Prediction of outcome of preterm infants with severe bronchopulmonary dysplasia

Forty-four preterm infants of less than 30 weeks gestation and birthweight < or = 1250 g, with severe bronchopulmonary dysplasia requiring mechanical ventilation for at least 28 days, were reviewed. Twenty-seven infants (61%) survived; 17 died. There were no significant differences between survivors and non-survivors with respect to birthweight, gestational age, sex, Apgar score at 5 min or pulmonary diagnosis. Non-survivors displayed more severe changes on chest X-ray than the survivors. Peak inspiratory pressure (PIP), ventilator rate (VR), ventilator index and mean airways pressure were significantly higher in the non-surviving infants on days 2, 3, 4, 7, 14, 21 and 28, with non-survivors also having significantly higher alveolar-arterial oxygen gradients and lower arterial-alveolar oxygen ratios than the survivors. Discriminant analysis with cross-validation by pairing PIP and VR on day 28 produced a positive predictive value for non-survival of 88% and a negative predictive value of 89%. This result was better than was obtained for any other pair of ventilator parameter or oxygenation index. Discriminant analysis by combining X-ray appearances with ventilator settings did not improve the prediction. Having established a statistical model based on the PIP and VR of ventilator-dependent preterm infants on day 28, the outcome can be predicted with a high degree of confidence. This has the immediate potential application of indicating to staff in the neonatal unit a realistic approach to take when counselling parents of these infants.