Publications (2)8.18 Total impact
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Article: Three-dimensional digital capture of head size in neonates - a method evaluation.
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ABSTRACT: The quality of neonatal care is mainly determined by long-term neurodevelopmental outcome. The neurodevelopment of preterm infants is related to postnatal head growth and depends on medical interventions such as nutritional support. Head circumference (HC) is currently used as a two-dimensional measure of head growth. Since head deformities are frequently found in preterm infants, HC may not always adequately reflect head growth. Laser aided head shape digitizers offer semiautomatic acquisition of HC and cranial volume (CrV) and could thus be useful in describing head size more precisely. 1) To evaluate reproducibility of a 3D digital capture system in newborns. 2) To compare manual and digital HC measurements in a neonatal cohort. 3) To determine correlation of HC and CrV and predictive value of HC. Within a twelve-month period data of head scans with a laser shape digitizer were analysed. Repeated measures were used for method evaluation. Manually and digitally acquired HC was compared. Regression analysis of HC and CrV was performed. Interobserver reliability was excellent for HC (bias-0.005%, 95% Limits of Agreement (LoA) -0.39-0.39%) and CrV (bias1.5%, 95%LoA-0.8-3.6%). Method comparison data was acquired from 282 infants. It revealed interchangeability of the methods (bias-0.45%; 95%LoA-4.55-3.65%) and no significant systematic or proportional differences. HC and CrV correlated (r(2) = 0.859, p<0.001), performance of HC predicting CrV was poor (RSD ±24 ml). Correlation was worse in infants with lower postmenstrual age (r(2) = 0.745) compared to older infants (r(2) = 0.843). The current practice of measuring HC for describing head growth in preterm infants could be misleading since it does not represent a 3D approach. CrV can vary substantially in infants of equal HC. The 3D laser scanner represents a new and promising method to provide reproducible data of CrV and HC. Since it does not provide data on cerebral structures, additional imaging is required.PLoS ONE 01/2013; 8(4):e61274. · 4.09 Impact Factor -
Article: Continuous non-invasive monitoring of tidal volumes by measurement of tidal impedance in neonatal piglets.
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ABSTRACT: Electrical Impedance measurements can be used to estimate the content of intra-thoracic air and thereby give information on pulmonary ventilation. Conventional Impedance measurements mainly indicate relative changes, but no information concerning air-volume is given. The study was performed to test whether a 3-point-calibration with known tidal volumes (VT) during conventional mechanical ventilation (CMV) allows subsequent calculation of VT from total Tidal-Impedance (tTI) measurements using Quadrant Impedance Measurement (QIM). In addition the distribution of TI in different regions of the thorax was examined. QIM was performed in five neonatal piglets during volume-controlled CMV. tTI values at three different VT (4, 6, 8 ml/kg) were used to establish individual calibration curves. Subsequently, each animal was ventilated with different patterns of varying VT (2-10 ml/kg) at different PEEP levels (0, 3, 6, 9, 12 cmH(2)O). VT variation was repeated after surfactant depletion by bronchoalveolar lavage. VT was calculated from tTI values (VT(calc)) and compared to the VT delivered by the ventilator (VT(PNT)). Bland-Altman analysis revealed good agreement between VT(calc) and VT(PNT) before (bias -0.08 ml; limits of agreement -1.18 to 1.02 ml at PEEP = 3 cmH(2)O) and after surfactant depletion (bias -0.17 ml; limits of agreement -1.57 to 1.22 ml at PEEP = 3 cmH(2)O). At higher PEEP levels VT(calc) was lower than VT(PNT), when only one fixed calibration curve (at PEEP 3 cmH(2)O) was used. With a new calibration curve at each PEEP level the method showed similar accuracy at each PEEP level. TI showed a homogeneous distribution over the four assessed quadrants with a shift toward caudal regions of the thorax with increasing VT. Tidal Impedance values could be used for precise and accurate calculation of VT during CMV in this animal study, when calibrated at each PEEP level.PLoS ONE 01/2011; 6(6):e21003. · 4.09 Impact Factor
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Institutions
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2013
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Carl Gustav Carus-Institut
Pforzheim, Baden-Wuerttemberg, Germany
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