use of early nasal CPAP associated with lower rates of chronic lung disease and retinopathy of prematurity? Nine years of experience with the Vermont Oxford Neonatal Network

Abstract Objective: The neonatal regional tertiary care center of the University of Vienna (VC) has been a member of the Vermont Oxford Neonatal Network (VONN) since 1994. During the period 1994–2002, important differences between the VC and the VONN in both pre- and postnatal management and in late morbidities such as chronic lung disease (CLD) and severe retinopathy of prematurity (ROP) were observed. We hypothesize that stabilization of very-low-birth-weight (VLBW) infants on nasal continuous positive airway pressure (NCPAP) immediately after birth, combined with a restrictive use of artificial ventilation, might be responsible for lower rates of CLD and ROP. Patients and methods: Obstetric and neonatal data for all 1299 VLBW infants (401–1500 g) from the VC were compared with corresponding data for the 201,167 VLBW infants from the VONN for the period 1994–2002 with regard to respiratory management and patient outcome. Morbidity criteria were in accordance with VONN definitions. Results: The percentage range for treatment and morbidity criteria for the VC and VONN are related to differences among various years within the observation period. Infants were stabilized at birth on NCPAP in 45–86% of cases in the VC vs. 37–63% in the VONN, the rate of mechanical ventilation was 40–59% vs. 66–74%, and use of surfactant was 31–50% vs. 55–64%. CLD was diagnosed in 14–32% of cases in the VC vs. 27–39% in the VONN, discharge on supplemental oxygen took place in 2–4% vs. 12–17% of cases and ROP (stages III and IV) was found in 1–10% vs. 8–12%. Conclusion: The association of lower rates of CLD and ROP in the VC compared to the VONN might be related to differences in early respiratory management of VLBW infants at high risk of development of respiratory distress syndrome. This needs to be confirmed in a large multicenter trial.

Hippocampal metabolic proteins are modulated in voluntary and treadmill exercise rats

Systematic protein expression studies in the brain of exercising and sedentary animals have not been carried out so far and it was therefore decided to determine differences in metabolic protein levels in rat hippocampus of sedentary, voluntary and involuntary exercising rats by a proteomic approach. Aged, male Sprague-Dawley rats, 23 months old, were used for the study: the first group consisted of sedentary rats, the second of rats with voluntary exercise from five to 23 months and the third group was performing involuntary exercise on a treadmill from five to 23 months. Two-dimensional gel electrophoresis with subsequent mass spectrometrical identification of spots followed by quantification of spots was carried out. Identification of significantly differential proteins was validated by the determination of the corresponding enzyme activity. Five individual metabolic proteins showed differential protein levels in the three groups: mitochondrial precursors of ornithine aminotransferase, isocitrate dehydrogenase [NAD] subunit alpha, malate dehydrogenase, ubiquinol-cytochrome-c reductase complex core protein 1, and ubiquitin carboxyl-terminal hydrolase isozyme L1. The unambiguously identified metabolic proteins were mainly of mitochondrial localization and fit the expectations of altered mitochondrial activity in exercise. Reduced ubiquitin carboxyl-terminal hydrolase isoenzyme L1 levels in treadmill (forced) exercise show the involvement of the proteasomal pathway as a novel finding. These results not only form the basis for functional studies elucidating mechanisms and differences between voluntary and forced exercise in hippocampal metabolism but also highlight the most intriguing aspect that exercise is affecting the brain at the protein level.

In vitro Comparison of Noise Levels Produced by Different CPAP Generators

Introduction: Minimization of noise exposure is an important aim of modern neonatal intensive care medicine. Binasal continuous positive airway pressure (CPAP) generators are among the most important sources of continuous noise in neonatal wards. The aim of this study was to find out which CPAP generator creates the least noise. Method: In an experimental setup, two jet CPAP generators (Infant Flow® generator and MediJet®) and two conventional CPAP generators (Bubble CPAP® and Baby Flow®) were compared. Noise production was measured in decibels in an A-weighted scale [dB(A)] in a closed incubator at 2 mm lateral distance from the end of the nasal prongs. Reproduction of constant airway pressure and air leak was achieved by closure of the nasal prongs with a type of adhesive tape that is semipermeable to air. Results: The noise levels produced by the four generators were significantly different (p < 0.001). Values measured at a continuous constant flow rate of 8 l/min averaged 83 dB(A) for the Infant Flow® generator with or without sound absorber, 72 dB(A) for the MediJet®, 62 dB(A) for the Bubble CPAP® and 55 dB(A) for the Baby Flow®. Conclusion: Conventional CPAP generators work more quietly than the currently available jet CPAP generators.

Variety of Expiratory Resistance Between Different Continuous Positive Airway Pressure Devices for Preterm Infants

Continuous positive airway pressure (CPAP) systems for preterm infants work with conventional ventilators or use a jet ventilation system. It is assumed that the most important advantage of jet-CPAP systems is a lower expiratory resistance (R(E) ). We investigated the R(E) of seven different CPAP systems. We studied two primary-care CPAP systems, three jet-CPAP generators, and two conventional CPAP devices. All devices were adjusted at 6 mbar and connected with a test lung simulating a standardized expiration volume. Maximum pressure increase during expiration was measured and maximum R(E) was calculated. In primary-care CPAP devices, the maximum R(E) of the Benveniste valve was 9.7 mbar/L/s (SD 1.2) while that of the Neopuff was 102.8 mbar/L/s (SD 7.9) (P < 0.01). In jet-CPAP devices, the R(E) of the Infant Flow was 6.8 mbar/L/s (SD 1.7), the one of the Medijet REF 1000 was 43.5 mbar/L/s (SD 1.5), and that of the Medijet REF 1010 was 36.7 mbar/L/s (SD 0.3) (P < 0.01). In conventional CPAP systems, the R(E) of the Baby Flow was 29.7 mbar/L/s (SD 1.1) and that of the Bubble CPAP was 37.1 mbar/L/s (SD 4.3) (P < 0.01). All CPAP devices created an R(E). Jet-CPAP devices did not produce lower R(E) than conventional CPAP devices.

Trends in infant mortality in Austria between 1984 and 2002

SummaryInfant mortality rate is an important medical indicator and is often used for comparing countries with respect to welfare and public health. Among other factors, effective medical technology, better access to pre- and postnatal care for all socioeconomic groups and better nutrition have decreased infant mortality in Austria from about 200 deaths per 1000 live births at the beginning of the 20th century to about 5 deaths per 1000 live births at the end. In this study we present the trends in infant mortality, based on 1,654,519 individual birth records, in Austria since 1984. The infant mortality rate dropped rapidly from about 12 per 1000 live births in 1985 to 4.6 per 1000 live births during the last two years of our study (2001/02). Infant mortality rates stratified by cause of death show somewhat differing trends. In particular, the number of deaths due to peripartal problems decreased as the result of improvements in obstetrics and neonatology, but in 1995 a change in the definition of live birth led to a rise of about 20% in the stillbirth rate. At present, Austria has one of the lowest infant mortality rates of all European countries; however, between 1999 and 2002 the mortality rate has been fairly static. A further reduction in mortality clearly cannot be achieved by advances in medicine alone. It remains a challenge for health politicians, physicians and society at large to reduce the prevalence of well-known risk factors such as alcohol abuse, heavy overweight and smoking during pregnancy.ZusammenfassungSäuglingssterblichkeit ist ein wichtiger medizinischer Indikator und erlaubt Vergleiche einzelner Länder in Bezug auf Sozialwesen und öffentliche Gesundheit. Einflussfaktoren wie effektive Medizintechnologie, besserer Zugang zu prä- und postnataler Schwangerenbetreuung für alle sozioökonomischen Gruppen, als auch bessere Ernährung senkten die Säuglingssterblichkeit von circa 200 Todesfälle zu Beginn auf circa 5 Todesfälle je 1000 Lebendgeborenen am Ende des 20. Jahrhunderts in Österreich. In dieser Arbeit zeigen wir den Zeitverlauf der Säuglingssterblichkeit in Österreich seit 1984 basierend auf 1.654.519 Geburtsblättern. Die Säuglingssterblichkeit fiel drastisch von 12 je 1000 Lebendgeburten im Jahre 1985 auf etwa 4,6 je 1000 Lebendgeburten in den letzten zwei Jahren des Studienzeitraumes (2001/02). Betrachtet man die Todesursachen im Einzelnen, so ergeben sich etwas unterschiedliche Kurvenverläufe. Im Besonderen verringerte sich die Anzahl der peripartalen Todesfälle auf Grund von Fortschritten in Geburtshilfe und Neonatalogie. Eine Änderung der Definition von Lebendgeburten führte zu einem scheinbaren Anstieg der Totgeburtenrate im Jahr 1995 um etwa 20 %. Österreich gehört derzeit zur Gruppe der europäischen Länder mit der geringsten Säuglingssterblichkeit. In den letzten Jahren stagniert diese allerdings. Ein weiterer Rückgang kann offenbar nicht nur durch Fortschritte im Bereich der Medizin erfolgen. Gesundheitspolitiker, die Gesellschaft und die Ärzte sind gefordert, um die Prävalenz von bekannten Risikofaktoren wie Alkoholabusus, starkem Übergewicht und Rauchen während der Schwangerschaft zu reduzieren.

A new modified Seldinger technique for 2-and 3-French peripherally inserted central venous catheters

This study describes a modified Seldinger technique for 2- and 3-French peripherally inserted central venous catheters: A device similar to that used in heart catherisation with a standard micro-introducer serving as sheath and an arterial catheter serving as inner dilator was pushed forward over a wire guide that had before been inserted via a peripheral venous catheter. With this method 2-and 3-French catheters could be safely inserted into peripheral veins of 14 paediatric patients. In conclusion successful insertion of a small peripheral venous catheter offers in most cases a possibility for the placement of a central venous line.