Survival rates in extremely low birthweight infants depend on the denominator: Avoiding potential for bias by specifying denominators
The objective of the study was to assess whether recent data reporting survival of preterm infants introduce a bias from the use of varying denominators.
We performed a systematic review of hospital survival of infants less than 1000 g or less than 28 weeks. Included publications specified the denominator used to calculate survival rates.
Of 111 eligible publications only 51 (46%) specified the denominators used to calculate survival rates: 6 used all births, 25 used live births, and 20 used neonatal intensive care unit admissions. Overall rates of survival to hospital discharge ranged widely: from 26.5% to 87.8%. Mean survival varied significantly by denominator: 45.0% (±11.6) using a denominator of all births, 60.7% (±13.2) using live births, or 71.6% (±12.1) using used neonatal intensive care unit admissions (P ≤ .009 or less for each of 3 comparisons).
Variations in reported rates of survival to discharge for extremely low-birthweight (<1000 g) and extremely low-gestational-age (<28 weeks) infants reflect in part a denominator bias that dramatically affects reported data.
Available from: Evgeniy Shustin
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ABSTRACT: We compare two ways to control the distribution function of ions on the isolated structure which is treated in a plasma reactor based on beam plasma discharge. In the first case, the periodic pulse voltage is applied to the substrate holder. The calculation of currents and voltages on the surface in contact with the plasma in a simple empirical model has been performed; the comparison of results of calculation and experiment is presented. In the latter case, the pulsed voltage is applied to the discharge collector, thus modulating the plasma potential. The comparison shows that the second method provides more efficient control of the distribution function of ions, acting on the treated substrate.
Vacuum 01/2011; 85(6):711-717. DOI:10.1016/j.vacuum.2010.11.004 · 1.86 Impact Factor
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ABSTRACT: To develop and pretest a decision-aid to help parents facing extreme premature delivery during antenatal counseling regarding delivery room resuscitation.
Semistructured interviews with 31 clinicians and with 30 parents of children born <26 weeks' gestation were conducted following standard methods of qualitative research. These characterized perceptions of prenatal counseling to identify information that parents value when making decisions regarding delivery room resuscitation. These parental needs were formatted into a decision-aid. We assessed the primary outcome of how effectively the decision-aid improved knowledge during a simulated counseling session. Two groups of women were studied: parents with a history of prematurity ("experienced") and healthy women without prior knowledge of prematurity ("naïve").
Interviewees thought that visual formats to present survival and short- and long-term outcome information facilitated their own preparation, recall, and understanding. Accordingly, we designed a decision-aid as a set of cards with pictures and pictographs to show survival rates and complications. There was significant improvement in knowledge in 13 "experienced" parents (P = .04) and 11 "naïve" women (P < .0001). Participants found the cards useful and easy to understand.
A decision-aid for parents facing extreme premature delivery may improve their understanding of complicated information during antenatal counseling.
The Journal of pediatrics 10/2011; 160(3):382-7. DOI:10.1016/j.jpeds.2011.08.070 · 3.79 Impact Factor
Archives of Disease in Childhood - Fetal and Neonatal Edition 11/2012; 98(2). DOI:10.1136/archdischild-2012-301880 · 3.12 Impact Factor
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