TABLE 1.

Vermont-Oxford Network, 1991-1999: All Infants 501 to 1500 g

199119921993199419951996199719981999
Number of NICUs*516882114137192248295325
Number of infants386850336474836410 88814 67819 59923 53726 007
Patient characteristics
 Mean birth weight (g)106510551057105310541052104410501048
 Mean gestational age (wk)28.628.628.528.428.428.428.428.528.5
 Race (%)
  Black27.627.628.024.024.025.925.726.026.7
  White*63.963.061.965.064.359.458.156.354.1
  Hispanic*5.96.67.37.67.19.310.711.312.7
  Other*2.72.82.83.54.65.45.56.36.5
 Male (%)52.650.851.751.851.850.751.751.151.3
 Inborn (%)79.581.782.683.984.684.485.485.483.9
 Multiple birth (%)*21.223.323.924.224.626.126.726.927.2
 Small for gestational age (%)20.320.319.820.220.520.421.421.021.3
 1-min Apgar ≤3 (%)*32.833.431.027.827.427.126.025.624.9
Interventions
 Prenatal care (%)*90.790.291.492.993.994.294.794.994.4
 Antenatal steroids (%)*23.827.232.446.859.165.468.971.071.6
 C-section (%)*58.554.856.856.958.459.860.860.860.9
 Nasal CPAP (%)*34.133.135.437.943.645.952.054.255.2
 Surfactant (%)*53.153.654.255.256.957.459.660.662.3
 Conventional ventilation (%)*80.878.177.775.675.374.272.472.071.6
 High-frequency ventilation (%)*7.77.78.512.413.817.021.522.523.6
 Any assisted ventilation (%)*80.878.277.876.676.474.874.574.374.4
 Postnatal steroids (%)*19.118.922.126.127.128.128.528.226.5
Outcomes
 Death (%)*18.117.515.715.914.514.214.514.514.8
 Pneumothorax (%)*8.68.07.05.95.75.15.76.46.3
 Respiratory distress syndrome (%)71.169.369.167.968.067.167.568.869.2
 Necrotizing enterocolitis (%)6.36.86.16.16.06.67.16.46.7
 IVH grades 1 to 4 (%)*27.428.627.926.026.126.924.925.525.3
 IVH grades 3 and 4 (%)*10.110.110.39.58.88.98.08.38.4
  • 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).