A COMPARISON OF MORTALITY AND MORBIDITY ASSOCIATED WITH PRESSURE-LIMITED AND VOLUME-LIMITED INFANT VENTILATORS IN THE TREATMENT OF SEVERE HYALINE MEMBRANE DISEASE

Abstract

The effect of pressure-limited (PL) and volume-limited (VL) infant ventilators on mortality and morbidity in severe hyaline membrane disease was examined in a prospective controlled study. Criteria for mechanical ventilation were CPAP failure (PaO2 <50 mm. Hg. at FiO2 ≥ 0.8 and CPAP ≥ 8 cm. H2O or PaCO2 ≥ 70 mm. Hg.) or severe perinatal asphyxia. Consecutive patients were alternately assigned to either PL or VL infant ventilators. 22 infants (900-2600 gms; 27-36 wks. gest.) were ventilated with PL machines using low peak inspiratory pressures (mean Pmax = 29 cm. H2O), relatively low PEEP (mean = 5.4 cm. H2O) and prolonged inspiratory times. 20 additional infants (600-3350 gms; 26-42 wks. gest.) were ventilated with VL machines using essentially unlimited peak inspiratory pressures (mean Pmax = 62 cm. H2O), PEEP (mean = 8.1 cm. H2O) and prolonged expiratory times. There were no significant differences in mortality (PL=37%; VL=40%), or in the incidence of pneumothoraces (PL=32%; VL=45%), or bronchopulmonary dysplasla (PL=4.6%; VL=10%). Intraventricular hemorrhages and pulmonary hemorrhages occurred with equal frequency in both groups. These data fail to demonstrate any significant advantage of one ventilator system over the other, and fail to confirm the impression that limiting peak inspiratory pressures to <35 cm. H2O significantly reduces the incidence of bronchopulmonary dysplasia.