TABLE 2.

Vermont-Oxford Network, 1991–1999: Infants 501–1500 g at 39 NICUs Common to All Years

199119921993199419951996199719981999
Number of infants303832693310333534583645359837993767
Patient characteristics
 Mean birth weight (g)*106210581055105010451042103710401032
 Mean gestational age (wk)28.628.528.428.428.428.328.428.428.2
 Race (%)
  Black26.125.024.324.023.323.222.524.323.5
  White65.766.466.966.566.666.366.064.765.9
  Hispanic*5.35.55.76.17.07.48.17.36.7
  Other3.03.03.13.43.13.13.43.73.9
 Male (%)52.450.151.954.152.150.951.551.353.2
 Inborn (%)78.981.182.382.283.383.284.783.583.0
 Multiple birth (%)*21.724.025.125.225.228.428.027.829.5
 Small for gestational age (%)20.020.619.420.820.220.420.820.419.2
 1-min Apgar ≤3(%)*32.231.731.428.928.127.225.426.226.4
Interventions
 Prenatal care (%)*92.193.093.593.895.395.694.795.795.4
 Antenatal Steroids (%)*24.227.633.149.263.266.974.073.875.0
 C-section (%)*58.756.660.059.259.159.559.561.161.5
 Nasal CPAP (%)*36.336.738.843.646.152.158.060.662.5
 Surfactant (%)*54.554.054.955.656.158.858.761.163.4
 Conventional ventilation (%)*81.578.678.778.176.575.473.672.773.7
 High-frequency ventilation (%)*6.77.410.013.614.617.023.224.526.2
 Any assisted ventilation (%)*81.578.778.878.677.276.675.074.876.2
 Postnatal steroids (%)*19.119.823.327.027.128.130.629.628.1
Outcomes
 Death (%)*17.716.815.714.814.814.013.414.315.1
 Pneumothorax (%)*8.68.07.65.45.95.06.16.47.3
 Respiratory distress syndrome (%)68.968.368.767.266.766.066.466.970.7
 Necrotizing enterocolitis (%)6.56.66.87.16.27.38.47.37.4
 IVH grades 1 to 4 (%)*27.428.527.925.625.025.023.224.624.6
 IVH grades 3 and 4 (%)*9.79.29.58.48.66.96.87.68.2
  • CPAP indicates continuous positive airway pressure.

  • * Significant time trend based on univariate analysis (P < .05).

  • Significant time trend after adjusting for infant characteristics (P < .05).