Predicting survival among ventilator-dependent very low birth weight infants

Ventilator-bound very low birth weight (VLBW) infants represent an increasing proportion of our nursery population. We reviewed the hospital course of 38 VLBW infants who required more than 1 month of intermittent mandatory ventilation (IMV) between 1976 and 1978. Twenty-eight infants survived; 10 died. There were no significant differences between survivors and nonsurvivors in estimated gestational age (EGA), Apgar scores, first pH, first mean arterial pressure (MAP), h of IMV required, or birth weight; nor did the incidence of patent ductus arteriosus (PDA), respiratory distress syndrome (RDS), or transport differ. Pneumothorax was significantly more common among those infants who died. When ventilator settings were reviewed, significant differences were found consistently between the 2 groups of 3, 5, and 7 days of age, but not at 1, 14, 21, or 28 days of age. A predictive model for estimating the probability of survival of such infants was developed based upon these data, employing birth weight, mean airway pressure (MAWP) at 7 days of age, and occurrence of pneumothorax, and was applied prospectively to a group of 29 such infants born in 1979 and 1980. Prediction of outcome was significantly more accurate than chance alone. We conclude that prolonged ventilator dependence is largely confined to VLBW infants; that it is the rule among infants less than 750 g; and that accurate, objective assessment of an individual infant's prognosis may lead to improved care.