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Biomedical subjects

Manfred Weninger

Publications and source records attributed to Manfred Weninger.

10 recordsLinked to original sources
PubMed2006

Amnionitis with Ureaplasma urealyticum or other microbes leads to increased morbidity and prolonged hospitalization in very low birth weight infants.

OBJECTIVE: To investigate the influence of culture proven intrauterine infection on preterm morbidity and to test the effect of antimicrobial treatment. METHODS: Retrospective cohort study conducted between October 1997 and February 2001 in patients with preterm premature rupture of membranes or preterm labor. Vaginal swabs were sampled and amniocentesis for microbiologic culture of the amniotic fluid was performed. Patients with Ureaplasma urealyticum in the amniotic fluid were treated with josamycin. Infants were followed post partum according to birth weight, gestational age, APGAR score and infant morbidity. RESULTS: In 49 eligible patients, 40% of cultures were positive, 22% for Ureaplasma urealyticum, 12% for other bacteria and 6% for candida. Children of mothers with positive amniotic fluid cultures had significantly lower gestational ages (26+4 weeks for Ureaplasma urealyticum [p=0.04] and 25+5 weeks for other microorganisms [p=0.0017] versus 28+6 weeks for mothers with negative amniotic fluid cultures) and lower birth weights (975 g [n.s.] and 828 g [p=0.0072] versus 1,041 g) but were appropriate for their gestational ages. 33.3% and 66.7% versus 24% of the children were mechanically ventilated [n.s.], duration of mechanical ventilation was 5.3 [p=0.02] and 10.1 days [p=0.04] versus 1.4 days, and prevalence of chronic lung disease was 38% and 33% versus 11% [n.s.]. Prevalence of severe intraventricular hemorrhage (12.5% [n.s.] and 33% [p=0.04] versus 3.4%) and nosocomial infections (50% for both groups of positive cultures versus 10.3% for negative cultures, p=0.02 and 0.03, respectively) was higher and median length of stay was significantly longer (121 [p=0.02] and 107 days [p=0.03] versus 60 days) in these patients. Maternal positive vaginal swab cultures were not associated with any of the above-mentioned factors. In none of the patients treated with macrolids for proven Ureaplasma urealyticum amnionitis could the microbes be eradicated. CONCLUSION: Maternal positive amniotic fluid cultures have been associated with lower gestational age and lower birth weight. Rate of infant morbidity was higher and length of stay was significantly longer in this group. Positive vaginal swabs were not predictive for infant morbidity. Treatment of mothers showing positive amniotic fluid cultures with macrolids was not effective.

Chorioamnionitis↗
PubMed2006

A flow sensor suitable for use with split-flow ventilation--first preclinical data.

Volutrauma caused by artificial ventilation represents a major morbidity risk for premature infants. Our working group has recently developed an innovative "split-flow ventilation" system aiming at the reduction of tidal volumes (TVs). The main problem for the practical use of this system is the fact that conventional measurements of commercially available flow sensors are distorted by the split flow. In this study, we present the first preclinical data from testing an adapted flow sensor combination recognizing the split flow. A preterm infant test lung was conventionally ventilated, modified by insertion of a split-flow line. In addition to the customary flow sensor (FS-1), a second flow sensor (FS-2) was integrated into the split-flow line, and a third (FS-3) was placed at the exit of the test lung for reference measurements. The signals of all three flow sensors were read and processed by a computer. The program was set to graphically add up flow curves 1, 2, and 3 during one ventilation loop. After 10 runs, a mean curve of FS-1+2 was calculated and compared to the mean curve of FS-3. Furthermore, the mean TV of 10 runs measured by FS-1+2 was calculated and compared with the mean TV calculated by FS-3. The summation curve FS-1+2 proved identical to the reference curve FS-3. FS-1+2 yielded a TV of 6.6 +/- 0.01 mL (inspiratory) and 6.7 +/- 0.02 mL (expiratory). The corresponding values of FS-3 were 6.5 +/- 0.20 mL and 6.6 +/- 0.09 mL, respectively. According to our results, the presented flow sensor constellation allows exact flow measurements in the experimental setting and appears suitable for usage in a split-flow ventilation circuit under clinical conditions.

Equipment Design↗
PubMed2005

Intra- and extrauterine maturation of amplitude-integrated electroencephalographic activity in preterm infants younger than 30 weeks of gestation.

OBJECTIVE: To prospectively investigate the longitudinal changes of amplitude-integrated electroencephalographic (aEEG) activity in preterm infants <30 weeks gestational age (GA). METHODS: Infants (GA <30 weeks) without evidence of neurological abnormalities had weekly aEEG recordings performed. The relative duration of the three aEEG patterns (discontinuous low voltage, discontinuous high voltage and continuous) was determined and the influence of GA and postnatal age (PNA) on the occurrence of each pattern was assessed. RESULTS: Ninety-eight infants (median GA 26 weeks; range 23-29 weeks) were studied. With higher GA (OR 1.68, 95% CI 1.33-2.13) and PNA (OR 1.91, 95% CI 1.53-2.38), the likelihood for the occurrence of continuous activity increased. The discontinuous low-voltage pattern was less likely to occur with increasing GA (OR 0.68, 95% CI 0.55-0.83) and PNA (OR 0.70, 95% CI 0.61-0.81). CONCLUSION: Maturation of aEEG activity in preterm infants is influenced by both GA and PNA.

Aging↗
PubMed2005

Dead-space washout by split-flow ventilation. A new method to reduce ventilation needs in premature infants.

OBJECTIVE: Chronic lung disease caused by volutrauma is one of the most important consequences of preterm delivery. In this pilot study a new method is presented that consists of flushing part of the dead space with fresh gas in order to reduce high tidal volumes, the chief cause of volutrauma. The aim of the study was to evaluate if the new method could reduce ventilatory effort in preterm infants by diminishing dead space. DESIGN AND SETTING: In split-flow ventilation, gas required for dead-space washout is split off from the regular ventilation circuit. The split flow bypasses the apparatus dead space and fills it retrogradely with fresh breathing gas, mainly in the pause between exhalation and inspiration. The mean per-minute ventilation and ventilation index after 12 h of conventional ventilation were compared with corresponding mean values after 12 h of split-flow ventilation in 17 preterm infants weighing <2,000 g. Statistical analysis was performed using the T -test for matched pairs. RESULTS: After switching from conventional ventilation to split-flow ventilation, the mean per-minute ventilation per kilogram of body weight decreased significantly from a mean value of 0.314+/-0.097 l/kg/min to 0.190+/-0.043 l/kg/min ( p <0.001), while the ventilation index decreased significantly from 28.47+/-7.48 to 16.10+/-4.13 ( p <0.001). CONCLUSION: Split-flow ventilation significantly reduces apparatus dead space during ventilation in preterm infants. This leads to reduced ventilatory effort.

Bronchopulmonary Dysplasia↗
PubMed2005

Mortality and morbidity in extremely preterm infants (22 to 26 weeks of gestation): Austria 1999-2001.

OBJECTIVE: The aim of this retrospective study was to analyze the mortality and morbidity for extremely preterm infants with a gestational age from 22 to 26 weeks. All infants were born in Austria during the years 1999-2001. METHODS: Data were collected from 16 neonatal intensive care units in Austria. Main outcome criteria were mortality, the rates of chronic lung disease (CLD) and severe retinopathy of prematurity (ROP, stage > or =3) to determine the short-term outcome; the rate of cerebral palsy (CP) at the corrected age of twelve months to assess the long-term outcome. RESULTS: Overall, 796 preterm infants with a gestational age less than 27 weeks were born in Austria and 581 (73%) were registered as live-born infants. Of those live born, 508 (87%) were analyzed. The mortality rates were 83%, 76%, 43%, 26% and 13% for 22, 23, 24, 25 and 26 weeks' gestation, respectively. The rates of CLD were 33% (22 weeks), 36% (23 weeks), 42% (24 weeks), 31% (25 weeks) and 22% (26 weeks). The rates of ROP of stage > or =3 were 0% (22 weeks), 29% (23 weeks), 23% (24 weeks), 18% (25 weeks) and 10% (26 weeks). The rates of CP at the corrected age of 12 months were 33%, 50%, 33%, 26% and 25% for 22, 23, 24, 25 and 26 weeks' gestation, respectively. CONCLUSIONS: The results of this national study are in accordance with the international literature: mortality and morbidity increased with decreasing gestational age.

Age Distribution↗
PubMed2005

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.

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.

Austria↗
PubMed2004

Reference values for amplitude-integrated electroencephalographic activity in preterm infants younger than 30 weeks' gestational age.

OBJECTIVE: To prospectively investigate the development of amplitude-integrated electroencephalographic (aEEG) activity during the first 2 weeks of life in neurologically normal and clinically stable preterm infants <30 weeks' gestational age (GA). PATIENTS AND METHODS: Infants with a GA of <30 weeks admitted to the neonatal intensive care unit of the Vienna University Children's Hospital (Vienna, Austria) were studied prospectively by using aEEG and cranial ultrasound. Clinically stable infants without clinical or sonographic evidence of neurologic abnormalities were eligible for inclusion in the reference group. The distribution of 3 background aEEG activity patterns (discontinuous low-voltage, discontinuous high-voltage, and continuous), presence of sleep-wake cycles, and number of bursts per hour in the reference group were determined by visual analysis. RESULTS: Seventy-five infants (median GA: 27 weeks; range: 23-29 weeks) were eligible for inclusion in the reference group and had aEEG recordings during the first 2 weeks of life available. Analysis of aEEG background activity showed that with higher GA the relative amount of continuous activity increased while discontinuous patterns decreased. The number of bursts per hour decreased with increasing GA. Cyclical changes in aEEG background activity resembling early sleep-wake cycles were observed in all infants. CONCLUSIONS: Normal values for aEEG background activity were determined in preterm infants <30 weeks' GA. Clinically stable and neurologically normal preterm infants exhibit at least 2 different patterns of aEEG activity. There is a correlation between the GA and the relative duration of continuous aEEG activity.

Circadian Rhythm↗
PubMed2002

Three-dimensional volume measurement of the lateral ventricles in preterm and term infants: evaluation of a standardised computer-assisted method in vivo.

BACKGROUND: Assessment of ventricular size still represents a challenge for two-dimensional cranial sonography. OBJECTIVE: Three-dimensional (3D) volume acquisition and volume quantification are easily accomplished by an automatic scanning system without additional examination time. The development of a computer-assisted ultrasonic device will offer new perspectives for the quantification of ventricular volume. MATERIALS AND METHODS: In total, 250 healthy neonates between 27 and 41 weeks' gestation and infants up to 6 months of age without neurological pathology were examined with 3D cranial ultrasound (US). The volume of both lateral ventricles and the third ventricle were separately quantified and summated for the calculation of ventricular volume. The correlation between body weight (BW), head circumference (HC), gestational age (GA) and ventricular volume was statistically analysed. RESULTS: There was a statistically significant correlation between GA, BW, HC and ventricular volume. Normal values for premature and mature infants were established. CONCLUSIONS: 3D US appears to be an accurate imaging modality for the exact calculation of ventricular volume and should, therefore, be incorporated into the cranial sonographic assessment of ventricular size in infants.

Body Weight↗
PubMed2002

Spontaneous localized intestinal perforation in very-low-birth-weight infants: a distinct clinical entity different from necrotizing enterocolitis.

BACKGROUND: Idiopathic spontaneous intestinal perforation (SIP), a distinct clinical entity different from necrotizing enterocolitis (NEC), has an increasing prevalence in very-low-birth-weight infants. The aims of our study were to define patient characteristics and potential risk factors for premature infants with SIP compared with infants subjected to surgical treatment for NEC. STUDY DESIGN: The medical records of 29 premature infants with either SIP (n = 13) or NEC (n = 16) were reviewed retrospectively. RESULTS: Infants who experienced SIP were smaller at birth, had lower Apgar scores, and required more intensive neonatal resuscitation. An increased rate of premature rupture of membranes in infants with SIP (8/13 versus 6/16) was not associated with a higher rate of infection in mothers or infants. The onset of illness in SIP was significantly earlier than in NEC (p = 0.022). In contrast to patients with NEC (7/16), 11 of 13 patients in the SIP group had received indomethacin (p = 0.02). Bluish discoloration of the abdomen (8/13), a gasless abdomen (8/13), and the absence of pneumatosis intestinalis (0/13) were further significant markers in infants with SIP. At operation, SIP was always located in the terminal ileum in an antimesenteric position (13/13), and the remaining bowel appeared grossly normal. In most cases of SIP (10/13), the histologic investigation revealed an area of hemorrhagic necrosis without the typical coagulation necrosis seen predominantly in NEC. CONCLUSIONS: Based on clinical presentation and radiologic and intraoperative findings, SIP is a distinct pathologic entity in very-low-birth-weight infants and can be differentiated from classic NEC. Detected early, SIP can be treated by simple procedures (sutures, or resection and primary anastomosis) with a low rate of morbidity and mortality.

Chi-Square Distribution↗