N W Svenningsen

Lund University, Lund, Skane, Sweden

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Publications (123)371.3 Total impact

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    ABSTRACT: A new method has been evaluated for measuring ventilation and lung mechanics in spontaneously breathing infants by means of a face chamber. Airway flow is measured with a pneumotachograph inserted between the face chamber and a stable pressure source. Oesophageal pressure is measured via a water-filled oesophageal catheter. The method is suitable for use in conjunction with continuous positive airway pressure (CPAP) treatment in neonatal intensive care. A flat frequency response curve up to 15 Hz for the two measuring systems (i.e., airway flow and oesophageal pressure), and a time shift between the two respective signals of less than 2 msec are prerequisites for correct evaluation of respiratory mechanics. In preterm infants with chest distortion, the inhomogeneity of pleural pressure affects the significance of resistance and compliance values, as calculated from oesophageal pressure. Supra-diaphragmatic pressure variations reflect the resistive and elastic load on the diaphragm exerted by the lungs and thorax. Thus, oesophageal pressure is still useful in studies of respiratory mechanics in preterm infants.
    Acta Paediatrica 01/2008; 78(2):194 - 204. · 1.97 Impact Factor
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    ABSTRACT: Total and regional cerebral glucose metabolism (CMRgl) was measured by positron emission tomography with 2-((18)F) fluoro-2-deoxy-D-glucose ((18)FDG) in 20 term infants with hypoxic ischemic encephalopathy (HIE) after perinatal asphyxia. All infants had signs of perinatal distress, and 15 were severely acidotic at birth. Six infants developed mild HIE, twelve moderate HIE, and two severe HIE during their first days of life. The positron emission tomographic scans were performed at 4-24 d of age (median, 11 d). One hour before scanning, 2-3.7 MBq/kg (54-100 microCi/kg) (18)FDG was injected i.v. No sedation was used. Quantification of CMRgl was based on a new method employing the glucose metabolism of the erythrocytes, requiring only one blood sample. In all infants, the most metabolically active brain areas were the deep subcortical parts, thalamus, basal ganglia, and sensorimotor cortex. Frontal, temporal, and parietal cortex were less metabolically active in all infants. Total CMRgl was inversely correlated with the severity of HIE (p < 0.01). Six infants with mild HIE had a mean (range) CMRgl of 55.5 (37.7-100.8) micromol.min(-1).100 g(-1), 11 with moderate HIE had 26.6 (13.0-65.1) micromol.min(-1).100 g(-1), and two with severe HIE had 10.4 and 15.0 micromol.min(-1).100 g(-1), respectively. Five of six infants who developed cerebral palsy had a mean (range) CMRgl of 18.1 (10.2-31.4) micromol.min(-1).100 g(-1) compared with 41.5 (13.0-100.8) micromol.min(-1).100 g(-1) in the infants with no neurologic sequela at 2 y. We conclude that CMRgl measured during the subacute period after perinatal asphyxia in term infants is highly correlated with the severity of HIE and short-term outcome.
    Pediatric Research 05/2001; 49(4):495-501. · 2.67 Impact Factor
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    ABSTRACT: Little has been published about specific problems that may occur during long-distance transports of newborn cardiac patients. During a 4-year period after centralization of pediatric heart surgery in Sweden, 286 transports were prospectively investigated. A majority (77.3%) of the transports were carried out by nonspecialized teams. Ten severe adverse events, including the death of 1 infant, occurred during the 286 transports (3.5%). Another infant died later of cerebral complications from hypoxia, rendering a transport-related mortality of 0.7%. Twenty-two infants (7.7%) were severely hypoxic (oxygen saturation < or =65%) at arrival, and 12 of these infants suffered from transposition of the great arteries. During the second 2-year period increased use of intravenous prostaglandin E1 and transportation from tertiary-level units was associated with better transport outcome. During the same time period, overall 30-day postoperative mortality for pediatric cardiac surgery decreased from 4.0% to 1.2% in our hospital. When highly specialized treatment is centralized for quality reasons it is also important that risks associated with transport are considered and that the quality of transport is high. For some cardiac malformations antenatal diagnosis and referral of the mother for delivery to a center with pediatric cardiac surgery would probably further increase the chance of healthy survival in some infants.
    Pediatric Cardiology 01/2001; 22(5):380-4. · 1.20 Impact Factor
  • K Stjernqvist, N W Svenningsen
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    ABSTRACT: Since the mid-1990s several studies have reported poor school performance in extremely preterm infants. The necessity to provide a full picture of the child's situation has been indicated. In a southern Swedish population 32,120 infants were born during the 2-y period 1985-1986. In total, 121 infants (0.4%) were reported liveborn before the 29th gestational wk and 12 (0.04%) were reported stillborn. Only 65 infants (50%) survived to the age of 10 y. The aim of this study was to evaluate the situation of extremely preterm (EPT) children at school, compared with that of full-term (FT) control children, at the age of 10 y. Health, cognitive development, school achievement and behaviour were measured. Ninety-two percent of the preterm children had no major neurological disability and most were in good health. The EPT children had an IQ of 90 +/- 15 vs 106 +/- 15 (mean +/- SD) for the FT children (p <0.001), and on the test of Visual-Motor Integration, the EPT children had 93.3 +/- 12.2 vs 109.6 +/- 14.2 for FT peers (p < 0.001). On both tests the differences between the groups corresponded to approximately one standard deviation. Thirty-eight percent of the EPT children performed below grade level at school. Thirty-two percent had general behavioural problems and 20% had attention deficit hyperactivity disorder, compared with 10% and 8%, respectively, in the FT group. EPT children require interventions to support their development and reduce behavioural problems.
    Acta Paediatrica 06/1999; 88(5):557-62. · 1.97 Impact Factor
  • Lakartidningen 04/1999; 96(13):1560-2, 1565-7.
  • Pediatric Research 01/1999; 45. · 2.67 Impact Factor
  • D Ley, M Lindroth, S Polberger, N W Svenningsen
    Pediatric Research - PEDIAT RES. 01/1999; 45(6).
  • Pediatric Research 01/1999; 45. · 2.67 Impact Factor
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    ABSTRACT: A prospective national investigation comprising 633 extremely low birthweight (ELBW) infants born alive in the 2-y period 1990-1992 with a birthweight of < or = 1000 g and gestational age of > or = 23 completed weeks was conducted regarding neurosensory outcome and growth. Three-hundred and sixty-two (98%) surviving ELBW infants were assessed at a median age of 36 months, using a specially designed protocol. At follow-up, mean height, weight and head circumference in both boys and girls were significantly lower than the reference values. The incidence of cerebral palsy was 7% among all children and 14%, 10% and 3% in children born at 23-24, 25-26 and > or = 27 gestational weeks, respectively. At least one obvious handicap was present in 14%, 9% and 3% of these three groups of children, respectively. After adjustment for gestational age, a significantly increased risk of handicap was found in children with intraventricular haemorrhage grade > or = 3 and/or periventricular leucomalacia and in children with retinopathy of prematurity stage > or = 3. The results show that more than 90% of ELBW children born at > or = 25 completed gestational weeks were without neurosensory handicap at 36 months of corrected age. In infants born at 23-24 weeks of gestation, both survival and long-term outcome were less favourable.
    Acta Paediatrica 11/1998; 87(10):1055-60. · 1.97 Impact Factor
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    ABSTRACT: We tested the hypothesis that controlled hypoxemic resuscitation improves early cerebral metabolic and electrophysiological recovery in hypoxic newborn piglets. Severely hypoxic anesthetized piglets were randomly divided into three resuscitation groups: hypoxemic, 21% O2, and 100% O2 groups (8 in each group). The hypoxemic group was mechanically ventilated with 12-18% O2 adjusted to achieve a cerebral venous O2 saturation of 17-23% (baseline; 45 +/- 1%). Base excess (BE) reached -22 +/- 1 mM at the end of hypoxia. During a 2-h resuscitation period, no significant differences in time to recovery of electroencephalography (EEG), quality of EEG at recovery, or extracellular hypoxanthine concentrations in the cerebral cortex and striatum were found among the groups. BE and plasma hypoxanthine, however, normalized significantly more slowly during controlled hypoxemic resuscitation than during resuscitation with 21 or 100% O2. We conclude that early brain recovery during controlled hypoxemic resuscitation was as efficient as, but not superior to, recovery during resuscitation with 21 or 100% O2. The systemic metabolic recovery from hypoxia, however, was delayed during controlled hypoxemic resuscitation.
    Journal of Applied Physiology 04/1998; 84(4):1208-16. · 3.48 Impact Factor
  • Ingrid Hansen, Staffan Polberger, Nils Svenningsen
    Pediatric Research 01/1998; 43. · 2.67 Impact Factor
  • Pediatric Research 01/1998; 43. · 2.67 Impact Factor
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    ABSTRACT: Doppler-derived indices of cerebral blood flow velocity (CBFV) and echocardiographic parameters of left ventricular function were measured in 18 patients with hypoxic-ischaemic encephalopathy HIE (group I) and in 28 normal controls (group II). Group-I infants had a subnormal distribution of CBFV values increasing over the first 85 h postnatally. CBFV values were constantly higher in the internal carotid than in the anterior cerebral artery. During the first 24 h postnatally, pulsatility and resistance indices of cerebral blood flow were significantly higher in group-I patients. From 30 to 85 h after birth, resistance indices were lower in group-I infants with severe HIE. Depressed left ventricular function and/or hypotension was documented in 50% of group-I patients.
    Biology of the Neonate 01/1998; 73(5):275-86. · 1.90 Impact Factor
  • H. Klette, K. Thorngren-Jerneck, N. W. Svenningsen
    Pediatric Research 01/1998; 44(3). · 2.67 Impact Factor
  • Pediatric Research 01/1998; 43. · 2.67 Impact Factor
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    ABSTRACT: The recently introduced intrauterine growth curve, based on ultrasonically estimated foetal weights, was retrospectively applied to an inborn population of 883 infants born before 33 gestational weeks at the University Hospital of Lund, during 1985-94. The estimation of birthweight deviation resulted in 630 (71.3%) infants with a birthweight appropriate for gestational age (AGA), 244 (27.6%) infants with a birthweight small for gestational age (SGA) and 9 (1.1%) infants with a birthweight large for gestational age. Birthweight deviation was associated with an increased mortality [odds ratio (OR) adjusted for gestational age 1.29 per SD (12%) change in birthweight for gestational age, 95% CI: 1.10-1.50; p = 0.002]. At gestational age 25-28 weeks, SGA-infants had an increased incidence of respiratory distress syndrome (RDS) as compared to AGA-infants (OR adjusted for gestational age: 1.98, 95% CI: 1.12-3.52; p = 0.019). At gestational age 29-32 weeks, SGA-infants had a lower incidence of RDS as compared to AGA-infants (OR adjusted for gestational age: OR 0.52, 95% CI: 0.34-0.80; p = 0.003). After adjustment for confounding variables, infants born at gestational age 25-28 weeks from mothers with pre-eclampsia, appeared to be a high-risk group for RDS, whereas at the age of 29-32 gestational weeks, negative birthweight deviation had a protective effect against RDS. Antenatal corticosteroid administration appeared to have a less beneficial effect on mortality, RDS and cerebral haemorrhage in infants born SGA vs in those born AGA.
    Acta Paediatrica 11/1997; 86(10):1090-6. · 1.97 Impact Factor
  • N W Svenningsen, L Björklund, M Lindroth
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    ABSTRACT: Perinatal care of the extremely preterm and low birthweight (ELBW) infant is founded on basic principles of physiology and knowledge about the prevailing pathophysiological mechanisms. New therapies in clinical care are usually introduced non-uniformly, so more often there is a gradual rather than a sudden change in the development of perinatal care, conceivably involving also an important learning process. This was confirmed in an evaluation of respiratory care for ELBW infants (n = 325) over a 9-year period (1986-1994). Although birthweight (mean 815 g) and degree of immaturity at birth (mean 26.7 weeks of gestation) did not change over the years, our trend analysis showed that the survival rate increased from 47% to 70% (p < 0.04) and the percentage of survivors without bronchopulmonary dysplasia and/or major intracranial haemorrhages (ICH grades 3 and 4) increased from 67% to 87% (p < 0.006). We suggest that besides medical treatment per se, refinement and tuning of nursing and medical care procedures will also affect the total outcome of ELBW infants.
    Acta paediatrica (Oslo, Norway: 1992). Supplement 08/1997; 422:89-91.
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    ABSTRACT: In a 2-year (1990-92) prospective national investigation, comprising all stillborn and live-born ELBW infants with a birthweight of < or = 1000 g born at 23 completed weeks of gestation or more, we examined the incidence, neonatal mortality, major morbidity and infant survival in relation to level of care and place of residence. A total of 633 ELBW infants were live-born, i.e. 0.26% of all live-born infants, and 298 were stillborn. The average neonatal mortality was 37% and 91% at 23 weeks, 70% at 24 weeks, and 40% at 25 weeks of gestation. Of neonatal survivors, 8% had intraventricular haemorrhage grade 3, 10% retinopathy of prematurity of stage > or = 3, 2% necrotizing enterocolitis, and 28% were oxygen-dependent at a time corresponding to 36 weeks of gestation. In all, 77% were treated with mechanical ventilation, whereas 19% survived without, almost all of them being CPAP treated. Infant mortality among infants born at level III (tertiary centres) was 30%, at level IIa (with full perinatal service) 46% and at level IIb (with basic neonatal service) 55%. Only 1% was born at hospital level I. Regarding the relation to place of residence, the mortality rates among infants residing in the areas served by levels III, IIa and IIb hospitals were 36%, 45% and 41%, respectively. The referral system thus functioned well, but can be improved, and increased perinatal referral, at borderline perinatal viability, might provide a better quality of care and a better chance of survival.
    Acta Paediatrica 06/1997; 86(5):503-11. · 1.97 Impact Factor
  • Pediatric Research 01/1997; 41(4). · 2.67 Impact Factor
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    ABSTRACT: The effect of natural surfactant on respiratory system mechanics in infants with respiratory distress syndrome (RDS) is incompletely understood, possibly because the analysis has usually been confined to the tidal breath. We studied 11 paralyzed neonates weighing 540 to 1,850 g before and approximately 30 min after surfactant, which was instilled at 4 to 41 h of age. Diagrams relating airway pressure to expired volume were obtained by having the infant exhale passively through a flowmeter, starting at 30 and ending at 0 cm H20 of pressure. An interrupter intermittently stopped the flow so that pressure could be recorded under static conditions. FRC was measured by sulfur hexafluoride washout, and TLC was calculated from FRC and the pressure-volume (P-V) curve. Ventilation homogeneity was assessed from the washout curve as pulmonary clearance delay (PCD). TLC increased by 10% or more in five infants, but it remained unchanged in the others. Median TLC was 19 ml/kg before and 21.5 ml/kg after surfactant (p = 0.39). The P-V curve became markedly steeper at low pressures after surfactant in most infants, the slope of the steepest segment, i.e., maximal compliance, increasing from 0.65 to 1.22 ml/cm H20/kg (medians, p = 0.008). Dynamic compliance (Cdyn) was unchanged at 0.28 ml/cm H20/kg, whereas specific dynamic compliance (Cdyn/FRC) decreased (p = 0.04). There was no significant immediate change in PCD. The findings imply that during the first 30 min surfactant acted mainly by stabilizing already ventilated air spaces.
    American Journal of Respiratory and Critical Care Medicine 11/1996; 154(4 Pt 1):918-23. · 11.04 Impact Factor

Publication Stats

2k Citations
371.30 Total Impact Points


  • 1973–2001
    • Lund University
      • • Department of Paediatrics
      • • Department of Psychology
      • • Department of Pediatric Cardiology
      • • Department of Clinical Physiology
      • • Department of Obstetrics and Gynecology
      Lund, Skane, Sweden
  • 1997–1998
    • University Hospital Linköping
      • Department of Paediatrics
      Linköping, OEstergoetland, Sweden